RV compressor fridge power usage

Or on blogs on this site go to
Electricity for camping
Very usefull to work out what you need.

I agree with Gronk,
But if you can get more Solar panel into your setup you’ll be better off. Panels are the cheapest bit. And hopefully get your batteries full every day.
Cheers
Shane

Any charging from a vehicle alternator via a cable to the van batteries has to be through very heavy cable so amps will actually flow. Any resistance will see the vehicle system quickly approach normal reg voltage when started and the cable limiting flow. Because there is little potential difference between an alt which is possibly 14 v and the batteries, already depleted and around 12 v or 12.2v, there is only 1.8v differential to make make/force amps to flow. If the cables are heavy enough, the alternator reg voltage will be lowered while amps flow. Unfortunately, at idle a vehicles alternator isn't really able to provide much amperage output until it is spinning at a reasonable speed to allow rotor magnetism field strength to be converted to amps in the stator. SO, above idle may be better than at idle. Idling will indeed take a long time because all electrical parameters are near their lowest and not approaching the optimum. Quicker with a 40 amp 240v ac smarter charger running off an Eu 10 Honda as suggested.

Good on ya RMD, we should call you captian obvious.
What if there was a BC DC unit in the van?
If the vehicle was set up to charge the vans batteries dont you think all that would have been considered?
Most late model alternators are capable of producing 20 amps or more at idle so the van batteries would get a fair kick,
but like said, it would take a very long time to recharge the batteries but would get the fridge cold again.
The small genset would be the better option.
Solar is good but it has its limitations.

There was no mention of DC DC units. What if the seller has thought of everything charge related and the posters questions are redundant? 20 amps at idle is still subject to cable resistance and subsequent losses in charge rate delivery. You may realise some of those things but the replies here are for the poster to evaluate. 20 amps is only 10 amps per battery, of course you know that, but the OP may not realise the batteries can take double that charge rate if it is available to reasonably promptly recharging the batteries. Just idling isn't going to be realistic is it? So faster will be better/ more effective The fridge is only going to demand around 4 amps and only when it is trying to cool, so not a large relative load at any time. Unless the batteries were below the fridge threshold dropout voltage then it will still be running and no cold lost at any time. Therefore it can't get cold again if it is already cold and operating via it's thermostat control. I hope this clarifies items for the OP even if you can't accept any clarification. I simply stated items which you did not.

RMD,

I simply stated that solar alone can not be relied on for extended periods without some form of mechanical energy production as a back up and mentioned 2 practical forms.
You seem to have took it upon yourself to demonstrate your uncontrolable urge to convince yourself you are an expert on everything by stating some obvious facts that are totally irrelivant. If the vehicle was intended by the OP as the only form of back up IF he intended extended stand alone trips he would have had the vehicle set up for it and everything you found on the net would have been addressed by a professional that doesnt rely on google.

Now if you can describe a solar set up that can sustain extended periods of poor light conditions without back up then please do so.

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Hi Bob,

Perhaps you should tell this to WAKO on Thread 139982 above? Although I doubt he will accept it. lol

Excellent answer, thank you.

So...
4x150w @ 299ea =1196
2xFullriver @ 469ea =938
MPPT controller =499
Tot 2633 + fitting

I'm thinking one panel, one battery, 3-way fridge, no noise. The compliance plate for a 190lt gas fridge states 36gms gas per hour = 10days per bottle (lets say near enough). $75ish per month, $900 per year, but halve that 'cos I'm expecting half the time in a caravan park.

So $450 a year to feed a gas fridge. That's about 6 years to breakeven.

Hi Alistair P,

You need to factor in the cost of staying in a caravan park. If you are self sufficient with power, you do not need to stay in a caravan park, but can stay in a cheaper camp ground that has a shower &/or toilet if that is all you need.

Personally, for efficiency, I would rather have a compressor fridge over an absorption fridge. Do not have to be perfectly level to work efficiently, the three I have are not noisy, 1 Engel, 1 Dometic & 1 Waeco. Yes, if stationary for persistent cloudy days, you do need to top up the batteries either with the car or a genny.

Macca.