When I received the A123 batteries, I wasn’t exactly sure which vehicles to use them in, as they have a unique voltage and size. I decided to take them home and look around my collection and see what would be the best fit. Thankfully, a couple of vehicles popped out right away. The 1100mAh battery was a perfect fit for my Losi Mini Rock Crawler, and the 2200mAh was a match for my HPI Sprint 2.
First, a little about A123 cells. They use Nanophosphate lithium-ion cells that put out a voltage of 3.3V per cell. This means the 2-cell packs put out a total of 6.6V. They are very safe and known for not catching fire. Because of their unique chemistry, they also put out a constant 30C rating, and can handle bursts of up to 60C. This is very impressive. Dean’s plugs came standard on these packs, and after I soldered Dean’s plugs to my speed controls, I was ready to charge and test. One of the best features about A123 cells is the ability to charge them at 4C with no loss in performance or cycle life. I hooked them up to my Hyperion 720i from MaxAmps.com and charged the 1100 pack at 4.5amps and the 2200 pack at 9amps. They both charged in less then 15 minutes and weren’t even warm to the touch. I installed them in both vehicles then started testing.
In the Losi Mini, the 1100 pack worked great. Not only did runtime increase compared to the stock pack, but I had that constant voltage during the run. The pack was much lighter then the stock NiMh pack, and this really helped lower the CG of the crawler. There were no hiccups or glitching with the slightly less voltage, the drag brakes held strong and the truck crawled with authority. This pack is a perfect match for the Losi Mini Rock Crawler.
In my Sprint 2 drifter, the A123 cells were noticeably lighter then the NiMh cells I used before, and that made it a lot easier to initiate a drift. The car felt smooth and even with the slightly less voltage of the A123 cells, the vehicle felt punchier and faster. Runtime was about equal with a regular NiMh pack, but it seemed easier to drift as the car was much lighter.
At the end of the day, all I can say is that these packs are great. They charge in record time and are extremely light. They put out a continuous 30C, so I know I won’t be stressing these batteries any time soon. There are a number of applications where I can see these batteries used, but for rock crawling and drifting, they seem to be ideal.