View Single Post
  #9  
Old 19-09-2009
djmcnz djmcnz is offline
Member
 
Join Date: Jan 2007
Posts: 197
Default

Hi again.

@ bigred5765: Just time, just precious time...

----
So, I've done a quick test after running two packs down. The results below are by no means conclusive because of the sample size but it's actual data at least.

Pack 1 - New, Fully Charged, Run Down in Vehicle
Charge: 3.21/3.23v (measured with a multimeter)
Charged at: 4.2A (1C)
Time taken: 60:52
Temp @ end: Room temp (<25 degrees C)
Charge @ end: 4.20/4.20v

Pack 2 - New, Fully Charged, Run Down in Vehicle
Charge: 3.22/3.22v (mulitmeter)
Charged at: 6.3A (1.5C)
Time taken: 39:24
Temp @ end: Room temp (<25C)
Charge @ end: 4.20/4.20v

Findings:
  • LVC on the ESC works just fine
  • Balancer on the charger works just fine
  • Charging at 1.5C makes a considerable difference to charge time (-33%)
  • Charging at 1.5C has no measurable effect on cell temps
As a result I will continue to charge pack #2 at 1.5C and pack #1 at 1C to see how many cycles I can get before noticeable difference in battery charge capacity, run capacity, temps etc.

From this rather simple exercise I am happy that the risk of properly charging these packs at greater than 1C is not terminal or particularly dangerous. Indeed with no appreciable temp differences between the two methods it would actually be incorrect to claim these cells have a 1C safe charging limit.
__________________
Dave
TRF511 w/upgrade kit | LRP Flow Works | LRP X20 6.5
Reply With Quote