Solar charging quandry

[j24jam]

I've had a solar system up and working for circa 18 months.

Went to the boat this morning and the PV panels were not putting any power into the batteries.

The batteries were low due to it being unplugged from shore power overnight and the fridge left on.

On the PV controller screen it was showing a PV voltage of 10.8V and Battery Voltage of 11.8V.

In the user manual for the system it states that if PV Voltage < Battery Voltage then it wont charge the battery.

So... why would the PV voltage be so low? (PV panel is clean, full sunshine today)

If it makes any difference its a 85W semi flex PV panel and photonics universe branded MPPT charge controller.

 

[pcatterall]

PV voltage seems very low. Have you had the 'proper' voltage out of them previously? (14+volts)? Is your PV check on volts before the MPPT ( which could be at fault)?

 

[j24jam]

Previously the panel has been able to provide enough power to keep up with the fridge onboard, so can only assume a yes to that question. I vaguely remember 20+ Volts from it, but I may be making that up!

We've got a victron smart shunt so I quite often monitor it while we are at anchor and its always been ok.

I've been searching for any photos to prove that but cannot find any.

The PV voltage check is displayed on the MPPT screen - I've not checked directly with multimeter.

 

[j24jam]

 

[Minerva]

Check your connections - but your panel there is producing heehaw.

If connections are all good, looks like your PV panel has died for whatever reason

 

[j24jam]

Thanks, will do that next week

 

[wrr]

If your connections are ok it might be worth checking if you have a small circuit board in the connector box with bypass diodes. This allows charging when the panel is partly shaded. If there is 17v or so on the panel side and less on the connectors after the diodes, then the diodes have failed. A replacement circuit board with diodes should be available from Marlec , among others.

 

[William_H]

As said get your volt meter right up to panel check for voltage there. If you have good voltage there 17 to 20v then it is a diode or wiring problem. If not then panel is kaput. You can often see damage through the glass if an area of panel is discoloured. ol'will

 

[j24jam]

If your connections are ok it might be worth checking if you have a small circuit board in the connector box with bypass diodes. This allows charging when the panel is partly shaded. If there is 17v or so on the panel side and less on the connectors after the diodes, then the diodes have failed. A replacement circuit board with diodes should be available from Marlec , among others.

By the connector box, do you mean the small box on the pv panel itself, or where the cables enter the MPPT?

 

[wrr]

It depends on the individual model. As William_H said, if you can open the box on the solar panel, test the voltage at the leads from the pv cells. There should be more than 17v in sunlight. If there is a small circuit board there, test the voltage after this, it should be the same. If the voltage directly from the panel is less than 17v, the panel is dead. If the panel cells are 17v or more and there is a circuit board with diodes, if the voltage after this circuit board is less than 17v in sunlight, then the problem is with the diodes. If there is 17v incoming at your MPPT, then the problem is with the MPPT or the connectors downstream of this. Hopefully, you can find a fault that is cheaper to rectify than the cost of a new panel.

 

[j24jam]

To round this thread off, having been sent instructions on how to further test the panel by the supplier (Also the same as described above) its confirmed the panel is dead.

Same voltage at the panel circuit as down at the MPPT (circa 10.9V). No obvious damage to the panel.

Luckily for me, the manufacturer has retrospectively increased its warranty from 1 year to 2 years, and the panel was purchased in July 21, so fortunately it's a warranty replacement heading my way. (Still have to cover the removal / fit of the new panel but thats better than paying for a new panel too!)

 

[Minerva]

To round this thread off, having been sent instructions on how to further test the panel by the supplier (Also the same as described above) its confirmed the panel is dead.

Same voltage at the panel circuit as down at the MPPT (circa 10.9V). No obvious damage to the panel.

Luckily for me, the manufacturer has retrospectively increased its warranty from 1 year to 2 years, and the panel was purchased in July 21, so fortunately it's a warranty replacement heading my way. (Still have to cover the removal / fit of the new panel but thats better than paying for a new panel too!)

Can’t say much fairer than that! Result!