Air Conditioning while on the water

[brineair]

I have a Maxum 2500 SCR. I has marine A/C but as of now it can only be used while hooked up to shore power. The boat does not have a generator built in.

I am trying to avoid buying a portable generator that would have to be harnessed down to the back of the boat to plug into for A/C while I'm out on the lake/river.

I thought I could buy this type of set up and it would work...2 extra marine batteries, large inverter and a second battery switch. I would have this all stored down in the engine compartment and it would also be hooked into the alternator (might need to enlarge that). With this set up I would connect the inverter to my A/C so that I could use it while not plugged into shore power and even with the engine being off. I was recently told that this would absolutely not work as the A/C would drain the batteries very quickly meaning I would have to have the engine running whenever the A/C was on. Could someone clarify if this is true?

Secondly I was looking to see if I could buy a generator that would mount and wire into the boat like it would be from the factory on a bigger boat. Now I understand that the engine must run for this to work as well which is why its my second option. This is mainly due to carbon monoxide building up in the cabin (I do have detectors).

The long and short of it is this...if anyone has suggestions on how to get A/C on my 25' 2001 Maxum 2500 SCR while not plugged into shore power I would greatly appreciate it. Thanks again for all you help!

[mmwjr]

I would go with a generator, either installed in the engine compartment on tempary strapped on the swim platform. The propulsion engine does not need to be running for either of these options.

Two batteries will not last long, run the numbers. What is the amp hour draw of the AC? You will need an inverter that can achieve this with 10% margin. Then calculate the amp hour draw on the batteries to see how many hours they will last but take into account a 10 - 20% efficiency loss through the inverter and that once the batteries discharge to a certain level the voltage will drop to low for the inverter to provide adequate power to the AC.

[shrew]

Running A/C off of a 12 V battery bank through an inverter will work, but be very limited in duration. Effectively not worth the effort. It's not impossible, though it would be impractical.

My Honda 2K portable can run my AC. That is the cheapest solution. You might be able to shoehorn a 3K onboard generator, but it will be an expensive aftermarket install. You'll need to have a new intake installed and an exhaust port. I'd guess somewhere over 7K installed.

[brineair]

Shrew,

Sorry for the long delay in replying. What boat do you have? I am wondering if it has the same size A/C (BTU rating) as mine?

[shrew]

2800 scr. I don't recall the size of the AC unit.