Running a 12v fridge

[Wheelie]

Hi guys
I'm hoping some can answer my question, I want to install a second battery to run my fridge whilst overlanding. The problem I have is my fridge is 12v, 75w and draws 6.25 amps, which is fine all the time the engine is running but when I stop overnight say finish driving at 1700 hours and start again in the morning at 0900hrs that's 16 hrs the fridge is using the battery so I worked it out that I would completely discharge a 140 ah battery every night. Would I use less battery if I ran it off a 12v to 230v inverter. Fridge spec for 230v is 82w and 0.36amp. 1.2kw per 24h.
Would I actually use less battery as I converting 12v to 230v.
Hope you can understand my question.
Regards

 

[macabethiel]

Hi guys
I'm hoping some can answer my question, I want to install a second battery to run my fridge whilst overlanding. The problem I have is my fridge is 12v, 75w and draws 6.25 amps, which is fine all the time the engine is running but when I stop overnight say finish driving at 1700 hours and start again in the morning at 0900hrs that's 16 hrs the fridge is using the battery so I worked it out that I would completely discharge a 140 ah battery every night. Would I use less battery if I ran it off a 12v to 230v inverter. Fridge spec for 230v is 82w and 0.36amp. 1.2kw per 24h.
Would I actually use less battery as I converting 12v to 230v.
Hope you can understand my question.
Regards

Makes no difference Watts is a measure of energy and the product of Volts x Amps gives you Watts. If you up the voltage the amps go down but watts consumed stay the same.

 

[don simon]

Don't forget that the fridge is unlikely to be pulling for all of those 16 hours. Pre cool the fridge before leaving home and throw in a few frozen cool box packs to reduce consumption.

 

[Wheelie]

Makes no difference Watts is a measure of energy and the product of Volts x Amps gives you Watts. If you up the voltage the amps go down but watts consumed stay the same.

So it wouldn't make any difference to the length of battery time?
Sorry I'm a bit thick when it come to this

 

[Wheelie]

Don't forget that the fridge is unlikely to be pulling for all of those 16 hours. Pre cool the fridge before leaving home and throw in a few frozen cool box packs to reduce consumption.

There is no thermostat operation when running off 12v so constantly pulling 6amps

 

[don simon]

There is no thermostat operation when running off 12v so constantly pulling 6amps

What fridge is it and how old?

 

[Blocky10]

Would a solar panel help?

 

[Wheelie]

What fridge is it and how old?

It's a quest 3 way, I know what your going to say, run it off the gas. I have thought of that but I'm trying to avoid taking it in and out as I want it on a slide. And if it's raining I will need shelter so trying to avoid gas.

 

[Wheelie]

Would a solar panel help?

Yes probably, but how much,

 

[don simon]

It's a quest 3 way, I know what your going to say, run it off the gas. I have thought of that but I'm trying to avoid taking it in and out as I want it on a slide. And if it's raining I will need shelter so trying to avoid gas.

Not at all. I was looking at the cost of a new fridge vs the cost of batteries to run an older or high amp fridge.
I made the mistake of buying a 5amp fridge, which does have a stat though. I wish I had found this this website before buying mine.
Spending more on a 0.32Ah fridge and less on the battery/solar set up has to better than a cheaper fridge then the headache of powering it.

 

[Blocky10]

Yes probably, but how much,

I dunno but I'd like to:lol
Not much help :doh

 

[Lazy-Ferret]

In answer, no using an inverter will not help. As thay say, you don't get anything for nothing, and inverters are not very efficient, most only hitting 75% if the best, so you would actually use about 25% more power.

Sent from my SM-G930F using Tapatalk

 

[solarman216]

As many of you know I run on 24v DC at home with one tonne of batteries, my fridge (which is the biggest user of power, including the washing machine but not the tumble drier) it is the 12/24v dc compressor version and pulls 5 amps at 12v when running but as thermostatically controlled only runs around 12 hours out of 24, (runs on 12v as have completely separate 12v battery just for the purpose with solar panel to supplement charging, to be honest with the three way style fridge it is best run off gas, batteries are a no no in your situation, Rick

 

[panelbeater]

i got a new fridge from obriens for my mates van,very good they were too crossref the old fridge to find a direct replacement,not cheap though.
now as said a normal van fridge should be run on gas,however i know a vanner that runs it on the 12v set up.
2x110 batteries,2x100w solor panels but the crucial bit is an inline thermostat so it cuts in and out saving power.
it runs when engine is running then it uses the batteries from then on through the stat.
it also depends on daylight hours sun etc.
but it does work.
rick knows more about it as is off grid.
do not forget that fridge will be closed most of the night.

 

[macabethiel]

Probably not relevant but !

We have a cool box that we bought from Aldi last year to keep milk and frozen stuff cool when we go shopping and for keeping drinks cold when we have a picnic. It also has a mains plug so it works on the thermostat at home.

We plug it in the Mains for about half an hour before we go shopping and drop in a couple of those plastic blocks out of our freezer to give it a head start.

I leave it running from the boot auxiliary socket of the Jeep. When we get home I am always a bit alarmed that the plug in cigarette lighter type connection is burn your fingers hot to the touch. This might be usual but I suspect the female connection might be corroded or the spring finger on the male side is a poor fit.

Not flattened the battery yet, longest ever run has been around 3 hours.

 

[Wheelie]

Think it's gonna be to much of a PITA to fanny around with the 2nd battery as primerly it's only for the fridge I'll just have to run it on the gas when stopped overnight. Anyway I've since spent my money on other things.Thanks for the responses anyway.
Oh new additions are
Triton roof rack full length
Hawkwing awning, got to have shelter from the sun and the rain :clap:thumb2

 

[terranosaurusdoug]

Think it's gonna be to much of a PITA to fanny around with the 2nd battery as primerly it's only for the fridge I'll just have to run it on the gas when stopped overnight. Anyway I've since spent my money on other things.Thanks for the responses anyway.
Oh new additions are
Triton roof rack full length
Hawkwing awning, got to have shelter from the sun and the rain :clap:thumb2

Ooh, pics of the awning when fitted mate :thumb2

 

[Wheelie]

Will do matey :thumbs