LFP battery absorption and float - report
Bought this 120AH LiFePO4 a while ago https://www.lynaclithium.com/wp-content/uploads/2022/03/12.8V-100Ah-True-Series-Quick-Sheet-USA.pdf. 120AH marketed as 100AH. Don't see this now but on the old...
Forum Discussion
Don, input for Victron was 60V from 490E solar.
Also the controversial Float matter with LFP. It might not be strictly necessary but in camping there is always discharging going on, at least 1A standby current of fridge, radio, LP detector. I consider Float a continuous (in daytime) charging of battery that is being discharged continuously and thus is never really full. By setting Float to 13.5 I am getting 1 or 2 amps above the standby current in daytime only, ensuring SOC close to upper 90s by the evening.
3 tons - yes, the harvest was less than daily draw, because with zero Float current the controller stops charging shortly after the Bulk is reached. I set it up this way according to the LFP manufacturer recommendations - zero or short Absorb time, zero Float current. This is not a controller defect. Just wanted to note that contrary to the manufacturer's promise this LFP was not getting fully charged just by reaching Bulk 14.2V (my mistake, it was 14.2 not 14.4). Not even close to full. After reaching Bulk it was drawing same 8A for almost 2 hours when I set Absorb time to longer.
Again, Victron factory pre-set for their "Victron Smart LFP" is 2 hours Absorb time and 13.5 Float so I can't blame my particular LFP either. Makes me wonder about the popular mantra "no Absorb time, no Float".
Also the controversial Float matter with LFP. It might not be strictly necessary but in camping there is always discharging going on, at least 1A standby current of fridge, radio, LP detector. I consider Float a continuous (in daytime) charging of battery that is being discharged continuously and thus is never really full. By setting Float to 13.5 I am getting 1 or 2 amps above the standby current in daytime only, ensuring SOC close to upper 90s by the evening.
3 tons - yes, the harvest was less than daily draw, because with zero Float current the controller stops charging shortly after the Bulk is reached. I set it up this way according to the LFP manufacturer recommendations - zero or short Absorb time, zero Float current. This is not a controller defect. Just wanted to note that contrary to the manufacturer's promise this LFP was not getting fully charged just by reaching Bulk 14.2V (my mistake, it was 14.2 not 14.4). Not even close to full. After reaching Bulk it was drawing same 8A for almost 2 hours when I set Absorb time to longer.
Again, Victron factory pre-set for their "Victron Smart LFP" is 2 hours Absorb time and 13.5 Float so I can't blame my particular LFP either. Makes me wonder about the popular mantra "no Absorb time, no Float".
