Minimal Amount of Mileage per Day to power a mini camping fridge?

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Hi there

So in short, I have been living the car life instead of the van life for about 2 years now. (yes, I am living in my car). I guess I found myself in this way of living in order for me to earn and save a tonne of cash without the limitation and responsibility of rent , bills, etc. The long and short, is its really worked well.

There is however the limitation that, my diet currently runs on tescos, as well as tinned foods etc. While quite healthy, its expensive, probs spending about £15-£20 per day, as I work about 60hrs/week and also attend the gym 4-5 times a week. With this said, I know that I could probably half these costs, if I had access to my own basic facility whereby I could grill and fry my own food, as well as power a fridge unit, which could hold enough basic food items for 3-5 days e.g. steak, chicken, salad, etc.

Everyone talks about vans, which dont get me wrong, is a good idea, if you can afford it and have the resources, however, the car life is something I have grown into and so I want to build on this, instead of changing my vehicle. With that in mind, as far as cooking and food storage goes, I have considered the idea of purchasing a mini camping trailer, and fitting it with a basic foldable worktop, as well as a compartiment for a small water bowser and a section for a fridge. The fridge (I imagine), would be powered by the battery which would draw its energy from the daily driving I do per day.

Now this is where I need expertise:
-if I wanted to power a fridge which ran on 60watts, could operate through 12/24v and had a DC of 4.5/2.2A, would driving say 10-20 minutes per day, be enough to power the battery and the fridge for 24hrs (working on the basis that I do about 10-20minutes of driving everyday).
-would my battery for the fridge, need to be connected to the main car battery in anyway? I am assuming not, as because the trailer, the fridge and the battery are their own self contained facility, I would not need to do this.
-lastly, is there an apparatus, that can be attached to the wheels of the trailer, that transforms the kinetic energy of the wheels moving during transit, into storeable energy in the battery?

Thank you for reading, if someone can help me out with this, it would be a great help. The last 2 years have been pretty interesting, this project, would be a great advancement.

Trooper

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10 - 20 minutes won’t do it, if your fridge runs at 4.5 amps for 24 hours you are looking at a total draw of 108 amp hours. You’d need two 100 amp hour batteries to pull that off.

Batteries will have an input limit as well. Meaning they can only charge so fast. For lithium that is not the case and will take what you can five them. Still if you alternator puts out 108 amps to the battery, you would need to run an hour to pump back up the 108 amps. You could look at a solar briefcase to supplement when you are no moving. Our Dometic averages about 2 amps per hour. Good luck.

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Hey Bretty, thanks for that - very insightful, great to see how the numbers breakdown.

Say if I was to go for: " Dometic Mobicool MM24 DC 20litre electric coolbox, blue, 12 V" from the site Freewheel, then with a wattage of 48watts and a rated input of 3amps, then it would draw a total of 72 amps over 24hours. For a 100 amp Lithium alternator, this could power the fridge for 24hours, on 45 minutes of run time?

If I was to have 2 batteries instead of 1, could I halve the charge time to 22.5 minutes (my logic deducing that each battery would store 31 amps each)?

Cheers

Edit: I guess bottom line, is there any sort or set up, whereby I could charge a 20litre fridge-box, so that it can run for 24hours, on 10-20 minutes of driving time at an average speed of 40-50mph?

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watts / volts = amps (for reference)

I highly doubt you will get what you need out of driving 10 - 20 minutes a day without some extra power. There are some other factors involved here. For instance the alternator on your car is probably not capable of pushing out that much amperage plus what you car uses while running. You need to determine what alternator you have and how much amperage it can push. Some alternators push 30 amps and some push 220. Typically a heavier alternator for a heavier duty vehicle.

Also remember that these amp draws on the fridges are at full power. My dometic has a rating of around 5 amps max draw (could be 8) I can’t remember, but this is only initially when the compressor is turning on. It’s about 3 amps while running. It only runs a few times an hour. So my actual draw is only about 1.5 amps per hour. The fridge is only running while cooling and will shut off once it reaches temp until if falls back out of range again. My fridge really only pulls 30 - 40 amps a day and is much larger as I havre the cfx3 dz75

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