Wiring li-ions in parallel

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Life of Brian
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Wiring li-ions in parallel

Post by Life of Brian » Sun Oct 22, 2006 9:42 pm

Correct me if I'm wrong - wiring batteries in series adds up their voltages, but wiring them in parallel adds up their capacity, right?

For example, two 1.5 volt AA batteries at say 1500 mAh wired in series would equal 3.0 volts at 1500 mAh. The same two batteries wired in parallel would equal 1.5 volts at 3000 mAh, right? I know this is basic info but I need to make sure I'm right.

More specifically, what are the possible pitfalls of wiring two li-ion batteries in parallel? I'm thinking about buying two Sony Infolithium L batteries at 1850 mAh because they would be small enough to fit into the space I have for them rather than buying one larger battery at 3000 mAh (retrofitting SNESp for li-ion batteries - AA's aren't lasting long enough for my liking). They're 7.4 volts, so assuming I'm right then wiring them in parallel would give me 3700 mAh. The cost works out to pretty much the same on eBay for buying two of those as opposed to one of the other.

Am I right or missing an important point? Anyone with experience with li-ions have any advice?
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Post by CronoTriggerfan » Sun Oct 22, 2006 9:48 pm

You're absolutely correct in your analasys of parallel and series.

As for wiring together the Li-Ions, your only potential problem would probably be charging them; you'd have to build your own integrated charger, and make a toggle to switch off the charger before it reaches dangerous levels. I think... :mrgreen:

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Post by Life of Brian » Sun Oct 22, 2006 10:15 pm

Nope, I'm buying an external charger for them. Why not? It's only like $13 for it, and it works with any Sony Infolithium L battery (I think) so for future systems that'll work too. I already have a DC Aux In jack on the system, so hopefully this will be minimal work.
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Post by CronoTriggerfan » Sun Oct 22, 2006 10:25 pm

In that case, you should be fine. The only other probelm would be soldering to the batteries themselves, but you should be able to do it with a steady hand. I can't think of anything else that would go wrong, although I've never had an accident with them *cough*Gamelver*cough* :lol:

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