Solar inverter over voltage reports.

Victor_RH18

I’ve recently had a 14 panel, SOFAR inverter plus battery storage installed at my house. Although all seemed to work ok at the start the battery is not charging up now. Installer says it’s due to my house input voltage being too high and the inverter not charging it due to safety issues. I’ve had the input voltage checked by an electrician and it is 250/251V. UK Power tell me their operating range is 216-253V so nothing they can do.
Has anybody else experienced similar issues? Unless voltage drops my battery will be out of use.

QrizB

Hi @Victor_RH18.

Is your inverter a hybrid, or do you have separate inverters for PV and battery?

1961Nick

Victor_RH18 said:

I’ve recently had a 14 panel, SOFAR inverter plus battery storage installed at my house. Although all seemed to work ok at the start the battery is not charging up now. Installer says it’s due to my house input voltage being too high and the inverter not charging it due to safety issues. I’ve had the input voltage checked by an electrician and it is 250/251V. UK Power tell me their operating range is 216-253V so nothing they can do.
Has anybody else experienced similar issues? Unless voltage drops my battery will be out of use.

You could really do with more voltage readings from you supply or monitoring over a longer period. It's likely that your supply is exceeding 253v periodically & that's causing the tripping. The inverter should reset once the voltage drops back within range?

If not, send an email to Sofar explaining the problem & ask for some help. They may give you the passcode to get into the safety parameter settings so that you see what the maximum voltage is set to & possibly tweak it up a bit - these inverters will run upto 270v so there's plenty of headroom. 

[Deleted User]

According to my installer, the PW2 Gateway will take the home off the grid if the voltage exceeds 253 + 1%. Having had a series of Gateway disconnects, my installer appears to be right. The home remains off grid for 5 minutes whilst the Gateway monitors voltage; frequency etc.

Thirty minute voltage information can be pulled from a smart meter by a DNO.

Victor_RH18

Thanks to you all above, the equipment installed is shown below but unfortunately I am not very educated about solar panels etc!

Sofar 3000 A/C Charge    Solar Edge Inverter    Ja Solar 385 BLACK Panels

i understand the unit may cutout for whatever reason but expected it to reset to normal. System installed just three months ago. I’m trying to get installation company to sort but they are dragging their feet about this.
Your posts above give me hope that this can be sorted out soon.

QrizB

Victor_RH18 said:

Thanks to you all above, the equipment installed is shown below but unfortunately I am not very educated about solar panels etc!

Sofar 3000 A/C Charge    Solar Edge Inverter    Ja Solar 385 BLACK Panels

i understand the unit may cutout for whatever reason but expected it to reset to normal. System installed just three months ago. I’m trying to get installation company to sort but they are dragging their feet about this.
Your posts above give me hope that this can be sorted out soon.

OK, so you've got a rooftop PV system with a SolarEdge inverter and a separate standalone AC-coupled Sofar battery inverter.

Here's wht might be happening (it would take a bit of investigation to confirm this).

• The grid voltage at your house would normally be a little lower than at the substation that feeds it, due to transmoission losses.
• Before your solar installation, the grid voltage at your electricity meter was within the permitted range of 230V +10%/-6% (ie. 216.2V to 253V)
• Now, post-solar install, when the sun shines on your solar panels and the SolarEdge inverter kicks in, you're no longer a consumer; you're a generator. The transmission losses between you and the substation are reversed; your house needs to be at a slightly higher voltage than the substation is.
• If the voltage at your house exceeds the G98 voltage limits (230V +14%, ie. 262.2V) your inverters will cut out. It sounds as though your Sofar battery inverter is slightly more sensititive to this than your SolarEdge PV inverter is, with the result being that the SolarEdge keeps generating to a higher voltage than the Sofar is happy with.

Do either of your inverters have the ability to report line voltage, either instantaneously or (better) logged through the day? This will let you confirm (or refute) these thoughts.

Can you also check the Sofar "System Information" screen and confirm that it's set to UK G98 mode, not one of the other European or international standards?

I’ve had the input voltage checked by an electrician and it is 250/251V. UK Power tell me their operating range is 216-253V so nothing they can do.

Did the electrician check these voltages under bright sunshine, at a time when the Sofar was tripping out? And did they check at your consumer unit *and* at your inverters?

Victor_RH18 said:

Installer says it’s due to my house input voltage being too high and the inverter not charging it due to safety issues.

Or it could be that the installer needs to do a proper check of your wiring and see if there are some poorly-made electrical connections in the AC system. This would be the first place I'd look, since shoddy AC installation work can result in higher contact resistance and that in turn would result in the voltage rising.

Only if you're confident the problem is outside your domestic installation should you then go and ask your DNO to log voltages and adjust their substation settings.

Victor_RH18

Many thanks OrizB for your time on this. Many things to take into account.
From what you say re generation surely this would be zero at night time so would expect ‘warning’ on app readout and alarm light on inverter to switch off at this time?
I’m hoping installation company will get more involved in checking inverter input information i.e. G98 for the UK etc.
Also interesting to hear from 1961 Nick that these inverters should operate normally up to 270v.

QrizB

Victor_RH18 said:

From what you say re generation surely this would be zero at night time so would expect ‘warning’ on app readout and alarm light on inverter to switch off at this time?

Yes, I would. You should also be able to cancel it by switching off the SolarEdge inverter (there will be a prominent AC isolator for this purpose).

I’m hoping installation company will get more involved in checking inverter input information i.e. G98 for the UK etc.

Your installer, if they're in any way competent, should be able to give you a much more detialed diagnosis than I have. I would expect them to come over with calibrated instruments and work out exactly what is wrong - noting, as before, that the grid is permitted to be at 253V and their system should work as intended under those conditions.

1961Nick

Victor_RH18 said:

Many thanks OrizB for your time on this. Many things to take into account.
From what you say re generation surely this would be zero at night time so would expect ‘warning’ on app readout and alarm light on inverter to switch off at this time?
I’m hoping installation company will get more involved in checking inverter input information i.e. G98 for the UK etc.
Also interesting to hear from 1961 Nick that these inverters should operate normally up to 270v.

It won’t be set to 270v for G98 in the UK by default. That’s the absolute limit in settings for the ME3000SP. 

If You can persuade Sofar to give you the PIN, you could have a look & see what the setting is on your inverter. The other way is to download the data into a spreadsheet & have a look at what voltage it tripped at.

QrizB

I've just had a look at one of my inverters (the easy one to get to!) and with the panels in full sun it was seeing 258V *at the inverter*. The voltage at the consumer unit will be a bit lower but I don't fancy poking it with my multimeter on a whim!

Edit: sorry for the terrible photo. My Sofar ME3000SP shows the country setting on page 2 of "System Information". G98 and 99 are, in practice, equivalent.