Ring RSDC30 solar voltage

Londonboii

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This unit has been working well (at least I thought so) but now there's less sun I have noticed the batteries aren't getting charged as much as I'd expect.

After looking at the unit the solar input voltage is jumping all over the place. Between 10 and 20 volts. I have removed the cables and checked the incoming voltage from the panels and they are a nice solid constant 20v.

However when I put the cables back in the unit the display shows the current jumping all over the place. And its jumping very fast, a few times a second and up to 10v.

If I put a multimeter on the screws that hold the cable in it also shows the voltage is unstable and jumping all around.

Any ideas what could cause this?
 
It sounds like low current from the panels that is causing a voltage drop when the unit tries to pull a load. Have you made sure that your panels are clean, in direct sunlight, that there are no shadows cast on them and that the connection on the roof are good?
 
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Thanks Phil. The panels are clean, they are wet but clean. There are no shadows on them, its not sunny today but the light there is is constant and even over the panels.

I have disconnected every connection between the panels and the controller and checked the voltage at each point and its showing the 20v everywhere. Although thats without a load and I dont know how to test if theres a loose connection or something other than to check the voltage.

I am using mc4 connectors on the roof. Which should be waterproof I believe. The 2 panels are linked by couple of 2 to 1 mc4 connectors then just 2 cables go through the roof into the controller.

Other than testing theres voltage coming through how can I test what the available current is at the connections? Or should I just order some new connectors to rule out that fault?
 
Its showing just 0.5A - 1A again changing but not as much as the volatage.

But the batteries are at 12.1V so I'd hope for more.

I will try Google how to read the availble current on the panels with my multimeter and then check it at each connection again to see if there's an issue along the way to the controller.
 
What is the rated output of your panels?

I have 1280w of panels and right now they are outputting 130w, so about 10% of rated output because of the time of year and the weather.
 
320w.

I realise I'll be getting a lot less charge than I was in summer. But should the voltage reading be dancing around like it is? I thought it'd stay reasonably constant, changing as the conditions do.
 
The minimum input voltage for solar on the unit is 10v. So I suspect that as the unit is trying to pull the max output from the panels and the PV voltage is dropping below 10V, then the unit is stopping the charge. The voltage then recovers, and the unit then starts charging again. The RSDC30 displays the same behaviour when charging from the starter battery when the connection cable is not large enough to prevent a voltage drop.

If this stops when the sun is directly on the panels, then I think you will find that this is a characteristic of the RSDC30 rather than a fault.
 
You could try connecting the panels in series rather than parallel to see if this keeps the voltage above 10v.
 
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