Parallel Batteries

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Parallel Batteries

Post by W9PXZ »

Not broadcast related, but basic electronics.

Circuit design was never my strong suit, but I want to parallel two 48V lithium battery packs for my e-trike. Both packs will be the same rated voltage and capacity, but I want to allow for variances on discharge curves without one pack feeding the other. Would a simple diode setup like this work?

2P battery1.png
2P battery1.png (11.14 KiB) Viewed 739 times

The setup would need to be capable of conducting up to 25 amps. My thinking is that doubling the diodes would halve the current each one would need to carry and broaden the part selection.

Am I off base or is there a better way to do it?
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Re: Parallel Batteries

Post by DaveSt »

Yes that could work. However, the paralleled diodes would not current share exactly, so it is better to forget that. Also, the diode voltage drop would reduce the efficiency of the setup depending on the battery voltage as to how much.
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Re: Parallel Batteries

Post by ChuckG »

I don't think anything is necessary other than to just parallel the batteries. Assuming they have similar ratings any cross current will be negligible. All my Multiple battery UPS's have simple parallel connections with no issue.
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Re: Parallel Batteries

Post by Deep Thought »

Lithium packs generally have their own internal charge (and discharge) controllers, but you may want to verify that with these before you parallel them with any scheme.
Mark Mueller • Mueller Broadcast Design • La Grange, IL •
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