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Alternative Battery sources
Posted: Tue Apr 11, 2017 12:01 pm
by RetroRocket
I saw on the boards some clever folks using a cell phone battery with the four pin connectors wired up into the DMG battery slot. I think that's an elegant solution (and possibly cheaper) Although I ordered a 2000 mAh battery like wermy's original build, I got to thinking (and dissecting every electronic device in my house) about other cheap sources.
I picked up these USB battery chargers last summer from a Radioshack that was going out of business for about $5 US each but there were flat variants as well. I think they were 3000 or 3500 mAh and I think without the connection supports two could fit in neatly. The board may be superfluous but has a built in charging and fully charged indicator.
Thoughts?
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Re: Alternative Battery sources
Posted: Tue Apr 11, 2017 12:14 pm
by abrugsch
What does it say on the battery itself? 3.6v, 3.7 or 3.8? If it's 3.6 i'd steer clear since almost all lipo chargers are calibrated for 3.7/4.2v batteries. A 3.6v one will be overcharged and that's bad news (like burn down your house bad!)
Re: Alternative Battery sources
Posted: Tue Apr 11, 2017 12:28 pm
by RetroRocket
abrugsch wrote: ↑Tue Apr 11, 2017 12:14 pm
What does it say on the battery itself? 3.6v, 3.7 or 3.8? If it's 3.6 i'd steer clear since almost all lipo chargers are calibrated for 3.7/4.2v batteries. A 3.6v one will be overcharged and that's bad news (like burn down your house bad!)
It's 3.7v. Obscured by the foam support. On the back of the case it says 5v input and output, 12.95Wh (3500 mAh) capacity.
Re: Alternative Battery sources
Posted: Tue Apr 11, 2017 1:14 pm
by ICMF
Since I've been researching power banks for my build, a couple of thoughts:
If you want to keep the board, you need to make sure it can do passthrough (draw an input charge while outputting charge to the device). A lot of power banks don't; they cut output as soon as the input gets plugged in.
If it does passthrough, make sure it can input more charge than it outputs. Doesn't do a lot of good if it recharges at 1A but your device is consuming 2A.
Looks like the battery itself has a charge protection circuit on it. Which is good; a lot of power bank batteries don't. In that case, I'd be inclined to ditch the power bank's recharge circuit and attach it to a powerboost instead. I probably wouldn't trust the bank's integrated charge circuit to be very good; the powerboost is a known quantity and works well, so it would probably be simpler and less frustrating to plug the battery into that, rather than trying to make the included board work for you.
DIYing parallel lipo circuits is generally frowned upon. Pretty much everything I've ever seen has said, unless you absolutely know what you're doing, buy a bigger battery if you need higher capacity; don't wire multiple lipos. So if you do use these, don't try to squeeze two of them in the case.
Re: Alternative Battery sources
Posted: Tue Apr 11, 2017 3:35 pm
by RetroRocket
ICMF wrote: ↑Tue Apr 11, 2017 1:14 pm
Since I've been researching power banks for my build, a couple of thoughts:
If you want to keep the board, you need to make sure it can do passthrough (draw an input charge while outputting charge to the device). A lot of power banks don't; they cut output as soon as the input gets plugged in.
If it does passthrough, make sure it can input more charge than it outputs. Doesn't do a lot of good if it recharges at 1A but your device is consuming 2A.
Looks like the battery itself has a charge protection circuit on it. Which is good; a lot of power bank batteries don't. In that case, I'd be inclined to ditch the power bank's recharge circuit and attach it to a powerboost instead. I probably wouldn't trust the bank's integrated charge circuit to be very good; the powerboost is a known quantity and works well, so it would probably be simpler and less frustrating to plug the battery into that, rather than trying to make the included board work for you.
DIYing parallel lipo circuits is generally frowned upon. Pretty much everything I've ever seen has said, unless you absolutely know what you're doing, buy a bigger battery if you need higher capacity; don't wire multiple lipos. So if you do use these, don't try to squeeze two of them in the case.
Thanks for the input; I'll definitely avoid stringing together these suckers... Not for this build but since the form factor works well, I was curious if an auxiliary set up could be made ie battery 1 and battery 2 on separate, switchable circuits to the powerboost. Not sure if bigger batteries come in the double stuft size. Again, complete noob, just thinking.
I'm working through a powerboost anyway because I'm less confident repurposing special purpose boards, plus it is circular and wouldn't fit the DMG case well.
Re: Alternative Battery sources
Posted: Tue Apr 11, 2017 10:43 pm
by Brett82
Parallel lipo cells is fine that's how larger capacity batteries are made. It's series connecting you have to be careful with as you need to balance the cells.