Fridge lead too long/thin?

[Jacob100]

I've just taken a punt on a cheap second-hand 42L fridge (Indel B TB42A).

The compressor runs perfectly on mains and from the rear 12v outlet in the truck as long as the engine is running. With the engine turned off or hooked up to a leisure battery it just shudders and cuts out instantly.

I have taken the homemade lead apart (standard cig plug/10A C14 connector) and cut the H05VV-F 3x1.0 cable from 2.5m to 1.7m to no avail. Then I tried again with a similar length of H05RN-F 3x0.75 with the same result.

Is the cable likely to be too thin? What spec should I be looking for? Anything else I can try in the first instance without taking the fridge apart?

Many thanks as always.

 

[David]

What volts does the leisure battery read with the engine not running

 

[Jacob100]

The leisure battery is freestanding in a battery box and showing 13.4-13.6. I've not been able to check the voltage in the LC.

 

[karl2000]

The leisure battery is freestanding in a battery box and showing 13.4-13.6. I've not been able to check the voltage in the LC.

is the battery box cig connector working OK? What you connect the fridge directly to the terminals of the leisure battery - does it work then?

 

[Towpack]

What is the voltage drop on the leisure battery with the fridge running and engine off? The 13.4v from the battery could drop significantly under load, more so than with the engine running and backed up by the alternator.

 

[Jacob100]

All the connectors appear to be fine.

I have just disconnected the battery box and wired up an inverter to the leisure battery and now the 12v lead works fine. The temp has dropped from ambient to 5 degrees in a matter of minutes. The inverter is reading 12.1v.

Leads me to think I should be looking into the wiring in the battery box ...

 

[Chris]

Looks to me like you have a 3 pin 240 volt plug wired onto a 12v cigar plug. The 12v supply should be with a 2 pin plug. In other words you're plugging 12v into the mains plug on the fridge, no?

 

[Jacob100]

No, it’s definitely the right connectors. Believe this range was geared towards the Russian/Eastern European market. I bought it from a Polish lorry driver in Wakefield.

 

[Chris]

OK the plug is a 3 pole but only two must be being used. I can see that the design is poorly thought out though. Any live lead plug should have the shrouded female end rather than in this case the exposed male prongs. I guess they've done that to prevent plugging the 12v into the 240 v which is fine, but it really should be a different plug completely. There isn't a 12/24 change over switch I suppose?

 

[Chris]

Sorry Jacob, in terms of the question about the cable, it should only pull 4 amps or thereabouts so really pretty much fuse wire would carry that current. I doubt it's too thin

 

[Jacob100]

There isn't a 12/24 change over switch I suppose?

No, not even an on/off switch. There's a thermostat and that's about it. Looks like they were sold as a basic, rugged model for commercials and 4x4s.

The good news is that after some fettling with the lead and the wiring in the box it now runs smoothly both from the leisure battery and in the car with the engine turned off down to around 12.3v. Always nice to know you haven't been ripped off when you strike deals off the M1.

 

[Chris]

Excellent