Zimbo

Out of interest I changed my inverter setting from UPS to APL (for appliance) and it no longer freezes

Yes. My inverter's charge controller is designed for an operating voltage of 30-80 v DC and a maximum Voc of 102V. Interestingly my inverter's MPPT charge controller maximum current is given as 40 amps which to me means up to 6 panels if wired as three pairs of two in series then the three pairs paralleled. That is about 320 x 6 = 1.9kWp but the rated capacity is only 1kW (more or less the power of three 320Wp panels in parallel). Maybe they are playing it safe or the cooling system can only cope with 1 kw. I plan to play it safe and stick to using no more than the "two pieces in serial and 2 sets in parallel". Because our roof does not face due north and the slope of our roof is not optimal that should give a maximum of around 1kW

...I am referring to a 72 cell panel in series with a 60 cell panel from the same manufacturer. Yes, to connect a 72 cell panel in parallel with a 60 cell panel is unlikely to make sense because of the voltage difference between them

Thanks Vassen The panels in question are a Jinko "Eagle" with 60 cells (6 x 10), 275Wp poly crystalline panel with Imp = 8.61 Amps in series with a Jinko "Eagle" with 72cells (6x12), 330Wp poly crystalline panels Imp = 8.66 Amps. Yes the Imp of each are close and I would expect the combination to have an Imp around 8.61 Amps. Both are poly crystalline but the larger one needs more cells to yield the power. That makes it a bit longer but the same width. I had assumed that with that cell configuration it would be OK to mix the 60 cell panel with the 72 cell panel. Maybe I am wrong.

Greetings I am very aware of the advice that solar panels with different power ratings should not be connected together. It is said that doing so would result in the other panel/s only providing as much power as the lowest rated panel. When I looked at the specs of a 275w and a 330w panel from the same manufacturer I noted that the mppt current and short circuit current from each was very similar. The main difference is that the more powerful panel has a higher mppt voltage. I wonder whether this means that if these two panels are connected in series the output would be a little less than 275+330=605w (limited by the mppt current of the slightly lower one) but more than 275+275=550w. Have any of you tried something like this?

Thanks Coulomb Thanks for your ideas regarding voltage balancing. I have a voltage balancer connected but will monitor it more carefully over time.

I woke up this morning to discover that our inverter had "frozen" again. The battery voltages were 13.70v and 13.18v before I did anything. Immediately after "rebooting" the inverter they were 12.85v and 12.81v respectively. A few moments later the inverter read 25.4v. (The initial imbalance may be because one battery is a few months older than they other).

Thanks Coulomb. I will check voltages when it happens again

Hi I have a 3kva/3kw Axpert VM hybrid inverter ("Solar Solved Africa" brand) and two 230ah flooded lead acid batteries. The inverter is set to prioritise our two 275w solar panels. At irregular intervals the inverter display "freezes" and there is no power output. On advice from the installer who sold it to me I solve this by :- *Switching off utility power *Disconnecting the solar panels *switching off the inverter * I then disconnect power from the batteries, wait a couple of minutes then reconnect. *then switch on the inverter, utility and solar power. It always happens when there is little or no input from the solar panels. My inverter firmware versions are U1 06 23 U2 01 12 Has anyone found a way to permanently prevent this behaviour?