Running an A/C unit on an inverter

[Foghorn]

I have a 29' Back Cove with no generator. On rare occasions I need to run the A/C (for the Admiral) when away from the dock and shore power. Looking at the $12K + cost to install a generator, I'm looking for a cheaper alternative. Does anyone have experience with running an A/C system on an inverter? Or it that just a a bad idea? The A/C system is a Marine Air Systems 9K BTU.

 

[DavidM]

It can be done for overnight use with a big Li battery bank and a 2000 watt minimum inverter. If you want to run it for a second night, the problem will be recharging the battery.

To run ten hours overnight requires 500-750 amp hours of Li battery capacity depending on local climate.

With Li battery prices dropping you should be able to do it for roughly $2,000 in parts cost, ignoring recharging.

You could recharge while moving five hours to a new anchorage but that will require upgrading to a high output Balmar alternator for roughly another grand.

How about a no name inverter based portable generator to run the A/C overnight for $500 or $1000 for a Honda.

David

 

[Graeme Walker]

We have run our 6k unit for a few hours to cool down. We have 960ah Lithium and 990watts solar, neither is quite enough, should have ~2x solar for each ah Lithium if you want to use solar to recharge. Our twin dc-dc chargers are not enough over the roughly 3-4hrs of travel each day.

 

[more]

9K BTU super easy this is 500-600W but non inverter 12 000 btu mobile AC is under 1000W around 700w you need minimum 2000w or best victron inverter 3000

I testing soon my AC 48000 btu, but I must try on inverter I have 20 kw generator

 

[READY]

It is the start current that might be the biggest obstacle. It could be 30-70 amps. Recently installed Velair ACs in my 48LRC. Variable speed compressor so the start up has no spike. Have not pulled the actuals yet but amazingly efficient and quiet. I think they probably pull less than 10amps start up for 16k BTU.

 

[Turtle Blues]

DavidM gave you good numbers in post #2.
The addition of a Soft Start module (assuming it does not have one) will make it much easier to get it past the initial voltage surge and running on it's operating amperage. Especially if you go the small genset route.
I am referring to a real soft start module with a programmed ramp up, Dometic's for example. Not a cheap HVAC hard start capicator.