AC200Max and PV350 panels

I sent this email to service, but thought I’d reach out here to see if any other users had ideas.

I have two PV350 panels connected to my AC200Max. The maximum solar input has been 400W and normally I only see 320-350. This has been the case for the last two months. I have used the panels in several different locations and have not seen a difference. The input will increase slightly with alignment adjustments, but even when perfectly aligned I only see an increase of 15-20W.

The panels are connected in series. When I connect them to the AC200Max, I see the input voltage at 80-90 volts. This then drops to around 65 Volts as the input power goes up. It then stays around that 65 volt range.

I will also sometimes notice a drop in input power from the panels. The input watts often will drop 20-40 watts without a known cause When I see this, I have been able to unplug the panels from the XT90 connector, wait until the input voltage drops to zero, and then reconnect. This then gives me the input power back in the 350-400W range.

Aside from alignment, I have cleaned the panels and this has minimal impact on the input power.

I have also connected each panel independently to the AC200 Max. Both panels are performing nearly identically. When connected I see an input voltage of 40-43 volts. This drops to around 30-33 volts while the watts climb to 160-200W.

I also see the same performance if I use an extension from the panels to the Bluettie supplied mc4/XT90 adapter or if I plug the panels directly into the adapter. I have ruled out a bad extension cable.

While I understand that many factors can affect the efficiency of solar panels, only receiving 50% of the rates output is not expected.

I think that the voltage coming from the panels looks proper, but I would appreciate confirmation. If that’s the case, could you point to any other fixes? Could this be an issue with the AC200Max MPPT charge controller?


The voltages don’t sound quite right to me. The Voc for the PV350 should be ~46 volts. Have you measured directly off the panel’s cables while not connected to anything? But similarly with your measurements while charging your AC200Max, the voltage sounds low. If the panels are in good sunny conditions, then the voltage should be around the Vmp of 37 volts, but you are only getting 30 to 33 volts. So, if one panel is providing 33 volts, and say 200 watts, then you are only getting 6 amps; whereas the Imp should be around 9 amps. To me it seems that the panels are not getting full solar brightness, both the current and voltage appear to be low. Obviously I don’t see your panel setup, so this is just a guess based on your numbers.


Thanks for the input. These are full sun readings with clear skies. Was in the desert outside of Moab when I posted this.The Max voltage around 45 is what I saw when I would first plug in, then the voltage drops within seconds. I am assuming that the system voltage is the lower reading that I’m getting.

@BruceW Possibly a longshot, but do you have the DC input for the AC200Max set to PV rather than Other/Car?

Secondly, check you have the PV cable connected correctly into the Max. I have seen a reduction of input due to the cable not being connected properly. Make sure you line up the 1 and 2 pins.


I have the same issue. I just bought the AC 200 max and PV350 panel and am only getting around 170-190 watts into the Max! Not sure if this is some sort of bug but all my updates are current. Please help!


I have a same issue. But i connect my ac200 max to pv from solar roof which 900w.

Thanks! The input is correctly set to PV. The AC200 Max only has one way that the connector can be plugged into the input port. There are three notches in the connector that prevent it from being put into the port the wrong way.

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