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Craig Myatt avatar image
Craig Myatt asked

PowerAssist & ESS - is Powerassist ignored, with an ESS?

In the ESS manual, it states that when an ESS assistant is added, PowerAssist will be ignored. However, I have found it is still possible to check the Power assist box and set an assistance level. Does anyone know if Powerassist is entirely ignored, where an ESS is setup for a Multiplus? So for an on-grid Multiplus-II 5KVA, we have a transfer switch for occasional charging from a small 2KVA generator. But when that 2KVA generator is operating, the inverter output to the residence would be effectively very limited, and possibly removed in favour of AC power from the generator, would it not? Without Powerassist being set to say 3.0, which is what I wish to do. Perhaps there is another way to approach that, too?

Multiplus-IIESSpowerassist
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dennison-p-pulgarin avatar image dennison-p-pulgarin commented ·

Good morning everybody

i have a ESS that is using a Venus XG, i have a question, if i have actived the ESS on the Venus, i understand that i haven't to put the assistent ESS on the multiplus.

thanks you.

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Daniël Boekel (Victron Energy Staff) avatar image Daniël Boekel (Victron Energy Staff) ♦♦ dennison-p-pulgarin commented ·

Hi @Dennison P Pulgarin

You do need the assistant, please read the manuals:

https://www.victronenergy.com/live/ess:start

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1 Answer
boekel avatar image
boekel answered ·

Hi @Craig Myatt
I'm afraid it won't be easy to combine ESS and a small generator, is it for a site with lot's of grid-outages?

It might work if you set the input current limit low enough for the generator, and set ESS mode to 'keep batteries charged'
But...boost factor is not active due to the way ESS works, so a large load being switched on could overload the generator (ESS can take a second to ramp up).

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Craig Myatt avatar image Craig Myatt commented ·

Thanks Boekel, yes, it is really for an on-grid "backup" system, to deal with outages, although in this part of the world...they are infrequent. Actually I have setup the Multiplus-II, so that when the generator transfer switch is switched (transfer switch ON), a relay tells the multi, via the Aux-In contact, that the input current should be limited to 7A. (Used the 12V out on Aux I/O on the Multiplus-II, reduced voltage to 3.8V, then used a current limiter assistant, to limit the input current to 7A, when the Aux1-input reads above 2V, IE when transfer switch/relay is ON.)

That works, however, I think for the generator use, it may be a case of manually adjusting the "Keep batteries charged setting", but that is OK. ...unless there is a way of automatically setting that, when the transfer switch is on.

I think your solution may work, in that when "Keep batteries charged" is selected in ESS on the ColorGX, then the generator AC will recharge the batteries (as intended), and the Multi's inverter will supply other loads, up to, in this case, 4000W. If that works, they will have everything they want...for them 4000W is unlikely to be used, when there is a blackout, so should be OK. Thanks for the assistance...

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