SparkFun Forums

[TobyA]

Hi,

With this board, https://www.sparkfun.com/products/10217

Is it possible to charge two lipo batteries together? For example, two 850mAh Lipos at the same time in parallel.

Thanks

[Mee_n_Mac]

From the comments on the product page;

jdwander | about 2 years ago

I saw a question from a while back about using this charger (or another sparkfun charger) to charge multiple LiPo’s simultaneously, though the question was asking about charging batteries configured in series. I’m curious if anyone has tried to use this or another charger to charge multiple batteries configured in parallel and if it did/didn’t or would/wouldn’t work. I’m also unclear as to how to compare the charging rate listed above to maximum USB load ratings (e.g. 500 mA for USB 2.0 from http://en.wikipedia.org/wiki/Universal_Serial_Bus#Power) to know if charging three parallel would even be feasible. Charging the batteries separately is just a nuisance, so any advice is appreciated! Thanks!

IgnacioV | about 2 years ago

This is a single-cell charger, so it won’t work on batteries in parallel.

MikeGrusin | about 2 years ago

Sure it will. In fact, our larger 3.7V LiPo batteries are just multiple cells in parallel and it charges them quite well. The maximum USB current is indeed 500mA, but that only means it takes longer (our largest 3.7V LiPo, at 6Ah, takes 12h to charge).

The only gotcha is that you’ll want all the batteries you have in parallel to be fairly closely matched. They should be the same capacity, and preferably the same age. If they’re mismatched, the charger will get false indication of full charge and won’t charge the entire stack properly.

[waltr]

Right. The other possible gotch is that both batteries need to have been discharged to the exact same level. This means that the two batteries should always be keep in a parallel connection during discharge as well as charging.

[TobyA]

I plan on getting two 2000mAh batteries and wiring them in parallel from the beginning. Then they will be charged and discharged together from then on. Hopefully this will work well in the long term also.