Solar Panel to Dometic Fridge S+ Signal

[MikeJJ]

Hi,

I found out that the Dometic RMD 8505 installed on my m/h has the ability to receive an S+ signal to allow it to run from a solar panel through a regulator which has AES terminals. This automatically selects solar output when there is a suitable excess available.

 

My solar panel runs through a Schaudt solar regulator to a Schaudt Electroblok EBL271; nowhere in the wiring diagrams can I find any S+ signal and in fact there is no wire connected at the S+ terminal on the fridge. So I am sure my m/h is not enabled.

 

But has anyone had experience of this capability on their m/h?

[aandncaravan]

The Votronic MPPT 250 and larger models (Schaudt EBL compatible) have a Fridge driver circuit but it is not as simple as you might think?

 

You write, "This automatically selects solar output when there is a suitable excess available", but what usually happens is that it 'activates the Fridge 12v' when Solar power is available, which may vary from an excess of Solar to only 'just enough' to trickle charge a battery.

 

 

You need to be sure that your configuration can both put back the charge taken out the night before and power the Fridge, sometimes requiring upto 20+ amps for both Fridge power and battery recharging?

If there is a short fall in power, but a small Solar output enough to 'trigger' then the Fridge risks draining down the Habitation battery.

 

 

To get it right either requires a lot of manual monitoring or some sophisticated electronics.

 

When all you are going to save is a small amount of Gas (probably £29 for a whole season?) it is rarely worth the effort.

 

While the total Gas consumption for all Appliances (Water Heater, Fridge, Space Heating, Hob, Oven, etc) can be significant, the Fridge itself is a very small consumer of gas, hence it rarely being cost effective to try and power with Solar.

 

On most Fridges, Gas is generally regarded as more efficient anyway.

Also bear in mind that some 12v Fridge circuits are not linked to any temperature control.

 

 

You could do what some customer did, against our advice, to install 4 batteries, 4 Solar panels driving an Inverter to power the 230v Fridge circuit!!!!!!

 

His batteries were decimated overnight by the Invertor (only 60% efficient) which ended up having a 2 year life.

The battery running costs alone, replacing 4 x 100Ah every two years at £200 a year, to save £29 worth of Gas a year just didn't make sense to me.

.

 

 

 

[Bop]

Mike,

 

I see what you mean about the S+ signal concept but if you check the circuit diagram for the EBL 271 unit then you'll see that the solar panel and its regulator is only there (as an additional accessory) to supplement the power to your MH. In basic terms the Pilote MHs supplied to the UK market uses solar power, via the 271 and the additional regulator to help monitor and maintain the vans integral batteries.

 

Allan may be able to assist you further but in the case of the Pilote-fitted EBL271 then I don't think that solar can be used exclusively.

 

Cheers,

 

Andrew

 

EDIT: Well done Allan B-)

[MikeJJ]

Allan and Andrew - thank you both for your replies.

[Bop]

MikeJJ - 2017-08-06 4:52 PM

 

Allan and Andrew - thank you both for your replies.

 

All I can say is that I'm pleased Allan is here or else you'd be in right jiff with my response.

 

We picked up our new Pilote P740GJ on Monday gone so I'll be interested to see how this unfolds.

 

I've interrogated the destructions but I'm not able to find any reference to direct solar usage. I'll check again.

 

BTW, our Pilote is a fantastic vehicle and the missus and I are over the moon with it; the quality is superb.

 

All the best,

 

Andrew

[monique.hubrechtsgm]

Dometic fridges do no run on solar power. Show me That S+ signal and that will be not solar but another power source like fuell cells etc.

[aandncaravan]

Monique, you can use Solar to drive any 12v element on most modern Motorhome Fridges, it doesn't have to have an S+ as you can use electronics to drive the Fridge D+ circuit.

It just isn't usually worth the hassle to save so little gas.

 

 

Andrew, we like the build quality on the Pilote manufactured vehicles. Not just well screwed together, but choice of components that make up everything seems to be the better quality items.