PV over voltage

[ian.blackshaw]

Hi
I am new to Solar, and have taken the plunge to fit an off grid solar system to my house. (3kw Hybrid inverter, 2700w pv. 24v Lifep04 100ah battery. supplying max 12a load circuit. )0.5 - 1.5a base load with occasional heating and motor loads from dishwasher, washing machine etc. ( one high load unit active only)
In general all seems to be well other than:-
I seem to have an issue relatively frequently where according to the monitoring software (Smart ESS) the PV input Voltage goes OVER VOLTAGE and de-energises the screen PV "ON" status.
When I visit the Inverter the PV input seems to be ok, also The battery BMS shows Battery charge from PV source.
I don't know if I am getting a physical voltage excess blip from the panels which is correcting itself before I can check it or something else.
Any ideas would be welcome
Thanks

 

[summit]

Since it's cool/cold now, your panels may be indeed running at higher voltage. Check your panels' spec for temperature coefficient. Are the over-volt events usually in the early morning hours ?

 

[TomC4306]

You need some way to monitor constantly. Not just when you visit the inverter and look at the display and try and catch a blip in the voltage readout.

 

[Mattb4]

Would you give your panels Voc and how you have them connected? Also need the specs for the hybrid inverter.

 

[740GLE]

Would you give your panels Voc and how you have them connected? Also need the specs for the hybrid inverter.

agreed, the SCC of the hybrid inverter has a VOC limit.


How do you have the panels connected, 4S2P? It might be a simple fix to make it 3S2P (yeah you lose two panels but way better than blowing the SCC)

 

[ian.blackshaw]

agreed, the SCC of the hybrid inverter has a VOC limit.


How do you have the panels connected, 4S2P? It might be a simple fix to make it 3S2P (yeah you lose two panels but way better than blowing the SCC)

The panels are 49.5 voc , 41.75 @normal running voltage. The inverter is spec,d to pv array 90 -430vdc mppt voltage range, with nominal pv voltage of 240v. 13.89 Isc, 12.94 Imp. fuse rated at 25a, but 20a trip fitted The panels are connected in series on 6mm cable.. 5 off panels =248v total VOC
Don't know what SCC, 4S2P OR 3S2P is?

 

[ian.blackshaw]

Since it's cool/cold now, your panels may be indeed running at higher voltage. Check your panels' spec for temperature coefficient. Are the over-volt events usually in the early morning hours ?

The inverter shows approx max pv 240vdc. I cannot check spikes. yes the event seem to occur first thing in the morning.

 

[ian.blackshaw]

You need some way to monitor constantly. Not just when you visit the inverter and look at the display and try and catch a blip in the voltage readout.

The inverter software does graph pv voltage and kw;s generated but the time frame looks to be 5 min intervals.. I cannot measure in real time.

 

[summit]

sounding like you have 5 PV in series (~50voc x 5 ~= 250vdc); and 240vdc is well below the inverter 450vdc PV max. The problem may be in the inverter, possibly just the display. Other than the error status display, does it work as expected autonomously ?

 

[timselectric]

Not enough information to

Don't know what SCC, 4S2P OR 3S2P is?

SCC is Solar Charge Controller
4s2p is 2 parallel strings of 4 panels in series.
3s2p is 2 parallel strings of 3 panels in series.

 

[ian.blackshaw]

sounding like you have 5 PV in series (~50voc x 5 ~= 250vdc); and 240vdc is well below the inverter 450vdc PV max. The problem may be in the inverter, possibly just the display. Other than the error status display, does it work as expected autonomously ?

Yes i don't seem to be having any physical issues, so it could just be a gliche in the software. I am only a little concerned as it is new DIY installation.

 

[ian.blackshaw]

Not enough information to

SCC is Solar Charge Controller
4s2p is 2 parallel strings of 4 panels in series.
3s2p is 2 parallel strings of 3 panels in series.

Thanks