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Settings for Li-Ion batteries


JRW
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Hi can someone advise me of the settings needed to get the voltage settings for 2 x 2.4 Pylontek batteries to discharge to 20% and load to 90%.

I have;  12 = 48V,   13 = 51V,   26 =53.2V,   27 = 51V,   29 = 46V, 

Could I drop 13 to get back on batteries sooner as the sun charges up?

Thanks

            

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1 hour ago, JRW said:

I have;  12 = 48V,   13 = 51V,   26 =53.2V,   27 = 51V,   29 = 46V, 

I assume that these are for an Axpert inverter of some sort, not using a BMS cable. Pylontech batteries are 15S LFP.

53.2 V is 3.55 VPC; that's a lot more than 90% SOC. I'd use 51.8 V. You could float at 50.3 V.

To have the inverter automatically cut off at about 20% SOC, you'd want setting 29 at 48 V. Unfortunately with unpatched firmware, that makes setting 12 effectively 50 V, which means your inverter will switch to utility powering the loads at about 90% SOC, because of the problem in FAQ #2. With an LFP flavour of patched firmware, the effective back to utility setting is 0.5 V above the cut-off voltage, or 48.5 V, or about 24% SOC (assuming light discharging). These inverters are not designed for frequent load shedding. If your inverter has a 145 V max solar charge controller, then you could run patched firmware; see what can I update firmware to.

1 hour ago, JRW said:

Could I drop 13 to get back on batteries sooner as the sun charges up?

Yes, though you'll get a solar charge controller reset, meaning that the solar charging will stop for ~30 seconds, stay at 1 A for ~15 seconds, then ramp back up over another 30 seconds. If you want to get back to battery sooner, you could put setting 13 2 V higher than setting 12 permanently. I would not put the two settings any closer, or you could be switching to and from utility and battery modes every several minutes.

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