On Thursday, February 23, 2017 at 5:44:33 PM UTC+3, wrote:
On Wednesday, February 22, 2017 at 9:20:46 PM UTC-6, Papa3 wrote:
Are LiFePo4 batteries not rated using a standard 1C discharge rate like SLA batteries? So, for a 10ah battery the rated capacity would be achieved at a discharge rate of 1a. 2.5a seems on the high side for a glider, even one with a fair number of electronic goodies. My ship draws not too much over 1a with FSG71, Trig, Clearnav, Flarm, and CNv. No?

P3

Eric, a 1C rating for charge and discharge would be 9 Amps for the batteries we are discussing. LiFePo4 will do that all day long but I doubt you would get 1,000+ cycles out of the battery. RC flight batteries are routinely sujected to 20-30C discharge rates (these are LiPo's) and they rarely make 100 cycles. They can also be aggressively charged at 3-4C. Wonder what that number would be for a Tesla battery on the quick charger. Compared to the older chemistries such as NiCd an NiMh, the new ones can sure take a beating.

Tesla's own "Supercharger" stations supply up to 120 kW (depending on the size of the car battery and it's existing charge state), and take 20 minutes to charge to 50%, 40 minutes to charge to 80%, and 75 minutes to 100%.

So the initial twenty minutes of charging is at an average of 1.5C and next 20 minutes at an average of 0.9C. So, not very extreme on the batteries.

Normal driving uses around 320 - 340 Wh/mi (200 - 210 Wh/km), so at 120 km/h a 75 kWh battery is being discharged at 0.32C, or a top end 100 kWh Tesla at 0.24C.