Sometimes More C's Isn't More Better
Oct 23, 2012 11:18:06 AM
Three years back when SpyderBatteries - then based in Austin, Texas - brought us their 30C rated packs for independent testing, we were frankly blown away by the results. We performed initial qualification testing at 30C and found they outperformed every 45C+ rated pack we could test them against.
Moving forward a couple of years to present day, Spyder packs have proven their performance and longevity. In the same period of time, other manufacturers have marched forward with 50C and even 60C+ rated packs. The manufacturer of our cells has also offered updated product lines, including “improved” 40C rated cells, followed by presumably better 45C rated cells. With increased C ratings the respective pack weights have gone up, and the capacity has gone down.
Rather than choosing to quickly package and release these packs to consumers, we take the unconventional next step of qualifying the manufacturer’s cells against their ratings. To provide a glimpse, here’s a snapshot from discharge testing at around a kW of power to illustrate this point. Three different cells are shown: a 45C 5000mAh sample from last week, a 40C 5000mAh sample from 2010, and an original 30C 5300mAh sample tested three years ago:
Lo and behold, much to our surprise we found that the newer 40C and 45C rated cells did not perform any better than our high performing 30C rated cells under load. Testing shows the 30C cell held the highest average voltage under load and provided the greatest capacity, while ringing in at a lower weight than the higher C rated packs.
So we’re not just going to slap a 45C label on them and put them up for sale. We’re committed to marketing our batteries honestly. Until we see higher rated packs that outperform our current generation, we’ll stick with the 30C packs that even now, outperform optimistically higher C rated packs.
Testing is forever ongoing here, and we’ll keep you posted when real progress is made in this arena. But for now, it would seem more Cs on the label are not always better, and it makes me wonder what is being sold out there…
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