A BATTERY MOOCH POST: LiPo’s don’t perform like crap

Just because LiPo’s might have preposterously exaggerated ratings doesn’t mean they don’t still perform well against 18650’s.

My recent testing update post mentioned the wildly exaggerated ratings I saw for a couple of 3S 1800mAh LiPo packs. I received quite a few messages from people wondering how I can say that because they get great performance from their LiPo’s. And they should! Not meeting the 100C, 70C, or even the 50C ratings these packs have doesn’t mean they are lousy performers. It just means they don’t perform anywhere near their ratings. They can still be better than the 18650’s we use.

For example, see the graphs linked to below.

I tested two 3S 1800mAh-1850mAh LiPo packs against a 3S setup of Sony VTC5A batteries in a good quality battery sled at 10A, 20A, and 30Ap. Their DC internal resistances are:

Green LiPo = 0.028 ohms
Red LiPo = 0.044 ohms
VTC5A’s = 0.078 ohms

You can clearly see the difference the different internal resistances make. The higher the internal resistance, the greater the voltage sag and the lower the battery voltage is.

The Green LiPo is the clear winner here with the Red LiPo performing next best and the VTC5A’s performing the worst of the three. Interestingly, the Red LiPo is a very expensive pack from a very well respected manufacturer. The Green LiPo is slightly larger but is about half the cost and performs a lot better. I won’t be revealing the manufacturer’s name for either LiPo until I can test a second pack from each company to make sure my results are correct.

Neither LiPo performs anywhere near its ratings but in spite of that they still outperform a pack using one of the best 18650’s available.

There are safety issues when using LiPo’s though. I’ll be addressing these, and other considerations, when I have finished testing the rest of the 1800mAh-1850mAh LiPo packs. I hope to be able to do that within a couple of weeks.

https://imgur.com/a/fch74

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Author: John Muchow