I would like to buy some Lithium batteries for our boat, probably going with 2 x 330Ah NG Lithiums. Might be 12 months or so before they are installed, and the local supplier receives them in 50% SoC - just wondering should they be kept in this SoC while awaiting install?
Whats the self life like at the best SoC?
The datasheet says at most 3% SOC loss to self consumption per month at 25degC.
Probable best to charge to circa 70% and check after 6 months and top up if required. Without a BMS connected the SOC will be hard to measure.
Right so keep at 70%, probably top up every 3 months?
Not necessarily keep at 70, it is just that if they get to you at 45% they will not last 12 months with a good SOC, so boosting them to 70% to start with gives you the headroom for 12 months. My NGs turned up at the start of 2025, were installed end March and were at about 40%, so lost about 10% in 3-4 months from production.