Running Fridge on Solar (Leisure Batteries) (1 Viewer)

[Jean-luc]

On the CBE unit in my Rapido there is what appears to be a bridge/shunt available, which when used overrides the normal AES and brings the fridge onto 12v mode from the leisure batteries. See FA2 & FA3 in the top photo of the tabs and the bottom photo for the mention in the manual, it's item 16

.

Has anyone (you reading this Techno) tried this, it looks like if the shunt is made incorporating a switch or voltage operated relay it could be used to bring the fridge onto 12v one the batteries are up to voltage and drop back to AES when the voltage goes low.

 

[Snowbird]

I do believe all modern AES fridges are wired to run on solar when in full sun with the batteries charged. I had occasion to replace a fridge some time ago and instead of replacing like for like I replaced with an AES fridge. The fitting manual gave instructions for the fitter to alter some wiring and hay presto it worked.

 

[Jean-luc]

Bump

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[Sheddy]

@Techno
Bump

 

[funflair]

I do believe all modern AES fridges are wired to run on solar when in full sun with the batteries charged. I had occasion to replace a fridge some time ago and instead of replacing like for like I replaced with an AES fridge. The fitting manual gave instructions for the fitter to alter some wiring and hay presto it worked.

You are right that modern AES fridges are designed to utilise "spare" solar power BUT it is my understanding that the fridge needs a signal to the S+ terminal in the same way as D+ works when the alternator is running, I have this running on an older AES fridge that doesn't have the S+, I have a Votronic solar regulator that has sends the AES signal that I then connected to the D+ with a diode on the alternator side to simulate the S+ terminal.

Martin

 

[Snowbird]

You are right that modern AES fridges are designed to utilise "spare" solar power BUT it is my understanding that the fridge needs a signal to the S+ terminal in the same way as D+ works when the alternator is running, I have this running on an older AES fridge that doesn't have the S+, I have a Votronic solar regulator that has sends the AES signal that I then connected to the D+ with a diode on the alternator side to simulate the S+ terminal.

Martin

Not many know that .

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[funflair]

This is the Votronic controller with AES signal output.

http://www.votronic.de/index.php/en...trollers/standard-version-mpp/mpp-350-duo-dig

Martin

 

[Techno]

On the CBE unit in my Rapido there is what appears to be a bridge/shunt available, which when used overrides the normal AES and brings the fridge onto 12v mode from the leisure batteries. See FA2 & FA3 in the top photo of the tabs and the bottom photo for the mention in the manual, it's item 16View attachment 130184 View attachment 130188 .

Has anyone (you reading this Techno) tried this, it looks like if the shunt is made incorporating a switch or voltage operated relay it could be used to bring the fridge onto 12v one the batteries are up to voltage and drop back to AES when the voltage goes low.

No I've never noticed this.
My work around was to use a CBE CSB2 relay to put voltage onto the D+ signal with a diode to stop this back feeding to the alternator

 

[Techno]

http://www.motorhomefun.co.uk/forum/threads/fridge-on-solar.84589/page-3#post-1003469

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[funflair]

On the CBE unit in my Rapido there is what appears to be a bridge/shunt available, which when used overrides the normal AES and brings the fridge onto 12v mode from the leisure batteries. See FA2 & FA3 in the top photo of the tabs and the bottom photo for the mention in the manual, it's item 16View attachment 130184 View attachment 130188 .

Has anyone (you reading this Techno) tried this, it looks like if the shunt is made incorporating a switch or voltage operated relay it could be used to bring the fridge onto 12v one the batteries are up to voltage and drop back to AES when the voltage goes low.

If you want to do this and you are capable of building the switching unit that you describe (I'm not) then all you need to do is provide a 12volt 0.2amp signal to the S+ on a modern Dometic fridge or the D+ with a diode to stop the signal going down the alternator signal wire on an older fridge, you should not need to use the bridge point.

Yes I think that Andy Techno built something very similar.

Martin

EDIT Andy beat me to it.

 

[Boringfrog]

But do I need 14amps of solar charge before my leisure batteries start to feed the fridge?

 

[Techno]

Hi Martin
As I discovered, the S+ on the fridge is useless because it is the CBE panel that controls the supply to the fridge via a relay which is controlled by the D+. In other words the relay on the fridge itself would operate but would not receive 12 volts unless the CBE panel allowed it

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[Techno]

But do I need 14amps of solar charge before my leisure batteries start to feed the fridge?View attachment 132379

Not initially. The control would be voltage operated but without enough solar power the voltage would drop to the point where it would disconnect the fridge

 

[Techno]

Personally I rarely switch my fridge to solar as I now have much higher demands of my inverter batteries with microwave kettle hairdryer etc and the fridge uses so little gas anyway

 

[funflair]

But do I need 14amps of solar charge before my leisure batteries start to feed the fridge?View attachment 132379

No you just need the batteries charged and some "spare" solar and the Votronic controller will switch the fridge over to 12volt from the habitation batteries and then monitor the state of charge of the batteries and available "spare" solar power and switch as applicable.

Martin

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[funflair]

Hi Martin
As I discovered, the S+ on the fridge is useless because it is the CBE panel that controls the supply to the fridge via a relay which is controlled by the D+. In other words the relay on the fridge itself would operate but would not receive 12 volts unless the CBE panel allowed it

I only have the D+ so when the Votronic solar regulator sends the signal the fridge thinks it's the alternator and goes over to 12volts.

Martin

 

[funflair]

Personally I rarely switch my fridge to solar as I now have much higher demands of my inverter batteries with microwave kettle hairdryer etc and the fridge uses so little gas anyway

I guess that the advantage of it running off the Votronic controller, I just leave the fridge on "auto" and it works it all out for itself.

Martin

 

[Techno]

I don't have "auto" anymore. To fix my fridge I had to do a complete redesign to overcome Dometics inability to fix it.
Also as my relay is only voltage switched without regard for battery capacity my fridge could be taking 16 amps when really I want it to recharge my inverter batteries

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[Techno]

I think I just hit the nail on the head there for my own installation. Solar power is finite.......do I want it to recharge my hammered inverter batteries or use it to run my fridge that uses very little refillable cheap as chips gas?
It was a good project for learning but in practice little use unless you're living in Morocco.

 

[Techno]

I'd say for anyone who does not use an inverter and large battery banks it is feasible.
A two battery installation that has plenty of solar and only doing LED lighting TV etc will probably do quite well

 

[funflair]

I think I just hit the nail on the head there for my own installation. Solar power is finite.......do I want it to recharge my hammered inverter batteries or use it to run my fridge that uses very little refillable cheap as chips gas?
It was a good project for learning but in practice little use unless you're living in Morocco.

Andy I guess you are still running two banks of habitation batteries, so I understand that it's not quite so straightforward as our set up.

Martin

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[Techno]

Andy I guess you are still running two banks of habitation batteries, so I understand that it's not quite so straightforward as our set up.

Martin

Yes exactly