Hello I wonder how you have set your SOC.
I use an ESS and wonder how much battery charge I should leave for emergencies.
How do you handle it?
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The default value seems to be 10% for ESS. I used the voltage settings recommended by victron for the pylontech batteries, and tested how much was between 10 and 5% to see if it was worth pushing the voltage of the batteries down. There seems to be <0.5kWh in it so left mine at 10%. At 10% the lowest cell voltage was 3.14V and at 5% 3.08V, but each system may be different so maybe test yours to make a decision.
The reason why there isn't much capacity at the high/low ends of the voltage is illustrated on the graph below. This is for EVE 304h LFP cells and may vary a bit between LFT batteries but gives an idea.
It all depends. How often are your outages and for how long, how much power do you need to consume?
How big are your packs and how quickly can you charge your batteries from solar, what if the weather is bad?
It's all down to your setup, environment and requirements.
In my own system It will be left at 30%, that's plenty of juice in the tank for most scenarios and offers a good battery life. When the grid falls apart and the weather is poor, I raise it.
Same as @nickdb 30% not taxing the bat too much.
Alternatively overnight usage +/- seasonal adjustment - so no surprises when waking up.
ESS design and installation manual
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