Lithium 12v WalMart Battery

reed cundiff wrote:
6000 BTU is 1758 W (6000 x 0.293 =1758).

700 W is 2400 BTU.

The Dometic a/c we have draws around 1750 W with a maximum of around 1.4 kW from solar so we are drawing around 500 W or more from the battery suite. I believe that it is supposed to be 13,500 BTU but this is 4 kW.

We have considered getting a small a/c that draws around 750 W. The Aussies apparently use the semi-split a/cs. The semi-split a/cs are inexpensive (sorta') but require some invasive modifications.

So I guess we shall just avoid hot areas as best we can.

Reed and Elaine

Air conditioners that work on the compression/expansion of gas principle are heat pumps and are able to be greater than 100% relative efficiency. This is why our 6000 BTU air conditioner only consumes 2400 BTU (700 watts).

An electric heating element can only be 100% efficient, not more (it very likely is almost exactly 100% efficient).

The mini split is even more efficient than our little unit, because the hot condenser is mounted somewhere far away from the living space (like under the truck) such that there is no conduction of waste heat from it back to the living space. With our A/C (and your 13,500 BTU roof unit?) there is just some insulating foam between the hot condenser and the air in your living space. I don't know the exact figure, but maybe they work 20% to 40% better?

edit: When I say a compressor air conditioner is greater than 100% efficiency, I don't mean it is a candidate for perpetual motion :-) It is just transferring heat from one location to another, actually consuming power to do so.

6000 BTU is 1758 W (6000 x 0.293 =1758).

700 W is 2400 BTU.

The Dometic a/c we have draws around 1750 W with a maximum of around 1.4 kW from solar so we are drawing around 500 W or more from the battery suite. I believe that it is supposed to be 13,500 BTU but this is 4 kW.

We have considered getting a small a/c that draws around 750 W. The Aussies apparently use the semi-split a/cs. The semi-split a/cs are inexpensive (sorta') but require some invasive modifications.

So I guess we shall just avoid hot areas as best we can.

Reed and Elaine

Rbertalotto wrote:
AC on a battery bank......Will need a trailer for all the batteries and whole bunch of solar panels.....I'm not aware of anyone running AC on a battery bank in an RV ( for any usable amount of time).....Can someone prove me wrong as I'd like to see how they did it.

We did it this weekend at the Northwest Overland Rally. Our 6000 BTU air conditioner is small, but kept the inside of our camper at 79 degrees from 10am to 5pm while everyone in tents died in the 105 degree sun. It ran purely off of solar during that time period (actually put a few amps back into the battery bank).

Solar is 1080 watts
Controller is a Midnite Classic 150
Battery bank is 24V made up of two Lifeline 12V 125AH AGM
Inverter is Magnum MSH4024 4kw 24V input
Air conditioner is small 6000 btu that was drawing about 650 to 700 watts.

Solar was producing over 650 watts by 10am and stayed above that until 5pm. Peak solar power was over 850 watts and the Midnite controller said 6200 watt-hours were produced during the day.

M.A.Taylor wrote:
The evap cooler I saw on the Wynn's video was made something like this one in the video, only it was made using one of those big blue & white ice/water cooler. Here's the video:

https://youtu.be/aHbQYajfGqM

We plan to do a lot of boondocking, everywhere. Never done it before, but over the two vacation trips we've taken so far in our Sightseer we've learned that being in what is essentially a mobile home park is not what we had in mind. We're both looking forward to spending a lot of time on BLM public land and other remote unplugged, so to speak, locations. Having never done this before we're just trying to get as many bases covered as we can before we get started. Fortunately we have about 1 year to practice and make our mistakes before hitting the road for extended periods of time when I assume those mistakes could be more costly.

One of the great things about being able to hit the road is you can follow cool climate, go up North of a summer and south of a winter. You maybe will be able to negate the need for heating/cooling.

I think Naio has the best plan. Go boondocking and find out what you require in the future to be comfortable.

This was not a DIY project; son and grandson did the work while I passed up tools and got in the way. It was said when I was a lead scientist on field projects at White Sands Missile Range that "Your showing up is like having two good technicians leave!"

If older son was not in the solar/wind business and wanted to design and fabricate the system we have for us, we would have been quite satisfied with far less. Heck, he makes fun of us for having excess. When I reply that is what he designed and built (just to see if he could build an autonomous system), he counters with "Dad, you much were to easy a sell!"

However, we are full-timers and only go to RV parks to dump and wash clothes(if there are no other facilities available) so we are quite happy to be self-sufficient and not have to use a generator. Wildlife and birdlife pretty much ignore us and wander/flitter about/under our rig.
Reed and Elaine

Reed,
That is an amazing set up you have. Looks like you figured it out. Thanks!

Rbertalotto

Have posted the below information a few times on varied fora.

There are a few of us that do use a/c as a combination of solar/battery suite. We have run the Dometic a/c energy hog (1750 W) for 3.5 hours several times (it just happens that after 3.5 hours it was getting to dusk and things were cooling down). We have also run the a/c quite a few times at dusk on battery bank to get main cabin below 85 F. A window a/c only uses around 750 W and we could run this all day in the mountain west. If you are boondocking in the US South-East in summer with 80% humidity, it will be a lot different. The Aussies run something called a split-level a/c that uses a lot less energy.

We have room on roof for 2 to 3 more 235 W panels, another 500 to 700 W of solar (move some things about) and for another 4400 W-hrs) but cannot figure out a reason (OK, a reason that wife will accept). Wife is very happy with the system.

Evaporative cooler is a grand idea if you have a lot of water. This is not usually an option when boondocking in the desert.

We primarily boondock/mootchdock and have used line power once in two years (for two days) and generator not at all. We prefer to be "Goldilockers" as in "not to hot and not to cold, just right!" so we go north and/or up in elevations (up to 10,400 feet) and reverse in winter.

Reed and Elaine
2006 Chevie 3500 4 x 4 diesel (dualie) with 45 gallon auxiliary tank
1400 W of solar (90 V to controller)
Morningstar MPPT-45 (converts 90 V to 48 V)
8700 W-hrs (48 V nominal) of LFP (CALB cells), 7 kW-hrs usable
Magnum 4.0 PSWI
Mean Well 508 W converter (48 V to 12 V)

M.A.Taylor wrote:

We plan to do a lot of boondocking, everywhere. Never done it before, but over the two vacation trips we've taken so far in our Sightseer we've learned that being in what is essentially a mobile home park is not what we had in mind. We're both looking forward to spending a lot of time on BLM public land and other remote unplugged, so to speak, locations. Having never done this before we're just trying to get as many bases covered as we can before we get started. Fortunately we have about 1 year to practice and make our mistakes before hitting the road for extended periods of time when I assume those mistakes could be more costly.

I strongly recommend that you try boondocking without solar first.

It's not possible to anticipate how you will want to do things, in a new environment. And, after all, most people who camp on BLM lands are tent camping and don't have any batteries at all. It's not like you can't do it without that that stuff.

Go on a few trips. Learn what you like to do and how you like to do it. Learn what electrical things you will want to run and in what conditions. If it's hot, go to higher elevation where it is cool, or go swimming.

Once you know what you want, then design your system around that.

Lots of diesels are now running on Propane. All the waste trucks here in my city have switched over to propane. All the city buses are now running their diesels on Natural gas. Many of the refrigeration units on the trailers are now propane.

free radical wrote:
I've noticed that refrigerated semi trailers are cooled by propane powered coolers..isn't such a AC cooler available for RVs??

They run on diesel.