Fridge wiring for travel (1 Viewer)

[Tris]

Hello All,

I hope someone may be able to give me a sanity check here. When building our van I chose to connect the elderly 3 way fridge to the leisure battery, naively thinking the solar panel would cope with the draw. As it turned out we spent a lot more time on the road than I thought we would so the battery was not up to the job. Now I am getting round to fitting the VSR and was wondering whether it would be better the keep the fridge hooked up to the leisure battery or hook the vsr up to the fridge alone?

Apart from the fridge the leisure battery runs the water and toilet pumps, diesel heater and LED lighting, so not much drain there and the solar panel/onboard charger will cope with that.
We are usually on sites with EHU for various reasons and can use gas when parked up. Obviously the leisure battery route requires someone to remember to flick a switch once the engine is off, not that I'd ever forget

 

[GeoffnDee]

The fridge controls are normally connected to the leisure battery , using little power , with the 12v fridge heater element being connected to the starter battery via a relay using the D+ signal from the alternator to switch the supply on only when the engine is running . (a switch will not then be needed)

 

[Tris]

Thanks for the reply. In this case it is a selfbuilt van using a proportion of cannibalised caravan components, so pretty basic.
At present the leisure battery doesn't connect to the vehicle charging system at all, and as the load on the leisure battery is pretty small apart from the fridge I could get away without connecting it at all. In this instance I would look at disconnecting the fridge from the leisure battery altogether and having it's 12v supply from a VSR from the starter battery, with gas or 240v ehu when parked

As best I can tell the fridge draws around 8 amps on 12v, the renault alternator is rated 150 amp so there should be plenty of capacity.

I'm not sure if the VSR is capable of two way working, and whether it would charge the starting battery if the solar is charging the leisure battery to above 13.4v?

Sorry, this is getting more involved the more I think about it

 

[GeoffnDee]

Have a look at the Vanbitz battery master it will charge your starter battery from your leisure battery that has solar going to it , they are not expensive and easy to fit and are designed for this use.
Using a normal relay for operating the fridge from the starter battery will avoid the battery going flat if it is not switched off 12v when parked up.

 

[Guigsy]

3 way fridges are great on gas. On mains hook-up they work fine, provided you aren't on a metered connection. On 12v, you see how inefficient they are and that they eat a lot of amps. Many motorhomes only allow you to run 12v mode from the alternator because they'll flatten a leisure battery in a few hours. Mine chomps through up to 15amps.

Your options are to either get a lot of solar (and only use the fridge on sunny days), run on gas, or convert to a compressor fridge, which is far more frugal on electricity.

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[Tris]

Thanks for taking the time to reply. We're used to 3 way fridges from caravanning days, but operating one in the van has been a steep learning curve. Wasn't helped by only having 3 months to build from scratch so now I'm trying to iron out the kinks. In the ideal world/next build (sshh, don't tell the other half) it'll have loads more solar and be completely off grid capable, but getting a few years out of this one is my main goal ATM.

I have a basic vsr ready to fit, so I'm really hoping to get opinions on the best way to get 12v to the fridge whilst driving

 

[Sleeveless]

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[Guigsy]

Does your build not have gas?

Some people have fitted slimline domestic 240v fridges and not had issues.

There are also conversion kits to switch 3 way fridges to compressor to run on 12v/240v much more efficiently.