Poor Fridge performance

[horns]

The silver one? That fell off some time ago...

[TimR]

I can't remember where I heard it (probably on here!) but I recall someone suggesting filling your fridge with a few ice packs before setting off then switching to 12v for the journey and by the time you arrive for your EHU the fridge should already be down to the right temperature. Well, it works for me.

[Rich Tea]

I think I'll try to raise it up also so there's, some airflow below it.

.

No need if you have an 8 X 3 hole in the floor.. that's how Autosleepers fit Rm 212's

The hole is covered with a some steel mesh, it looks quite fine, also theres a panel fitted below the hole, stood off from the floor about 40mm (i guess it's to prevent splashes). I thought these might reduce air flow. I had the space to raise the fridge up 16mm so I did that in the hope that I might flow more air round the back of the fridge.

I followed the advise and turned the fridge upside down for 12 hours, I cleaned all the dust off, especially around the fins.

I took the van away for the long weekend, and I'm afraid to say that the problem still remains. It seems to cool very well on hook up. It takes a while but will dropped to about 1°C over night. Unfortunately once out and about neither the gas or 12V seem to have any effect on the cooling reaching about 15°C by mid afternoon.

I have to be honest, I'm not even sure if the 12V is wired in correctly. Theres a RYDER split charger relay mounted next to the battery and another relay behind the fridge. I'm not sure why I'd need two relays?

Help, what's the next step?

Is there something else I can try myself?
Does anyone service these fridges?
How much would a relpacement cost?

Thanks again for everyones time, please help me I envy those that can make ice, I'd settle for keeping my beers cold and my milk fresh.

Rich

[1664]

I'm not even sure if the 12V is wired in correctly. Theres a RYDER split charger relay mounted next to the battery and another relay behind the fridge. I'm not sure why I'd need two relays?

One relay for the split charge and the other for running the fridge on 12v while the engine is running. Get yourself a cheap little multimeter and check the fridge is getting 12v when the engine is running. The van has to be level for the gas to work efficiently.

[Rich Tea]

I have to keep the van in storage, so I only have access to it at weekends. I spent a little while with my volt meter and have figured out the wiring.

First issue was the main fuse to the smart relay was blown, so no power to the fridge.

The next observation was that the relay behind the fridge (once fuse replaced) is constantly energised, powered from the car battery, so when the fridge is turned on it's hooked up directly to the leisure battery. All this without the engine running.

With the engine running, once the car battery is charged, the smart relay switches and it starts charging the leisure battery and running the fridge.

I'm not overly happy with this set up as the relay behind the fridge is permanently on, and will flatten the car battery over time. Also the leisure battery is actually not a proper leisure battery but a normal car battery, I'm therefore concerned that connecting it to the fridge (and acidentally leaving the fridge on 12V) will deeply discharge it, which wouldn't be good.

The thing I don't understand is that the Smart relay has a second switched output on it, so I don't know why whoever wired it up wouldn't have run the fridge directly from this. The only thing I can think of is, was this done because the the smart relay only has a 20amp input. Is this enough to charge the leisure battery and power the fridge at the same time?

Cheers

Rich

[1664]

The fridge will draw almost 10 amps on 12v so best to keep it on a separate relay since the smart relay is only 20 amp (you said 'input'; do you mean 'output'?)

Check the smart relay drops out as soon as the ignition is turned off and the engine stops by checking the voltage on the smart relay control wire. Take the fridge relay control wire off the starter battery and connect it to the smart relay output terminal, that way it will disconnect the fridge as soon as the engine stops.

Now because your fridge's 12v side is fed from the leisure battery, both the smart relay and the split charge cable have to handle the current demand of re-charging your leisure battery AND running the fridge as that is the route back to the alternator, which as I previously mentioned is far from ideal as the relay is only 20 amp.

Disconnect the fridge 12v cables from the leisure battery and connect them to the starter battery, and hence the alternator, without going through the smart relay which leaves the split charge system only taking the re-charge current to the leisure battery.

Frankly though, 20 amps is bugger all to a significantly discharged battery which will want to suck a lot more through the system - why not invest in a larger smart relay and upgrade your split charge wiring?

My 'leisure' battery is also a standard battery (exactly the same as my starter battery) - advantage is that if your starter battery dies on you, you can jump the van off your leisure as long as it's got enough juice in it

[Rich Tea]

Thanks 1664, I think I see where you're coming from.

If it makes any difference the smart relay is a Ryder TF1170-2

http://www.rydertowing.co.uk/pricelist/login.aspx" onclick="window.open(this.href);return false;

When I mentioned a 20 amp input, I was refering to the fact there's a 20 amp fuse between the relay and the Car battery. As mentioned earlier this was blown when I checked it. It also blew whilst I was fiddling around.

I wanted to ask what size cable I should be looking at between the smart relay and the liesure battery? The Ryder catalogue diagram shows 2x 2.5mm square cables between the car battery (after the 20 amp fuse) and the split relay. Unfortuately the diagram does not show how to wire in the fridge or the leisure battery.

I'm not exactly impressed with the wiring for a number of reasons. As I'm the lucky 10th owner there's been a good deal of chopping and changing over the years, some of it does not look that safe. Also no one has ever gotten around to wiring the radio or the cigar lighter to the leisure battery, so I will do that too.

I'm gathering components as we speak.

Many thanks for your time and your opinions.

Rich

[1664]

One 2.5mm takes 20amp easily. (That relay is only rated at 18 amps though.) Volt drop is a consideration though, not just the current a cable can handle comfortably, as v.d (*snigger*) increases with current for a given size of cable so the bigger the better. Like I said, I'd upgrade since you're going to have to virtually pull the bugger apart anyway.