Powering a Mint Split unit in an RV by solar and lithium batteries

[HaldorEE]

Those are the exact units I reference above, and I mis-remembered the power specs. We're actually in Mesa, and our off-grid property is about 20 miles ENE of Show Low in the high desert. I literally used one last weekend when it was pushing mid-90s at 6800 ft elevation.

We have one in each RV. Also a great roll-around fan too.

One is keeping me cool as I make this post. Local Ace hardware had them on sale for $150. I couldn't pass this up.

 

[snoobler]

Nice! Didn't know they were available locally. Would have been better to get them in Show Low than haul them up...

Got mine from Amazon for $129 and $139 in two separate purchases.

I like the contrast on your switch. Our knob is light, and I have trouble seeing the indicator. Damn Presbyopia.

 

[DonPhillipe]

Referencing a camper and not a home installation (OP), from all I have heard from owners who have gone the evaporative cooler route in a low humidity environment, they say the better these work, the more water they are consuming. While boondocking (parked away from water, power etc.) water is often a more precious comodity than energy. So make sure you have a good water source before adding an evaporative cooler to a camper of any kind and if a water supply will often be scarce.

Referencing the window unit in the video and assuming you are asking about perhaps a solution for the van you are building, I am sure you saw how many panels were there in that array and that's not even to say they will run the unit 24/7; as I recall that was sort of left open as to how it will perform long-term. There are far too many panels to fit on most campers. For small campers I have never seen a 24/7 demonstration for an acceptable battery powered AC that works well in vans or small RVs. I have a 24' RV and for example in 107F heat, a 15KBTU unit will cool my space only to about 85F at high noon, so a 9KBTU I would estimate would be the sort of break over point where one rolls down the windows and gives up in desperation by setting fans ablast. My coach has 2" insulation all the way around, so I imagien a van would be even hotter in the direct sun.

A few German "overlanding vehicles" I have seen with what the owners say is a workable small AC solution but most of these big truck rigs are covered in plenty of panels and built like a reefer truck - no windows to speak of (a couple of port holes perhaps), so in effect you are living in a large ice box like container to make this work for you, so there's always a balance to seek and for the most part I don't believe that vans or smaller RVs have the solar real estate nor the weight capacity for the setup that will be needed for running an AC system 24/7 or minimally, one that can offer true comfort and not simply serve as a novelty to offer perhaps half the BTU's needed to keep it sufficiently cool or run for a subset of the day.

So in short if you are doing a van build out and want to run some AC based only on solar (without long generator sessions intermixed) then I would guess that you would likely not be happy with the outcome. Still the energy requirements of keeping any area cool are totally driven by the efficiency of the insulation of the barriers of the room. Make the walls thick enough or a high enough R-factor and run the AC off the kinds of energy that small campers have available, but then there is no room or light inside. If you do take the plunge, which many do, don't forget to also provide your daily energy requirement to accompany any ideas for AC power.

P.S. I solved my own energy problems by always trying to drive to acceptable climates. Even if the day arrives when we are able to cool these small boxes to a perfectly cool level inside using just a few high efficiency panels, this in and out activity all day causes me to have a splitting headache, therefore for me personally just getting used to the heat with some good flow through ventilation and fans blowing directly on my body is a much better solution I have found over the years than playing the freeze/boil game. As a native of a southern US state, this comes clear after too much time moving between 75F & 105F. So except in dire emergencies, an AC is not on my wish list. Still I hope this info helps you not to invest a lot based on some youtuber trying to get clicks with 24/7 solar AC claims. (My own rule of thumb is in an inefficient camper like I have and you are talking about building, if the AC is clicking off from reaching the set temperature, it is cool enough outside you don't need the AC anyway). Still the best of luck in your project.

 

[Bob B]

I really. liked that Gone Boondocking video. With my Lance truck camper, if I removed the roof A/C and installed a mini split it would free up roof space for more solar and only use about 1/2 the power of my existing A/C unit. That might make it possible to boondock almost anywhere. The current roof A/C is not only taking up roof real estate, but also shading a significant area.

Very interesting that he is improving the efficiency even more by controlling the load by leaving it run all the time.

 

[HaldorEE]

My van (not sure you were talking to me) only has 300W of solar so AC is totally out of the question.

You are right about water being a concern (I mentioned this). I am planning around traveling, not staying anywhere for long so hopefully water is something I will be able to resupply on a regular basis.

My travel plans will have to take this into account.

 

[snoobler]

Absolutely true about water consumption. My last use involved about a gallon an hour. Fortunately, we have about 300 gallons on site with storage for 935.

 

[HaldorEE]

Better to travel to places that are not as hot. Whole point of a camper van.

 

[Bob B]

Better to travel to places that are not as hot. Whole point of a camper van.

That's a good general strategy .... but not always possible. I would rather have a system that will support whatever environment I choose to encounter .... yes, it's going to make setting it up more expensive.

 

[HaldorEE]

That's a good general strategy .... but not always possible. I would rather have a system that will support whatever environment I choose to encounter .... yes, it's going to make setting it up more expensive.

You have the room to do what you want.

A Ford Econoline like mine has very limited roof space. I could add a second 300W panel, but then I would have to lose to the luggage basket.

One good thing about living in Phoenix. It is pretty hard to find someplace hotter to travel to and we have a totally different idea of what hot means.

 

[CascadeOffGrid]

I don't have a ton of experience with mini-splits in RVs yet but I do have quite a bit of experience with air conditioning and batteries.

I recently finished a 5th wheel trailer off-grid conversion with 840W of tiltable solar and 6 - 100aH Battleborn batteries. They can run one of their standard RV rooftop air conditioners for about 4-6 hours with solar input.

You will have to max our your roof with solar. Usually the 500-600W range is all you will be able to get on a van roof unless you get very creative. You will also need to invest heavily in your battery bank. I am doubtful that you will be able to sustain air conditioning but with enough batteries, you will be able to get through the night in moderately hot climates.

The other big important factor here is INSULATION. If you are really serious about making this happen, invest in insulation. I work with a lot of DIY van builders and there is a big difference in the comfort inside of a spray foamed van vs a fiberglass/wool/ecobat solution.

 

[mjbeam]

I have a Ford E250 van with Maxxair fan in the roof towards the back and was able to fit four 175 watt panels on the roof. I could fit 200 watt panels but they would overhang the roof a bit and 700 watts works for my needs. I run a 5000 BTU window AC during the day. The solar fully powers the AC until about 3-4pm, then the batteries start providing current. By around 5pm the batteries are providing almost all the power. So far the solar has been able to recharge the batteries the next morning by the time I need the AC again the following day. This is in Oregon though and most days I don't need the AC until 11am-1pm. I keep the thermostat pretty high though, 84 degrees. I find that is about as high as I can remain comfortable with fans blowing on me.

 

[DonPhillipe]

That's a good general strategy .... but not always possible. I would rather have a system that will support whatever environment I choose to encounter .... yes, it's going to make setting it up more expensive.

Can one really "buy their way out" of the physical solar panel size restrictions and van-wall energy efficiency restrictions that a van imposes when addressing the concept of full vehicle climate control? I personally don't think that money can buy a solution and only future increased solar energy density is going to fix that. Sure if one wants to tap into a special alternator and make running a very large petro engine the heart of the system and part of the daily life ritual, that can happen but here you are really just re-routing foscil fuel energy and stuffing that energy into a lithium bank and at this point can you really even call your setup a "solar power system" any longer? Proportionally speaking, all the solar in this situation is providing is the standard appliance power needs that a lead/acid setup would likely address fine. Maybe this is where my own disconnect occurs and that is in what such a system is called.

I know another owner of a camper just like mine and he hails that we have now reached the day of all solar. He runs all induction burners, has removed his propane tank, has an electric refrigeration, electric water heater, etc. He also casually mentions that he is constantly on the move. Had I listened to the final description of his system (constantly on the move and his earlier "souped up alternator setup" statement), then it would have come clear to me that his system is a petroleum energy storage system and not a solar system and that would have made more sense to me. I also recall comments from him of how running the engine every day or two is not a big deal. So in this case, I don't think this qualifies any longer as a "solar system".

So this alternator as the heart of your system and giant lithium battery bank stratedy needs to be addressed for all those who have small vehicles and are looking at youtube videos lusting for the 24/7 full-facility, 100% duty cycle (to make up for the lack of insulation) spit AC systems that the youtube content click-bait enticers are tempting everyone with. I don't think the divided port ABS with a 200aH battery pack and 300-500w space on the roof top that the typical DIY project is providing is going to cut it.

 

[HaldorEE]

Can one really "buy their way out" of the physical solar panel size restrictions and van-wall energy efficiency restrictions that a van imposes when addressing the concept of full vehicle climate control? I personally don't think that money can buy a solution and only future increased solar energy density is going to fix that. Sure if one wants to tap into a special alternator and make running a very large petro engine the heart of the system and part of the daily life ritual, that can happen but here you are really just re-routing foscil fuel energy and stuffing that energy into a lithium bank and at this point can you really even call your setup a "solar power system" any longer? Proportionally speaking, all the solar in this situation is providing is the standard appliance power needs that a lead/acid setup would likely address fine. Maybe this is where my own disconnect occurs and that is in what such a system is called.

I know another owner of a camper just like mine and he hails that we have now reached the day of all solar. He runs all induction burners, has removed his propane tank, has an electric refrigeration, electric water heater, etc. He also casually mentions that he is constantly on the move. Had I listened to the final description of his system (constantly on the move and his earlier "souped up alternator setup" statement), then it would have come clear to me that his system is a petroleum energy storage system and not a solar system and that would have made more sense to me. I also recall comments from him of how running the engine every day or two is not a big deal. So in this case, I don't think this qualifies any longer as a "solar system".

So this alternator as the heart of your system and giant lithium battery bank stratedy needs to be addressed for all those who have small vehicles and are looking at youtube videos lusting for the 24/7 full-facility, 100% duty cycle (to make up for the lack of insulation) spit AC systems that the youtube content click-bait enticers are tempting everyone with. I don't think the divided port ABS with a 200aH battery pack and 300-500w space on the roof top that the typical DIY project is providing is going to cut it.

I agree. I am following in your friends footsteps with an inductive cooktop and microwave oven. No propane for me. But I don't see AC for my van application. A swamp cooler works well enough in the SW desert, you just have to have enough water.

 

[travelbike]

[/QUOTE] Will a swamp cooler(<100w) and a dehumidifier(100 w) could act as an air conditioner alternative? With a small solar ice maker(100w) to feed the swamp cooler? Or use the water from the dehumidifier for the ice maker? Think it might use less electricity and still be comfortable? Any one tried from dry and humid places?
[/QUOTE]
Swamp coolers work well up to temps in the mid 90's and in dry condtion. Higher than that, cooling becomes less effective. Problem I'm experiencing is climate change. I'm at elevation of 2500 ft in the foothills of CA and humid muggy days are becoming more common. Swamp coolers is becoming less effective. Will follow this thread hopefully to find a solar ac solution as well.

 

[HaldorEE]

Swamp coolers work well up to temps in the mid 90's and in dry condtion. Higher than that, cooling becomes less effective. Problem I'm experiencing is climate change. I'm at elevation of 2500 ft in the foothills of CA and humid muggy days are becoming more common. Swamp coolers is becoming less effective. Will follow this thread hopefully to find a solar ac solution as well.

Luckily muggy is a word very rarely used in the desert. I was sitting on my shaded patio in 110 degrees, and that little cooler kept me comfortable.

 

[Bob B]

Instead of 200AH ... go with 560. 8 of the 280AH cells and make a battery that won't take up that much more room. Instead of a single layer of panels on the roof, stack them on a slide mechanism that can expand them into a single layer when parked .... there are creative ways to get more solar, but that's where the expense comes in.

 

[Ledsun]

Wow thanks for all the information... I'm getting an education.
I guess I should of added that vehicle of choice or chance is a 1996 Ford E350
15 passenger bus. I have been lately looking at attaching four 195 watt panels on top which should fit.
I'm planning to also use a fantastic 12v fan and using the alternator for supplement power.
SInce this thread I'm now looking a small honda generator to help.
I won't mind running during the day, but do not want to run it all night for ac, it would draw too much
attention.
I want the comfort of ac and the quiet of the spit unit on batteries,
The video I posted said his unit only full 9 amps on high, but I don't know if to believe it.
It a lot of money to spend for it not to work... If it works I would money well spent.
AT least 8 s hours of ac is the goal... for a comfortable night in SC, you know in the middle called a
swamp. The mountains are close and no problem but I also love the beach.... which is as muggy as here.
I want to go to TX and the Midwest,,,

 

[Bob B]

Wow thanks for all the information... I'm getting an education.
I guess I should of added that vehicle of choice or chance is a 1996 Ford E350
15 passenger bus. I have been lately looking at attaching four 195 watt panels on top which should fit.
I'm planning to also use a fantastic 12v fan and using the alternator for supplement power.
SInce this thread I'm now looking a small honda generator to help.
I won't mind running during the day, but do not want to run it all night for ac, it would draw too much
attention.
I want the comfort of ac and the quiet of the spit unit on batteries,
The video I posted said his unit only full 9 amps on high, but I don't know if to believe it.
It a lot of money to spend for it not to work... If it works I would money well spent.
AT least 8 s hours of ac is the goal... for a comfortable night in SC, you know in the middle called a
swamp. The mountains are close and no problem but I also love the beach.... which is as muggy as here.
I want to go to TX and the Midwest,,,

He has been monitoring his system for a year to make sure the numbers he mentioned were real .... but will the Pioneer unit perform in the same way and be able to throttle back to the low level in the same way?
It might be possible to find the same model he used "somewhere".

 

[HaldorEE]

Wow thanks for all the information... I'm getting an education.
I guess I should of added that vehicle of choice or chance is a 1996 Ford E350
15 passenger bus. I have been lately looking at attaching four 195 watt panels on top which should fit.
I'm planning to also use a fantastic 12v fan and using the alternator for supplement power.
SInce this thread I'm now looking a small honda generator to help.
I won't mind running during the day, but do not want to run it all night for ac, it would draw too much
attention.
I want the comfort of ac and the quiet of the spit unit on batteries,
The video I posted said his unit only full 9 amps on high, but I don't know if to believe it.
It a lot of money to spend for it not to work... If it works I would money well spent.
AT least 8 s hours of ac is the goal... for a comfortable night in SC, you know in the middle called a
swamp. The mountains are close and no problem but I also love the beach.... which is as muggy as here.
I want to go to TX and the Midwest,,,

9 amps at 120V is 1080W. Figure close to 1160W draw from the battery. You would need a 10KWH battery to run that for 8 hours.

I would be interested to know the starting amps are too.

 

[Bob B]

9 amps at 120V is 1080W. Figure close to 1160W draw from the battery. You would need a 10KWH battery to run that for 8 hours.

I would be interested to know the starting amps are too.

The unit he is running in that video runs at various amps depending on the load .... did you watch the video? The reason he runs it 24/7 is so it stays in at the low load level.