DualDesertEagle
So I just had this idea of simply making an adapter for the balancer / equalizer cable on a LiPo battery that puts the cells in parallel to keep their discharge rate even while supplying 3.7 volts to my chainring camera that I've already used on planes before but modified to take external batteries after the internal one was just not durable enough to even record a single flight. But since I don't know much about LiPos except how to charge them properly I need to ask this question:

Will this work or be a way to destroy the battery instead?
Will this work.png 
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Grantman
Pretty sure you end up with a bunch of shorts if you do that. Your battery is already wired series, adding parallel wiring kills it.
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JTiger
This has me very curious now so I looked up how a 3s Li-Po is wired:

LiPoWiring.jpg 

If I'm understanding this correctly, balance leads 1 (ground) -> 2 would give 3.7v, 1 -> 3 would give 7.4v, and 1 -> 4 would give all 11.1v. Right?
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Grantman
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This has me very curious now so I looked up how a 3s Li-Po is wired:

[ATTACH=full]56280[/ATTACH]

If I'm understanding this correctly, balance leads 1 (ground) -> 2 would give 3.7v, 1 -> 3 would give 7.4v, and 1 -> 4 would give all 11.1v. Right?

Correct. Now if you connect balance leads 4, 3, and 2 you will have shorted cell 2 and 3 = smoke!
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quorneng
You could always buy another battery for the key ring camera!
I bought a replacement from ebay.
Some of the later versions of the camera even use tiny battery connectors but I soldered mine.
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Argonath
This is your LIPO.

These are some of the things you should never do to a LIPO and why:

D.I.L.L.I.G.A.F.
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DualDesertEagle
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[ATTACH=full]56280[/ATTACH]


Yeah, that made it crystal clear to me how my adapter would kill my battery. Gonna have to come up with a circuit that reduces the 5 volts supplied by the receiver to 3.7 for the camera.


Quote:
You could always buy another battery for the key ring camera!
I bought a replacement from ebay.
Some of the later versions of the camera even use tiny battery connectors but I soldered mine.


The thing is that I want to avoid packing an extra battery for the camera when I can just use the power supplied by the flight battery. The camera with its BEC connector for the external battery weighs only 12 grams and I'd like to keep it that way, plus maybe 5 grams of voltage reduction circuitry. If I can make that happen the camera and all its external power supplying hardware would still weigh less than with its original internal battery that died after at best 5 minutes.


That said, I DO have a camera that looks like a slightly bigger USB stick and weighs 21 grams altogether, 18 without the protective cap for the USB connector.

But it records at only 720x480 (9x6 ratio) and I haven't had a chance to test the battery life yet.



Long story short, I'd prefer a lighter 720p camera that can record for as long as the plane can fly over a heavier 480p camera with a potentially short-lived internal battery.
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Grantman
Why not mod a usb cable with a servo connector? Plug into the rx and let the camera step-down the voltage thru the charging circuit, I used to do this on my FPV quads.
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DualDesertEagle
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Why not mod a usb cable with a servo connector? Plug into the rx and let the camera step-down the voltage thru the charging circuit, I used to do this on my FPV quads.


True, never thought of that. The BEC-cable is connected to the contacts that the internal battery was soldered to, so I probably bypassed an internal reduction circuit. If I soldered the cable to the Vcc and GND contacts of the camera's mini-USB instead I shoult be able to plug the whole thing directly into the receiver and have the thing work fine.
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