Votronic MPP240 Solar Controller (1 Viewer)

[OldAgeTravellers]

Hi all,
On the way to Morocco this year my mains charger failed as a result, I think, of very low supply voltage. So my mind has been concentrating more on solar.
I have two 9x4 cell panels, don't know the wattage but perhaps 85w each and two 110ah (old money) leisure batteries.
I had more or less decided on the 20amp controller that Trikeman is using because of its high input voltage so I could put the panels in series but then found that Dazlin was running his fridge manually (I think his relay has welded on) almost permanently on Solar while in Morocco so I started looking more and discovered the Votronic MPPT controller from Amazon.de has an AES output to switch the Dometic AES fridge onto leisure battery when the batteries are charged and their is excess output from the panels. However the recommended input voltage is 21 to 28v with a maximum of 50v. But looking at Trikeman's recent post he is getting 60volt odd which of course would damage the controller.
The installation instructions of the Votronic show panels in parallel which of course loses the major benefits of series connection with MPPT controllers of being able to still charge at low light levels. (I once met a German parked in the street, who said he was getting a decent charge from the street lights above him at night).
So, anybody got any thoughts, do you know of another controller with the AES output?
Or perhaps I could duplicate it with a simple electronic circuit which switched the Fridge to Solar if the Battery voltage was say 13volt with a timer to hold it on for half an hour to stop cycling, like the Votronic does.
Thoughts please?
Steve
P.s. Nice tidy installation, Trikeman

 

[OldAgeTravellers]

Another thought, my panels are not exactly the same, but are the same physical size and number of cells. Would there be any problem putting them in series and I also thought that if it works well I might add a third, I have enough space for a wider than long 100watt panel so would have to use a different controller, exactly which one and from where did you use Trikeman?
Also are there any electronic engineers out there could design the AES switching cuircuit? I have a mechanical engineering background so have the understanding but not specific skill.
Steve

 

[Snowbird]

When I bought a new AES Dometic fridge to replace the original fridge in my previous van, it came with instructions to wire it into the solar system. It was a fairly easy task and the fitter wired it into the solar system. It worked fine and switched over to solar when the batteries were full. If you dont have the diagram am sure its available online.

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[OldAgeTravellers]

Yes it is very simple wiring it in just goes to the S+ terminal to switch the relay to switch on to 12volt.
It just needs the output from the controller when the batteries are fully charged and there is excess Solar Power.
If there is no S+ connection then the D+ can be used but protect from feeding into the Alternator with a Schottky diode.
It is just getting the appropriate signal from the regulator.
Steve