Voltronic AES function...

[Garry - June]

Hi All, i realise this has been discussed before but just looking for a bit of clarity... i have a Voltronic MPP350 with the AES Fridge supply output... have been sat here for a whilst now and the power AES availability led is constantly glowing.... so with all this spare solar power maybe i should hook it up to my AES capable fridge... Is it just a case of connecting a cable from the voltronic to the fridge socket..... i presume the fridge will then automatically switch to 12v and take power through the elektroblock... can anyone clarify this... and if not what i have to connect and to where.... and if it is all automatic... Thanks..

 

[funflair]

If you have a fridge with S+ terminal you just take a light signal wire to it from the AES on the Votronic.

 

[Wh05apk]

How does it work?

I switch my fridge to 12v when the batteries are full, and the solar is producing, but if the fridge needs say 10a, but the solar is only producing 5a presumably it draws from the batteries?

I know Lenny has mentioned this, and I think his runs in 30 minutes blocks?

 

[Lenny HB]

As Martin says, mine is wired like it. So as not to flatten your batteries it works in ½hour blocks. Also the Dometic firmware is a bit dumb and has 12v Solar at top of the list of power options so often when on EHU the fridge switches to 12v. I originally fitted a switch in line with the AES cable I have since fitted a relay.

 

[camoyboy]

It depends on how the fridge gets it 12 volts. On our Carthago the fridge 12 v power is direct from the alternator, it does not run from the batteries, therefore the Votronic AES feature doesn't work.

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[funflair]

It depends on how the fridge gets it 12 volts. On our Carthago the fridge 12 v power is direct from the alternator, it does not run from the batteries, therefore the Votronic AES feature doesn't work.

I don’t see how it is direct from the alternator, it must be via a battery either habitation or starter, OK it only runs on 12v when triggered by the 12v D+ from alternator/engine running but that is the same as the AES signal from the Votronic unit.

 

[jongood]

If you have a fridge with S+ terminal you just take a light signal wire to it from the AES on the Votronic.

Is that all thats needed Martin? I thought I remembered complications with steps operating on previous discussions?

Ours definitely runs straight off the batteries and doesnt seem to need the engine running, I ran it that way through the tunnel this week.

 

[sallylillian]

Lenny's post makes clear the real problem with using the AES feed from the Votronic and why I disconnected it, Dometic have Solar at the top of the switching food chain. The 12vdc element is simply not satisfactory, except in low ambient temperatures, to maintain reasonable operating temperatures and the use of solar is a contradiction to that caveat for the most part. Jon, you can switch manually to 12vdc on the control panel, in effect switching off the AES functionality and run the fridge on 12vdc by default, but while Auto is selected the D+ from the alternator will switch it to 12vdc from the batteries, as indeed will a feed to the S+ from a Solar charger like the Votronic. In earlier Dometic fridges there was not a S+ and if I am right Martin took a feed (via a diode to overcome back feed) to his D+ from his solar charger.

 

[funflair]

Quite right Michael I had to use a diode to make our older non S+ fridge work from the Votronic AES and the fridge D+, as far as switching priority is concerned it was fine but every half hour block of running on 12v would be followed by 15 minutes of down time before switching to gas as it thought it was in a refuelling station this did impact on the cooling efficiency of the fridge, on the Palace I have not pursued this option even using S+ as the 12v element is not as powerful as the 240v and now I don't have the Votronic's anymore anyway.

 

[funflair]

Is that all thats needed Martin? I thought I remembered complications with steps operating on previous discussions?

Ours definitely runs straight off the batteries and doesnt seem to need the engine running, I ran it that way through the tunnel this week.

Yes we can switch our 10 series directly onto 12v as we could the older 7 series and both would then run from the habitation batteries.

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[sallylillian]

Another point of regular confusion, not by most I hasten to add, is that of 12v feed to the fridge. There are 2 of course, a heavy duty one for the 12v heating element and a feed for the control circuits. It is sometimes incorrectly assumed that somehow the AES connection on the Votronics provide the actual dc power for the heating element. This is of course wrong, the connection is purely a signal wire, waving a flag if you like, to the fridge that there is sufficient solar charge to enable the fridge to auto switch to 12vdc. In the same way that the D+ is a flag waving from the alternator.

 

[Lenny HB]

It depends on how the fridge gets it 12 volts. On our Carthago the fridge 12 v power is direct from the alternator, it does not run from the batteries, therefore the Votronic AES feature doesn't work.

Fairly certain Carthago's like most German Vans the fridge is wired to the hab battery, if you switch it to 12v manually it will run from the hab battery. If doesn't check the fuse hasn't been pulled on the distribution unit.

Lenny's post makes clear the real problem with using the AES feed from the Votronic and why I disconnected it, Dometic have Solar at the top of the switching food chain. The 12vdc element is simply not satisfactory, except in low ambient temperatures, to maintain reasonable operating temperatures and the use of solar is a contradiction to that caveat for the most part.

On our 8505 fridge/freezer I've not found it to be a problem, the 12v element is a bit smaller 190w compared to the mains one at 250w.
In use because it only works when plenty of power avalible and it switches back to gas after 30min generally it only runs on 12v for 2 or 3 hours in 24 hours.

But because of the stupid Dometic firmware you do need to fit a switch or relay inline with the AES feed from the regulator to stop it running on 12v when you are on EHU.

 

[Off da Grid]

I fitted a relay to the AES output on ours to feed a 12v socket as our fridge doesn’t support the aes function.
In the winter I run a mini dehumidifier off it. So the solar controller switches it on when the batteries are charged, works a treat.