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

[grizzzman]

They runed

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.

Well they ended up ruining v there

 

[HaldorEE]

No. Just going off his posted number.

 

[grizzzman]

They runed

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.

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.

 

[Archetype-IS]

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

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.

 

[Bob B]

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.

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.

 

[Michael B Caro]

"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

 

[Archetype-IS]

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.

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

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

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.

 

[cwstnsko]

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.

 

[snoobler]

Aren't we getting pretty close to Will's solar shed here? That might be a good template for what works.

 

[Dzl]

Aren't we getting pretty close to Will's solar shed here? That might be a good template for what works.

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

 

[cwstnsko]

Aren't we getting pretty close to Will's solar shed here? That might be a good template for what works.

I think Will's solar shed is one of the reference points that piques people's interest. I have watched his videos on the Air Conditioner portion, but have not researched all of the details. The climate is definitely extreme enough! For it to be a good parallel to a vehicle mounted system, the total panel area would need to be less than about 75% of the area you were trying to cool. There would need to be a fair number of windows on the shed and at least in my case, you'd need to avoid hanging blankets and such as part of the decor

I keep reminding myself that even though my RV is well insulated (for an RV) with double pane windows etc., On hot days, the existing power hungry roof AC still struggles to keep up until after the sun goes down. I can't imagine being able to attach enough solar generation and/or batteries to my RV to power that unit around the clock, and I have a bit of a hard time believing that a small mini-split, with less cooling capacity than the roof AC has, is going to magically be able to keep up with the cooling load either. Maybe mobile systems in hot climates are still out of reach, but we're getting closer....

 

[Archetype-IS]

I think Will's solar shed is one of the reference points that piques people's interest. I have watched his videos on the Air Conditioner portion, but have not researched all of the details. The climate is definitely extreme enough! For it to be a good parallel to a vehicle mounted system, the total panel area would need to be less than about 75% of the area you were trying to cool. There would need to be a fair number of windows on the shed and at least in my case, you'd need to avoid hanging blankets and such as part of the decor

I keep reminding myself that even though my RV is well insulated (for an RV) with double pane windows etc., On hot days, the existing power hungry roof AC still struggles to keep up until after the sun goes down. I can't imagine being able to attach enough solar generation and/or batteries to my RV to power that unit around the clock, and I have a bit of a hard time believing that a small mini-split, with less cooling capacity than the roof AC has, is going to magically be able to keep up with the cooling load either. Maybe mobile systems in hot climates are still out of reach, but we're getting closer....

Here is another well documented off grid person running a lot of stuff with a lot of solar panels and battery with extra power house trailer.

http://offgrid100.com/

It has data logger analysis of the solar and usage. Plus cold, hot, shady, and cloudy data. Please read the blog and technical articles to learn more. Not so much on youtube videos. Mainly blogs. It is like having a house for the trip without worries.

 

[Dzl]

Here is another well documented off grid person running a lot of stuff with a lot of solar panels and battery with extra power house trailer.

http://offgrid100.com/

It has data logger analysis of the solar and usage. Plus cold, hot, shady, and cloudy data. Please read the blog and technical articles to learn more. Not so much on youtube videos. Mainly blogs. It is like having a house for the trip without worries.

Cool website from the look of it.

 

[gnubie]

FWIW my Fujitsu 240V split (ASTG09KMTC) is drawing about 167 watts right now in heating mode as it warms a room, outside is 16c, target inside is 25c. A decent unit doesn't use lot of power.

 

[snoobler]

That's maintaining 25°C, correct?

That's the benefit of an inverter-type unit where it can vary the power vs. being 100% ON or OFF.

 

[gnubie]

Yes, 25C. Once it gets there it will use even less power with the inside blower accounting for most of the draw (set to a fix speed rather than auto)

 

[snoobler]

Nice. Eventual permanent dwelling in the high desert will have little need for A/C, but I envision a couple of these mini-split units as an option for optimal comfort.

 

[vtx1029]

Have you seen this video?

I would seriously consider a generator. You could power the mini split and charge during the hottest parts of the day. Look into a diesel heater when dealing with the cold.

 

[Archetype-IS]

Have you seen this video?

I would seriously consider a generator. You could power the mini split and charge during the hottest parts of the day. Look into a diesel heater when dealing with the cold.

Another cool video. Thanks for sharing. The diesel heater are the thing for campers for a while. If the car is already using diesel, you have spare fuel to use in the colder weathers. The ForestAir unit are cool for RVers. Just use more power compared to the others. Regardless, I would still pack a generator as a backup. You will never know. What if the battery bank is not working? Everyone is going electric stoves to cook nowadays. You have fuel for the car(if the same fuel types as the car), that could be use for the generator, or use the car to charge the battery via DC to DC charger.

 

[Bob B]

It doesn't seem that unit can throttle the compressor load like the one in the other video .... but seems he has enough solar that it doesn't matter.
Not sure I like the way he routed the air from the condensor unit.