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diy solar

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

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 said:
Better to travel to places that are not as hot. Whole point of a camper van.
Click to expand...
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.
 
Bob B said:
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.
Click to expand...
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.
 
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.
 
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.
 
Bob B said:
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.
Click to expand...
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.
 
DonPhillipe said:
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.
Click to expand...
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.
 
[/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.
 
travelbike said:
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.
Click to expand...
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.
 
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.
 
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,,,
 
Ledsun said:
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,,,
Click to expand...

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".
 
Ledsun said:
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,,,
Click to expand...

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.
 
HaldorEE said:
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.
Click to expand...

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.
 
They runed
Archetype-IS said:
That's cool.

Long ago, a YouTuber Technomadia (I can't find that video now, it was like 4 to 5 years ago) did their bus with Victron inverter, Lithium batteries, generator,DC to DC charger because their bus has a huge alternator to help charging it. Forgot how much was their solar. They were able to use the air conditioner with power assist from the Victron inverter. For example, the solar is low, the battery would use more power, or battery low, the generator would kick in to help or combination of all three. They should a picture of how that juice flows on the color display. Definitely do-able with mini-spilt or the newer LG dual inverters windows type air conditioner. Just expect to use minimal of 1000 Watt an hour. For the mini-splits, not sure how the compressor likes it when driving on the road.
Click to expand...
Well they ended up ruining v there
 
They runed
Archetype-IS said:
That's cool.

Long ago, a YouTuber Technomadia (I can't find that video now, it was like 4 to 5 years ago) did their bus with Victron inverter, Lithium batteries, generator,DC to DC charger because their bus has a huge alternator to help charging it. Forgot how much was their solar. They were able to use the air conditioner with power assist from the Victron inverter. For example, the solar is low, the battery would use more power, or battery low, the generator would kick in to help or combination of all three. They should a picture of how that juice flows on the color display. Definitely do-able with mini-spilt or the newer LG dual inverters windows type air conditioner. Just expect to use minimal of 1000 Watt an hour. For the mini-splits, not sure how the compressor likes it when driving on the road.
Click to expand...
Well they ended up ruining there LFP bank due to heat. They have changed to battleborn batteries. All there equipment was in a non temp controlled environment at first near the engine bay (they moved it but on the late side), then add high amp pull from a/c. Heat kills and this is a great example.
 
Ledsun said:
Wow that was a lot of responses,,, it will take me a bit to digest all of that,
First it was a typo... it was supposed to be 9 amps.
Second of all I haven't bought a unit yet... I don't want to spend over a 1000 or more dollars on a chance.
I live in the south about 200 feet above sea level ie a swamp plenty of moisture, plus I want to travel with it.
There was a video on this site Solar Shed that showed a small ac cooling a workshop, maybe 5000 btu unit. which may cool
my van.
One of the videos I watched is from Gone Boondocking, Solar Mini split air conditioner runs 24 7 365
This video says that his Meda 24.4 seer unit 1100 btu with turbo mode uses less than 460 watts on high and once it reaches the set temp it drops
1/4 of that... 24 btu for one what
I have no idea of what I'm talking about. Please watch the video
So here's what I need as simple as possible:
1 Is this possible ?
2. Would a five hundred watt solar system do this ?
3 How much lithium batteries would I need ?
4 I could also add the alt from the van to help charge the batteries.
My main goal is to have heat and ac in the very van for sleeping overnight with electricity and very quite.
Generators are too noisy, parks won't let run them after a certain hour.
Parks with electricity slots are expensive for every night
That is a RV Holy Grail
If this is possible I would spend the money.
Thanks for all y'all help
Click to expand...

Sorry this gone off topic to swamp coolers. Back to topic:

So here's what I need as simple as possible:
1 Is this possible ? [Yes, or maybe , read the analysis below]
2. Would a five hundred watt solar system do this ? [ Maybe not, look at the numbers below, not enough solar to charge or shared power]
3 How much lithium batteries would I need ? [His video example 7200W with 6 Battleborn Lifepo4 batteries]
4 I could also add the alt from the van to help charge the batteries. [DC to DC charger should work]

My main goal is to have heat and ac in the very van for sleeping overnight with electricity and very quite. [Cooling use less energy than heat on the same unit. I have a heat/cool (heatpump) minisplit, it uses more energy for heat mode during winter months]

The Gone Boondocking video analysis:

He has:
1440 Watts of Solar,
7200Watts of Batterborn
12V / 3000W Victron inverter
100/50 Victron MPPT Solar Charge Controller.
The Midea 24 SEER unit 110V @ 9000 BTU
Class C RV (well isolated)

With his setup, it will work with his sun hours on the south to run it during the day time on solar and still have spare power to charge the battery, or sun is shady/cloudy, the Victron will power assist from the battery bank. His original 900 Watts of Solar and 600 amps of AGM (50% usage 300amp) won't do it because AGM takes a slower charge, but with his Battleborn battery, he can use 80% of that without issues. Plus his solar will charge it up in a hurry.

I could tell you that I have a mini-split at home with 9000 BTU with 27 SEER and it does use very little power once the room is cooled.

For his setup, the unit will use 6 hours on solar power @ 1440w should be able to run the AC unit. If the battery is full at 100% 7200 Watts and use 80% of that 5,760 Watts usable, and assume the unit runs at 400 W of power once the temperature cools, that gives 14.5 hours of run time.

5,760 / 400 = 14.5 hours(no sun) + 6 solar hours = 20.4 hours
5,760 / 300 = 19.2 hours(no sun) + 6 solar hours = 25.2 hours.

Then what about the next day or cloudy day? Will there be enough solar to charge back the battery? I guess DC-DC Alternator would work here when needed. The car engine is much quieter vs a generator in a park.

If we use the 300 Watts when AC is running, the spare 1440 solar - 300 usage = 1140w could charge the battery up in 5 to 6 hours. His south location should get at least 5 to 7 hours.

So, maybe it should work if the RV is well isolated, but it will not work with 500 Watts of solar.

Battery package cost for the 6 batteries, victron inverter and scc, and misc $8841 (bundle package at their website)
https://battlebornbatteries.com/product/getaway-couple-600ah-lithium-bundle/

Used panels to get 1440 or 1500 Watts -- 100 or less a pieces for 330 Watts on the used market.
New panels ...3 times of that, looking at 250 each for 330 Watts... around a $1000.
Mini Splits unit, in the 1000 range.

Total cost: $10,000 should be do-able.
 
Last edited:
Archetype-IS said:
Sorry this gone off topic to swamp coolers. Back to topic:

So here's what I need as simple as possible:
1 Is this possible ? [Yes, or maybe , read the analysis below]
2. Would a five hundred watt solar system do this ? [ Maybe not, look at the numbers below, not enough solar to charge or shared power]
3 How much lithium batteries would I need ? [His video example 7200W with 6 Battleborn Lifepo4 batteries]
4 I could also add the alt from the van to help charge the batteries. [DC to DC charger should work]

My main goal is to have heat and ac in the very van for sleeping overnight with electricity and very quite. [Cooling use less energy than heat on the same unit. I have a heat/cool (heatpump) minisplit, it uses more energy for heat mode during winter months]

The Gone Boondocking video analysis:

He has:
1440 Watts of Solar,
7200Watts of Batterborn
12V / 3000W Victron inverter
100/50 Victron MPPT Solar Charge Controller.
The Midea 24 SEER unit 110V @ 9000 BTU
Class C RV (well isolated)

With his setup, it will work with his sun hours on the south to run it during the day time on solar and still have spare power to charge the battery, or sun is shady/cloudy, the Victron will power assist from the battery bank. His original 900 Watts of Solar and 600 amps of AGM (50% usage 300amp) won't do it because AGM takes a slower charge, but with his Battleborn battery, he can use 80% of that without issues. Plus his solar will charge it up in a hurry.

I could tell you that I have a mini-split at home with 9000 BTU with 27 SEER and it does use very little power once the room is cooled.

For his setup, the unit will use 6 hours on solar power @ 1440w should be able to run the AC unit. If the battery is full at 100% 7200 Watts and use 80% of that 5,760 Watts usable, and assume the unit runs at 400 W of power once the temperature cools, that gives 14.5 hours of run time.

5,760 / 400 = 14.5 hours(no sun) + 6 solar hours = 20.4 hours
5,760 / 300 = 19.2 hours(no sun) + 6 solar hours = 25.2 hours.

Then what about the next day or cloudy day? Will there be enough solar to charge back the battery? I guess DC-DC Alternator would work here when needed. The car engine is much quieter vs a generator in a park.

If we use the 300 Watts when AC is running, the spare 1440 solar - 300 usage = 1140w could charge the battery up in 5 to 6 hours. His south location should get at least 5 to 7 hours.

So, maybe it should work if the RV is well isolated, but it will not work with 500 Watts of solar.

Battery package cost for the 6 batteries, victron inverter and scc, and misc $8841 (bundle package at their website)
https://battlebornbatteries.com/product/getaway-couple-600ah-lithium-bundle/

Used panels to get 1440 or 1500 Watts -- 100 or less a pieces for 330 Watts on the used market.
New panels ...3 times of that, looking at 250 each for 330 Watts... around a $1000.
Mini Splits unit, in the 1000 range.

Total cost: $10,000 should be do-able.
Click to expand...
What is the model of that 27 seer unit? Is it 220V?

If you are handy at all, you could do your own battery for a LOT cheaper.
 
"Mini Splits unit, in the 1000 range"

Personally I think that there is very little difference on most of these mini-split units....I just make sure you get one with a Toshiba comprtessor.

Just bought a 20 seer heat pump unit for a little over $600.00
 
Bob B said:
What is the model of that 27 seer unit? Is it 220V?

If you are handy at all, you could do your own battery for a LOT cheaper.
Click to expand...

My SEER 27 is a 7 years old Fujitsu 9K BTU @ 240v @ 60hz. I just checked, they have a 33 SEER model now.

www.acwholesalers.com

Fujitsu 9RLS3YH 9,000 BTU 33.0 SEER Ductless Mini Split Heat Pump

The Fujitsu 9RLS3YH 9,000 BTU 33.0 SEER Ductless Mini Split Heat Pump 9RLS3YH has been discontinued. Check out Expert's recommended alternatives for another top mini split system.
www.acwholesalers.com www.acwholesalers.com

I know we can do the new 16s @ 280ah batteries with 14KW of energy. I was just pulling numbers from the video to do the analysis to make it apple to apple comparisons.
 
I think there are a lot of us tracking on the feasibility of solar and/or wind based off-grid climate control. That video of the mini-split system running 24/7 off grid got my attention too. It seems to me that with current commonly available devices, this CAN be done, but is not yet as simple as watching a YouTube video, ordering a solar kit, battery and AirCon unit from Amazon and spending a weekend fitting the components to your vehicle. There are still a lot of variables to account for that make it a slightly more advanced DIY undertaking. I think that looking into the future a few years, this will get to be much more mainstream. Bigger, cheaper batteries, cheaper, higher output panels, and wider availability and lower cost of DC Air Conditioning units that avoid the inefficiencies of inverting our solar/battery power to AC.

One of the things that I keep going back to in my head is whether it makes sense to segment my RV power systems, each with separate generation and battery bank sized to the loads/needs. Perhaps one 12V system targeted to the RV essentials, and an independent 24 or 48V system targeted to "nice to haves" like air conditioning, television etc.
 
Aren't we getting pretty close to Will's solar shed here? That might be a good template for what works.
 
snoobler said:
Aren't we getting pretty close to Will's solar shed here? That might be a good template for what works.
Click to expand...

Maybe, but the context is pretty different, still likely some good lessons to be learned/takeaways.
 
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