Mains adaptor for 12 volt fridge (1 Viewer)

[Dorwyn]

I notice that my 12 v compressor fridge has a connection for a 240 volt mains power pack. I think it takes about 5 amps max, so wondered if this device would work.

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If so, not sure what sort of switch I would need so that I can use is when on EHU, assuming it would not be self switching.

 

[DBK]

If you are on EHU dos it not work on 12 volts? I have a compressor cool box which I have a mains adaptor for but that is only so I can use it in the house. In the MH it runs on 12 volts all the time.

 

[Jaws]

If your unit is drawing 5 amps constant I would look for a PSU able to handle at least 8 amps to be even slightly on the safe side .
Those switch mode PSU's are actually ( usually ) rated at 4 amps with 6 amp surge

Personally I would not bother at all.

If you are on hook up, then the van charger will be the thing supplying the amperage ( when you think about it ) so why double up ?
The only time you would need a mains supply for it is if you remove it completely from the van and away from the 12v supply

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[Jaws]

Sorry DBK.. we both posted at the same time !

 

[Dorwyn]

The reason I was thinking of doing that is to reduce the load on the battery.
When I'm on EHU it doesn't last more than a couple of days before it starts to struggle. I do occasionally use a battery charger but cannot use the one I have on permanently, since once it is charged fully, the charger switches off, and has to be manually restarted.
While I'm paying for electric I thought I could use it to run the fridge.
I recently changed the battery configuration from 2x 110amps to one 130amp, for reasons of storage space. I do not have a van charger as such.
Regarding the amperage the fridge uses, I am not sure what it does run at, it's only a small 70 litre fridge, but I do not have the manual to check the spec.
Anyway, it was just an idea, which seems to have been shot down.

 

[Jaws]

There is something very wrong with your charger in that case !
I would address the problem rather than do a work around to be honest ....

If it all worked correctly you would still be using more or less the same amount of electric .. The charger is really only a semi-intelligent power supply anyway...

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[scotjimland]

am with Jaws..
invest in a new charger/power supply unit

for example..
ESPX300 Sargent 25A Batter Charger. about £100
http://sargentshop.co.uk/PX300-Intelligent-Battery-Charger

 

[Dorwyn]

I do not have an on-board Zig or similar system. There is nothing wrong with the charger, it is designed to need a reset. Another make charger would be an obvious choice, but they are so expensive. Since there is a connection for a mains power pack, I was thinking of using that. After all, the 3-way systems can do that.

 

[Dorwyn]

... although the Sargeant model does seem good value for a 25 amp unit

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[DBK]

The reason I was thinking of doing that is to reduce the load on the battery.
When I'm on EHU it doesn't last more than a couple of days before it starts to struggle. I do occasionally use a battery charger but cannot use the one I have on permanently, since once it is charged fully, the charger switches off, and has to be manually restarted.
While I'm paying for electric I thought I could use it to run the fridge.
I recently changed the battery configuration from 2x 110amps to one 130amp, for reasons of storage space. I do not have a van charger as such.
Regarding the amperage the fridge uses, I am not sure what it does run at, it's only a small 70 litre fridge, but I do not have the manual to check the spec.
Anyway, it was just an idea, which seems to have been shot down.

No one is shooting down your idea now we understand the reason for asking but I think in the long term it will be better to sort out the on-board charging. One reason is if you can't charge the battery when on EHU it is going to be repeatedly run down and I don't think that is good for it, better to keep it topped up continually.

As for current, my Dometic compressor cool box uses 5 amps when it is running, which in typical UK temperatures is for about 5 minutes then it shuts down for about half an hour or so before starting up again when it has warmed up a bit inside so I suspect your 5 amps estimate is about right but it is probably a bit more than that momentarily when the motor kicks in.

Sad person that I am I logged the temperature changes with a Raspberry Pi over a twelve hour period after I got it so I could work out the best setting for keeping the beer and wine cool. Note how it fluctuates quite a lot to begin with including several excursions into the negative zone before levelling off around 4C. This was with it empty and I suspect the temperature fluctuations will be much slower when it is full - but I haven't tried that yet.