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Residential Fridge

Spooby_Doo

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Howdy -

I have 16 3500 Cummins with a 220Amp alternator. Stock Batteries.

I'm looking for a intelligent solution to run my 120v residential camper fridge with truck power on travel days.

I see two ways to accomplish this:

1. 1000W inverter wired to truck with power being supplied via the 240v Input then isolate the fridge so its the only draw.


2. Upgrade the RV batteries and try to maintain them with the standard 12v supply


Any help would be appreciated
 
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Probably both voltages.

This has to be a common desire on campers, someone has to have the easy answer I would think. Not sure I'd want a 1000 watt inverter in continuous use like that, powered by the alternator.
 
There is an easy answer, but it depends on the fridge. A fridge that runs on 12v and 120v would be extremely rare. Most RV fridges are either 120v and propane, or 12v.

This kind of stuff is what my company does.
 
"Residential" fridge in an RV means 120V AC. 'Cmon, you guys should know this...
My RV claims to have a residential fridge but it's 12v. They've changed the terminology in the last few years:

 
My RV claims to have a residential fridge but it's 12v. They've changed the terminology in the last few years:


Valid data point and Furrion should be bitch slapped for doing that. Is that like "Military Style" weapons of war? LOL
 
So the fridge is 120v.

But I wouldn't mind having both solutions just for my own knowledge. I agree that a dual voltage fridge sounds like a Temu product
 
So if since the fridge is 120, if you want to install a power inlet on the front of your trailer so you’re not running a cable down the side, you may be best going the inverter route.

If the fridge was DC I’d probably suggest using a DC to DC converter, but for your fridge that would require running an inverter in the RV anyway, so you may as well just save the wiring and get the power to the trailer via extension cord.

If you wanted to add the second alternator to your Cummins you could even run a 2400W inverter off the truck, and then you’d be able to run the AC in the trailer.
 
Would I need to upgrade the batteries from stock on the truck to handle the output from dual alternators?
 
Would I need to upgrade the batteries from stock on the truck to handle the output from dual alternators?
My 6.4 has single battery but dual alternators. No need to change battery specs. I do like the idea of dual alternators if you run an inverter full time.
 
I second what Dave said above. No need to upgrade the battery.
 
Would I need to upgrade the batteries from stock on the truck to handle the output from dual alternators?
Only if you were not running the truck while powering the inverter.
 
Starter batteries are intended for high performance ( fast charge / discharge rates) for short time periods.

RV and Marine batteries are designed for more moderate performance over longer time periods.

While there is overlap - using either one for the wrong application will shorten the lifetime, sometimes quite a bit.

_____________

So let's look at two "use concepts".

1) The refrigerator will only be powered when the truck is running:
- In that case, just hook an inverter up to the starter batteries with a relay that turns the inverter on / off with the engine running.
- It is important that the inverter turns off when the engine goes off, as they have a standby power draw even if no power is being used, usually in the 15 - 50 watt range.

2) The refrigerator will be powered when traveling and you want it to stay on:
- In this case, the truck power system is used to charge up a separate / auxiliary power system for use by the refrigerator
- A battery to battery charger or inverter to 120 vac charger are used to move power from the truck to the auxiliary power system

The auxiliary power system has it's own Marine or LiFe batteries and inverter to keep the refrigerator running ( like a modern RV )

On conversion vans, this is the primary motivation for putting solar panels on top of them, to keep the beer cold.

You can buy canned "portable power systems" , DIY, or there are marine / mobile electrical system builders all over the country - really all over the world. I do it and so do many other people. It isn't complicated, but there are a lot of small details and the tools are expensive. Just like tires, wheels, and suspensions, there are a range of components and price points.

The canned "portable power systems" are the lowest cost initial purchase path. Similar to a cell phone, they don't work when it is below freezing and mostly cannot be repaired or have the battery replaced.

The ones built by marine / mobile electrical system builders usually use marine grade components, relatively standardized methods and anyone can edit / repair when someone else built, even in another country. They "tend" to be more vibration resistant.

Any of these paths work, it is just a matter of choosing what makes sense for you.
 
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