Solar problem

[Algarvedave]

I recently bought a 200w portable solar panel and a Vitron mttp 75/15 charge controller to charge my leisure battery. For two weeks all was good, it was producing around 150/160w when in full sun on a trip to Morocco. Now I’m back home but can’t get more than around 20w, admittedly on a less than full sunny day. However when I switch on my compressor fridge the charge controller shows that I’m getting around 50w. Is this increase normal or do I have a problem somewhere?

 

[Admin]

Is your battery full?

 

[Algarvedave]

Yes I think so. It’s at 13.84v

 

[merl]

Is your battery full?

Indeed. You can't keep pumping in power to the battery forever, when it's full the charge controller will stop sending it power and the current will fall/ stop. Turning on your compressor fridge allows the solar controller to start delivering current in order to keep up with the drain caused by the fridge.

 

[Algarvedave]

Indeed. You can't keep pumping in power to the battery forever, when it's full the charge controller will stop sending it power and the current will fall/ stop. Turning on your compressor fridge allows the solar controller to start delivering current in order to keep up with the drain caused by the fridge.

Thanks. I’m new to solar so thought the watts shown was the watts produced by the panel not the power needed for the battery. That makes a lot of sense and really answers my question.

 

[wildebus]

I would say Admin has hit the nail on the head. To see a full harvest potential you need a less than full battery, and possibly pretty low if a lead one.
You could try turning on everything - Fridge, TV, all the lights, whatever you have - and see what it goes upto.