Mini Split Air Conditioner / Heat pump

Walkdog wrote:
Honestly, I think most here no nothing of mini split air conditioners/heat pumps.

The unit you provided a link to is 240v-60hz drawing 4.05amps to produce 12k btu.

You are in texas so let's assume a 75% duty cycle: It's hot in texas so it will run a good part of the day and 12k btu is smaller than the typical 13.5/15k btu RV air/con units.

When running it will draw 972w or 17496w-h over a day. Assuming a 12v battery bank, you need 1458amp-hr of USABLE power. That translates to around 3000amp-hr with lead acid (assuming an agressive 50% of rated capacity) or about 1850amp-hr of lithium (assumes you can use 80% of the rated capacity).

Solar panels don't generate 24/7. Generally you can assume about 4 times the rated output per day, (ie: a 100w panel will put out about 400w-h per day). So to get 17496w-h, you will need just shy of 4400w of panels (this assumes you have ZERO other electrical loads). Assuming good panels putting out a generous 20w/sft, that's 220sft of panels needed. Assuming losses or hatches and other roof protuberances, you will need a 30' trailer with every available sft covered with panels.

The inverter to power this needs to be significantly larger than 972w as starting the compressor typically needs 2-3 times the continous draw, so figure on a 3000w inverter.

So let's total things up:
- Air/Con Unit: About a wash with a standard RV Unit.
- Custom installation of a split unit (as opposed to a couple hours to swap out a standard installation): Let's say $500.
- Sealing the existing Air/Con hole: Let's say $500.
- 1850amp-hr litium batteries: I just did a quick check and found a 60amp-hr (12v) for $300. So figure around $10,000 by the time you add in wiring, charge controllers, etc... (assuming you know what you are doing and don't have to farm it out to an expert).
- 4400w of solar panels: Assuming $1/w, that's another $4400.
- Solar panel installation: SWAG, $2000
- 3000w Inverter: $1500.

So grand total $18,900 for a solar powered air/con that totally dominates the RV and doesn't handle the other electrical loads...and in really hot weather may run out of power (12k btu isn't a lot in 110F weather).

By contrast, a $2000 generator will run the unit and assuming 4 gal per day at $4/gal 24/7 when camping and you camp 1 month per year, you have enough to cover 30yrs of fuel.

This ignores the fact that the batteries will eventually need to be replaced and work to keep the roof sealed will be substantially more expensive.
So yes, it can be done just not very practical.