Lithium Ion battery for the E/X-Mag?

[AGDRetro]

There's no doubt that battery technology has advanced from the time the E-Mag was initially introduced and I was wondering if there has been anybody that has looked into developing a Lithium Ion battery pack for the E-Mag.

You probably need to develop a new charger as well, but I think the increased shot count per charge and weight savings VS the stock NiMH might make this an appealing upgrade for E/X-Mag owners.

Thoughts AO?

[Levi]

There is probably a battery pack ready made for the RC Airplane and heli market that would be readily adaptable to the emag.

Plenty of charger options too. Would just take some research to find one that fits and at the right voltage. I believe the lithium cells come in at 3.7 Volts nominal. So you could expect to get packs in multiples of that voltage.

[Levi]

The lithium polymer cells are commonly used by the electric rc airplane and helis. These are popular because they lack the heavy protective casing around the cells. Since the E-Mag has a metal battery "case" anyway I see no reason that these batteries couldn't be used safely for this application.

If you go messing around with lithium batteries make sure you take some time to learn about their quirks and how to safely use them.

For instance, they like to catch fire if seriously abused. Also if they are over discharged there is a risk that they can catch fire when recharged. Or if they are charged with the wrong type of charger.

[BTAutoMag]

Someone get me some specs. I just happen to work for a conpany that makes lith car batteries. Ill talk to the engineer

[knownothingmags]

its hard to get the size right. 4 cell lipo is your go too.
3 cell would work i think at 11.1 v.
4 cell is 14.8 v
but with lip you need a cutoff installed so you dont balloon your packs and have it melt your gun when it goes bye bye.

ive been looking into getting packs that will fit but its really hard to get the size down.

the the MaH would be small. but that wont be an issue since the lipos would run you for days.

could get ahold or Orion, Maxxamps, Venom, etc, but they are big guys in the industry and an order would have to be for a 1000+ i think, if they could make 100+ for good price i may be able to buy em and resell to you guys.

issues:-
-size
-price
-cutoff for to save the battery.
-and hookup to the marker.
** question for the techs who know:
*_* can you opperate the emag off of 11.1 v? if so i will run testing.

[athomas]

Here is a copy of a battery pack explanation I did a while back.

A 4 cell pack would have a 14.8V nominal rating. 14.8V would cause a reduction in power by about 22%. That should still trip the sear, but it would cut into any buffer needed to maintain operational consistency in all instances. That means you better keep the mechanism clean. It would probably be better to add an extra cell.

Don't go exactly by the rating on the cells or packs. In reality, Lipo cells have a fully charged voltage value of 4.25V so most charger limit it to 4.2V. The minimum safe voltage is 3V so most use a cutoff of 3.3V. That gives a four cell pack a voltage range of 13.2V to 16.8V. The discharge line from 16.8V to 13.2V is fairly linear and results in the 14.8V nominal rating. The calculations show a 15V average but in reality its not perfectly linear so the real average is 14.8V.

NiMh cells have a fully charged voltage value of about 1.4V but it drops to 1.3V very quickly so the 1.3V value is used for the upper value when determining average operating outputs. The minimum voltage is 1.0V, but the drop from 1.1V to 1.0V occurs very quickly so the 1.1V value is used for the lower voltage. The resulting average is 1.2V which is the industry value used for packaging. A 14 cell pack rated at 16.8v actually ranges from 18.2V to 15.4V.

Checking the voltage values of the lowest value for each pack type, it shows a reduction in power by 27% for the LiPo compared to the NiMh pack. This is worst than the 22% calculated using nominal values. As the pack gets discharged, you might end up with firing issues using a 14.8V LiPo pack.

Therefore, I would recommend the 5 cell LiPo. The overall voltage will be a bit higher using the 5 cell LiPo pack. This will cause higher current draw which will heat the solenoid more. Its a 20% increase in power consumption when the battery is fully charged. I don't think the dwell of the solenoid will allow it to catastrophically overheat. If it proves to be a problem, put a 5Watt 0.5ohm resistor in series with the battery pack. That will bring the pack down to the same operating parameters as a NiMh pack.

LiPo packs and lithium chargers in general are easily configured to be safely charged these days. An off the shelf RC charger has the ability to properly balance a lithium based battery pack and the packs have charge/discharge regulators built in so that you can't charge or discharge them past their danger point.

[Levi]

*_* can you opperate the emag off of 11.1 v? if so i will run testing.

If a 3 cell is all that could be fit into the Emag battery pack a voltage "boost" circuit could be added provided there is a little room left over.

There is always another way to skin the cat... it just depends on how much work one wants to do.

I just did a google search for lipo cells and came up with a few promising links but don't have the time to investigate in depth right now.

Could someone post the internal dimensions of the Emag battery?

[rukh013]

They have the 22v cell's I've done some searching and will post up links when I get home tonight.
I have noticed that the inside if the battery packs could be milled to accept slightly larger cell's or a whole new pack and battery combo


Where's Luke at?

[athomas]

You could build a voltage booster but they generally don't handle high currents. Starting with a lower voltage would require a higher current to maintain the wattage plus a bit more to allow for losses in the conversion. If you are going to add circuitry, consider using a solenoid with a rating closer to that of the lithium pack you want to use.

[Levi]

You could build a voltage booster but they generally don't handle high currents. Starting with a lower voltage would require a higher current to maintain the wattage plus a bit more to allow for losses in the conversion. If you are going to add circuitry, consider using a solenoid with a rating closer to that of the lithium pack you want to use.

That's a very good point. Not to say that a suitable boost circuit couldn't be built... but by the time you build one that can supply enough current at the required voltage the bulk of it may large enough that you haven't gained anything.

So far my experience with voltage boosting power supply circuitry has been limited to excercises that are just for curiosity sake. In all of my real world designs I have had the luxury of plenty of voltage overhead and I'm always stepping it down.

I just wanted to throw some ideas out there to maybe get some wheels turning in someone's head.

Your idea to swap the solenoid out for a lower voltage unit is promising. You would need to take a look at the driver circutry on the board and make sure that it is able to supply the additional current that would come along with a lower voltage coil. I don't have an Emag, otherwise I'd start pulling up some datasheets and checking this out myself just out of curiosity.

I'm just shooting from the hip here but if necessary, I suppose one could build a solenoid driver circuit that would do the job, provided there is room inside the grip for another small add on board.

[oldironmudder]

How about going green?

87873

[blackdeath1k]

How about going green?

87873

Isn't that what us with mechanical guns are doing.

[oldironmudder]

Isn't that what us with mechanical guns are doing.

Thats green before it was being green. So...... pick a color then. Ive seen dirt range from red, blue, green to orange.

[rukh013]

They have the 22v cell's I've done some searching and will post up links when I get home tonight.
I have noticed that the inside if the battery packs could be milled to accept slightly larger cell's or a whole new pack and battery combo


Where's Luke at?

Battery (http://heli-heli.com/items/batteries/hyperion/hyperion-g3-ex-45c/HP45C33005S-detail.htm)
charger shield (http://www.espritmodel.com/lipo-shield-low-voltage-cutoff.aspx)
low voltage alarm (http://www.ebay.com/bhp/lipo-low-voltage)

[athomas]

I'm just shooting from the hip here but if necessary, I suppose one could build a solenoid driver circuit that would do the job, provided there is room inside the grip for another small add on board.The driver on the board is more than capable of handling more current, so a lower voltage solenoid at the same wattage is just a drop in part without any additional circuitry.

And a LiPo battery pack is a plug-in pack that has its own built in circuitry for charge protection. A new battery case with LiPo would be the easiest thing to make and it would be smaller and lighter than the regular emag battery and pack.

[Levi]

The driver on the board is more than capable of handling more current, so a lower voltage solenoid at the same wattage is just a drop in part without any additional circuitry.


Considering that its AGD, I figured it was significantly overbuilt. But I try to never assume without verifying.

I think you're on to something here.

Hmm... this thread make me wish I had an emag or xmag to tinker with... too many more mags and the wife might start asking questions.

[rukh013]

Considering that its AGD, I figured it was significantly overbuilt. But I try to never assume without verifying.

I think you're on to something here.

Hmm... this thread make me wish I had an emag or xmag to tinker with... too many more mags and the wife might start asking questions.

Ha, sounds like my wife

If the 22v battery pack fit in the emag pack, wouldn't we just need to change the connections to the board?

[athomas]

The 22V packs are slightly different dimensions than the emag pack. Other than that, any pack can be made to fit the existing emag pack connections.

[Justus]

Would going with something like a 22v lipo pack make the thing lighter, and could there be something made with it to make it a drop-in replacement for current Emag batteries and work with current packs (meaning, all you would need besides the new battery is a charger, and all those custom milled battery packs wouldn't be going obsolete?)

[athomas]

The LiPo pack battery rating to get the same rating as the Emag is the 5 cell pack which would be a 18.5V rating. The 6 cell pack gives a 22.2V rating which would be quite a bit higher than the emag battery. You would need to change the solenoid to use this pack.

The LiPo packs are typically lighter than equivalent mAh packs made from NiMh cells. The dimensions are slightly different though. A 5 cell pack, which is closest to the emag pack rating so that you wouldn't have to change soleoids, is an odd size. You either have a really long skinny pack, or a really fat short pack, or a 3 + 2 pack. I would use a stacked (3 on top, 2 on bottom) 600mAh series pack. It will fit into the existing emag battery pack with room to spare and will be less weight.

[Justus]

Is there a battery pack like that on the market right now, or are we in "custom" territory? I'm putting a lot of search terms through Google but coming up empty when it comes to a pack like you're describing...

[athomas]

Is there a battery pack like that on the market right now, or are we in "custom" territory? I'm putting a lot of search terms through Google but coming up empty when it comes to a pack like you're describing...Yes and no.

The individual cells are available that will allow you to put together the configuration you want. The packs are available through anyone who builds custom packs. The 600mA cells are approximately 70mm long x 20mm wide x 7mm thick. You can make your own arrangement using a serial connection of the batteries. You can even add a balance connector so that you can keep the pack together and balance charge them properly without having to charge the cells individually.

I think the smaller ones are often referred to as nano cells.

[Justus]

I really don't know anything about making custom battery packs. But if a pack could be made that is significantly lighter than the standard NiMH pack, I'd be very interested. Anyone interested in taking the bull by the horns and seeing if this can actually happen?

[mostpeople]

I've got 2 dead packs now, so I'm hurting as well.

I think its clear we are in custom territory on this one, however there are many options for groups that build custom battery packs.

The questions become:

1. Do we want NiMH? Or do we want LiPO?
2. What are the "No Kidding" Operating limits of the xmag circuitry? What is the ideal battery output?
3. Do we want a drop in replacement for all battery housings? Or do we want a new battery housing as well?
4. If you go LiPO how are you going to charge it? (I was thinking a hole in the bottom for a charging plug?)

Food for thought..

[athomas]

1. Do we want NiMH? Or do we want LiPO?LiPo has more capacity for the size, so it will always be the smaller, lighter option.


2. What are the "No Kidding" Operating limits of the xmag circuitry? What is the ideal battery output?The circuit board itself is quite robust, although I can't look up the specific limits because my emag is packed away for a change of address. The solenoid is designed to operate at a specific voltage in order to draw the correct amount of current to develop the required power needed to consistently work properly.


3. Do we want a drop in replacement for all battery housings? Or do we want a new battery housing as well?This is a possibility for both types of packs.


4. If you go LiPO how are you going to charge it? (I was thinking a hole in the bottom for a charging plug?)You could put the charging plug between the two top contacts, in the bottom of the pack (it would be easy to change the bottom piece), or on the lower back of the pack inside the groove (where it would be protected, but would require some machining).

[Justus]

My opinion and reasons:

LiPo pack for lightweight. A NiMH pack is what we have already, right?

Needs to be able to drop-in to current battery housings. If not, then people with finished custom (anodizing, milling, or both) or original restored Emags and Xmags won't be customers. A secondary option of a new battery housing isn't a problem, but backwards compatibility is a must.

It would be better if the battery pack could be taken out to be charged, that way a person could have two of them, keeping one as a backup. Then if they forget to charge it and it dies, they don't have to sacrifice their battery housing to charge the battery. Instead, they can take it out to charge it and pop the fresh battery back in and keep going.

[mostpeople]

I am on the same page with you Justus, backwards compatabity is a must.

Ideally though, we could charge a new battery with it still in the pack, making it easy to use.

Let me do some research on this one. What I don't have and need to know is the board and solenoid specifications.

[Justus]

What I don't have and need to know is the board and solenoid specifications.

How are those acquired? I can take off my grips and read any of the numbers you want, if that will work. Maybe even provide a high-res photo?

[absocountry2]

This place can build custom packs. My emag pack has 14 AAA batteries. It would cost $42 to get a duplicate pack made. The only difference would be 14000 mAH instead of 650. Should just last longer

http://www.cheapbatterypacks.com/custompacks2/CustomPacks.aspx?mid=20

[athomas]

This place can build custom packs. My emag pack has 14 AAA batteries. It would cost $42 to get a duplicate pack made. The only difference would be 14000 mAH instead of 650. Should just last longer

http://www.cheapbatterypacks.com/custompacks2/CustomPacks.aspx?mid=20The pack using 1000mAh batteries would be a 1000mAh pack at 16.8V because the cells are in series. If the cells were in parallel, then you would have 14000mAh, but the pack voltage would only be 1.2V instead of 16.8V.

Those batteries are expensive. I typically pay about $1.00 per cell or lower when I buy 1000mHA AAA cells, but that doesn't include building the pack.

[mostpeople]

We could try a group order from them?

[absocountry2]

The pack using 1000mAh batteries would be a 1000mAh pack at 16.8V because the cells are in series. If the cells were in parallel, then you would have 14000mAh, but the pack voltage would only be 1.2V instead of 16.8V.

Those batteries are expensive. I typically pay about $1.00 per cell or lower when I buy 1000mHA AAA cells, but that doesn't include building the pack.

You are correct, thank you for fixing that. I knew better but I type numbers on the keypad and hit the one and four together. 14000 would be very impressive for AAA in 16.8v.

[Justus]

Still have a lightweight, LiPo Emag battery pack on my wishlist. Anyone with superior battery knowledge than me (read: a lot of people here on AGD) have any suggestions?

[BTAutoMag]

I love how every is excited about the possibility but glazed over my post.

[knownothingmags]

I love how every is excited about the possibility but glazed over my post.

car batteries are kinda different,(yes a battery is a battery), lipo is a different monster, even if it is a carbattery,
unless you are talking about a max amps starter battery, then you are on the right track.

[AGDRetro]

So I just started this thread and walked away, has anybody had any luck creating a drop-in, backwards compatible pack?

[2xFast]

I've got a 3 cell (http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=25505) and a 2 cell (http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=25504) 500 mAh pack on order (1 ea) that I'm planning to use in series for prototype purposes. I probably won't end up test firing for a month or two still. I'm going to run it through a morlock and I have to wait for that board.

The catch I ran into is that a lot of LiPo's don't have the C rating for the solenoid:

Solenoid is a S-15-75-26AD
Which if I'm reading the spec sheet right means:
Design voltage: 14.6
Watts: 80
therefore required amps = ~4-5.5 (depending on input voltage?)

The NiMH pack for reference can put out around 22A...for short periods at least.

500mAh x35 = 17.5A sustainable output, higher burst...that should be plenty to drive the solenoid and not so far off from the stock pack. 500 mAh isn't 650, but it's close and should be functional for a day of play unless I'm missing something.

What I found was that the cells that fit my needs aren't AAA shaped or even round, which means a custom battery housing is probably going to be required if you want to maintain performance AND shave weight.

[2xFast]

I love how every is excited about the possibility but glazed over my post.

I would be all over some help if the offer still stands. The specs are in my previous post. Let me know if you need more info.

[knownothingmags]

I've got a 3 cell (http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=25505) and a 2 cell (http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=25504) 500 mAh pack on order (1 ea) that I'm planning to use in series for prototype purposes. I probably won't end up test firing for a month or two still. I'm going to run it through a morlock and I have to wait for that board.

The catch I ran into is that a lot of LiPo's don't have the C rating for the solenoid:

Solenoid is a S-15-75-26AD
Which if I'm reading the spec sheet right means:
Design voltage: 14.6
Watts: 80
therefore required amps = ~4-5.5 (depending on input voltage?)

The NiMH pack for reference can put out around 22A...for short periods at least.

500mAh x35 = 17.5A sustainable output, higher burst...that should be plenty to drive the solenoid and not so far off from the stock pack. 500 mAh isn't 650, but it's close and should be functional for a day of play unless I'm missing something.

What I found was that the cells that fit my needs aren't AAA shaped or even round, which means a custom battery housing is probably going to be required if you want to maintain performance AND shave weight.

be carefull putting together 2 and 3 cell packs.
im sure you know what to do. but sometimes they don't play nice together, and these batteries love to start amazing fires.
<iframe src="https://www.facebook.com/video/embed?video_id=2132903130515" width="1280" height="720" frameborder="0"></iframe>

[2xFast]

I'm learning as I go. Assuming the packs are ~ equal in nominal voltage it shouldn't be an issue. If they aren't terribly close I thought the only real risk was my low voltage warnings wouldn't be reliable. If I'm not getting near full discharge it seems like the risk there would be minimal and obviously I wouldn't be charging them as a single battery. Is there something else to watch out for?

It's not ideal, but it's just to verify that the cells used in these packs would work...if they do I'll try to source the cells themselves and build a proper 5 cell pack.

[knownothingmags]

I'm learning as I go. Assuming the packs are ~ equal in nominal voltage it shouldn't be an issue. If they aren't terribly close I thought the only real risk was my low voltage warnings wouldn't be reliable. If I'm not getting near full discharge it seems like the risk there would be minimal and obviously I wouldn't be charging them as a single battery. Is there something else to watch out for?

It's not ideal, but it's just to verify that the cells used in these packs would work...if they do I'll try to source the cells themselves and build a proper 5 cell pack.

not sure if what you are doing is ok,
I just don't want you burning down your house.

there are companies that will build packs for you at whatever spec you want.

I make our in house. but im not able to bring them to the public, for a lot of reasons.

best of luck keep us posted.

[need4reebs]

not sure if what you are doing is ok,
I just don't want you burning down your house.

there are companies that will build packs for you at whatever spec you want.

I make our in house. but im not able to bring them to the public, for a lot of reasons.

best of luck keep us posted.


KNM: wait wat? you make wat in house that you cant bring them to the public? im confused?

2xfast:a battery store can make you a battery for your Mag pretty cheap.

[2xFast]

need4reebs: I'm trying to make a LiPo replacement. If you can find a battery store willing to do it I'm all ears. NiMH is easy, already have one don't need another.

knownothing: Specific pitfall issues would be helpful, vague "might be dangerous" statements are not. I'm aware lipos can be risky...

[need4reebs]

need4reebs: I'm trying to make a LiPo replacement. If you can find a battery store willing to do it I'm all ears. NiMH is easy, already have one don't need another.

knownothing: Specific pitfall issues would be helpful, vague "might be dangerous" statements are not. I'm aware lipos can be risky...


try batteries plus...take your battery in with ya and see what they say or can do for ya? and if they cant/wont make ya one maybe they know where you could buy one or get one made?

[2xFast]

I've tried shopping around the RC battery places (specifically the one linked in this thread earlier). No dice. As I mentioned the trick is the C rating. Getting something that can dump enough amps fast enough requires non AAA shaped cells.

[rukh013]

Hell if we can't fit them in the existing emag/xmag battery case can we get dimensions and maybe change the pack geometry?

maybe bump the front of the pack out?

http://i1325.photobucket.com/albums/u632/Brandt_K_Mangum/Untitled_zpsadd1e389.png (http://s1325.photobucket.com/user/Brandt_K_Mangum/media/Untitled_zpsadd1e389.png.html)

[knownothingmags]

KNM: wait wat? you make wat in house that you cant bring them to the public? im confused?

2xfast:a battery store can make you a battery for your Mag pretty cheap.

I don't know the details of how they are made, I have only seen them made.
I just can back them with the funds they need.

[knownothingmags]

I've tried shopping around the RC battery places (specifically the one linked in this thread earlier). No dice. As I mentioned the trick is the C rating. Getting something that can dump enough amps fast enough requires non AAA shaped cells.

c rating isn't just how fast the pack will dump its juice, its how fast the battery needs to dump it,
I have rc packs that can dump at 150-200 c rating, they have never ever dumped that high, but they can if needed,

c rating is the allowance of dumpage.

[2xFast]

OK poor choice of words. Was my may wrong? mAh capacity X C rating = available amps?

150 c is really damn high! I don't think anything that powerful is available in our size / weight range. If this isn't somewhere around half the weight of the stock pack there's probably not much point in doing it.


c rating isn't just
how fast the pack will dump its juice, its how fast the battery needs to dump it,
I have rc packs that can dump at 150-200 c rating, they have never ever dumped that high, but they can if needed,

c rating is the allowance of dumpage.

[knownothingmags]

OK poor choice of words. Was my may wrong? mAh capacity X C rating = available amps?

150 c is really damn high! I don't think anything that powerful is available in our size / weight range. If this isn't somewhere around half the weight of the stock pack there's probably not much point in doing it.

no, you are right, you would be fine with 20-40 c rating, actually that should be plenty.

[JimBobFett]

I see many mentions of battery configurations with "similar" voltages and currents listed. I am an EE. If someone could post what the OEM battery's voltage and current requirements are, I could lend a hand.

There may be an electro-mechanical solution that is possible that could replace the need for batteries all together. A small pneumatic generator could be used to charge a capacitor with every shot. Standby power could be maintained with a smaller battery.

[athomas]

The AGD voltage is 16.8VDC for that solenoid, which translates to about 6 amps of peak current draw but for much less duration than the 100ms pulse at 14VDC listed on the spec sheet. Most LiPo cells can produce that current output. The 5 cell pack is the way to go for LiPo. At the low end of the voltage range a four cell pack would provide a really low voltage which would cause the solenoid activation to become unreliable.

[2xFast]

I see many mentions of battery configurations with "similar" voltages and currents listed. I am an EE. If someone could post what the OEM battery's voltage and current requirements are, I could lend a hand.


Here's the solenoid
http://www.solenoidcity.com/solenoid/tubular/s-15-75p1.htm


Here's the pack:
Stock weight: 185g
Nominal output of 16.8V
650 mAh stock, my rebuilt one is 850mAh (still NiMH)
Again, I believe this pack can do ~22 amps
(it's 14 AAA sized cells wired in series)

[GoatBoy]

I think you guys are making things way more complicated than need be, and trying to overpower things as usual while still fumbling around in the dark somehow.

1. Get the exact dimensions of the current pack. No dancing around, pull out a set of calipers and actually measure the exact thing and post it, or post the exact topology of the 14 cells, and make sure that they really are AAA cells (44.5mm x 10.5mm diameter).
2. Get the exact dimensions of the space you can fill. No dancing around, pull out a set of calipers and actually measure the exact thing and post it.

My recommendation would be to go with a 4s LiPo pack. No boost, no PCB protector -- just go straight in.

Someone should run some tests, but I think you will get away with a 4s pack.

Were all the E/X-Mag electronics, solenoid, and parameters chosen during the age of L7 bolts? Because a properly tuned L10 bolt may lower the operating requirement enough to reliably operate off a 4s pack for the majority of the useful charge.

[athomas]

Someone should run some tests, but I think you will get away with a 4s pack.

Were all the E/X-Mag electronics, solenoid, and parameters chosen during the age of L7 bolts? Because a properly tuned L10 bolt may lower the operating requirement enough to reliably operate off a 4s pack for the majority of the useful charge.A 4S pack has a low end voltage of 13.2VDC compared to a low end voltage of 15.4V for NiMh. That's a 27% reduction in available power when the battery pack gets towards the lower end of its usable range.

The lower force on the sear is somewhat offset by the increased pressure pushing down on the on-off pin. The resulting sear activation force is not much different on the level 10 when compared to the level 7.

[GoatBoy]

A 4S pack has a low end voltage of 13.2VDC compared to a low end voltage of 15.4V for NiMh. That's a 27% reduction in available power when the battery pack gets towards the lower end of its usable range.

The lower force on the sear is somewhat offset by the increased pressure pushing down on the on-off pin. The resulting sear activation force is not much different on the level 10 when compared to the level 7.

Did you mean "dominated by" instead of "offset by"? There's no "offset by" involved here. If the system was designed with L7 in mind and you straight dropped a tuned L10 in there, the force goes down.

If it's still dominated by the on/off, I can understand, but there's only one direction that force can go, and that's down.

The threshhold voltage needs to be determined first. That is the critical point, and until you figure that out, you're all pretty much just talking in circles. I'd test it myself, but I don't own an E/X-mag. I might be able to borrow one... but I'm not feeling super motivated. I just feel bad watching you guys go around in circles.

Assuming the spec from 2xFast is accurate (thanks for those numbers), the solenoid is spec'd to run at about 80w at 14.6V. Let's assume that's correct.

For a 4s 500mah pack, that's maybe around 12C discharge, which is pretty manageable for a modern LiPo battery. Actually, that's a cakewalk.

A decent pack is going to maintain 3.6V per cell over at least 3/4 of its charge. You can find the discharge graphs all over the RC forums to verify this.

That puts a 4s pack at 14.4V or greater for 3/4 of its charge.

If it were me, I wouldn't care about that last 1/4 of charge. I don't carry 5 games worth of air on my person when I know I'll be back in staging after 2-3 games. I don't carry 5 games worth of paint on my person when I know I'll be back in staging after 2-3 games. Anything battery operated... I'd be perfectly happy swapping a battery out mid-day if it meant smaller, lighter, faster. That's what I do with my helmet camera batteries. Except my helmet camera doesn't have a "mechanical mode". *cough*

http://images4.wikia.nocookie.net/__cb20121026150329/borderlands/images/6/68/SmallerLighterFasterIcon.png

[athomas]

"Offset" definition: Counteract (something) by having an opposing force or effect: "the deficit was offset by capital inflows".


The forward force applied to the sear decreases when you install the level 10 compared to when you have a level 7. That force only negates some of the friction of the sear sliding off the bolt. The chamber pressure increases by 50% so the downward force on the back of the sear increases by that much. So, the result is that the force exerted by the on-off pin increases by 50% and the friction force is decreased by X amount. I'm guessing the friction reduction is about the same as the on-off increase resulting in a similar pull force requirement.

The maximum force the solenoid can exert at any given voltage is measured when the solenoid is fully pulled in. As the distance from bottom increases, the solenoid force decreases. You can see it on the charts for the solenoid. The distance of pull for the sear to safely clear the bolt is about 1/8", so the solenoid must pull 1/4" because the solenoid arm is approximately twice the distance from the pivot as the on-off contact and the bolt catch. At the rated 14.6V, the solenoid can pull 36oz of force from a distance of 0.25 inches. The on-off part results in approximately 32oz of downward force on the back of the sear which translates into 16oz of solenoid force requirement. At the low range of voltage for the 4S LiPo, the force would be 26oz of solenoid force based on the charts. The sear rotational friction from the forward bolt force and other mechanical frictions results in the rest of the pull force requirement. That is minimal due to the level 10 setup, but there is some. I'm not sure how much. It should be measured.

The problem is not that the solenoid won't do the job using a lower voltage. It might. The problem comes when you combine lower voltage, longer pull, greater friction, and a few other unknowns due to tuning and setup that are not perfect. Using a 4S LiPo, you have less than 60% reserve allowance for things that aren't ideal. This number is further reduced if you use higher chamber pressures for shorter or longer than ideal barrels, stiffer bolt springs, etc.

3.65V is the 50% charge point of a LiPo cell. The discharge of a LiPo is fairly linear in its operating range.

[GoatBoy]

The maximum force the solenoid can exert at any given voltage is measured when the solenoid is fully pulled in. As the distance from bottom increases, the solenoid force decreases. You can see it on the charts for the solenoid. The distance of pull for the sear to safely clear the bolt is about 1/8", so the solenoid must pull 1/4" because the solenoid arm is approximately twice the distance from the pivot as the on-off contact and the bolt catch. At the rated 14.6V, the solenoid can pull 36oz of force from a distance of 0.25 inches. The on-off part results in approximately 32oz of downward force on the back of the sear which translates into 16oz of solenoid force requirement. At the low range of voltage for the 4S LiPo, the force would be 26oz of solenoid force based on the charts. The sear rotational friction from the forward bolt force and other mechanical frictions results in the rest of the pull force requirement. That is minimal due to the level 10 setup, but there is some. I'm not sure how much. It should be measured.

Is 32oz the max force? Or is it the typical force? If I'm not mistaken, the RT valve produces max force when it decides to recharge, but that's not the same force as when the system is at rest, ready to fire. So the worst case for the on/off force implies that you're trying to pull it at the worst possible moment, which might not be particularly realistic.

Measurements are great and all, but there's probably a real fast way to test this. Mag, variable power supply, go.

I mean, really, even by your numbers, it sounds like you guys got this.



The problem is not that the solenoid won't do the job using a lower voltage. It might. The problem comes when you combine lower voltage, longer pull, greater friction, and a few other unknowns due to tuning and setup that are not perfect. Using a 4S LiPo, you have less than 60% reserve allowance for things that aren't ideal. This number is further reduced if you use higher chamber pressures for shorter or longer than ideal barrels, stiffer bolt springs, etc.


True, if I wanted to make this work for everybody, I'd overpower and overdesign things as AGD is wont to do.

But by now, I'd consider this more of an "expert level" mod, and you guys might as well aim for the bleachers.

[athomas]

The 32 oz of force exerted by the on-off pin is the force when the chamber is full and only the small diameter of the pin has any affect. This is the required force to push the pin up into the valve.

The max force applied to the pin during recharge is much larger than this (approximately 140oz) due to the larger size of the head of the on-off pin, but at that time the plunger will be fully engaged in the solenoid and it will be developing maximum pull force of over 76 oz which equals 152oz due to the 2x distance of the lever. This is all measured at 14.6V. At 13.2V, the force delivered by the solenoid when fully engaged would be 73oz or 146oz at the pin. If the tank regulated pressure is higher than 850psi, then the force applied down on the sear will be even greater than 140oz. The maximum pull force for the solenoid is also measured with the solenoid fully engaged. If the solenoid plunger is adjusted such that it doesn't bottom out, then the applied force is less than that. A 0.04" gap where it doesn't bottom out will reduce the applied force by about 15%.

Using a 4S cell pack would definately be an "expert level " mod due to requiring everything being adjusted perfectly and not using high output tanks. Use a 5S cell pack and you have a bit more power than you have now, and are guaranteed that it will always work for all conditions.

[2xFast]

I'll pickup a 4S pack as well and see if that does the trick. It certainly would be MUCH simpler to source.

[JimBobFett]

My suggestion would be for someone to hook up a variable power supply with a scope to see what the minimum voltage and actual current spike is when hooking up an E/X-mag directly to a power supply. Then, if you can play with the maximum current output and see what the minimum needed to fire the solenoid actually is, we can go from there to get the right battery pack.

[Justus]

I'm just happy that this thread didn't completely die. ANYTHING to help shave some ounces off the weight of an Emag, coupled with perhaps better battery life, will help.

[2xFast]

Far from it.

If anyone wants to try the 4S before me here's what I'll probably pickup in the near future:

http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=20418

It should fit in the existing housing and have plenty of available amps...just a question of voltage. Also for some reason its actually slightly heavier than my proposed 5S option. I'll let folks know once i have it in hand...still won't be testing until I get the new board.

[athomas]

That hobbyking pack is 30mm thick. The standard emag battery housing only holds a 20mm thick pack. If you split the pack into two sections, it still doesn't fit due to the length.

This one will work for you and will drop into the existing housing. It is only 450mAh, but that's still more than 6 cases of paint before it needs a recharge. If you need more capacity, get two and keep one in reserve in case you need it. http://www.cheapbatterypacks.com/product/1848/Elite-450-148V-4S-pack.aspx

[GoatBoy]

I'm just happy that this thread didn't completely die. ANYTHING to help shave some ounces off the weight of an Emag, coupled with perhaps better battery life, will help.

Don't you run with a warp+rotor as well?

In your case... wonder if you could consolidate all the batteries.



Also, forgot to mention -- do the E-mag electronics have any sort of low voltage cutoff? What is it, and can it be overridden?

[Justus]

Don't you run with a warp+rotor as well?
Normally, yes. But I sold the Rotor and will be ditching the warpfeed as I go with a Halo warpless. Just need to finish cutting a custom bracket.

Also, I picked up a Qloader from Freedy, so when I can get a CMS again, I'll have that option for smaller games where I won't need more than 300 rounds at a time.

Both of those feed systems save a lot of weight. And ditching the warpfeed should allow me to set my gun down without it being all lopsided. :tard:

[Justus]

That hobbyking pack is 30mm thick. The standard emag battery housing only holds a 20mm thick pack.
I've checked this thread, but didn't see that anyone has posted the dimensions of the standard Emag battery pack. Anyone? I can grab my calipers and post the dimensions tonight if nobody posts this morning or afternoon. Just need to make sure that a new Lipo pack will drop into an existing Emag battery pack housing.

[GoatBoy]

Wait, was that was those Q-loader elbows were for?

I haven't seen any specs posted so far. Data, guys. Data, data, data.

[Justus]

Wait, was that was those Q-loader elbows were for?
Yeah, trying to see if I can get the ball stack coming out of a Halo Too to turn upward and into my warp breech without modding the hopper at all, making it completely reversible yet still extremely low-profile. I'm pretty sure it will work just fine - I just need to bracket it and connect everything.

[2xFast]

I haven't seen any specs posted so far. Data, guys. Data, data, data.

The data's around if you look for yourself but here it is all in one place (https://docs.google.com/document/d/1Slcg2pWEXFt0hsoTFtZIwO-jAMj11Rj04wggTiRPPUw/edit?usp=sharing)....such as it is. This isn't rocket science, just a packaging issue. Possibly a fire hazard :)

In the end I'll probably make myself a new battery housing for the LiPo pack, seems like there are too many trade-offs trying to get something that matches the stock housing.

[2xFast]

I got the packs in today. Again this is where it stalls for me until I get my new circuit board. That said here's option one for me.

http://img30.imageshack.us/img30/404/93gr.jpg (http://img30.imageshack.us/i/93gr.jpg/)

http://img819.imageshack.us/img819/1648/a3b2.jpg (http://img819.imageshack.us/i/a3b2.jpg/)

http://img51.imageshack.us/img51/9135/1zwb.jpg (http://img51.imageshack.us/i/1zwb.jpg/)

http://img855.imageshack.us/img855/5999/ud2n.jpg (http://img855.imageshack.us/i/ud2n.jpg/)

I'll eventually charge these and do a few test cycles...check that they can handle high rof without catching fire...if we're good I'll try to source individual cells for a single pack. If that falls through I may look at buying more of these and dissecting until I can scavenge enough cells for a proper balanced pack.

[GoatBoy]

The data's around if you look for yourself but here it is all in one place (https://docs.google.com/document/d/1Slcg2pWEXFt0hsoTFtZIwO-jAMj11Rj04wggTiRPPUw/edit?usp=sharing)....such as it is. This isn't rocket science, just a packaging issue. Possibly a fire hazard :)

In the end I'll probably make myself a new battery housing for the LiPo pack, seems like there are too many trade-offs trying to get something that matches the stock housing.

Good deal. Yes, it is convenient to have it all in one place. And if we're talking about it here, then this is that one place :)

It looks like you can fit a single 500 in there if I'm seeing that correctly. I would make like an e-mag adapter, which would be spring connectors on one side adapted to JST or whatever on the other. It looks like you'll have enough space to do so, if there's not too much excess wire. Dunno if those spring clips are readily available elsewhere or there's some other way to source them. Given the extra space you could get ... somewhat creative. Like mounting the spring clips and JST adapter onto a small PCB, and adding a few other goodies, like a low voltage/cell health alarm.

I wouldn't worry so much about pack semantics like balancing or whatever. Get into that later.


Last thing is to simply test if the voltage really is good enough. Make sure to have your Level 10 tuned...

[athomas]

I got the packs in today. Again this is where it stalls for me until I get my new circuit board. ...

...I'll eventually charge these and do a few test cycles...check that they can handle high rof without catching fire...if we're good I'll try to source individual cells for a single pack. If that falls through I may look at buying more of these and dissecting until I can scavenge enough cells for a proper balanced pack.These will handle the load quite well. Their specs indicate that they can handle 17.5A which is much more than the required 6A. The voltage for a 5S pack (3S + 2S) is more than adequate and will produce the required 6A.

To run them just connect in series. For charging, you'll have to connect each pack to a charger independently for proper balance charging, or make an adapter to convert both plugs to interface a single plug so that both packs can be balance charged together.

The packs are too long for the emag case. Make a piece that bolts onto the bottom of the emag pack to extend its length, and you can still use it.

[Xmagterror]

I am playing around with this light battery idea too. I will leave the battery packs to someone else with the know how but i was thinking about 5 axis machining a new battery housing for the new pack.....make it look cool.
If done right it could give the gun a new look.

[GoatBoy]

Oops didn't notice you were shooting for 5s. Voltage should be plenty. Good luck with that.

[Sk8ermog]

Time to refresh this thread. I'm in the market for a new battery for some lowers I just bought. I always disliked how big the battery is on Emag lowers. So has anyone made any progress on a new battery option? I'm not an engineer, but I work with a few. My co-workers had a few ideas, but nothing that hasn't already been said.

So now my question is could we just get a company to custom make a new battery pack for us Emag owners? I found these 2 websites that might be helpful:

http://www.batterygiant.com/custom_pack_builder/start.asp

http://www.houseofbatteries.com/custom-batteries-c-1-l-en.html?gclid=CJf71-_gzLsCFeJF7AodLQYAuw

If we just gave either of these companies the specs of what we need couldn't they just make a new battery?

[knownothingmags]

Time to refresh this thread. I'm in the market for a new battery for some lowers I just bought. I always disliked how big the battery is on Emag lowers. So has anyone made any progress on a new battery option? I'm not an engineer, but I work with a few. My co-workers had a few ideas, but nothing that hasn't already been said.

So now my question is could we just get a company to custom make a new battery pack for us Emag owners? I found these 2 websites that might be helpful:

http://www.batterygiant.com/custom_pack_builder/start.asp

http://www.houseofbatteries.com/custom-batteries-c-1-l-en.html?gclid=CJf71-_gzLsCFeJF7AodLQYAuw

If we just gave either of these companies the specs of what we need couldn't they just make a new battery?

ive been doing some searching of lipo batteries out there with like 1000 mah, which is more then we need.
and the back are sizably bigger then the current battery housing,

so I have been looking for new options on sizes but none that can be custom made yet.
im actually going out tomorrow to a guy to see if he can help.

[dodge3500]

There is a custom battery shop near me.I will take my emag there and let them see what can be done as far as a new battery and charger set up.they are able to do custom packs to whatever voltage required. I'll try to go this weekend if I can.

[knownothingmags]

so im a little fuzzy.
will the lipo 4S(4 cell) battery with a high C rating work in a emag ?(Atomas I think this is you knowledge base)

if so I may have what we need. or can at least get ahold of it.

what is the minimum Mah (milliamp hours) that is desired?

hit me up asap on this so I can let people know what I can get my hands on, without having my guys come up with a custom pack, that no one will be able to buy reasonably.

[dodge3500]

Well things came up so i didnt make it to the battery shop Saturday but i did call them and they seemed like they could do something. Ill try to get by there this Saturday i hope.:)

[Sk8ermog]

Does anyone have the specs needed for an Emag battery? I have been looking and either I'm blind or they are harder to find then I imagined. Also would any of these new batteries work:

http://shop.valken.com/c/energy

[knownothingmags]

no none of them would work unless you some how make a reusable encasement for the AAA battery cells.
I tried printing a skin to encase the AAA batteries and have the proper connections inserted in the right places. but the first attempt I got a power outage on my outlet, and the printer stoped printing :( no power no print.
and I jump back onto the trimag project.

[need4reebs]

The data's around if you look for yourself but here it is all in one place (https://docs.google.com/document/d/1Slcg2pWEXFt0hsoTFtZIwO-jAMj11Rj04wggTiRPPUw/edit?usp=sharing)....such as it is. This isn't rocket science, just a packaging issue. Possibly a fire hazard :)

In the end I'll probably make myself a new battery housing for the LiPo pack, seems like there are too many trade-offs trying to get something that matches the stock housing.


hey sk8ermog and KNM did you guys get a chance to read this post? has the specs your looking for and even the battery packs that will work.

[chi town saint]

I know, i know, bringing back the dead. I was just wondering has anyone one of you geniuses come up with an alternative option?

[Justus]

I'm gonna bring this zombie back up to ask if anyone has the gumption to go where my battery knowledge fails, and point to something that wasn't available way back in 2013/2014, being a new, lightweight battery that's drop-in-capable to replace the bulky, heavy Emag NiMH battery packs.

I sure hope so... my warpless rotor is getting closer to completion and this would be the last thing I could do to lighten up my E-Tac. Everything else is pretty milled out.

[knownothingmags]

It's on the list I have I know that

Sent from my SM-G930V using Tapatalk

[Justus]

Umm... been awhile since I posted on a forum with all the tech changes going mobile....

There's no "like" button here, but I like what you have to say. Thanks man, lol

[athomas]

There are lots of small and inexpensive battery packs available now. Just get a 5S pack that will fit inside the emag battery holder. Better yet, have a lighter milled design that will bolt onto the existing battery top, and fit the new LiPo pack sizes. Any LiPo battery charger will charge the pack and they are inexpensive as well.

[Justus]

I think my primary problem is finding a 5S pack that's thin enough to fit in the emag battery well.

[knownothingmags]

Very true.

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[athomas]

I think my primary problem is finding a 5S pack that's thin enough to fit in the emag battery well.

Use a shorter 2S and 3S stacked combination. Put the groups end to end. You can buy 700 mAh LiPo individual batteries that are 43mm long, 30mm wide, and 5.5mm thick. That would result in a 5S pack that is 17.5mm thick, 86mm long, and 30mm wide. Add some thickness for wrapping and it gets a tiny bit larger in all dimensions but fits into an emag battery pack.

[knownothingmags]

Since these won't be powering an esc for an rc vehicle do the packs need to have the same C rating?

Just asking just in case some one is like hey I have those.

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[knownothingmags]

Also a pack with more than one cell will need to be balanced when charging,

I for one have the cells to produce the right size pack but have no idea how to wire a balancing plug.

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[knownothingmags]

Would 500mah 5s pack do ok?

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[knownothingmags]

Can I combine 2 3.7 volt 450mah lipo batteries to make 900mah batteries without them blowing Up? I know lipo is different than nimh batteries.

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[BLachance75]

Can I combine 2 3.7 volt 450mah lipo batteries to make 900mah batteries without them blowing Up? I know lipo is different than nimh batteries.

Sent from my SM-G930V using Tapatalk

Yes if you are connecting them in parallel the end result would be a 3.7v 900mah battery. If you hooked them in series then you would have a 7.4v 450mah battery.

What are the internal dimensions of the emag battery housing? Or how big is the existing emag battery?

What is the operating voltage of the emag board both high and is there a cut off where it will stop working? A fully charged 5s lipo will be 21v can the board handle that? You also don't want to over discharge a lipo so if the board won't stop at about 16-16.5v then you could be bringing the lipo cells to low.

[knownothingmags]

Yes if you are connecting them in parallel the end result would be a 3.7v 900mah battery. If you hooked them in series then you would have a 7.4v 450mah battery.

What are the internal dimensions of the emag battery housing? Or how big is the existing emag battery?

What is the operating voltage of the emag board both high and is there a cut off where it will stop working? A fully charged 5s lipo will be 21v can the board handle that? You also don't want to over discharge a lipo so if the board won't stop at about 16-16.5v then you could be bringing the lipo cells to low.Well cool ima make a lipo pack then soon. I'll see if I can't make a nice housing for people. This will be easy

Yeah the cut off I think I'm going to see if I can't get one put in the pack when I make it
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[athomas]

Can I combine 2 3.7 volt 450mah lipo batteries to make 900mah batteries without them blowing Up? I know lipo is different than nimh batteries.

Sent from my SM-G930V using TapatalkAll batteries work basically the same. You need to make sure you use the same batteries so that the current output is balanced across the parallel combination. That way they will equally share the load. When you actually put both batteries in parallel, they have to be at the same voltage potential to prevent the higher voltage battery from instantly trying to top up the lower voltage battery. In lower capacity cells its not so much of an issue, but in high capacity cells, the inrush current can be significant and can cause a lot of heat.

You can combine quite a few parallel cells for increased capacity.

Load balancing for series combination is often just a wired plug. The charger can then monitor the charge of the individual cells and trickle charge those individual cells in the pack to top them all up following the initial high current charge.


BLachance75: The emag board operates on 5v which is regulated down from the battery voltage. It doesn't care about the battery fluctuation from full charge to empty. The high voltage is used to power the solenoid only. It also doesn't care if the voltage fluctuates a bit as long as there is enough charge to power the solenoid. I wouldn't go overboard with high voltage, because it will result in more heat generation, but a volt or two for that purpose won't adversely affect the operation or life. The 16.8V NiMh pack operated from 14V to 19.6V. A 5S LiPo pack operates from 15V to 21V.

[athomas]

Would 500mah 5s pack do ok?
I would think the 500mA pack would work quite well. I was searching around for batteries recently and found some small ones that were around 700mA. They would fit into the emag battery pack quite nicely with room to move. They would have been quite a bit less mass than the existing pack.

[knownothingmags]

I would think the 500mA pack would work quite well. I was searching around for batteries recently and found some small ones that were around 700mA. They would fit into the emag battery pack quite nicely with room to move. They would have been quite a bit less mass than the existing pack.

we now need to find a source for a very small voltage cut off board or something to put in the pack so we don't let the cells drop to low and destroy them from charging properly then.
wish p8ntball4me was around. he could talk on this a little more to help me with my knowledge of getting a board that can do what Im talking about it doing for a small package footprint.

because if i can get these ill put them together and get them to the public.
with a package and such put together these would be a neat option to have.

how many amps do we need?
do we need a fuse like the NiMh packs have? or do you think this feature would be in the voltage cut off board?

[BLachance75]

That makes sense that the board runs on 5v and the high voltage is for the solenoid.

It would be very helpful to have a low voltage cut off board so that people aren't over discharging the lipos. Personally I don't like taking a lipo below 3.2v so I'd set the cutoff at 16v. If it is something that is being produced for sale I may even have it set higher for liability, possibly 16.5v or 17v.

Running a 5s battery I would recommend that there is a balance plug. An issue that you may run into is that people will have to buy new chargers if they don't have one that will balance charge lipos.

[knownothingmags]

That makes sense that the board runs on 5v and the high voltage is for the solenoid.

It would be very helpful to have a low voltage cut off board so that people aren't over discharging the lipos. Personally I don't like taking a lipo below 3.2v so I'd set the cutoff at 16v. If it is something that is being produced for sale I may even have it set higher for liability, possibly 16.5v or 17v.

Running a 5s battery I would recommend that there is a balance plug. An issue that you may run into is that people will have to buy new chargers if they don't have one that will balance charge lipos.

yes on all this. exactly.
I found a board to manage the cutoff voltage, but its to big for my liking, it will fit in the current battery pack.
but then we have to tackle the pack size then.

if I can find something size wise to get this made for the public.
I would offer the batteries and the option to purchase a charger and a charging bag with it.

just shopping this stuff is time consuming. chargers and battery bags are easy.

[athomas]

There are a few small footprint pcb cutoff circuits kicking around. I've seen them, but couldn't point you to them off the top of my head. I'll keep an eye out for them and mark them if I happen to see them again. Those are critical to maintaining your batteries. Some individual batteries might actially have them built in. You can build one with a simple comparitor and a reference voltage, or get nice and fancy and use a small microprocessor. Texas Instruments actually makes a small battery protection IC. You can use their example design to build a protection device.