Fridges

[Chaddz79]

Just wondering how long people get out of there fridges when running on a deep cycle battery.

I have a waeco (non termostat) that flattens mine in around 6 hours but i realise that a fridge with a thermostat should give you longer? so what do you get?

[Jaffa]

Depends on the size of your battery, the way to work it out is find out the Amp Hour rating of your battery (Ah). The most common size for a standard lead acid 12Inch battery is 75Ah. Also find out what Amp draw your fridge is, it should say on the back of it, it may be in watts though, to convert Watts to amps divide the wattage by 12 (battery voltage) eg 240Watts / 12 is 20Amps.

Once you have your amp draw divide you amp hour rating by your amp draw eg. 75Ah / 20Amps = 3.75 this is how long in hours your "fridge" should run for. With a fridge it doesn't run all the time so with your run time times it by 2 eg. 3.75 x 2 = 7.5Hours.

It will never be exact because different battery manufactures rate their battery in different ways which can effect there stated rating, also your waeco may have a voltage cut off which may affect how long it runs for, if your battery is not getting to full charge or is old it wont have as much available capacity. Also if it is 35Degrees outside your fridge may run all the time then your run time will be greatly affected

Brendan

[DamTriton]

Just wondering how long people get out of there fridges when running on a deep cycle battery.

I have a waeco (non termostat) that flattens mine in around 6 hours but i realise that a fridge with a thermostat should give you longer? so what do you get?

What sort of fridge (model number if possible), compressor or "solid state" (Peltier effect)?? Usually the 10-15 litre ones ("travel fridges") are the Peltier effect type and are known to draw 5-10 amps continuously, whereas the compressor ones use an average of 1.5-2.5 amps. Going on the duration of operation I would say you have a Peltier effect one. Anything above about 25 litres and they are all compressor.

You could also have issues with the battery or charging of the battery. I don't have a second battery but have used mine (CDF-40) on my starting battery overnight with no issues.

[Chaddz79]

yea, its not a compressor fride, just a 15l waeco.

the battery is 720cca 800mca.

im sure that the contiunous running of the small fridge is whats killing it, but im wondering how long i would get out of a large (compressor type) engle or waeco?

[DamTriton]

yea, its not a compressor fride, just a 15l waeco.

the battery is 720cca 800mca.

im sure that the contiunous running of the small fridge is whats killing it, but im wondering how long i would get out of a large (compressor type) engle or waeco?

NOTE: CCA/MCA IRRELEVANT, need to know "amp hour" (AH) of the battery

Way to work out how long it will last safely.

Take battery AH, divide by two (safety margin for battery longevity), eg 90 AH/2 = 45AH

Assume 2.5 amps average used by fridge (compressor type, mid-worst case example).

In the given example, time = AH/amps
=45/2.5
=18 hours safely, could go to 24 on occasion if needed without charging or damaging the battery.


Leave the little fridge for mum's shopping trips, that's about all they are good for. They will keep things cool, but not cold, and generally don't have the ability to actually cool things down from room temperature. Invest in a decent compressor fridge for any "away trips".

[Chaddz79]

battery does not have this marked and cannot find it on the net

It is an Exrider Marine and RV