question

Gerrie avatar image

In an ESS system, what is the difference between Sustain voltage, Optimised and Keep batteries charged.

Good day,


I was wondering what is the actual difference between, " Keeping batteries charged and "optimized with battery life at 100% SOC"?


Also if set to either of the above what will happen to the sustain voltage?


Regards

ESS
2 |3000 characters needed characters left characters exceeded

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

1 Answer
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Hi @Gerrie

If you set to 'Keep batteries charged' - the ESS system will actively use the grid connection to charge the batteries back to 100%.

If you set to 'Optimised with battery life at 100% SOC', then (as long as the grid is connected) the system will not discharge the battery to run loads, and only recharge from the grid when SOC reaches 5% below the setting (so when reaching 95% SOC in this case.

It is not advised to use 100% SOC as setpoint, but rather to use a lower value or 'keep batteries charged'.

Both WILL discharge the battery if the grid is disconnected.

The sustain voltage is a floor voltage, so regardless of either of those settings, the battery will not discharge below that sustain voltage point. In both those above cases, the battery should not be doing much discharging anyway so the sustain voltage will not come into play.

I explain this further using some helpful motion graphics in an Introduction to ESS Online Training video course that is available here with a free registration - http://professional.victronenergy.com/online-training/


1 comment
2 |3000 characters needed characters left characters exceeded

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Thank you Guy


That makes a lot of sense, i appreciate the answer and time.


Regards