New to the TT world

valhalla360 wrote:

ChrispyjCSLT22 wrote:

valhalla360 wrote:

ChrispyjCSLT22 wrote:
This is alot of perspective to consider, and I'm appreciative of it, but I'm trying to avoid getting/using a generator and lugging around gas cans..

I get what you say about run time but would running the AC on low would help?

Let's say you want to stay comfortable for an 8hr overnight:
- Running on high at 1500w with a 50% duty cycle means it's pulling 1500w for 4hr for a total of 6000w-hr consumed.
- If it has a low output (most RV air/con units don't, they just have a lower fan setting to keep it quieter) of 750w but for the same cooling, it's going to have a 100% duty cycle. 750w for 8hr is still 6000w-hr.

If it's hot and you want it cooled, there is no free lunch.

In the end, your effort to avoid a simple reliable generator will cost more, be more hassle and reduce the quality of your experience. If you don't want a generator and you want to boondock, realistically, you aren't going to have air/con without a huge, expensive aftermarket system.

Even with a 3KW inverter, 400ah lith batts and a 11K slow start AC with the settings on low?

A 3KW inverter may or may not be able to start the air/con unit (some of them get picky about heavy startup loads) but start up is measured in milliseconds. Building a solar/battery/inverter system to kick the compressor over...easy. The issue is keeping it running for a meaningful period of time.

A 15000k BTU RV air/con unit typically will draw around 12amps @ 120v when running (startup might be 30-50amps but only for a second to get the compressor going). 12amps @ 120v is 1440watts. It will vary a bit depending on temp, altitude and a few other things but close enough for our purposes, we can call it 1500w to keep the math simple. 400amp-hr at 12v holds around 4800w-hr but you don't want to drag them down to 0% or it will quickly damage the expensive battery bank. Lithium can use around 80% of the rated amount, so let's say you have 4000w-hr of usable power. That gives you 2.7hr of run time at 1500w. If it's 50% duty cycle, you have 5.4hr of cooling but if you start with a hot RV, probably less because initially, it will run 100% until it gets the interior temp down.

As far as low setting:
- Traditional RV air/con, the fan makes up around 300-350w out of the 1500w. By dropping to the low fan speed, it will draw a little less wattage but the overall BTU output if the air/con unit will go down...that means it will take longer for the initial cool down and have a higher duty cycle...net effect, you don't really save on the total watt-hours consumed because it's running for a longer time period.
- If you were to retrofit an invert based mini-split, they can vary the compressor speed but you run into the same issue. If you run the 15k btu unit at 7.5k btu output, it cut consumption by roughly have but will run roughly twice as much of the time. Net effect no savings in total power consumed.

Other items of note:
- After the first day, those 400a-hr batteries are down by 4000w-hr. 570w of solar can only be expected to add around 2000-2500w-hr back in (the charging systems aren't 100% efficient), so the next day, you don't have the full battery capacity to work with.
- This also ignores consumption by lights, pumps, etc...while boondocking which will further reduce your available power for air/con.
- No, RVs have horrible insulation. Really they are more akin to the old WWII movies when the Japs would put prisoners in the "hot box" for punishment. When it's 90+, it's not uncommon for the air/con to run full blast continuously and you may still see the temp creeping up mid afternoon.
- "4 season" and similar terms are mostly marketing. Slightly better if dual pane windows but don't expect anything close to 1950's vintage household insulation.

Ultimately, it's your money and your call but you have been warned.

Thank you for taking the time to respone, but IIRC, we are not talking about a 15K BTU, but rather a 11K soft start AC that comes with this system..

I am weighing all options which is why I am taking my time and not rushing into a purchase.. as well as I am still considering this system as prices are starting to drop some now that there is an influx of inventory..


https://imgbb.com/4dSv1fn

https://imgbb.com/dJtxzsM