Emag battery?

[knownothingmags]

I'm going with these: GNB 550mah 2s 7.4v 80c Lipo Battery... https://www.amazon.com/dp/B079DCFLQJ?ref=yo_pop_ma_swf

Since I'm still using the 80watt coil, just half the voltage and double the amps roughly, its really just 1/4 the battery power. However, I could stuff 2 of those batteries in the emag grip if I wanted. But who cares? Its not a NiCad that costs $50 and takes half a day to charge. Its a $10 battery that I can swap out in a minute with its XP30 plug and charge during a beer break. Lipo chargers can do multiple at once too. I'm adding in a simple voltage sensing circuit also so that when its close to being out, it can use the bluetooth to give an alert on the phone.

thats awesome
dont pat yourself too hard on the back just poking fun,

you should track down the facility that those packs are sourced from, data sheets, honor stamps to show where they actually come from.
there are some facilities you should research and make sure your lipos dont come from. because there are facilities that make pretty good failure lipos and im pretty sure alot of people dont want their 400-????$ marker up in flames from a 13 $ purchase.
not saying those will do that.

there is a reason the EMAG batteries work. quality without question,(other than the specs you need to adhere to )
oh and i can charge multiple emag batteries at my place(mind you most people dont get that opertunity) and i can charge them all in less than an hour

it is great to see the work you are going toward on this.
i went a different route i started doing different things instead of perusing the lipo battery for the emags, otherwise like i said we would have them already.
my 2cents. and it may mean nothing.
and im no expert since i already know where your education lies.
keep the progress forward this is awesome.

edit ** when you say close to being out you mean the safe cutoff of 3.4 volts per cell correct?(bare min of 3.1 volts?)

[JimBobFett]

Lol, no I won't pat myself on the back too soon: Found a HES for the trigger that I like better than the original and others I've tried (it's self adjusting/tuning and just gives a digital out!!!), the battery/FET/coil works just fine... but there's something off about that Kodenshi sg-2bc reflective sensor. I haven't spent a whole lot of time on it yet since its not a functional requirement, but I've either got to spend more time tuning it, I need to pick a different circuit design, or I have a few bad samples. I think I saw a schematic a long time ago for a board, but if you know of any X-Mag circuit diagrams for the ACE board's eye circuit... I sure could use some reference material for resistor values or something. Something isn't right with that thing. I'm also looking at newer alternatives though too since that sensor is pretty old.

As for batteries, I've been going with online reviews mostly (hardly the most reliable, I know), but I'm not too scared. It seems LiPo's are the riskiest when charging... and they should be removed for that anyways. As for discharge... I'm only asking for ~12 amps at less than 10% duty cycle on a battery rated for up to 44 amps. I guess what I'm trying to say is that these hobbyist 'drone' batteries are meant for much tougher than what I'm asking from them. Still, sure... its always possible that they may catch fire... but what will it really destroy? The battery is cheap, some plugs/wiring, a $15 bluno board, and a $3 power FET board. If it starts to smoke, undo the thumb-screw, pop off the battery pack and yank the guts out (the battery, and 2 boards just slide right out).

As for the cutoff, I'm measuring the input voltage, not each cell. The threshold can be set to whatever I like. I'm just wiring up a couple 1M resistors to make a voltage divider circuit and running the middle node to an analog input. The voltage sensed will be 1/2 the actual voltage. I compare this to a number I can adjust, and if it falls below that threshold, I send out an alert. If I want to always run peak power, I could set the threshold at 8v (peak is 8.4v) and change batteries more often. Whatever works.