Solar geek question

[WaltBennett]

OK, I'll be putting 400 watts of PV on the roof and will have 4 Trojan T105's (or equivalent). We're not planning on spending a lot of time off grid, so I believe this will work for most of what we need. I've looked at all we use and a 2k inverter will work. BUT LOML wants to know if we can run the AC for a bit. Does anyone have an idea how many watts that 15.whatever AC unit draws? I know we could run our 13k in our old TT on a Yamaha, but the same gen won't run the Monty.

[Bigboomer]

With any RV solar you can forget running the A/C on it....the amp draw would deplete the batteries before the unit would actually cool anything. It would be no different if you turned on your microwave and ran it for an hour....Even with our system which we have 11kW of battery storage with 5.5kW usable (50%) we would not attempt the A/C.

What you plan on setting up will give you a comfortable off grid use for your basics if you monitor the usage. Do you have the system designed with all components? Type of panels? Charge Controller, etc.?

[DQDick]

Les is one who provided me with the knowledge to put our system together. I'm considered nuts by some and use our solar for microwave, vacuum and hours of TV while being in the shade until 2pm. The trick is to control your total usage which for us means no inverter for half the day and six batteries. I wouldn't attempt to run ac's however without using our generators or shore power. Since we pay for power at our home base we use shore power for ac, frig, and water heater and use solar for everything else.

[WaltBennett]

I'm still looking for an answer to the original question. Not planning to run the AC for any length of time, but would like to know if anyone knows what the REAL power draw is by our from the factory 15k unit. We could run our old TT's 13.5k off a single Yamaha generator, but needed to gang 2 to run the Monty. Obviously that's something over 2k watts - but how much?

[DQDick]

Here's the problem, you have the same model and year as I do and so we have older units. Dometic is bragging on the new units as being more energy efficient and I couldn't find any info on the older units. What I did find is that the new 15K units are supposed to draw 15.2 amps, but most of our rigs draw 10amps or more when nothing obvious is running so that's why one small generator has issues.

[twindman]

I have a surge guard that shows the power (amperage) usage. I live in Mesa, AZ so it gets HOT. If it is around 85-100, the AC starts at around 12-14 amps (after an initial surge when it kicks in). Then as it gets hotter on the roof and probably from the AC itself, the power usage goes up to 14.5 to 16 or so. I can barely run it from my house 20A circuit. I have to make sure nothing else is running.

[dieselguy]

Walt ... are you asking if you can run your 15K A/C off the batteries thru the inverter??? My 15K A/C alone draws 13 amps at 1.4 KW or 1400 watts on a 85 degree day. I'd liken your proposition to the fuel consumption of a top fuel dragster running a quarter mile ... "mass quantities".

[WaltBennett]

"My 15K A/C alone draws 13 amps at 1.4 KW or 1400 watts on a 85 degree day."

That's what I needed to know. I'm certain that start up draw must be over 2k since it would kill a single EF2400is, but I also run the AC at home on a 20 amp circuit & long extension cord. Our two EF2400's ganged together handle it easily though, but I'm selling them (see the for sale listings). Many different reasons I'm doing this, but I'd rather not get into all that. Thanks everyone!