LifePo4 Voltage at .5C - .6C Discharge
Our two GC2's (with 100% charge) drop below 12v while under a 100a - 125a load. When they reach 50% (at 100a - 125a), voltage drops into the low 11's while under-load. What kind of under-load volt...
Forum Discussion
FWC wrote:jaycocreek wrote:
Will Prowse says you can tell the state of charge for a Lifepo4 battery,or get a good idea without a load..He is talking about the Battleborn..
Will Prowse on SOC lifepo4
He seems just to be regurgitating the stuff from Battleborn. I have no idea why people seem to think this guy is some sort of expert.
Anyway, this should highlight the issue of trying to determine SOC from voltage:
This is the voltage of several different cells at 80 and 90% SOC vs temperature. First notice the difference is at most 0.004V, and that the curves cross as a function of temperature, so depending on the battery temperature 80% SOC may actually have a higher voltage than 90% SOC. At best you may be able to tell if a battery is full or mostly flat, but not much more than that.
I dont think he is any sort of expert, he is just curious with youthfull exubrance and a little goofy. he also seems to have access to a lot of stuff to test.
but yes on a static LFP you can get a very reasonable measurment of soc from voltage in a percentage of capacity, once you put a load on it thats out the window and you need predictive coulumb counting (did I butcher that?) I have ecen seen a couple meters that claim "advanced predictive coulumb counting" havent read of to see what the difference is yet but its suposed to be even more accurate.
Steve
