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isolar avatar image
isolar asked

Gridpower to help power the loads if the inverter starts to go into overload

I have a three phase setup (3) MultiPlus 48/5000/70-100 running 380V Ac three phase /the system is currently running offgrid and when the batteries drain to 46V it switches back to the grid and power the loads , i don't use the charging function on the multis as i want to keep the system as offgrid as possible , also have panels installed with mppt that charges the batteries . my problem is that i have a guillotine but when i switch it on it starts but as soon as it fully running it my inverters go in to overload , it draws too much current . Is there any way to let the Grid power assist the loads when the inverters go in to overload ? and how do i program it , basically just takes the required power from the grid if solar or battery / inverter power ,is not sufficient ? ,



3 phase
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shaneyake avatar image shaneyake commented ·
Is there a reason you don't want to be grid connected? You can be grid connected always but only use the power coming from the inverter. This is much better for the system as it isn't great to constantly connect and disconnect.
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JohnC avatar image
JohnC answered ·

Hi @ISolar

It's not possible to 'top off' with grid, but you could bring the grid on similarly to what you do already with V. Except use Load to trigger it.

Perhaps you already have an Assistant to do this, maybe even add another condition.. https://www.victronenergy.com/live/assistants:ignore_ac_input_using_the_generator_assistant

(Don't look at the Hz-fiddle part of the example)

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isolar avatar image isolar commented ·

Hi thanks for taking the time to answer my question, I have not assistant running at the moment I'll try to setup it like you mentioned and will keep you updated thanks again

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isolar avatar image isolar isolar commented ·

Good day John , i have done like you explained, but there is one problem now , the system keeps drawing current from the grid now , it does not stop drawing current when there is enough battery power to supply the loads , it on bypass , any ideas on how to change this ? thanks again for your help

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JohnC avatar image JohnC ♦ isolar commented ·

@ISolar

You may need another Assistant to turn it off, you can invoke more than one of the same type. But that example seemed to include that.

Can you provide a screen snip of the Summary of the Assistant. That might help diagnose.

Using these things is a bit of an acquired skill, and mine is very limited too. General stuff.. https://www.victronenergy.com/live/assistants:start

Don't let it beat ya.. :)

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isolar avatar image isolar commented ·

Here just so show the setup

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isolar avatar image
isolar answered ·

ok i have the pictures to show , Sorry but it you are right the system does not connect to the grid when the batteries are low just finished installing the unit 2 days ago thought my programming would do it but just tested it voltage drop , but no grid feed so that also have to be programed , sorry for my poor English its kind of second language

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JohnC avatar image JohnC ♦ commented ·

@ISolar

Ok, you're close. What you've missed is to use General Flag rather than the Primary Programmable Relay..

1637372719639.png

You have the General Flag Assistant set ok.

And you may need to change the polarity..

1637373269759.png

This is hard to explain, but General Flag is set to Ignore AC when 'closed', but you want ac to be On under the required conditions. (I hope I haven't fouled up here.)

Keep trying, you'll get there..


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isolar avatar image isolar JohnC ♦ commented ·

Hi John done like you said and the system works perfectly , thank you so much for your time and patience and for helping me with this , you are a real expert thanks again for everything ,

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isolar avatar image isolar isolar commented ·
Hi John sorry to bother again . It works great , but today was raining and the battery voltage dropped to cutoff but funny thing is the grid did not kick in to charge the batteries. Can you help or suggest a plan ?
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JohnC avatar image JohnC ♦ isolar commented ·
@ISolar

Post the Summary again, can't diagnose without info. What did you use before for the low V?, and is it still there?

If critical, delete the Assistant and put it back later.

Past my bedtime, so if anyone else can help, please do.

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basil katakuzinos avatar image
basil katakuzinos answered ·

Use ESS and set it up corectly. Grid should always be connected when available even if you opt to not use the grid power, this will do exactly what you want as your inverters have a transfer capacity of 70 Amps

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basil katakuzinos avatar image basil katakuzinos commented ·
Set your minimum SOC to whatever you want your battery to go down to, system will use solar and battery first and then when battery is flat it will use grid. By having the grid connected all the time you can start up larger motors without worry and if you pull alittle over the limit it is fine as grid will supliment what the inverter can not
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basil katakuzinos avatar image basil katakuzinos commented ·
This is more ideal, as connecting to the grid can take up to a minute.
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