Battery powered air condition system

[moonshadow]

In the past I have read of various attempts to use air conditioning based on the house battery bank. Recently I was watching a new SO440 being commissioned and a battery powered A/C system being installed. Not running off the house bank, but from a dedicated 48volt lithium bank. The installation was a big project that included the main unit, 3 air handlers, lots of solar, lots of lithium batteries, a huge alternator, lots of wiring etc. I was told the expectation is the ability to run air conditioning for 10-12 hours and then recharge the whole system with two hours of engine time.
There seemed to be a lot of work involved and the price was higher than a nice used boat. But I found it interesting so I looked it up online. I am not connected to this firm and I haven’t ever spoken to anyone that has been using the system. But if this information interests anyone here is the link to the installers I spoke with:
boatrx.com/

[zaphod]

10-12hrs of run time for an ac unit of any useful size will consume a huge amount of battery power. Replacing that power with only 2 hours of engine time? I'd like to see the size of that alternator!

I could see it being feasible if you have a very high capacity battery bank and a massive solar array, but for the typical sailboat? Pure fantasy!

[NZL50505]

It’s been done (but with big everything). Very informative vid:

[mehmet]

I have that in my boat ( J64 ) since 2 years and it works perfectly but recharging the batteries with alternaor or solar system is a fantasy. I have 8 x 24V 210amp/each batteries and charging them with 2 x 200 amp chargers with help of a 17,5kw generator.
I can run my AC for 10 hours and after 10 hours mostly 75% of the batteries are consumed. Ofcourse there is 2 x 8000w invertors, so it is a big system but if done correctly it works perfect and very comfortable.
My 17,5kw generator needs more or less 4 hours to recharge the batteries from 25% upto 100.

[NZL50505]

It seems like the difference between achieving solar as your primary charging system vs genset, is more about cat vs mono. The sheer amount of real estate a 45ft cat offers for a huge solar array is what enables the Parlay guys to survive on solar charging except after 2-3 consecutive days of cloud cover in which case they run a small portable petrol generator for a few hours until the sun comes out again. That’s not a bad solution and removes the need for a far heavier and more complex Genset installation.

[moonshadow]

Thanks Mehmet for reporting your experience. The 440 that I saw is not being equipped with a generator. They installed a large arch to provide room for an array of solar panels and the engine has a 480 amp alternator. I think the boat will remain local so hopefully I’ll get a chance to follow up and see how it all works out. It sounded like the installers have some experience with these systems and had the whole thing well planned.
Personally, I haven’t ever felt the need to go to these extremes. I do have a generator and A/C units on my boat but rarely use them except to dry things out after a day of warm rainy weather etc. But I am sure that in some cruising areas it is more important.