jcool3 wrote:Most of the time my 3 battery packs run from 42.4V down to 38V during the course of a day. This is for my ebay 36V 500 watt rear hub motor on mountain bike. Does anyone know if running 42V on this 36V system is bad for the motor? The BMS allows these
battery packs to be charged up to 42.4V - does this shorten battery life? I'm a newbie to ebikes, would like knowledgeable members
to chime in.
A nominal 36 volt Li Ion pack will normally range from a high of 42 volts to a low of maybe 34-35 volts through the life of its charge. The 36 volts rating is supposed to be the approximate average voltage as a battery goes from "full" to "empty" even though it seems like the real average is closer to 37 volts.
This is a graph of the full discharge of one of my 36v LG packs over about four hours of time.
Charging a 10s (36v nominal voltage) Li Ion battery pack to 42.4 volts will almost surely shorten its life. I charge mine to 41 volts precisely for the purpose of extending the battery life. Some people charge to only 40.5 volts. The longer a Li Ion battery sits at higher voltages, the worse it is for the battery. Some people will charge to a level below 42 volts like I mentioned above, and will do a short charge up to 42 volts right before riding.
You might want to read this article to get a better sense of things.
http://batteryuniversity.com/learn/arti ... _batteries
"Commuter - DC Booster"
Iron Horse 3.0 hardtail - 48V / 1000W / 470rpm generic Chinese DD Hub motor (ebay)
8 x 36v 4.3ah 10s 2P battery packs - 1500W 30A DC Boost Converter delivers 54v and about 1000 watts peak
53T/42T Sakae Road cranks - 30mph+ on flats