Been away for a few days, got back today expecting to see plenty of export from our gen.2 hybrid inverter, given no one was home and it's been a glorious, sunny week all week here.
But no, first couple of days solar production was as expected but then Wednesday through Friday solar production was below 2kWh?! (Typically 15-25kWh on a sunny day) It's picked up again today, but still lower than I'd expect.
Anyone any ideas? I've been trying to make sense of the inverter data for those days, on the PV tab there's voltage but no amps, hence no watts - is this an inverter issue?
K
#2killythebid
Potentially, not the inverter itself but the MPPT side of the Hybrid unit. There are other explanations other than a fault.
It will be worth looking at what the grid voltage was when you see voltage but no generation from the panels. If the grid voltage exceeds 253V or so, the Inv/MPPT will cut off generation, preventing it from increasing the grid voltage any further.
If that was the case, and you see this regularly, you can call the DNO in your area, and they will fix it. I had this issue, and our DNO fixed it reasonably quickly.
When the panels get overheated, they are less efficient, so you can see a reduction in output in full sun and on a very hot day. However, this will not reduce generation to zero or anywhere near in the UK. I think it would take panel temps of around 90 deg cent to stop the panels.
R
#3Rubikcube
Could be high grid voltage at a guess.
If you have (or can borrow) an Android device this app may help you see what is going on
killythebid thanks for the reply, never occurred to me to look at the grid, for the times when production was 0 the grid voltage was 257-258 throughout the day, high enough to trigger a cut off?
K
#5killythebid
Arron Yup anything above 253v which is the high limit the grid voltage range is supposed to be. It is the responsibility of the DNO to keep the grid voltage between 216v and 253 with an average of 235v.
You can contact your DNO and get them to monitor your supply then if it shows you are experiencing above the limit voltages they have a duty to rectify that. If they won't or can't (I would press them to conform to their obligations) the other possibility is to put a voltage limiting device on your house supply but this will cost you if you can't get the DNO to pay for a solution.
We went through this process but we had no trouble from our DNO (Scottish Power) and it was remedied fairly quickly. If your DNO steps the transformer you are connected to down you may experience lower voltages in the winter but I doubt it will be noticeable. In the winter since they made the adjustment we do not go beyond 245v or drop lower than 220v which is fine.
If you do not know who your DNO is you can find out in the link below.
killythebid thanks for the advice, I'll get on that with the DNO today, see what get say.
K
#7killythebid
Arron great! Please post when you have a solution or indeed steps along the way. It is useful for others doing searches of the forum about the same or similar issues.
A
#8Arron
So, DNO got in touch and monitored the voltage last week, they've confirmed that there's a fault on the local Extra High Voltage (EHV) network and they'd 'adjusted' our supply while the work is being done and this was the cause of the voltage issues.
Got an email today saying they'd further adjusted our supply and brought the voltage down, which my grid logs do seem to agree with and they've asked us to keep an eye on it and let them know if problems persist.
Interestingly, our neighbour was getting a voltage fault on his zappi charger and hasn't been able to charge his car, we'll see if that clears up as well.
G
#9geoffreycoan
Arron thanks for the reply, never occurred to me to look at the grid, for the times when production was 0 the grid voltage was 257-258 throughout the day, high enough to trigger a cut off?
you've got your answer already, but to answer your question above, if I'm exporting loads then my grid voltage can get pushed up and once it goes above 258V the inverter will stop generating. In my case grid voltage drops, then a few seconds later the inverter starts again and if the voltage is too high again it shuts down once more..
Part of my strategy to minimise this is to trickle charge the batteries during the day, this reduces grid export and stops most of the 'grid clipping'
If your voltage was consistently high it will stop the inverter from working and stop EV chargers working. The GivEnergy EV charger seems especially sensitive to high grid voltage, several people have reported similar issues here
K
#10killythebid
Arron As long as the grid voltage is below the max permitted, the Zappi will start charging correctly. All EV chargers must have upper voltage protection (by regulations) and will shut down when the voltage exceeds 253V.
