diy solar

diy solar

All-in-one 3.2KW not working on PV

OK, label matches previous numbers.

On a hot day, more current leaks back through the PV cell. But I think that affects power output more than Voc.

Have to wonder if inverter does want higher voltage, since you're near lower end of MPPT range.
Also, if there is a bad connection.

Could try boosting voltage somehow. If not a 5th PV panel, then a 12V car battery in series with panels, raising string to 152V.

Do you have an ammeter good for 10A? Cover PV panels, disconnect from inverter, connect ammeter between PV+ and PV- (that shorts out the PV string). Uncover panels and read meter. Check for any connections getting hot. With 1kW, it could get hot fast and melt a bad connection. Doing this first while sun is off-angle would reduce current and heating.
 
Could try boosting voltage somehow. If not a 5th PV panel, then a 12V car battery in series with panels, raising string to 152V.
I did not know you can do that. Is that only for testing or can it be used as a long term solution if it works? Any risk of harming the inverter etc.?
 
Just an experiment. 12V battery connected in series with 140V PV string isn't going to deliver any more current than the PV produces.
Long term it would only function until the battery was drained, in about 1 day for a car battery.

Directly connecting a high voltage battery could be a problem because it is capable of delivering unlimited current, would also have high inrush into capacitors.
A 140V battery in series with 12V PV would break down the PV.

But with low voltage battery, high voltage PV it should be no problem. So long as they are in series.

The possible outcome of the experiment is that inverter starts producing higher power indicating it does need higher input voltage.
When I first hooked up one GT inverter with short string of panels I saw a similar effect, but data sheet specs agreed with performance.

If so, your options are different inverter, additional panel fit somewhere, higher voltage panels or more smaller panels. (Basically more PV cells in series feeding the inverter, i.e. smaller size cells.)
 
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