Controlling Pylontech charge rate and target SOC for Sunny Island overnight charging

[Andy]

I'd likely do both.

I'd calculate an average current required over the time of the cheap rate and also change the soc of charge sent to the inverter so it definitely stops the charge at the required SOC. ( Thinking though, you could actually do that in the control mechanism to set the charge rate at zero, so no need to alter what the inverter sees.)

Yep. That’s what I do. Charge the batteries at low a rate as possible to reduce the wear and increase charger efficiency. The default victron programs charge as fast as possible from the start of the window. Every 4 cycles(400%) usage I will charge to 100% if solar hasn’t taken it there but aim to get there early so that the balancing can run for a while.

[Tinbum]

Just one thing regarding Pylontech batteries when using SOC. They always hang at 89% for some time. That's partly why I always recalculate the current every half hour.

[jonc_uk]

Ah yes, I see that. Last night, from slowing at 88% to passing 89% took 43 minutes at 17.5kW charge rate.

Having said that, it looks pretty straight line up to 100%, with only a small tapering of charge current in the last 15 minutes.



I will be reducing the max voltage anyway.