Air Conditioner to run off-the-grid?

[Joe M.]

I have been using that same set for about 3 years now and I love them. Haven't had one bit of problem with them. They are half the cost of Honda and Champion customer service is top notch.

[ebergler]

AC uses close to 1 KW continuously, therefore a generator is needed. My suggestion is a min. of 2kw.
Solar is not realistic as it would have a hard time to produce 1KWhour a day!

[Tundra 2014]

I agree w/ another poster, "boon docking and A/C do not go together"
If you are staying in national parks, they have 3-2 hr. periods daily you can run generators. Hard to maintain A/C under that condition.
There is no standard by manufacturers how far away from generator they measure with the DB meter. This is why Generac does not publish DB sound levels. Also many give the "ECO" sound level. Hard to compare one to another. W/ my Generac IQ 3500 at 20' on my DB meter I am at 58 DB @ full load. Also as the generators get bigger the DB goes up. Two small Hondas together under the 20' test-under load, are at 56 DB on my meter.

[Luisde]

Originally Posted by HeloSNA24

Appreciate it. Any recommendations? 13.5 BTU AC from Dometic

It takes approx 2800 watts to start a good 13500 ac! I set up a 3400 Watt Champion Inverter on a slide out from my front storage compartment on my fifth wheel!

[Texan99]

Originally Posted by jimmoore13

A favorite subject - battery power vs. real world - because the numbers are staggering.
If you intend to boondock, you absolutely MUST know this stuff. Fortunately, Rapid Tables makes it very easy.

13,500 BTU to watts = 4000 watts in round numbers.
https://www.rapidtables.com/convert/...U_to_Watt.html

4000 watts at 12 volts = 333 AMPS per hour = 333 amp hours. GULP!
https://www.rapidtables.com/calc/ele...alculator.html

So, you need god's own inverter to deliver enough wattage, and you need cable the size of your thumb to carry 300+ amps.

13,500 BTU is the startup power (which accounts for the need to add an easy-start [giant capacitor] to start the AC). Let's assume your AC unit will run, once started, on 60% of startup power. That's, conveniently, 200 amps at 12 volts. 200 amps for an hour are 200 amp hours (AH).

This is getting ugly in a hurry. You'll need 2.0 AWG wire from the battery bank to your inverter, and it needs to be a short run.
https://images.crutchfieldonline.com...auge-Chart.jpg

Now let's assume the "gold standard" RV battery bank: 4 x 6 volt golf cart batteries wired in series/parallel to deliver roughly 460 AH. You get to use half. (Another discussion, but believe me, you only get to use half of the rated amp hours.) So you have 230 AH on tap to power EVERYTHING until you recharge...say with solar.

Do the math, and you see that you'll drain your battery bank in just over an hour.

Go lithium, he says? Here's a good one at only a kilobuck, but wait, it's only 100 AH. Sure, you can dig much deeper that 50% into that Battleborn, so maybe 75 AH or so before you must recharge.
https://www.solar-electric.com/battl...gaAiQxEALw_wcB
But you see where this is going...in a helluva hurry.

Now comes the solar: Assuming a reasonably priced 400 watt system from Renology or Windy Nation. 4 panels will fit reasonably on most RV roof. Given that your rig has a 13,500 BTU AC unit, your rig is on the small side.
4 panels are about the limit. In sunny Colorado, each panel can pump out roughly 30 to 35 amp hours per day in good sun. So on a good day, you can "replace" about 120 to 140 AH with that solar array. If you have the gold standard battery bank, you'll operate at a daily deficit of about 100 AH unless you use less power or you supplement with generator.
https://smile.amazon.com/Renogy-Mono...NsaWNrPXRydWU=

To do what you're asking, you'd need a second trailer to haul batteries and solar panels, a solar system and battery bank from Tesla or similar to run your AC, or, you can go with a 2 KW inverter generator and an AC kickstarter, or you can do it right and get a 3500 watt genny like this one from Harbor Freight - VERY highly regarded by Consumer Reports - and do it right.

3500 Watt Predator: https://www.harborfreight.com/mercha...tor-63584.html

Tesla: https://www.gocamsolar.com/solar-bat...UaAiYCEALw_wcB

The hard facts of life with batteries are that batteries SUCK for energy storage. You absolutely NEED a generator to run AC. And with anything short of the gold standard battery bank, any kind of compressor fridge will suck your batteries dry in no time. That's why we have 2 way fridges in most small RVs. Nobody wants to use up 300 pounds worth of the roughly 800 +/- pounds of cargo capacity on batteries, inverter, solar panels, and related tonnage of copper wire to connect it all.

One more hard lesson on energy storage:
1 gallon of propane contains 91,500 BTU. https://www.google.com/search?q=btu+...hrome&ie=UTF-8
A 5 gallon tank holds about 4.5 gallons or 411,750 BTU.
One tank of propane contains 120,672 watts.
https://www.rapidtables.com/convert/...U_to_Watt.html
120 KW = 10,000+ amp hours at 12 volts.
The two puny propane tanks on the tongue of your rig contain 20,000 AH energy equivalent of battery power, or 87 times the USABLE energy equivalent of the gold standard battery bank!!

Gasoline contains 114,000 BTU per gallon. At 20% efficiency, your generator will turn a single gallon of gas into 550 AH at 12 volts - 55 AH at 120 volts (they are the same).

Put differently, a gallon of gas in a generator is the energy equivalent of almost TWO of the puny 12 volt group 24 batteries the dealer sent you down the road with. And, of course, you can carry spare fuel in a can.

The facts of energy life are hard...very hard. But now you have the tools to understand the limits of your battery bank...whatever the size...and how to choose the right energy delivery system for the job at hand.

I repeat. Batteries S. U. C. K. I have 400 watts of solar and 2 x 6 volt golf cart batteries, AND a 2 KW generator, AND a propane powered fridge. I can boondock indefinitely in sunny CO. We do not need AC in the mountains (though all campers have them). If I needed AC, I'd have a 3500 watt generator - period.

I love my propane fire pit. We have fire bans all the time in CO, but you can use a propane fire pit during all but the worst fire bans. It eats propane at the rate of 54,000 BTU/hour when turned up full. Used judiciously, I can get two days out of a tank of propane. I have two tanks on the tongue and two tanks in the TV for the fire pit. And I carry one gallon of gasoline in a can for the generator, too. I seldom have to refill, because we have "enough" solar for 12 volt needs, we don't use the AC, and we only use the genny for the microwave and coffee maker. More often than not, I give my gallon of gas to a neighbor who ran out.

Good luck boondocking. It's far better than RV park camping, but you really need these fundamentals if you want to do it successfully.

P.S. If you boondock, you'll soon discover that you need to do something with grey water. Black tanks hold a surprising amount of effluent. But grey water builds up quickly. In the very dry Rocky Mountains, a garden hose adapter for the grey-water dump, a short length of hose, and a 5 gallon bucket will get the job done. In the woods, I water the trees. In a federal or state campground, I go the the nearest vault toilet. I also carry 4 x 7 gallon Reliance jugs of fresh water to refill my holding tank.
https://smile.amazon.com/Reliance-Pr...s%2C200&sr=8-2

Boondocking below.

The numbers you are giving are not really correct. First of all, 13000 btu/hr (not btu) converted to watts (4000) is not the electrical power- it's the mechanical power. Correction, I should have said thermal power, not mechanical power.

According to Coleman, an RV air conditioner electrical power is about 1.25 kw/ton, so 1.13 tons x 1.25 - 1413 watts.

Using Coleman's info, the power factor of the ac unit is 0.9, so at 12 vdc and 95% inverter efficiency 1413/(12 x 0.95 x 0.9)=138 amps (not amps per hour).

If the AC runs a total of 5 hours during the night then 138 amps x 5 = 689 amp-hours of battery capacity.

Also, 13500 btu/hr is not startup electrical power-its continuous mechanical power. The starting power is based on locked rotor amps, which according to Coleman, is 61 amps.

The locked rotor power factor is about 0.5, so the starting power is 61 x 115 x .5 =3660 watts. The easy start device is a capacitor which raises the power factor on the line, thus reducing the current drawn from the source.

The correct numbers only support your conclusion that ac unit can't be run from batteries in a RV.

[Campah]

Originally Posted by HeloSNA24

What's the best way to get your AC to run off the grid? Solar set up combined with additional battery? Do I need an inverter?

I have a 13.5 Dometic AC unit and installed the Easy Start mod ($299) and can run this on my Champion 2000 Watt generator/inverter. I can also run this from a standard 15 amp outlet. Great mod.

[HeloSNA24]

Seems like this was a good topic to get startedy. Idea for boondocking was genny + solar combined. Off grid idea was for being on the Texas beaches for weekend camping and ac would only be used at night. Ocean breeze should cool us down with windows open during the day. Waiting on hard start cap delivery then will test it out. If unsuccessful, predator 3500 or champion dual fuel it is.

[Dhouse]

Originally Posted by HeloSNA24

What's the best way to get your AC to run off the grid? Solar set up combined with additional battery? Do I need an inverter?

It is physically almost impossible to operate AC with batteries and inverter and / or solar panels. A high power inverter can, the batteries too but for a few minutes (and more). First your inverter will shut down automatically when it reaches 10.5 volts as protection. In this condition you will have it for seconds .....! The difference of an inverter (with battery) and generator is the voltage. Ohm's law is P (watts) = V (volt) multiply by I (amperage). If we want to find I (amperage), we must divide P by V. This gives I = P / V. If you have for example 3000 watts divide by 120 volts you get 25 amperes. On the other hand, if you have the same 3000 watts but under 12 volts (batteries), you get 250 amps! ! This is why a generator '' honda '' which delivers 120 volts can support an AC but not the batteries (or so little long).

[boatnik]

my Yamaha 2800I powers up my tv lights and 1 air conditioning unit. it is not as quiet as the IQ3500 generac that was not available 8 years ago. I also got a Powerhorse 7500 watt inverter 50 amp 220v 3 blade with ground that is super quiet 55db that has enough power to run everything in the rv. That is primarly used as a backup home generator. After doing some research for backup home generators I thought I would have had to put in a transfer panel. Wrong. There are circuit breaker interlock plates that can lockout your generator from the street main breaker. This way you can shut all breakers down in an outage and turn on what breakers you need not back feeding to the street. With a transfer switch you are limited to certain breakers.

[5picker]

Originally Posted by Dlh1228

I have tried several different generators. The best deal right now is the GoPlus 3,500. It powers my 13.5k BTU air conditioner and my microwave no problem. It is as quiet as a Honda 2,000 and almost as small, and it is under $550 on Amazon.

Originally Posted by bikendan

How can you say that it's a quiet as a Honda 2000i inverter generator?

Amazon's description says "Relatively quiet operation, as low as 94db"[emoji32].
It states that 94db number 3x.
https://www.amazon.com/dp/B07SZ8LM9H...ing=UTF8&psc=1

That's WAY louder than a Honda 2000i, in fact that's louder than most open-frame contractor-style generators.

Originally Posted by Dlh1228

Because that is an obvious misprint. It should be 49db.

Originally Posted by bikendan

OK, just thought it was unusual that Amazon missprinted it 3x.

I have this exact same generator branded as a Ramsond Sinemate.
I believe them to be the main Chinese company that markets these generators.

I've had it now about 8 years and it has performed flawlessly, easily starting my last two 15k air conditioners.

In addition to Ramsond and GoPlus, it is also branded as a Lifan and Costway.
Mine is electric start and while some of the others are the same basic generator, a few of the others are manual start.

All the specs I've read said 59DB, including my manual.

I've never seen it listed at 49DB. I'd like to see that spec.

The 94DB rating comes from full load, wide open.

Ramsond Sinemate 3500w Generator

[babalu7420]

Originally Posted by HeloSNA24

Thanks folks. Seems like an expensive idea for all solar and boondocking if A/C is on for the long term.

Follow up question, if I got honda 2200 for example and parallel 2, can I store them sidewise in my travel trailer or do they need to be stored right side up? Asking because Cargo is 20" w by 13" h. I'm thinking no but I'll ask the folks, plus I can always store in the pickup.

NO don't do it !! gas will spill & oil could leak into the piston cylinder & lock up the generator . Consider a Harbor Freight 3500 watt Predator generator w/ 20% or 25% off coupon & also purchase w/ it the extended warranty. I questioned the extended warranty & response was any defect during the warranty period the unit would be replaced. I own one & it powers my RV completely.

[HeloSNA24]

Appreciate the feedback. Yeah we've got the predator 2200 and hard cap we are going to install later today. We'll see how it goes. If no luck, 3500 it is installed in the back of the truck bed.

[HeloSNA24]

Follow up, I was ready to install my hard cap on the Dometic 13.5K Penguin II https://www.dometic.com/en-us/us/pro...uin-ii-_-20667


SKU number 9105304180
Model 13.5K Btu
Model on label 640315CXX1J0
US Item Name 640315CXX1J0
Scope of delivery 1 Air conditioner, 1 Warranty card, 1 Registration card
Product Description 13,500 BTU Low Profile Rooftop Air Conditioner, Ducted or Non-ducted application - ADB required.
Thermostat Zones Single or Multi
Cool Only or Heat Pump Cool Only

Dimensions product depth 29 "
Dimensions product height 11 1/4 "
Dimensions product width 40 1/2 "
Net weight 101 lbs
ELECTRICAL
Input voltage (AC) 115 V
Input frequency 60 Hz
PERFORMANCE
Cooling capacity (ISO 5151) 3956.46 W
Power consumption - Cooling mode (ISO 5151) 1731 W
ADDITIONAL
Certificates CSA
LOGISTICS
EAN-13 0713814200503
Dimensions parcel depth 29.72 "
Dimensions parcel height 12.20 "
Dimensions parcel width 41.54 "
Parcel weight 107.60 lbs

Page 17 bottom left: HERM and start cap locations.
https://www.dometic.com/assets/28/57...7.pdf?att=true

Was trying to use this video as a guide:

https://www.youtube.com/watch?v=y52bADo5GlY&t=217s

and noticed there's already a capacitor there. I tried to turn on the generator without install to see if it worked. Low fan, high fan work, when I switch to low AC it worked for 5 seconds then powered off and the genny stopped. Bought the Predator 2200 harbor freight. This thing is quiet and nice alternative to Honda.

So what I'm getting at is I don't know how much power the capacitor that is already there is helping with, can I install an additional hard cap in series?

Dometic 3310727007 kit, Hard Start bought this.

[rsdata]

so looks like a good video to follow
you say there is already another hard start cap in the box the video shows he inserted the add-on hard start cap into?

If there is already one there is it the same size (physically) as the one the you bought?

Physical size is an indication that it may be the same thing ( although maybe a different mfg.)

Your description of genny shutting down after 5 seconds is indicative of the genny not having enough power to start the AC...

The hard start cap ADD-ON gives the AC compressor a little bit of boost in current flow at start-up to get the motor turning, and you are adding the CAP in parallel not in series, which adds MORE power to the OEM Cap.

Previous to the HF 2200 they had a Predator 2600 that I bought 3-4 years ago. I added hard start to my Coleman unit and the 2600 will start the AC, but without the hard start cap it will NOT.

[HeloSNA24]

Correct. It looked a similar size as installed. Not exact but similar and the one I bought was from Dometic. Can I install 2?

[rsdata]

Can I install 2?

well maybe, but I would try replacing the one in there with the new one and try it...

according to the video there is barely enough room in the electrical box for one...

make sure the wire connections you are making are tight and snug

[HeloSNA24]

my unit has bigger spacing for 2 potentially. I'll try with the replacement option first.

[Lyrd44]

Correction. We have 15K A/C not the 13.5K. so that's even more impressive really. Still love this generator.

Originally Posted by Lyrd44

We have a Harbor Freight Predator 3500. It will run our 13.5k A/C our 8cf fridge and most of the lights at 14 amps. If we turn the TV on it uses about 16amp so just over 50% of it's capacity. It's also crazy quite. Love it.