Results 1 to 30 of 103

Thread: Lithium Ion battery for the E/X-Mag?

Hybrid View

Previous Post Previous Post   Next Post Next Post
  1. #1
    Join Date
    Feb 2006
    Location
    Lancaster, PA
    Posts
    729

    Lithium Ion battery for the E/X-Mag?

    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?
    Steve Shuey , Team Crimson Reign

  2. #2
    Join Date
    Mar 2013
    Location
    Oregon
    Posts
    244
    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.

  3. #3
    Join Date
    Mar 2013
    Location
    Oregon
    Posts
    244
    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.

  4. #4
    Join Date
    Oct 2001
    Location
    Plymouth, WI
    Posts
    7,193
    Someone get me some specs. I just happen to work for a conpany that makes lith car batteries. Ill talk to the engineer

    To leave feedback: Click seller/buyers name, Click feedback score, Click leave feedback

  5. #5
    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.
    I sell new 800 mah Emag batteries, in dealers section, or pm for pricing. batteries ready to ship

  6. #6
    Join Date
    Jan 2002
    Location
    Halifax, N.S., Canada
    Posts
    7,960
    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.
    Except for the Automag in front, its usually the man behind the equipment that counts.

  7. #7
    Join Date
    Mar 2013
    Location
    Oregon
    Posts
    244
    Quote Originally Posted by knownothingmags View Post
    *_* 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?

  8. #8
    Join Date
    Jun 2002
    Location
    Mt Vernon, WA
    Posts
    88
    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.









    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.
    faster is better...

  9. #9
    Join Date
    Jan 2002
    Location
    Halifax, N.S., Canada
    Posts
    7,960
    Quote Originally Posted by 2xFast View Post
    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.

  10. #10
    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.

  11. #11
    Oops didn't notice you were shooting for 5s. Voltage should be plenty. Good luck with that.
    "Accuracy by aiming."


    Definitely not on the A-Team.

  12. #12
    Join Date
    May 2002
    Location
    Colorado
    Posts
    4,012
    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_p...lder/start.asp

    http://www.houseofbatteries.com/cust...FeJF7AodLQYAuw

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

  13. #13
    It's on the list I have I know that

    Sent from my SM-G930V using Tapatalk

  14. #14
    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

  15. #15
    Join Date
    Jan 2002
    Location
    Halifax, N.S., Canada
    Posts
    7,960
    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.

  16. #16
    I think my primary problem is finding a 5S pack that's thin enough to fit in the emag battery well.

  17. #17
    Very true.

    Sent from my SM-G930V using Tapatalk

  18. #18
    Join Date
    Jan 2002
    Location
    Halifax, N.S., Canada
    Posts
    7,960
    Quote Originally Posted by Justus View Post
    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.

  19. #19
    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.

    Sent from my SM-G930V using Tapatalk

  20. #20
    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.

    Sent from my SM-G930V using Tapatalk

  21. #21
    Would 500mah 5s pack do ok?

    Sent from my SM-G930V using Tapatalk

  22. #22
    Join Date
    Jan 2002
    Location
    Halifax, N.S., Canada
    Posts
    7,960
    Quote Originally Posted by knownothingmags View Post
    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.

  23. #23
    Quote Originally Posted by athomas View Post
    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?

  24. #24
    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

  25. #25
    Join Date
    Jul 2002
    Location
    Western Mass
    Posts
    570
    Quote Originally Posted by knownothingmags View Post
    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.
    The user formally known as Lancecst.

  26. #26
    Quote Originally Posted by BLachance75 View Post
    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
    Sent from my SM-G930V using Tapatalk

  27. #27
    Join Date
    Jan 2002
    Location
    Halifax, N.S., Canada
    Posts
    7,960
    Quote Originally Posted by knownothingmags View Post
    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
    All 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.

  28. #28
    Join Date
    Jul 2002
    Location
    Western Mass
    Posts
    570
    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.

  29. #29
    Quote Originally Posted by BLachance75 View Post
    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.

  30. #30
    Join Date
    Jan 2002
    Location
    Halifax, N.S., Canada
    Posts
    7,960
    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.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •