most affordable & simple way to run a mini-fridge and lights in RV for 4 days?

[yacht_boy]

Hi all,

I've been lurking for weeks, trying to soak it all in.

I'm renovating a 71 airstream. Propane fridge is dead. It came with a perfectly functional Fridgidaire AC mini fridge that I would like to keep. No model number or specs that I can find on the fridge so I am using 900wh/day as my placeholder for consumption, and hoping that it will not draw more than 750-1000w at startup (I don't have the right device to measure it).

Other than the fridge, nothing imperative that we need AC power for. 12v lights, fans, water pump. I'm ballparking 400wh/day for all that stuff.

I'd like to be able to take my family camping for 4 days and not have our food get hot or run out of juice for lights and fans. That's it. Not living in this thing, don't need bombproof $7k Victron/Battleborn systems, etc.

Not opposed to running the tow vehicle for a few hours to recharge via DC-DC, but I don't want to run it a few hours every single day. Fine with getting some folding solar panels but it's the northeast so we camp in the shade and sometimes it rains for a couple of days. So I guess I really want to be able to go 48 hours between charges, then quickly charge enough to get another 48 hours.

Replacing the propane fridge with a new one is $1500+ and then I still need to buy a house battery, charger, etc., plus I hate those fridges. Over $2k quickly.

Space available dictates a mini-fridge form factor, so low-draw chest/cooler DC fridges won't work. Isotherm DC mini-fridge that fits the space is $1700, and again I still need the battery and chargers and such so I figure I am better sticking with the cheap AC minifridge and buying more batteries. Probably over $2500 all in.

Victron stuff is expensive and complicated, quickly pushes me over $1k just in their junk to have inverter/charger, DC-DC charger with enough capacity to be useful, MPPT, comms, etc, then I still need to buy batteries. Everything about their system seems dauntingly difficult and overpriced for my needs. I think I can maybe do this for $1800, which seems like a lot, and install and just figuring out what to buy is so complicated.

Ecoflow Delta 3 with DC-DC charger and 220W folding panel is $1100 in my shopping cart right now. Seems like the best option except the standby draw is crazy high so it pushes me to having oversized house batteries and another big charger to power them, I end up back over $2k again.

Really don't want to have to bring a generator and gas with me to the woods.

Is there not a way in this day and age to run efficient lights, fans, and a small fridge for a couple of days for less than $2k? Was hoping to pull this off for about $1000, maybe $1500 max. I'm considering just going camping with two big coolers, one dedicated to block ice for the weekend and the other for food.

 

[HarryN]

Absolute cheapest way is to use a generator and 120 vac appliances.

________________

For just 4 days, the next cheapest path is to use dry ice and a good quality cooler setup.

Did this for years, tent camping with my family. For lighting, just use tent style lighting, things powered by AA or similar lights with stick to the walls and ceiling.

_______________

For a "start from scratch" arrangement, the next path in my mind is:

- 24 volt system built from 2 each, 12 volt AGM batteries
- Bogart engineering SC2030 based solar charger and monitor
- 12 position fuse block for charger inputs and loads connections.
- Any dual 12 / 24 volt refrigerator that you like.
- LED strip lights / 24 volt

Accurate Battery Monitor, Powerful Solar Charger & accessories

Save time & money with this kit consisting of the most recommended battery monitor, powerful & efficient solar charger , and accessories for use in RV's & off-grid cabins. AGM, flooded, lithium LFP & custom charging profiles.

www.bogartengineering.com

This is far better than any of the pre-built power systems and can handle solar panels either mounted on the trailer or placed far away into sunny spots.

_____________________

 

[HarryN]

Here is a little power system that I built under my work bench.

It has a 1 kW inverter, but you may not need that.

I made it double sided just because of where it was going, but no need either.

The DC side is literally just a 12 position fuse block, the bogart kit, and a couple of bluesea 187 breakers.

I originally had 2 Lifeline AGM batteries powering it, but have since gone to 4 of them as we now also sometimes run 2 refrigerators on it and outages here in CA are getting longer. (plus I already had the batteries )

___________

Everything in it - I already owned, so it didn't cost me much cash flow, but most people don't have this stuff sitting around like I do.

Example diagram - just use the parts that you need.

I use it as back up power for the garage refrigerator and misc.

My wife uses it as a handy place to plug in garden tools.

_______________

On the far left is a solar charger input, might not be able to see it.

To the right of the breakers is a USB port, that has become my favorite place to charge my phone and tablet.

 

[50ShadesOfDirt]

Trying to pick thru all your requirements AND constraints, the simplest answer seems to be a phased approach:

- install a battery-bank (sized to your needs), and strap an inverter to it ... choices are 12v, 24v, or 48v
- as you have a current 12v system, that leans things towards a 12v inverter to start
- recharge the battery-bank when you get home, with an appropriate battery charger for that bank

Operationally, you can run the inverter when needed and then power it off. 12v house lights and other critical items can continue to run directly off the battery-bank, as you started out at 12v.

Buy an inexpensive 12v inverter, sized to the things you want to run (1kw, 2kw or 3kw). Then buy as much 12v battery-bank (both in amp-hours, and in pairs) as you can then afford.

Next phases:
- consider propane gen, nice quiet model (allows recharge anywhere, emergency power, big loads)
- consider solar panels in the future, mounted on roof, plus mppt

At any point, when you've learned more and are ready to step up to reworking the RV wiring system, you can change to 24v or 48v, reusing the battery-bank, and changing out only the inverter (which was an inexpensive 12v model anyway ... use it in any other project at home).

Hope this helps ...

 

[LinuxGeek]

FYI, LiTime has a 280Ah 12v battery (3584Wh) which will almost get you 4 days at 900w/day. Currently they are $510 on sale.

 

[azjeff]

I too would suggest a small inexpensive inverter style duel fuel generator and run it on propane. We are approaching potentially the best shopping season of the year ( Black Friday)
Think Amazon, Walmart, Sam’s club, Costco, harbor freight etc.
Currently pricing is around $400-$500.
Forget solar “in the woods”
They make very quiet inverter generators that throttle the engine as power is required. Propane is a much easier and cleaner fuel to use for the unit also. Watch some YouTube reviews.

 

[OzSolar]

For just 4 days, the next cheapest path is to use dry ice and a good quality cooler setup.

Right!

I've had good luck with my knock off Yeti from Sam's Club and reusable ice packs. 3 is quite possible with proper cooler management and starting off with chilled or frozen food/beverages

Arctic Ice® Selector

Activity / Cooler Contents Alaskan Series Chillin' Brew & Cradle Tundra Series Freezing Temperature 32°F / 0°C 28.4°F / -2°C Cooling Temp 5°F / -15°C FOOD PICNICS DAILY LUNCHES BEER/BEVERAGES TAILGATING DAILY TRIPS ALL-DAY BARBECUES TRANSPORTING FROZEN GOODS HUNTING/FISHING FROZEN FISH AND...

arctic-ice.com

 

[Q-Dog]

Victron expensive ... blah, blah, blah. Here is your $2000 system.

$350 - A 1000 watt Victron inverter is $350 and will run that fridge easily plus give you ability to run a blender or other small AC appliance. You can go smaller (cheaper) if the fridge is the only load.

$170 - Victron BMV 712 battery monitor is $170, and that gives you accurate battery monitoring on a gauge you can mount anywhere inside the trailer, plus a bluetooth connection if you want to also monitor from your phone outside the trailer. You don't need any other comms. You can go cheaper if you don't want the gauge or the bluetooth option.

$200 - I would add a $200 IP22 smart charger so if you stay somewhere with AC power you can plug in and charge the batteries. (Smart means bluetooth is built in, so this can also connect to bluetooth network to coordinate charging with the battery monitor and solar charge controller.)

$350 - A pair of DC House batteries were about $350 delivered to me. Lots of similar deals can be had if you look around.

$90 - Victron 100/20 smart charge controller is $90 if you want to add some solar, and you can monitor it with bluetooth. The 712 and the 100/20 can network together with the built in bluetooth to make the system more versatile in the future (add a temperature sensor to better protect the batteries during cold weather charging.)

Now you are at $1160 plus tax. Add a few solar panels, wiring and fuses and you have a complete system and probably still under your $2000 limit.

 

[seneysolar]

Hi all,

I've been lurking for weeks, trying to soak

Hi all,

I've been lurking for weeks, trying to soak it all in.

I'm renovating a 71 airstream. Propane fridge is dead. It came with a perfectly functional Fridgidaire AC mini fridge that I would like to keep. No model number or specs that I can find on the fridge so I am using 900wh/day as my placeholder for consumption, and hoping that it will not draw more than 750-1000w at startup (I don't have the right device to measure it).

Harbor freight kill-a-watt meter $30 worth every penny

Other than the fridge, nothing imperative that we need AC power for. 12v lights, fans, water pump. I'm ballparking 400wh/day for all that stuff.

Hard to beat the Victron 1200w/12v $350

I'd like to be able to take my family camping for 4 days and not have our food get hot or run out of juice for lights and fans. That's it. Not living in this thing, don't need bombproof $7k Victron/Battleborn systems, etc.

Youll need a large battery. Lots of choices out there. Battleborn is at the bottom of my list.
Id look at Vatrer, something like their 460ah 12v if you have room. $1100 right now.

Not opposed to running the tow vehicle for a few hours to recharge via DC-DC, but I don't want to run it a few hours every single day.

Dc-dc is generally limited to about 40A unless you make vehicle modifications. That gets $$ fast. I wouldn't bother.

Fine with getting some folding solar panels but it's the northeast so we camp in the shade and sometimes it rains for a couple of days. So I guess I really want to be able to go 48 hours between charges, then quickly charge enough to get another 48 hours.

You dont need solar , but youll likely enjoy it if you have it.

Victron stuff is expensive and complicated, quickly pushes me over $1k just in their junk to have inverter/charger, DC-DC charger with enough capacity to be useful, MPPT, comms, etc, then I still need to buy batteries. Everything about their system seems dauntingly difficult and overpriced for my needs. I think I can maybe do this for $1800, which seems like a lot, and install and just figuring out what to buy is so complicated.

Victron is a good balance of quality and reliability. Ive had a little bit of everything. You dont need to buy into all the interconnect merchandise if you can live without the features and adjustments. Victron stuff can be used stand alone out of the box. Some of the retailers can even program for you if you want something changed.

Ecoflow Delta 3 with DC-DC charger and 220W folding panel is $1100 in my shopping cart right now. Seems like the best option except the standby draw is crazy high so it pushes me to having oversized house batteries and another big charger to power them, I end up back over $2k again.

Ecoflow is $$$ for what you get and its not that impressive.

Really don't want to have to bring a generator and gas with me to the woods.

You should. Honestly a suitcase generator is one of basics that everyone should have. The Powerhorse is on sale at Northern Tool for $450 right now. Great unit.
Add a charger for the battery and you can camp as long as you want, charge the battery on day 4 and only use $3 worth of gas.

Is there not a way in this day and age to run efficient lights, fans, and a small fridge for a couple of days for less than $2k? Was hoping to pull this off for about $1000, maybe $1500 max. I'm considering just going camping with two big coolers, one dedicated to block ice for the weekend and the other for food.

Remember that if you buy a really nice system and its neatly installed in the camper, youll likely see at least half of return in resale value. If you buy a bunch of cheap portable stuff. Its of no value after using it.

 

[yacht_boy]

Thanks all for the comments. Seems there really is no good offgrid solution to refrigeration yet.

Not interested in a generator, especially since for an AC fridge I would need to run it 24x7.

Leaning towards a big knockoff Yeti cooler packed with frozen gallon jugs of water and dry ice for long weekends. Run the fridge for a day or two until the big house battery is at about 1/2 power, then unplug it and throw a frozen gallon jug in each day. Not very space efficient and adds a whole level of complexity, but for the savings and only doing this a few times a summer it might be the best way.

BTW, my total power consumption for 4 days would be ~5200wh + inverter standby draws (which can be huge - more than the fridge itself on most inverters that aren't blue).

 

[azjeff]

My 1k watt, $110 pure sine wave inverter has been in use for 7+ months now, 24/7 duty and uses 6 watts at idle.
Came with a 3 year warranty. My “fridge” is a chest freezer ($200) that I control with a inkbird digital thermostat ($ 35) its uses very little power. Mine uses 700 watts for about 1 second, then uses 70 watts for another 1-2 mins. Get a kill a watt and measure exactly the start up and running watts of your fridge. Leave it connected for 24 hrs and get a record of the total energy used. Your situation isn’t complicated and certainly doesn’t require $2000 to solve. You could get a small inexpensive duel fuel gen, run on propane( much better for the gen and easier to deal with fuel) one decent sized battery and a small inverter and be all set. My 200ah Lifepo4 battery was $390. Charge the battery as needed with generator.
If you are certain you’ll be camping in a sunny area, you could get 200-400 watts of panels and a small Victron solar charge controller to replace the generator. But, shade, clouds etc…is gonna kill your solar harvest potential.
Generator would serve other emergency uses outside of camping tho.

 

[OTRwSolar]

Thanks all for the comments. Seems there really is no good offgrid solution to refrigeration yet.

Not interested in a generator, especially since for an AC fridge I would need to run it 24x7 . . . . . .

Why would you need to run a generator 24/7? A typical 300ah lifepo4 (via inverter) should be able to power a small, 1-2a/120vac 3-5cf compressor fridge for at least 15 hours (100% compressor duty cycle). Might even pull-off as much as 36-48 hours, depending on the fridge and compressor duty cycle (ambient dependent).

I hear ya ref your aversion to using a generator. However, on the flipside, for some, it's not a whole lotta fun to compromise an entire camping trip (on every level) in order to get your ah consumption low enough to dry-camp without a generator (or with limited solar). Pick your poison.

You previously mentioned using a dc2dc charger. We've used dc2dc chargers for years. They're awesome when you're on the road traveling. Not so great once you've reached your destination. It can take 5-8 hours to charge a depleted 300ah lifepo4 with a 40-60a dc2dc charger. That's a long, long time to be (high) idling a vehicle in a campground.

For what it's worth, we spent less than $2k installing a DIY 304ah lifepo4, Victron Multiplus II 3000, plus all the supporting hardware, in our tear-drop travel trailer. We can power the air conditioner (100% compressor duty cycle) or microwave for well over 3 hours before we need to charge. When it's time to charge, the Multiplus can output as much as ~100a of charge current while being powered by a Honda 2200 (semi-permanently mounted on the trailer tongue inside an aluminum enclosure; use it while driving or camping). Just 3 hours to charge from 0 to 100. Or . . . we can choose to power the a/c (or microwave) and, at the same time, push 35-40a of charge current into our lifepo4 using the Honda and the Multiplus power share/assist mode.

After using generic inverters and OEM RV converters for years, the Multiplus was a game-changer.

 

[seneysolar]

Thanks all for the comments. Seems there really is no good offgrid solution to refrigeration yet.

There is, but to be honest you have a lot of stipulations here with equipment. 4 days of refrigeration on your budget of $2k can be done but you still don't feel its worth spending the money on because you don't do it often enough. A little suitcase generator is the answer here. Its probably cheaper than the 2 coolers and your ice bill will outrun the gasoline consumed. I use an ICECO fridge/freezer that I cant even tell is running. It draws less than 1 amp when its running and it can run on AC or DC, Its amazing... If you are renovating an old camper, this is the time to install something efficient.

Run the fridge for a day or two until the big house battery is at about 1/2 power, then unplug it and throw a frozen gallon jug in each day.

So does your camper already have an Inverter? How do you run the fridge off your house battery? What are your house batteries? They could likely be replaced/added to with LFP to gain some useful capacity.

BTW, my total power consumption for 4 days would be ~5200wh + inverter standby draws (which can be huge - more than the fridge itself on most inverters that aren't blue).

There are several 460AH and 560AH battery options out there that can do this with a single unit. You are on the right track watching idle consumption. Staying small will help. Sounds like you can get by with a 1k inverter. That should be less than 20W from most manufacturers. Less than 10W from Vic. I would go "dark" and shut everything down at night while you sleep (including the fridge). This will cut power consumption significantly and I bet it will still be cold in the AM since nobody will be opening the door.

 

[Rednecktek]

Ok, as the resident broke ass anti-smurf on here, I feel like I gotta throw in my $0.02 worth of advice.

If you're up to a little work and have some basic electrical tools, I built my 304ah batteries with heaters for about $600ea. Some cells, a BMS, a pet blanket, some wires, lugs, and a cheap digital thermostat all packed into a Noco DC31 battery box gets you 4kwh of battery.

If you're not up to building, get all the capacity you can, there's a certain point where a 2nd battery is a better value, so check the watt-hours per dollar. If you can mount the batteries inside the living space it'll save you a good chunk of money over the "heated" versions.

Wzrlb or Giandel 1kw inverter might be overkill but they're well regarded and cheaper than anything blue. You'll definately want to grab a kill-a-watt and do a test run on the camper while it's still at the house. You can get a good reading by "camping" in the yard for a weekend using all the lights and fridge and MargaritaMaster-1000 so you can size appropriately. Well worth the $30.

I'm a big fan of either the PowMr or HQST solar controllers, but Vevor has a 50a MPPT for about $100 that will turn solar DC into battery DC just fine. No need to reinvent the wheel.

Folding solar panels are where the money is going to go. You pay for the premium but the weight reduction in the trailer and ability to move them around to the sunny spot is really handy. A couple good size 200w panels in parallel to a splitter jack mounted outside running to the MPPT will get you some charging. Ignore the name brands that go "on sale" for twice the price of anything else.

A 125a MRBF fuse or smaller, some DC outlets if you want them, some copper wire, you should be able to get your mini fridge happy all weekend.

On the fridge, get the largest one you can physically fit in there. The amount of energy used is pretty much nothing between a 6.8 and a 7.1 cubic foot fridge.

 

[robbob2112]

I would split the difference and buy all litime - battery, 20amp charger, inverter, and battery monitor. Not as labor intense as building a battery from scratch, good quality without being top tier, but they are responsive to and trouble or warranty claim. I've been using their stuff for a year without any trouble.

Add a MRBF fuse and battery switch and for around $700ish you have a system that will do the job.

 

[J.H.]

Not interested in a generator, especially since for an AC fridge I would need to run it 24x7.

Unless you’re in a very warm place place No one has to run a decent refridge 24/7 to have cold food … During hurricane Helene , I used a 2200/watt Honda inverter gen set to run a friends full size 20 year old standard kitchen refridge.

He ran it about 6 hours a day on eco-mode for 2.5 weeks ..
Kept frozen stuff froze and cold stuff cold..
( freeze up some water jugs to help maintain the temp in the reefer )

He turned it off the rest of the time …
used about 3/4 gallon of gas a day ..super quiet… 47 lbs.

Was it perfect …NO.
Did they stand and gawk at the food holding the refer doors open…NO..
Did they open the door every 3 mins…NO..

But it allowed them to live great , eat , microwave , boil water and make coffee when most everyone else lost all their cold food…and sat with nothing …

With your small refer , add 2 inch’s of insulation around it and you can cut energy use way down…

It’s not as hard as it sounds once you do it a bit , you will quickly become adaptive in ways you don’t know yet.. you will get good at workarounds…

Hint : great gear repays you with great results …cheap stuff just messes with your head.

J.

 

[yacht_boy]

Thanks for all the comments and helpful suggestions. Gave me a lot to think about. I appreciate the comments about a generator, but I have my reasons for not wanting to use one.

That list of equipment from Victron was helpful. Adding it up, it came out to over $800 before batteries, wires, solar panels, bus bars, plywood to mount it to, etc., etc.

I ended up taking advantage of some Black Friday pricing on Ecoflow equipment coupled with some coupon codes. I added a cheap Amazon 300Ah LiFePO4 battery and Ecoflow's 800w DC-DC bidirectional charger that lets the battery send power to the Ecoflow, or it can be reversed and the Ecoflow can charge the battery.

All in I spent about $1600 plus tax and I have 380AH of power between the Ecoflow and house battery, the built in inverter/MPPT/monitoring in the Delta 2, a 220w folding solar panel, DC-DC charger, and a backup 60A charger for the house battery and a shunt/monitor for the house battery. Could have made it a bit cheaper but I wanted the extra charger and shunt for the house battery.

 

[time2roll]

I'm renovating a 71 airstream. Propane fridge is dead.

Get a campsite with an electric connection. Still can be a bit remote... no need to be at KOA or some other pretend resort.

Put the saved money eventually to a propane fridge. Airstream is never going to be the low cost RV renovation. My propane fridge works perfectly for 19 years so far. They might be a bit improved since the old continuous pilot light system.

BTW still need a small 12v battery to operate the emergency breakaway braking system. (I assume this is a trailer) Spend your time to make sure the brakes work and the bearings are packed, lights work etc. Kids will have a ball... nothing much needs to be perfect as long as the RV is safe.

 

[DPC]

I keep circling around and around this particular Direct cool fridge.
And then I look at doing the Dc conversion on it myself....

Then I loop back and look at inverters and then look further into some simple modifications that turn the inverter on and off as required in a dedicated circuit for the fridge only while I save my big inverter for the big jobs...

I still can't decided

I really cant understand why a DC fridge cost so much and no one at a factory in China cant just run them down the line now and then in a bulk order to knock down the price.