Air Conditioning on Batteries Only

[sailingaway221]

Yes I do run the economy setting on it.

[Mark Johnson]

Originally Posted by Bash

welcome to the forum.

fans work when you're out on the water. really.

if ventilation is important to you, buy a boat that ventilates really well. then you won't have to air condition it.

I agree with Bash! You might also make yourself a really nice dark colored awning. With shade, fans, and ventilation, what more could you want...

Mark

[kolya]

Originally Posted by Mark Johnson

I agree with Bash! You might also make yourself a really nice dark colored awning. With shade, fans, and ventilation, what more could you want...

Mark

Mark you made that? That is impressive! Not to derail the thread, but do you have any more photos? Ever done a write up or possibly know of a quality one? I've never considered creating my own as I've always found the plastic tarp nonsense kinda hokey, but yours looks really good and if I could replicate I'd be extremely satisfied.

[Noname1]

What is your most important area to cool?
I our case we only wanted to cool our birth as to get a good nights rest or perhaps an afternoon nap or er something.
With this in mind one could hang a Pullman style curtain across the birth and supply cooling to only the birth making a battery powered unit quite doable.

[Clipper4730]

Hey folks some really great replies, and great info. Like some of you have said we are more concerned with just cooling our master berth or possibly the entire starboard side of an owners version lagoon 42. My wife has been trolling the ssca forum and found a number of cruisers using the portable Honda gennie approach. The yacht we ultimately purchase will more than likely have a diesel generator already installed but even at idle they seem to burn around a half gallon an hour. If we can provide most of our power from solar/wind a little gas on top is no big deal. We are planning on a six panel array with a wind turbine as a supplement. Two on the coach roof and four on a custom hard top connected to a minimum 1000amp/hr house bank(too much?) We are still pretty new so keep the advice and suggestions coming

Thanks again Will

[tao2]

For what it is worth:
Installed on our catamaran:
500 AmpHour on 24 Volt Gel batteries (compare 1000 AmpH on 12 Volt).
6 Solar panels 15 Amp on 24 Volt ( compare 30 Amp on 12 Volt).
Daily use: 70 AmpH (24 V)= Lights, computer(s), T.V., Fridge.
in summer covered by the Solar panels.
For washing machine, vacuum cleaner and tools we run the generator Mastervolt Whisper 3500, 3.5 Kva. Charges 75 Amps (24 V) for 1 liter per hour. This is a load of 75 %, ideal for the little diesel.
For the few times we use the airco we close off the rear-end of the cabin around the bed and use a 3500 BTU Portable unit, very small: it dries the air more than it cools and that is how we like it.
The generator has to run less than 2 hours extra for the airco.

Please note that the boat is not in the tropics, but in the Med.
After years of living aboard this set-up is balanced (for us).
We decided against wind-generators because of the noise and not many people here that have them are very positive.

Sunny sailing.

[capn_billl]

Like above, the only way you could get it to work is to cool the boat with a big A/C and generator, then late evening run a small portable A/C off of an appropriatly sized inverter and battery bank, aimed directly on Master bed. With the setup I have 250 amp hours of batteries barely runs the lights, and fridge overnight. To run even a small A/C 1000BTU you will have to triple or quadruple that.

Unfortunately there is a lot more energy in a gallon of gas than even the biggest and most advanced batteries.

[capn_billl]

Dometic's Cuddy dc is a compact 3,500 BTU/hr cool-only air conditioner designed to work with 12-volt power systems. Energized by a dedicated bank of batteries and a dedicated power module, the Cuddy dc makes your small cabin a refuge from the heat and sun.

300 amp hours of batteries should power this guy overnight.

[Florida Mike]

Somewhere I read about a generator system that basically uses a small generator size to carry most of the continuous load and then there was an inverter in the system that would pick up the high load levels such as starting motors or when you used more than it could supply. Basically what I got out of the article was a generator ran at or very close to its maximum continuous output rating an inverter picked up the difference, when the power demand fell it would recharge the batteries automatically. Seemed like a hybrid car. Mike.

[HopCar]

Florida Mike, Mastervolt produces a system like you describe. Sound like a good system to me.
Hybrid Power | Mastervolt Marine

[OceanPlanet]

Just finished working on a Chris White Atlantic 55 cat in Panama, with a 720Ah x 12V lithium battery system and a Victron 12/3000/120 Quattro inverter/charger with power assist. The inverter can't drive all three (2 x 12k BTU, 1 x 8k) of the boat's AC units at once, but 2 at a time no problem. Can make it through a night on battery/inverter with careful settings.

Installed two American Power 250A x 14V alternators (one on each engine), getting up to 450A x 14V charging with both engines running. So, they can charge back up after an 80% DOD (approx 580Ah) in roughly1.5hrs. Of course, they won't be running the DOD that low all the time so usually the recharging times will be MUCH shorter.

With the lithium batteries there is very little "taper" on the charging, you can get to over 95% full while charging at full blast.

So, yes you can run AC all night on inverter/batteries with careful use...IF you have a serious inverter/battery/charging system. The system on this boat is pretty spendy but certainly nice to have. Also could use a DC genset vs. the aux. engines of course.

Really fun to install this stuff and crank it up to see 450A of charging...however if it was my own budget, I'd likely still consider using a windscoop...;-)

[purdfootball]

I originally wanted to have a/c off shore for the few evening we are relaxing before and after the fireworks in the evening or the daytime air shows in Gary and Chicago while we are anchored. but....

Everywhere I read that it isn't practical but I figured what the heck and installed a 10,000 watt inverter and a battery bank of 6 group 29 (210 reserve each) walmart batteries. I already have 3 interstate group 24 batteries installed.

Material list to power my 16,000 btu marine air
1. set of four 3ft 0 gauge cables and set of three 3ft 2 gauge cables: $200
2. 40 ft 10 gauge shore line power cord cut down to 15 ft.: $50
3. 10,000 watt wagen tech modified sine inverter $940
A/C LRA rating is 62 amps so I figured 7440 startup watts
4. 6 walmart maxx-29 batteries: $480

so about $1700

how well did it work? I used it on memorial day for about 4 hours with the outside temp over 90 deg. I already had the cabin cooled down from shore power and did some stop watch tests at different temperatures to try to find the optimal settings. I decided to set the thermostat at 74 deg. We used the microwave and had 32" led tv consuming about 80 watts (why the kids watch tv on the lake.. who knows) and the fridge but the water heater was shut off.

After four hours I did notice the battery bank was getting close to 12 volts. The starboard engine cranked over little slower so I used the para switch.

In conclusion, if I only deplete my bank about 50% which I am sure I was very close to doing I would imagine I wouldn't get much more out of that bank. I'll test it next weekend by setting the thermostat to 78 deg.

My next step is to install a couple of 120 amp alternators. I really didn't want to install anything larger if I have to deal with changing the pulley and belt sizes and upgrading the wiring to handle the larger load. I figured if we cruised about 3 hours in a day (Chicago and back) that will help to get another couple of hours plus out of it???? That's my thoughts.

My other concern is the time to recharge these suckers when docked. I have a 20amp 2 bank charger installed. I am curios if I stick a 30 amp smart charger on the bank will it charge at 50 amps??

[Cheechako]

yeah...the little Honda 1000 and 2000 si's are amazing. I understand they are actually invertors...that's why they are so quiet. ( dont have to run at continuous 3600 rpm) i've run one at a river party to power a live band and lights. I dont think it used more than a gallon in 5 hours....actually I know it didnt cause we didnt put any more gas in it! Could be a life saver on a bigger boat for many reasons...dead starting battery? Engine problems with a freezer full of food? etc... I have stood with one at my feet when camping and didnt know it was running until I asked the person I was talking with how loud it was..... and he told me it was running!

[capn_billl]

Originally Posted by purdfootball

I originally wanted to have a/c off shore for the few evening we are relaxing before and after the fireworks in the evening or the daytime air shows in Gary and Chicago while we are anchored. but....

Everywhere I read that it isn't practical but I figured what the heck and installed a 10,000 watt inverter and a battery bank of 6 group 29 (210 reserve each) walmart batteries. I already have 3 interstate group 24 batteries installed.

Material list to power my 16,000 btu marine air
1. set of four 3ft 0 gauge cables and set of three 3ft 2 gauge cables: $200
2. 40 ft 10 gauge shore line power cord cut down to 15 ft.: $50
3. 10,000 watt wagen tech modified sine inverter $940
A/C LRA rating is 62 amps so I figured 7440 startup watts
4. 6 walmart maxx-29 batteries: $480

so about $1700

how well did it work? I used it on memorial day for about 4 hours with the outside temp over 90 deg. I already had the cabin cooled down from shore power and did some stop watch tests at different temperatures to try to find the optimal settings. I decided to set the thermostat at 74 deg. We used the microwave and had 32" led tv consuming about 80 watts (why the kids watch tv on the lake.. who knows) and the fridge but the water heater was shut off.

After four hours I did notice the battery bank was getting close to 12 volts. The starboard engine cranked over little slower so I used the para switch.

In conclusion, if I only deplete my bank about 50% which I am sure I was very close to doing I would imagine I wouldn't get much more out of that bank. I'll test it next weekend by setting the thermostat to 78 deg.

My next step is to install a couple of 120 amp alternators. I really didn't want to install anything larger if I have to deal with changing the pulley and belt sizes and upgrading the wiring to handle the larger load. I figured if we cruised about 3 hours in a day (Chicago and back) that will help to get another couple of hours plus out of it???? That's my thoughts.

My other concern is the time to recharge these suckers when docked. I have a 20amp 2 bank charger installed. I am curios if I stick a 30 amp smart charger on the bank will it charge at 50 amps??

Good work. I would have used a slightly smaller AC unit, and a pure sine wave inverter will be more efficient. Other than that doubling your battery bank should give you a working system.

[witzgall]

If you are drawing big amps from your battery bank, then having low resistance batteries, like Gels, AGMS or LIFEPO4 (best) would be a worthwhile addition, to minimize the power lost due to internal resistance (heat). You might improve the performance 20-30% over Wet Cells in this way.

Chris