Quiet Air Conditioning on Mooring

[Monterey385]

On a recent trip we had an incredibly hot night on a mooring in a harbor where boats were closely packed. While I have a Honda2K that can run my air conditioning unit, it just seemed wrong to disturb everyone else’s peace and quiet so we sweat it out and paid for a slip the following night.

Our 39 foot boat requires 16K to cool down and the AC works great at dock.

It appears that a 16K unit draws about 11amps of 120 volts of AC power when running which should be about 110 amps of DC and about 1,320 watts. I have an 1800watt inverter onboard already. Assuming one could handle the surge at start, has anyone considered/succeeded in using battery power for air conditioning while traveling without resorting to a generator?

If so, how did you do it?

 

[ggrizzard]

These Youtubers do it:

They have a series on the subject starting at the link above,
Be aware, it requires solar and lithium batteries!
Good luck.

 

[tfox2069]

Its all about having a big battery bank, and the ability to recharge it. One option to make the bank requirements reasonable is to not cool the whole boat, but just the cabin where you sleep with a smaller a/c unit. There's all sorts of discussion about whether it should be a 12v a/c unit, or 110 with an inverter, etc. There are some very compact units that work for a small cabin.

I do applaud you for taking other people's solitude into considering whether to run your Honda generator. I have one as well that I've used to run my 16k a/c that has a soft start installed. The vibrations were bad enough it made sleeping in the aft cabin very difficult, though the forward cabin is fine. Working CO monitors are definitely in order though. as well as an extended run tank if you're going to run it over night. And then you burn enough fuel that you need gasoline every 2 days. I just don't see the Honda as useful beyond the odd overnight when there are no other boats in an anchorage, which isn't often. In that case I'll just get a marina slip with power.

 

[DeniseO30]

If you can't find a quiet generator probably need about 5 tons of batteries 110 amp probably means 125 amp cable which if I remember right is number 2 copper

 

[Monterey385]

These Youtubers do it:

They have a series on the subject starting at the link above,
Be aware, it requires solar and lithium batteries!
Good luck.

This was really interesting. He seems to have dropped amperage draw at least 7X-10X but is only cooling one cabin. Not sure it requires Lithium or Solar but clearly requires ability to pump in amps during the day. In a coastal cruising situation, I imagine the alternator could/would do that too.

The key seems to be to have the right compressor, pump, and air handler.

I need to figure out whether there is some way to piggyback on a standard marine air conditioner install.

 

[Johann]

Yes, we run our 16k btu air conditioners off our batteries. At a minimum you will need a soft start, and even then the inverter maybe a bit small for the startup. A decent plan is to run the honda at dusk to precool the boat then switch to batteries. You will probably then need about 4-500 Ah usable (at 12v) to get through the night. Then you will need to put that back during the day. If you have lithium that’s over 1kw of solar needed… lead batteries a lot more… or more genset runtime for charging. It can be done but you need to get data specific to your boat and come up with a plan based on that. We ended up with 945 ah LFP, a 3kva Victron Multiplus, and 2x Frigomar 16k BLDC aircons. If we precool with the genset we can run both ACs all night and use about 60% of the battery capacity. We are increasing our solar from 1kw to 1.7kw since we only get about 6kwh a day.

 

[capta]

If you've got the money for LifePo, by all means go on ahead. Otherwise, for those few unbearably hot, humid wind-less nights, fans are about your best hope for a bit of sleep. 02 Cool has some excellent 10 " fans that actually run on 12 volts and cutting away the plug to the 115vac leaves you with a 12 vdc fan.

 

[NYSail]

I ended up with a new 3.5kw genset that I just installed. Quiet and runs both a/c units when needed. Plus have the added benefit of hot water without running the engine. My solar takes care of everything else including topping the batteries off every day.

Good Luck!

 

[tfox2069]

I ended up with a new 3.5kw genset that I just installed. Quiet and runs both a/c units when needed. Plus have the added benefit of hot water without running the engine. My solar takes care of everything else including topping the batteries off every day.

Good Luck!

Curious, if you don't mind sharing, what was the total cost of the install - and did you have someone else do the actual installation, or did you do it yourself? What brand generator?

 

[NYSail]

Curious, if you don't mind sharing, what was the total cost of the install - and did you have someone else do the actual installation, or did you do it yourself? What brand generator?

I installed a Next Gen 3.5kw genset. With the sound enclosure in weights 200lbs which was nice. I installed it myself...... I was fortunate in that the boat previously had a 5kw genset so the wiring and transfer switch was already there as well as the fuel tank setup. However had to run new exhaust, panel wiring and new fuel hoses...... I would say total cost was around $8,000.

Greg

 

[tfox2069]

Interesting. I'm talking to a company now about potentially installing a generator in my boat. They said that Panda's smallest generator now is a 5k, and the only WhisperPower generator they can get is an 8k. I only need a small generator, and 3.5k is perfect. The smallest Panda would be nearly 300 lbs. The Whisperpower 3.5 is a much more attractive option to me. BTW, total cost for a new install, parts and labor (sight unseen) is around $20,000.

Can you share any first impressions of the Next Gen 3.5? Where on your boat is it installed? Can you sleep while its running? Vibration and noise impressions? Fuel burn? I'm very interested as the 3.5 is the right size and weight for what I need. Not sure if anyone around here deals in them though.

Appreciate any comments - its tough to find folks with new installs of these more modern generators. Seems if you want one and your boat doesn't have one most folks just sell their boat and buy one with a generator on it.

 

[NYSail]

I had the option of fixing a 16 year old Onan that was 380lbs or go for new which I did. I have solar so I do not need a large genset.... anyway they say you will kill these premature if you do not push them so the 3.5kw for me was a perfect fit. The company is out of Fla and they shipped it to me with little delay http://www.nextgenerationpower.com/marinegen. One of the things I like about the unit is that there is minimal electronics.... no panels to go bad that shuts everything down. Basic engine with an electrical head, a couple capacitors and relays and that's it..... a very simple unit that one can deal with without hiring a tech and waiting for parts. It runs off a 1 cylinder kabota engine. I put the genset in my aft cockpit lazarette as center-lined as possible which puts it up against the aft sleeping cabin (guest). As I mentioned I got the unit with a sound enclosure which helps significantly with noise but main concern was vibration. I added an additional sound proof under the lazarette floor as well as beneath the genset and on the surrounding walls (Acoustiblok Soundproofing Material - Acoustiblok Website). I also got a second set of mounts (the genset has engine mounts inside the sound enclosure.... I added additional to the sound enclosure). I also put the unit on wood stringers, again to assist with vibration. This lifted the unit up which helps with running wires and hoses. Have to say, when running the unit when just my wife and I are on the boat (we sleep forward) it is no issue...... very reasonable and does not make you talk loud. The air conditioner was louder than the genset while we slept..... Also when in the cockpit it is very reasonable...... significantly quieter than a honda 2200 and not bothersome to surrounding boats. However I do have vibration from my water lift muffler (Centek) which I will wrap with the soundproof material and reattach which I think will eliminate this.
I installed the unit right before our month long trip at the beginning of July.... actually finished while heading out. We just got back and I ended up putting about 40 hours on it. The unit started right up and performed as advertised. I did have one issue after about 19 hours but was easily addressed and fixed (I'll explain more if you go to take to the next step). The people at the company are very responsive and more than happy to answer all questions. Again a very simple unit. I would be more than happy to speak over the phone if you have any questions.

Greg

 

[tfox2069]

Very helpful @NYSail . I may well hit you up with some more questions.