24 volt fridge compressor

[hatespoliticians]

i have a friend with a 24 volt fridge. he has installed 3 different inverters and all 3 will not run the fridge they will run motors on different things though. he can take 2 12 volt batteries and get 24 volts d,c and this will run the fridge. anybody got any ideas on what is happening? it's not making any logical sense anymore

 

[James]

A 24v D.C. fridge will not require or work with an inverter, it needs dc.
if you are trying to run it from battery, then use a bank of batteries at 24v.

 

[snowhead]

Is the output of the inverters 24v D.C?

 

[telectrix]

if you have mains electric, you need a 240V A.C. to 24V D.C, power supply.

(or in US 120V/24V., depending on the relevant supply voltage).

 

[Jim_e_Jib]

Fridge compressors typically have a high start up current. It may well be that the equipment you have cannot supply this current whereas the two batteries in series can.

It would be worth checking with the manufacturer of the fridge what the start up current is and spec-ing the power supply to suit.

 

[brianmoooore]

Fridge compressors typically have a high start up current. It may well be that the equipment you have cannot supply this current whereas the two batteries in series can.

It would be worth checking with the manufacturer of the fridge what the start up current is and spec-ing the power supply to suit.

Extra low voltage ones tend to be absorption types, which don't suffer from this, but we haven't been told what type this is.

 

[Lucien Nunes]

OP please confirm the model number of the fridge and exactly what power configurations have been tested.

Extra low voltage ones tend to be absorption types

Outside of perhaps specialist medical products I'm not sure that's still true. Certainly, absorption fridges for leisure applications tend to offer a 12/24V DC power option, but typically to allow an LPG-fired appliance to remain on and cold while on tow in a caravan when LPG cannot be used. But the power consumption is so high relative to a DC compressor fridge, even a 230V AC fridge run on a separate inverter, that it no longer makes sense to use absorption for battery operation.

E.g. my old Electrolux RM212, the standard 60 litre caravan fridge for decades, used a constant 96W on 12V just to stay cold in normal weather. Replacement R134a 98 litre compressor fridge uses 24W running at 25-50% duty, i.e. 6-12W average, as little as 1/8 of the consumption of the absorber.