48V Air Conditioner for RV

Maintenance Heating & Air Conditioning
1

I’m looking at AC options compatible with the EcoFlow 5kWh Power Kit for my Mercedes camper conversion. I live in Florida so it’s important to maximize energy to power AC and other small items for a couple days off grid.

I was originally considering the Nomadic X3 48V but it’s on backorder. The alternative is the Coleman-Mach 10 13.5K 48v but I hate how high profile it is.

I noticed RecPro just came out with a 48V but there is little info on the internet. Does anyone have any thoughts or experience on this unit?

2

Greetings & Welcome!

In my humble opinion, air conditioners are a poor choice for off grid use. Swamp coolers are not only much more energy efficient, but they’re more efficient at cooling a vehicle as well, because instead of trying to cool the interior air, which takes a lot of power, they replace the interior air with cooler air, which is not only a much quicker method, but much more energy efficient as well. Did I mention a whole lot cheaper too?

My swamp cooler kept me comfortable through many hot and frequently humid summers, and uses under 2a @ 12vdc. The only downside is that the portable units require filling them with water as needed. Mine was designed to sit on my front passenger seat, and vent out the the passenger side window.

The water reservoir in mine is about 5 gallons, which will last the better part of week. I live & work from inside my rig, and being comfortable is important to me.

For humid areas, you want the indirect type of swamp cooler that uses a radiator for the heat exchanger, so it doesn’t add moisture to the inside air. The indirect type will exhaust the moisture outside rather than into the living area.

A peltier powered heat pump is another option. They use up to 5a @ 12vdc, but have a thermostat so they’re not running 100% of the time. They will both heat and cool, and do not require refilling with water. Like with the swamp coolers, they can provide up to 40°F-50°F of cooling, with the added feature of a similar amount of heat for the winter.

In either case, you’ll probably need to DIY it, but they’re relatively simple to build.

Cheers!

"Failures are merely a learning oportunity." ~ Rubber Tramp


3

Err, you know swamp coolers work by raising the humidity right, and if we are talking about vanlife an exess of humidity can seriouslly damage your van over a prologed prioid, also where I live it’s humid enough already without adding ontop, if your talking about in the middle of a desert or simmilar, sure the extra humidity can be very welcome, but personlly I would want a heat pump for heating and cooling and to me the extra power wouldn’t be a consern as by the time I get a heat pump I’m going to have 15.5kWh of battery and when fully deployed and fold up solar pannels are out I’m going to have 2970W of solar.

Yeh I know compared to the battery size the solar is under sized, but personally I live in the UK and yes I will have a diesel heater as well, so the battery size is to give me a 7 - 11 days worth of autonemy with reduced consumption. Really the plan was orignally to go with only 10.24kWh mostly because you need 200Ah of 48V capacity for a 5000W inverter—I want to be able to run an induction hob (2000W) and a air fryer (2000W) simultaniously for cooking, and yes I know that is only 4000W, but I also want to have a little bit of leeway for other stuff as well—and for anything beyond a 3.6kW inverter the manual suggests a minium of 200Ah, but 2 x 51.2V 100Ah 5.12kWh server rack batteries already cost £2000+ and a single 304Ah 51.2V 15.5kWh battery costs £2500… … …

So why the F$%£ not, it’s slightly better than you buy 2 you get 1 half price, and it’s a vitical battery which actually takes up around about the same volume as 2 server rack batteries, but can be place up against the wall only protouding out 23cm (~9") which is a similar depth to my inverter and the unit is only 50cm (~19.7") wide which is about the same width my inverter needs with the clearance the manual calls for either side of the inverter and the unit is only 83cm (~32.7") tall which is not much lower than I would want to put the bottom of the inverter leaving space for a DC to DC converter 24VDC fuse box 48VDC fuse box and 230VAC fuse box.

Although most other stuff is going to run either directly off the batteries or off a DC to DC converter, eg. 48V lights running directly off the battery, fridge running off a 48V to 24V DC to DC converter. This means that I can turn off the inverter and stop the zero load consumption of the inverter and only have 0.5W total self consumption by the solar charge controller and DC to DC converter.

Yes the frigde will turn on occionally for example, but the average draw when it’s prechilled is actually rather small, around 100Wh every 24 hours, which like even on a pretty obissmal day with only the 885W of solar deployed assuming 6 hours of day light I should be able to charge a little over 100Wh in a day.

So yeh personally I would be interested in a 48V heatpump that can be fitted to a van.

PS; sorry for the rambling about my own specific system, still planning it out and am excited.

4

Greetings & Welcome!

Swamp coolers that utilize heat exchangers do not add to the humidity, and they actually dehumidify, just like an air conditioner would for a fraction of the price, a fraction of the power requirements, and far more efficiently. I’ve been using them for many years, and never had a moisture problem.

The 12v Peltier powered heat pumps are also a superior solution for any temperatures above freezing. They draw under 5a at 12v DC. Once again, more efficient heating/cooling, for a fraction of the price & power requirements.

As for the fridge/freezer, diesel heater, induction hob, and air fryer… WHY? There are better, simpler, non electric options for all of those.

It is far easier to conserve power, than to create it, and systems like you’re suggesting frequently burn down people’s campers. We have the option of making our lives simple, easy, comfortable, & reliable, or complicated & miserable. There’s simply nothing to gain by complicating things.

I have all of the comforts & conveniences of all the amenities you’re suggesting, including the power to run everything, for a fraction of the price & complications, and one of my focuses is on long term sustainability and reliability. My solutions for everything you’ve listed cost under $300 USD, and they will outperform everything you’ve listed.

We old timers use the KISS (Keep It Stupidly Simple) system for good reason. The 3 R’s of campers mean everything to us. Reliability, Repairability, and Replaceability. Complicated systems simply don’t meet that criteria. It’s not about doing without, or doing it cheaper, it’s about doing it better, and making better choices. Being cheaper is just an added bonus.

We don’t need to impress anybody but ourselves. We don’t need the latest & greatest, when the tried & true is still the better choice. My ego just simply wants the best options possible.

Cheers!

"Accountability, responsibility, sustainability,
& creative solutions for the win." ~ Old_Soul


5

using peltiers for cooling is by no means efficent, for cooling they are around 60 - 70% efficency assuming you cool the hot side well, while compressor heat pumps can be upto 600% efficenct in labretory conditions in real world conditions though 400% efficency is achivable.

For heating though peltiers can be more than 100% efficenct assuming heat the cold side very well, but to heat a whole van with peltiers would be cost inefficent, if we are talking about a frigde TECs can be cost efficent because of the scale, although they are energy inefficent compared to compressor coolers.

Also a swamp cooler where you use a heat exchanger is not going to create a large delta between the hot and cold side, you would be lucky to get a 10C delta at the souce with a reasonable swam cooler, with a large enough tower and active fans able to suspend the droplets for long enough to remove heat you can do much better, but one able to reasonably fit in a van and not make an exessive amount of noise you are very limited in the performance to the point that adding multiple heat exchangers and I count the water to air heat exhanger you use to cool the air as a heat exchanger, will reduce the delta even further which your only talking about 10C at the source that is a problem.

And the reason for the induction cooler is that I don’t want to have to buy cans of burane / propane when I have plenty of solar to use during the summer and with my system even during the autum / spring, I will have a burtane / propane hob for the winter, but it’s a backup rather than the primery.

As for a propane oven, I’m building this myself and I have no condidence that I wouldn’t blow myself up trying to do my own gas system, also I will have a diesel heater, but again after I get the heatpump it will be a backup / suplementary to the heat pump when I either don’t have enough stored electric to run it or it’s too cold for the heat pump.

PS: I’m not saying that a swamp cooler with a heat exchanger will make no difference, I’m just saying it’s going to be very limited maybe after an hour you will shave maybe 2 - 3C off the van which honestly if you just want to take the edge off a heat wave is enough to be getting along with , where as I want to a 40C day to be able to get it down to 20C inside.

6

Greetings!

Well, I guess I will just wish you good luck then…

With over 60 years as a nomad, I’ve made every mistake in the book, and some that weren’t. I’ve found solutions to every problem I’ve encountered, to make my homes on wheels the most comfortable, convenient, and efficient homes of any type.

I learned far more from the old timer’s I encountered, than anywhere else. Today, I’m one of the old timer’s that’s been there, and done that, and finally figured it out. Most people are short timer’s in this lifestyle, and frequently lose a fortune in the process. I try to do my best to prevent that, but it still happens all too often.

GOOD LUCK! :slight_smile:

Cheers!

"Beat Murphy's Law with a KISS! (Keep It Stupidly Simple)" ~ Van_Dweller


1 Like
7

Wow, there were a lot words in the responses and not one addressed your question. :woman_facepalming:t2:

Kara, I am here looking for same reviews. I just purchased the Ecoflow 10k power to support a 48v AC that I am 100% sure I need and want. I also live in FL, but I lived in AZ for 7 years and swamp coolers on the driest days were awful.

I’ve been debating between the nomadic X3 and RecPro. What did you end up getting and how do you like it?

1 Like
8

Greetings & Welcome!

Can you describe how your swamp coolers were awful? I’ve had very good luck with them when used properly, with ventilation, replacing the indoor air with cooler air. Most people with complaints are using them improperly.

Cheers!

"Smiles are extremely contagious, infect as many as possible" ~ Smiling_Sam


9

If you require an AC immediately, the Coleman-Mach 10 might be your best choice, but consider the impact of its size. If you can wait, gather more details about the RecPro unit to assess its performance. Additionally, explore other 48V AC options and implement energy-saving measures like insulation, fans, and potentially solar panels.

10

VanDweller, a question for you. I have very limited internet/can’t research things here in the middle of nowhere now, can you suggest links for something to buy or DYI inexpensive Peltier system?
I have regular AC in my RV but never use it, I just setup a canopy (back to 10x10, 6x4 just doesnt give enough shade when sun is low) and its very nice in the shade and overall just travel following the good weather, but want to have some emergency cooling which doesnt require me to run my generator.

11

Greetings!

I can’t really supply any links or resources, because mine came from the big RV show at Quartzsite. I can however tell you how it works…

Mine has a closed loop water/coolant, with a pump, and a peltier module with a water jacket attached in line. The water/coolant is pumped through a small radiator that sits behind what appears to be a radiator fan, which pulls the air through the radiator. The fan is variable speed, and in the water line is a valve to to vary the water flow. The water pump, peltier, and fan each have separate switches as well as a master on/off switch. The peltier switch has 3 positions, cool, off, & heat.

Mine was designed like a window shaker A/C, and has the option of using outside air, or recirculating inside air. It seems to work equally well whether it is mounted in a window or not for cooling, but I prefer the fresh air option, and keep a window on the far end open, to exhaust the stale air.

The electric model uses 5-7 amps @ 12 volts DC. It does better at cooling than heating, below freezing it can’t keep up, even with all the windows closed.

The peltier modules are readily available online, as well as the water line attachment for them. I bought mine ready made for $99, so you should be able to DIY one for even cheaper.

Cheers!

"A wise man learns from both the successes & failures of others." ~ Off Grid


12

I see, thank you.
Being on the road now I probably won’t go into building a unit from scratch and don’t seem to find ready-made peltier a/c anywhere. I might just go with portable evaporative cooler.

13

Greetings!

If you’re going through Quartzsite, I got my Peltier heat pumps at the big RV show there.

Cheers!

"A wise man learns from both the successes & failures of others." ~ Off Grid


14

Yes, I’m officially a resident of local LTVA :))) and will be spending part of the winter/spring close to Quartzsite way out in the remote desert ltvas are crazy, but I only go there outside of the gatherings month/January, I don’t deal with crowds well. Can’t imagine where people park their rigs to attend those events in town, whenever I drive into town for errands even in March parking my 26ft class C is a gamble! The whole point is visiting when other “150k RV enthusiasts” aren’t there :))))))) I wonder though if whoever is selling these machines stays after the show.

15

Greetings!

ohhhh darn… I thought I had the gentleman’s email address, but I guess I lost it when my old laptop died…

Live & Learn, now I’m keeping contacts on a USB stick.

Cheers!

"A wise man learns from both the successes & failures of others." ~ Off Grid


16

Why not a 12v backpack mini split? They are $700-$800 on amazon

17

Greetings!

And how much power does that require?

The one I just looked up says it draws 60-80 amps, so that’s 7200-9600 watts to run it for 10 hours per day. While you might be able to keep up with that while driving, there is no way you can keep up with that with solar while parked without some sort of generator or shore power, which defeats the practicality of it being 12v.

In contrast, a swamp cooler draws ~2 amps, and a Peltier heat pump draws ~5 amps, both of which are easily achievable with a minimal power setup, or even set up to be totally non electric, while using an absolute minimum of fuel. (I use under 1 gallon of cooking oil per month to power everything, heating, cooling, cooking, fridge/freezer, table top fire pit, and much of my lighting.)

Most of us have found that it’s much easier to conserve power than to create it.

Now if you want to get fancy, you could buy or build a “black box”, a fully self contained micro hydro generator. Mine gives me the equivalent of a 30 amp shore power service. Mine came from the big RV show at Quartzsite, and cost far less than a comparable gas generator. It’s nearly silent, and creates no pollution. It’s also pretty simple tech, so it could be easily DIY’d. (A generator head connected to a water wheel which is driven by a 12v bilge pump recirculating water from a reservoir.) Just a newer version of very old tech. (The water wheel can easily achieve the same RPM’s as a gas engine to power the generator head.) It does require a battery to get it started, but it quickly recharges it and keeps it topped up.

Cheers!

"Old school, cheap, simple, reliable, and easily replaceable for the win!" ~ Traveler@Heart


18

Confused, where does the energy come from in such hydrogenerator in absence of natural stream? Recirculating and pumping water to run the water wheel requires pump energy, so the system shouldn’t generate any new energy, there should be energy loss instead. Micro hydro generator needs natural stream to create new energy

19

Greetings!

The water pump emulates the natural stream, and the pump probably uses under 5 amps @ 12v. The generator head puts out 3600 watts AC power. A nozzle on the pump creates a very high pressure stream of water, which turns wheel attached to the generator head.

Conversions can create either energy gain, or energy loss, contrary to what physics might have to say. Look at a block & tackle, the conversion allows you to lift many times the weight with far less effort.

While it appears that straight electrical conversions always result in power losses, mechanical conversions can result in power gains. This device is a mechanical conversion, converting a high power stream of water into mechanical force to drive the generator head, just like a gas engine, or a fan belt on a car could.

This is just a smaller version of systems that have been in use worldwide for many years. A low power pump can create a very powerful stream of water, mimicking the head on a natural stream.

Cheers!

"Old school, cheap, simple, reliable, and easily replaceable for the win!" ~ Traveler@Heart


20

Hmmm …the science of physics always right but in this case physics isn’t straightforward to me. Seems like mathematically impossible Perpetuum Mobile to me.
If its as simple as putting pumped up water through narrow nozzle to generate extra energy why this is not used in industrial applications?
3600watt generator takes quite a bit of energy to run.
5w 12v pump does 5 watts of work per hour (watt is related unit of work, joule per sec), can’t see how this can drive 3600watt genny unless water pump run forever and generator runs for tiny period of time
Natural stream contains enormous solar energy, the one that was used to evaporate the water before it got precipitated at higher elevations.
Energy can not be created outof nothing. Hydroelectrical system cant output more energy than what went into it, energy conservation law…