LiPo Pack Testing January 17, 2025

Here I go again with my synopsis of what I found in LiPo shorty packs the second half of 2024. I will do more testing of current products in about six months.

I tested nine different manufacturers of 2S shorty packs and here is what I found for the top three, in order of how they performed. Some of the others were more than 20% less in capacity and higher IR (with the same numbers on the label).

As you see the numbers on the package is what I call 'marketing' numbers. Every manufacture of LiPo cells give you these inflated numbers (including cells in packs I had in the past) which you can achieve at very low discharge rates (< 1amp) and are discharged to 3.0 volts per cell. Not at real race rates. But these newer '6400' packs are much better than two years ago.

I use a constant charging current of 15 amps, charging to 8.4v total. They are discharged at a constant rate of 15 amps to 7.3v. I use 15 amp discharge because when using actual average discharge rates of 32 amps (or more) to simulate oval modified racing, you alter the cells by reducing the number of cycles available for competition use. Racing is kinder than constant high-rate discharge. My equipment will do constant 60 amp discharge rates for 2S packs, but pack life is now 10 cycles! You can ask me how I know.

I have used West Mountain battery discharge equipment for more than seven years which give repeatable (as much as you can say 'repeatable' as the results change with temperature, etc.) readings. Of all these numbers the 'C' rating is the worst accurate but give you a feel of how they will discharge. I use a tester developed by the electric aircraft guys; they have been doing this since the advent of lithium-ion cells. The tester shows how wide the 'C' rating numbers vary.

I sell what works. I like the brands below; all three will handle brushless 7.0t motors in sprint cars for at least 270 seconds at race speed when new (the TPP invitational team at the 2025 RC Chili Bowl used ProTek 6400 shorty packs). The Gens Ace 6000 140c gives you a lot of bang for the buck; we are still testing them for longevity and consistent IR. They look good after six months.

Here is my top three: