Managing State of Charge with the REC Active BMS

[rmarsh3309]

My REC BMS system has been in service for a month and I'm delighted at how well it is has integrated with the Victron system I installed at the same time. Another pleasant surprise was the Victron icon that popped up on my boat's B&G chartplotter when I connected the Cerbo to the boat network.

As I spend more time on the dock finishing up my other projects I'm trying to fight my predisposition to keep my batteries topped-up. 5 years of lead-acid battery experience has me wanting to "make hay while the sun shines". Lead acid banks thrive on full time full charge. LiFePO4 banks: not so much.

To keep my batteries at or below 50% SOC I've been fiddling with the end-of-charging parameter CHAR. Setting it to 3.3 on my LiFePO4 bank leads to the batteries backing down to around 50% SOC. But there is an unfortunate side effect. That same variable seems to trigger a recalibration of the SOC to 100%. This all straightens itself out when I set the CHAR variable back to a higher level, say 3.4, but it does lead to a false indication.

Before I start grabbing other levers and yanking on them, I thought I'd ask if anyone on here has developed a strategy for forcing their SOC to lower values - especially when the system is hooked to shore power for extended periods.

 

[HighTechLab]

Lithium isn't as picky as you think. Charge it up to 98% if you are worried (3.45/cell) and call it a day. Calendar aging (Them just getting old) will kill your cells long before charging them to full will.

 

[alctel]

My REC BMS system has been in service for a month and I'm delighted at how well it is has integrated with the Victron system I installed at the same time. Another pleasant surprise was the Victron icon that popped up on my boat's B&G chartplotter when I connected the Cerbo to the boat network.

As I spend more time on the dock finishing up my other projects I'm trying to fight my predisposition to keep my batteries topped-up. 5 years of lead-acid battery experience has me wanting to "make hay while the sun shines". Lead acid banks thrive on full time full charge. LiFePO4 banks: not so much.

To keep my batteries at or below 50% SOC I've been fiddling with the end-of-charging parameter CHAR. Setting it to 3.3 on my LiFePO4 bank leads to the batteries backing down to around 50% SOC. But there is an unfortunate side effect. That same variable seems to trigger a recalibration of the SOC to 100%. This all straightens itself out when I set the CHAR variable back to a higher level, say 3.4, but it does lead to a false indication.

Before I start grabbing other levers and yanking on them, I thought I'd ask if anyone on here has developed a strategy for forcing their SOC to lower values - especially when the system is hooked to shore power for extended periods.

Suuuuper late to this, but if you adjust the CHIS you can get it to hold it at a low SOC. It charges fully till it hits your CHAR, and then goes down and 'floats' at the CHAR - CHIS value. I set my CHAR at 3.5 and my CHIS at 0.25 which holds the cells ~40% SOC or so (3.25)