Paul B avatar image
Paul B asked

Multiplus II Not reconecting to grid

Just wondering if this is s design feature or a problem

MP II 48/5000 230v

FW 459

ESS used VE BMS frequancy shift used for solar on/off 50.5 52.5 54 hz

with general flag set to ignor AC in

Venus GX 2.30

VE BMS used to control HV and or LV disconnect of the MP II

autostart turned on manually to have grid connected or disconected using relay assistants on AUX 1

AC sensor for Solar using assistant on Aux 2 - 5kw inverter and 4.5kw solar

Now it the HV error is triggered and the red LED is on on the VE BMS

and the grid then is disconnected by general flag and or a power failure

then it the grid will not reconnect again until the HV disconnect has been cleared, then it reconnects straight away

at the same time as the disconnect the Hz also raise and stay there at the high Hz value set with the Solar connection using frequency shift to disconnect

if you turn the MP II off and back on then it reconnects

if you turn the mains off again it disconnects

turn it on it wont reconnect (IF HV error is present)

Also as a side issue I am still haing HV issues when the Batteries are full a 1.5 amps is always being added to the batteries and its ESS related and I cant find a way to stop that I had a 58 volt event last night as well. just mentioned in case.its related in that area

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1 Answer
boekel avatar image
boekel answered ·

The problem is: it takes a while to get back to 50Hz, and the PV inverters will start producing power again, this power has to go somewhere (the batteries) but the batteries are in error.

The solution: set a safe charge voltage so the BMS does not have to give a HV error.
(i know you're having problems with a system that creeps up in voltage, but that is another issue)

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Paul B avatar image Paul B commented ·

your interpritation of what I have writen is not correct or not how I thought I had explained it, but I did not mention, night time and NO PV AROUND

ITS NIGHT TIME and no PV this still happens by charging from the grid power

we can exclude PV 100% but not the ESS there is something there

1. even if I leave the MP II for 4 hrsit does not reconect to the mains

2. anyway its seems that if the HV is triggered by the BMS

3. if you turn the grid off it wont reconect EVER

4. if there is a grid power outage and then the grid comes back it still wont reconect ever

5. however as soon as I remove the HV BMS error it reconects straight away. (even iff the voltage is still high

6. the BMS HV error last night was not from the SOLAR it was from Grid power

Re the high voltage

I agree with the safe voltage idea and I have done that.

But that does not stop the HV error as it seems the voltage is ignored and a 1.5 amps or there abouts just keeps on being pumped in regardless of the voltage.

even when HV does go off it still keeps pumping in the 1.5 amps and the voltage just goes higher.

Its managable by not allowing the batteries to go over 90%

the thing to do in the longer term is to isolate the cause so that victron can fix it, or if its my end I can fix it.

I think the one above has been isolated on my system anyway.

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