I have a bank of 3-48 volt LFP batteries (11kw each) that I bought direct from a distributor in China at a fraction of the cost retail ($2k each including customs/shipping).
My problem is with the specs they gave me of 44v-54v.
The initial states of charge when I received them were between 48.2 and 48.8 volts.
When I charged them up, the voltage increase started stalling significantly at around 49.7 volts, and very very slowly worked up to around 51.1 volts and stalled there.
The batteries have inetgral BMS, so I'm thinking that the BMS started curtailing the charge at around 49.7 vols, indicating that I may be around 85% full there.
Conversely, the batteries cut out at around 44.5 volts, which the BMS may have curtailed at around 15%.
I ran the batteries through 2 succesive chage/discharge cycles, so this would seem indicative of a 5.2 volt spread between say 15% and 85% charge.
I also believe it to be a reasonable assumption from the info I've gleaned on the internet for other LFP batteries.
Is there any other means to derive a reasonable estimate of state of charge for these LFP's?
My problem is with the specs they gave me of 44v-54v.
The initial states of charge when I received them were between 48.2 and 48.8 volts.
When I charged them up, the voltage increase started stalling significantly at around 49.7 volts, and very very slowly worked up to around 51.1 volts and stalled there.
The batteries have inetgral BMS, so I'm thinking that the BMS started curtailing the charge at around 49.7 vols, indicating that I may be around 85% full there.
Conversely, the batteries cut out at around 44.5 volts, which the BMS may have curtailed at around 15%.
I ran the batteries through 2 succesive chage/discharge cycles, so this would seem indicative of a 5.2 volt spread between say 15% and 85% charge.
I also believe it to be a reasonable assumption from the info I've gleaned on the internet for other LFP batteries.
Is there any other means to derive a reasonable estimate of state of charge for these LFP's?
