How much solar needed to run 13,000 btu AC only occasionally in RV motorhome?

[rworell]

Will be traveling to Baja this coming winter in our small motorhome. We boondock for periods of time often and don’t have any solar and do fine. We are extremely efficient. But thinking some solar will be a great option if we do longer term stays out west and in Baja Mexico to run our AC only when needed ( just for quick cool downs) and to keep the batteries topped off.
Thoughts? So appreciate the help!
Rich

 

[MisterSandals]

You need to put a number value on "only occasionally" and "only when needed".


Typically, RV air conditioners come in 13,500 or 15,000 BTU ratings. Air conditioners in this range usually operate at 1,300 to 1,500 watts, although in some instances, they might peak at 1,800 to 2,000 watts during normal operation.

How Much Power Does An RV AC Use? A Guide To RV Air Conditioners' Power Usage | RenewableWise

The typical BTU rating for an RV air conditioner is 13500 or 15000. Air conditioners of this capacity will typically have a running wattage of around 1500 Watts.

www.renewablewise.com

So lets use 1300W to run for 1 hour = 1300Wh

Assume 5h quality sun per day (higher in Baja?):
1300Wh / 5h = 260W solar operating at 100%

But this hour run will need to come from energy stored in the battery (260W won't power 1300W A/C).

Battery:
1300Wh / 12.8V nominal battery / .5 dischargeable if lead acid = 203Ah (if operating at 100%)

The solar helping during the 1h run would add 250W / 1300W = 19%

The realist in me says you'd need at least 400W solar and 300-400Ah of useable battery.

If your A/C runs off AC current, add at least 15% for inverter losses.
You might get by with a 2000W inverter if you put a soft-start unit on your A/C.

 

[Suijkerbuijk]

Wy not a 8000 btu unit ?
If the motorhome is small it can cool it.
And use les power to run it.

I use on on my boat in the summer what can have temperatuur out side over 40 celcius.
Inside the boat with no ac it can go up to 60 celcius if it close.
Normal all Windows and roof top is open
If i close it the ac unit can easy cool it down.
I think a motorhome will be more isolation on it .
Than my iron boat .

But understand i do not life in that country so you have to see if ac unit like that model will do the job.
Or wait for other forum user .

For the power use .
You need a lot to fill it but if its only to cooldown like for the night so you can sleep.
And only run for 30 minuten .
Wel its easy to calculate.

This easy calculate just to show its done
600 watt : 60 min= 10watt in a min .
10 watt X use time like 10 min run time = 60 watt use
600watt : 12 volt = 50a + 10% for the inverter totaal 55a u use .
55a use : 60 min = 0.9a minute draw x 10 min 9.2 amps draw out of the battery .
A hour run time amps draw will be 55a
Running 10 hour you need a battery of
550Ah .

Now you know this .
Than the solar panels you can use on the mobile home will be wel you have to see what you can place on it .

Reason a lot use a 24 or 48 volt battery is that ampère go down .
But well that is a other information.

 

[rworell]

You need to put a number value on "only occasionally" and "only when needed".


Typically, RV air conditioners come in 13,500 or 15,000 BTU ratings. Air conditioners in this range usually operate at 1,300 to 1,500 watts, although in some instances, they might peak at 1,800 to 2,000 watts during normal operation.

How Much Power Does An RV AC Use? A Guide To RV Air Conditioners' Power Usage | RenewableWise

The typical BTU rating for an RV air conditioner is 13500 or 15000. Air conditioners of this capacity will typically have a running wattage of around 1500 Watts.

www.renewablewise.com

So lets use 1300W to run for 1 hour = 1300Wh

Assume 5h quality sun per day (higher in Baja?):
1300Wh / 5h = 260W solar operating at 100%

But this hour run will need to come from energy stored in the battery (260W won't power 1300W A/C).

Battery:
1300Wh / 12.8V nominal battery / .5 dischargeable if lead acid = 203Ah (if operating at 100%)

The solar helping during the 1h run would add 250W / 1300W = 19%

The realist in me says you'd need at least 400W solar and 300-400Ah of useable battery.

If your A/C runs off AC current, add at least 15% for inverter losses.
You might get by with a 2000W inverter if you put a soft-start unit on your A/C.

The number value is maybe 1hr at most probably before bed. Maybe the same occasionally during the days… we truely live outside and are efficient on just what we use not because we need to be. We have gas and percolate coffee. Grill for food. Never use the microwave etc…. Then nice to have batteries topped off.

 

[rworell]

Wy not a 8000 btu unit ?
If the motorhome is small it can cool it.
And use les power to run it.

I use on on my boat in the summer what can have temperatuur out side over 40 celcius.
Inside the boat with no ac it can go up to 60 celcius if it close.
Normal all Windows and roof top is open
If i close it the ac unit can easy cool it down.
I think a motorhome will be more isolation on it .
Than my iron boat .

But understand i do not life in that country so you have to see if ac unit like that model will do the job.
Or wait for other forum user .

For the power use .
You need a lot to fill it but if its only to cooldown like for the night so you can sleep.
And only run for 30 minuten .
Wel its easy to calculate.

This easy calculate just to show its done
600 watt : 60 min= 10watt in a min .
10 watt X use time like 10 min run time = 60 watt use
600watt : 12 volt = 50a + 10% for the inverter totaal 55a u use .
55a use : 60 min = 0.9a minute draw x 10 min 9.2 amps draw out of the battery .
A hour run time amps draw will be 55a
Running 10 hour you need a battery of
550Ah .

Now you know this .
Than the solar panels you can use on the mobile home will be wel you have to see what you can place on it .

Reason a lot use a 24 or 48 volt battery is that ampère go down .
But well that is an other information.

I have a lot of room on my motorhome roof. More than I’d use up with panels. I was thinking 400-600 watt panels. I do like the 48volt battery options too but I don’t know much about it.

 

[KnobCountry]

Sounds like OP already has a unit. Spending more money on another one is not very cost efficient unless the existing unit is just unbearably inefficient.

OP, you would need to post the exact model # of the AC unit for anyone to give you accurate info, as Sandals has constructively outlined.

 

[rworell]

My AC unit is a Dometic 13,500 BTU. It runs very well.

 

[time2roll]

I have 675 watts solar and it will not run the air directly. Probably need 2000+ watts for that.

But I do have 1200 Ah battery that can run the air if needed for hours at a time through my 2000 watt inverter.
Then recharges next day or three.

 

[rworell]

I have 675 watts solar and it will not run the air directly. Probably need 2000+ watts for that.

But I do have 1200 Ah battery that can run the air if needed for hours at a time through my 2000 watt inverter.
Then recharges next day or three.

Is this one large battery or a 6 200amp hr battery bank?

 

[time2roll]

Two DIY lithium batteries at 600 Ah each (12v). About the same space and weight as my previous 4x GC2.

 

[HRTKD]

Like time2roll, I run my air conditioner from my inverter and my battery bank is 560 Ah. I'm comfortable running the air conditioner for about 3 hours, but I do get some supplemental power from the 640 watts of solar panels on the roof.

I have a Victron Multiplus 12/3000 inverter. It ran the air conditioner OK, but I added a Microaire Easy Start to reduce the surge amps at startup. Despite the name, the inverter is rated for 2400 watts, not 3000 watts. The 3000 refers to Volt Amps.

 

[mnvista]

We use a Ecoflow Delta Pro, with our solar on roof, (we have 2000w now) we can run our one A/C unit all day when sun is out and not deplete our battery bank in the DP. If you had room in the bay with the shore cord it would be as simple as plugging into the DP's 30 amp outlet to power everything in the RV like your at a campground. I would place as much solar on roof as possible to keep the DP charged and it can be done today for around $2000 if you install the panels yourself.

 

[Sportzfann]

I have a 15k ac domestic on my fifthwheel, I ran it for the first time on my inverter it’s a Victron 3000 120x2
I have 3x Li time 200ah+ 600ah total. looking at my smart shunt, it said I could run for 3-1/2 hrs. this was in late afternoon so not much sun on the panels at that time so maybe the ac runs longer. I have 1300W on roof. I still have a small generator, i bring with me. If I need the ac for more than an hour I will just run the genny. Those small mini splits are kind of interesting super quiet too, low wattage running load, maybe more efficient.