Thursday, December 31, 2009

The results are in!

I was able to finish testing my batteries last night and here are the results listed as Battery, IR, Run time, Average Discharge Voltage; from best to worst:

SMC 5200mah 50C #1, 5.1, 598 sec, 7.71V
SMC 5200mah 50C #2, 5.1, 597 sec, 7.71V
Reedy 5000mah 35C #2, 7.3, 483 sec, 7.70V
Reedy 5000mah 35C #1, 7.9, 445 sec, 7.68V
Orion 3800mah 30C #2, 12.5, 173 sec, 7.63V
Orion 3800mah 30C #1, 13.0, 160 sec, 7.62V
SMC 4700mah 40C #1, 15.3, 166 sec, 7.60V
SMC 4700mah 40C #2, 15.3, 170 sec, 7.58V

My 4700 40C SMC's are my next newest packs, having bought them in May at the re-run of the JBRL round at Hot Rod's, but they been the worst performers the last few times I've tested them. I think this was due to the fact I've been storing them around 8V, which I think might have killed the capacity and voltage. I've also noticed the same thing occurring with the LiPo batteries I use for my helicopters. I used to store them fully charged for months at a time, and they have lost a bunch of capacity and voltage. Thus, I have begun storing all my packs at their nominal voltage, 7.4V for a 2cell and 11.1V for a 3cell, which stores them at about 20% capacity left in the battery. This was confirmed to be a good starting point, since my new SMC 50C packs were at about this voltage (~7.5-7.6V) when I pulled them out of the package. SMC recommends storing the packs at 6.6V, to maintain their capacity and voltage, but I'm a bit weary of that, as most other theories say to store them at 20% capacity. How do you store your LiPo packs?

Also, I really like my Reedy 5000mah 35C packs! They're over a year old and are producing numbers similar to my brand new SMC 5200mah 50C packs.

Have a Happy New Year!

1 comment:

Kevin Deselms said...

Happy new year, Rod! Man, the batteries just keep getting bigger and badder. My old Reedy 20c LiPo packs don't look so hot, anymore. I got some of the good SMC's (at the time) for my monster truck, but I might have to get a couple of the new SMC's for my SC10 too, and lose the Reedy's.

I have been eyeballing that 4x4 Slash though, I have to be honest...