How big of an inverter would be required to start a 15k btu a/c? I'm not interested in the 12v supply debate, just need to know how many Watts to start the unit. 2500 continuous/5000 surge?

What model of A/C? There should be a listing of what it takes to run it. Others here do run their A/C off of their system. I do but it's just a little window shaker.

How LARGE is your battery bank?

A 15K AC is typically going to require about 20-25 amps to start and around 18 amps running.Meaning your inverter would consume about 200-250 DC amps to start out of your battery bank.

2500/5000 would do it easily, the trouble being that any inverter you see advertised as 2500/5000 is almost certainly junk, and will never come anywhere near having that capacity.The units I have worked on that run air conditioners from inverters use 4K watt 24 volt inverters (along with water cooled alternators).

heh heh hehI had a 3000/6000w psw inverter that lasted until I started a 5000 BTU air conditioner once. Now it wont hold voltage and isn't worth fixing.A 24v inverter would be better IF you systems can be set up for it, including charging.

A/C and an inverter | Good Sam Community

23 Replies

3_tons
Explorer III
Jul 16, 2015
christopherglenn wrote:
Isn't that in my signature?
Batteries 3 PVX-840T.
Inverter XANTREX FREEDOM SW3012.

I said it would run it, just not for long. More of a proof of concept, for a day where I have 2+ kw on the roof.

I appreciate your kindly reply.
moresmoke
Explorer
Jul 16, 2015
Thanks for the replies, sorry I couldn't check back in sooner, work does that some times. I will look for something in the 3-6k range.
christopherglen
Explorer
Jul 16, 2015
Isn't that in my signature?
Batteries 3 PVX-840T.
Inverter XANTREX FREEDOM SW3012.

I said it would run it, just not for long. More of a proof of concept, for a day where I have 2+ kw on the roof.
3_tons
Explorer III
Jul 13, 2015
christopherglenn wrote:
My inverter is 3kw running 6kw surge. I can start either AC on it, and if I start one, wait until it is up to speed for a few seconds I can start the second one. FWIW I am just under 3kw running both.

What make and model is your inverter, and what type and number of batteries??

Thx
3 tons
bcbigfoot
Explorer
Jul 13, 2015
My cheapo 160$ Canadian tire 1000 watt PSW inverter fired up and ran a Dometic 7200 btu AC, I only ran it for 15 minutes, this was when it had new group 31 agm batteries and only did it the one time. The AC pulled approx. 700 watts if I remember correctly.
christopherglen
Explorer
Jul 13, 2015
My inverter is 3kw running 6kw surge. I can start either AC on it, and if I start one, wait until it is up to speed for a few seconds I can start the second one. FWIW I am just under 3kw running both.
JiminDenver
Explorer II
Jul 13, 2015
I understand the OP's desire. I've gone to considerable lengths to be able to have A/C without a generator in the rare times we need it and that's just a little 5000 BTU window shaker.
MrWizard
Moderator
Jul 13, 2015
the thread is NOT about generators
i do agree that is the ideal option
hbillsmith
Explorer
Jul 13, 2015
Simple. Just get a Champion 3100 Inverter. Choose the manual start about $750 or choose the electric remote start about $900. It will run a 15K A/C just fine. A smaller 13.5K A/C is even easier. Don't plan on running a microwave or hair dryer at the same time though. Just turn the A/C off for a few minutes if you need to run either. If money is no object, feel free to go for the Honda or Yamaha. All 3 are quiet at between 53db to 58db.
MrWizard
Moderator
Jul 12, 2015
it will take about 1400VA to run
12amp at 120v
the problem is the start surge, and how hot is it, when you push the button
a 3kw might start it at 80F in the shade
while at 101F in the sun you will need a 6kw
the LRA lock rotor amps on the compressor will be much higher at high temps and restarts as much as 50~60 amps
the tag on the compressor will tell you the LRA