Battery-powered air conditioning

[Statistical]

Originally Posted by CharlieJ

a64Pilot:
Comfortably cooling a 44' catamaran for 900W in a Florida summer is pretty breakthrough to me.

16kBTU = 1.33 tons; using traditional equipment, to achieve 1.33 tons of A/C requires 4.6kW(https://tinyurl.com/y2cywow9)

Your calculator is just converting between units. 16k BTU/hr IS 4.6 KW. They are both a measurement of power. 1 W = 3.412 BTU/hr.

Now I agree that 900W consumption for 16K BTU/hr of cooling is very efficient.

As a point of comparison here is a traditional marine AC unit (single speed compressor runs on 115VAC). It works but nothing fancy.
https://www.dometic.com/en-us/us/pro...specifications

It uses 11.1A at 115V (1,276W) to produce 17,000 BTU/hr. Adjusting to 16K BTU to get an apples to apples comparison it would be around 1,200W (1276 * 16K / 17K = 1201).

So traditional marine AC unit vs this newer high efficiency AC unit is 1,200W vs 900W to produce 16K BTU/hr of cooling. The AC unit in this thread uses a third less power for the same cooling. That is impressive don't get me wrong and it might be the single most efficient marine AC unit on the market but it isn't 200% or 300% more efficient which is what A64 was pointing out.

[SSgtPitt]

Originally Posted by sailorboy1

I have heard of people running AC off the batteries. They had 1200AH of lithium batteries and a generator to support that to do it.

Me, I just run my 16,000 BTU air conditioner off the Honda 2200

My 4 Trojan 6v T125’s (450amps 12v) and 1500watt invertor will run my 16K BTU AC whereas my 2K Honda generator will not......it keeps tripping the generator breaker.
I’m would like to figure out how to combine the two so the invertor gets it going and the generator keeps it running.....or if you can combine 2K of generator and 1.5K of invertor for a total of 3.5K of power. My limited knowledge of this frustrates me....I can build you a house or an entire subdivision and can’t figure this out.
I gave up and bought an additional Honda 2.2K generator as a spare and so I can join the two generators and run the AC when it’s miserably hot and to dry the boat out when we’re tired of the wetness.

[CharlieJ]

a64Pilot
You are correct...my fingers got ahead of my brain. My thermo prof would send me to the back of the room!

So apples to apples (900W vs 1200W for 16,000 BTU/hr), the AC unit in this thread uses about a third less power for the same cooling. That is impressive don't get me wrong and it might be the single most efficient marine AC unit on the market but it isn't 200% or 300% more efficient.

And that is the point I was trying to make is that Termodinamica has, in my mind, broken the code and are producing equipment that is significantly (we agree that ⅓ less power is "significant") more efficient than conventional marine A/C.

BTW: The Termodinamica equipment is not cheap.

BTW #2: When commissioning or troubleshooting this equipment; the controls are ported to the internet and the engineers in Italy make the adjustments.

[smac999]

Originally Posted by SSgtPitt

My 4 Trojan 6v T125’s (450amps 12v) and 1500watt invertor will run my 16K BTU AC whereas my 2K Honda generator will not......it keeps tripping the generator breaker.
I’m would like to figure out how to combine the two so the invertor gets it going and the generator keeps it running.....or if you can combine 2K of generator and 1.5K of invertor for a total of 3.5K of power. My limited knowledge of this frustrates me....I can build you a house or an entire subdivision and can’t figure this out.
I gave up and bought an additional Honda 2.2K generator as a spare and so I can join the two generators and run the AC when it’s miserably hot and to dry the boat out when we’re tired of the wetness.

some inverters like the victron have a boost mode and will combine the gen and inverter.

if you have a everyday normal inverter you can't do it.

[sailorboy1]

Originally Posted by SSgtPitt

My 4 Trojan 6v T125’s (450amps 12v) and 1500watt invertor will run my 16K BTU AC whereas my 2K Honda generator will not......it keeps tripping the generator breaker.
I’m would like to figure out how to combine the two so the invertor gets it going and the generator keeps it running.....or if you can combine 2K of generator and 1.5K of invertor for a total of 3.5K of power. My limited knowledge of this frustrates me....I can build you a house or an entire subdivision and can’t figure this out.
I gave up and bought an additional Honda 2.2K generator as a spare and so I can join the two generators and run the AC when it’s miserably hot and to dry the boat out when we’re tired of the wetness.

You need at least a hard start kit, but maybe a soft start and ne unit will start and run ac

[a64pilot]

Originally Posted by CharlieJ

a64Pilot:
Comfortably cooling a 44' catamaran for 900W in a Florida summer is pretty breakthrough to me.

16kBTU = 1.33 tons; using traditional equipment, to achieve 1.33 tons of A/C requires 4.6kW(https://tinyurl.com/y2cywow9)

See, I don’t believe that anymore than the 20% decrease in fuel consumption from affixing a magnet on your fuel line.
To put it not nicely, but Marketing depts just blatantly lie.

It’s likely harder to cool a 44’ Cat than it is to cool a 2,000 sq ft house due to lack of insulation and, large non energy efficient windows and no shade, and you don’t cool an average house with 900W, and house units are about as efficient as is possible. These aren’t magic units, they are just brushless DC motors, just exactly like our fridges are, but most of them are fixed speed, except the new AEO module adds variable speed, and it helps, but it’s no huge jump in efficiency.
I know it takes every bit of 21,000 BTU to cool our 38’ mono, I guess maybe it depends on what your definition of comfortably is?

[a64pilot]

Originally Posted by sailorboy1

You need at least a hard start kit, but maybe a soft start and ne unit will start and run ac

I tired a hard start, you get what you pay for

[a64pilot]

Originally Posted by SSgtPitt

My 4 Trojan 6v T125’s (450amps 12v) and 1500watt invertor will run my 16K BTU AC whereas my 2K Honda generator will not......it keeps tripping the generator breaker.
I’m would like to figure out how to combine the two so the invertor gets it going and the generator keeps it running.....or if you can combine 2K of generator and 1.5K of invertor for a total of 3.5K of power. My limited knowledge of this frustrates me....I can build you a house or an entire subdivision and can’t figure this out.
I gave up and bought an additional Honda 2.2K generator as a spare and so I can join the two generators and run the AC when it’s miserably hot and to dry the boat out when we’re tired of the wetness.

You must have a very interesting 1500W inverter, capable of way more than 1500W. The little Honda easily way exceeds 2,000W for start up surges, we’ll past 2,000.

A good soft start will get you there, the LRA for my 16k AC is something like 60 amps, the Honda or the 2800W inverter wouldn’t come close to starting it, but with a soft start the Honda will now start and run it in Eco mode, because the surge is almost gone, and replaced with a slow ramp up of current.

[a64pilot]

Inverter AC’s have been in houses for forty years or there about now, there is no code that’s been broken. I can remember them from the energy crisis of the 70’s. Then they were break though technology.

On edit, ALL brushless DC motors, even some of those little computer fans are “inverter” motors.

[wingssail]

Originally Posted by Peregrine1983

Hi all,

I’m very interested in a battery-powered air conditioning unit for our Pearson 424. The specs on the 24v 16k btu product from Termidynamica look amazing.

Is anyone here running air con with a unit like this without a generator? If so, would love to hear the details on your setup.

Thanks in advance.

I think you'd need an amazing battery bank and power generation system to run that unit, even if for only overnight. If it ran at 300 watts (optimistic?) that is 200 AH for each 8 hour overnight period. (and that is in addition to your normal power usage, and that is without considering the start up amperage.

That might be more common on catamaran but on a Person 424, it is going to be a squeeze. That would require 400 watts of solar going great guns for 6 hours, or genset, or whatever, and then there is your normal load on top of that.

[Adelie]

I don't know if this product has been discussed:

https://www.youtube.com/watch?v=9Ifhc6g2j08

[sesmith]

Concerning soft starts, I ran across an interesting product recently. It's pretty pricey as far as soft starts go, but I was considering it as I could use it on both my travel trailer and the boat without buying and installing a pair of soft starts. Anyone here use one of these?

https://active-controls-llc.myshopif...RoCaBMQAvD_BwE

[SailingHarmonie]

An alternative solution.

We can AC our 53 foot boats sleeping cabin with a 464 A-hr 24V AGM battery bank. We have an 8kBTU AC unit, powered by a Victron 3kW inverter/charger. Starting with full batteries, that goes for about 8 hours or so, depending on duty cycle. When the batteries drop to 65% SOC, our 3.5kW DC generator starts automatically, runs for 90 minutes, then automatically turns off at about 93% SOC.

In our years of cruising we have run our AC at anchor exactly once, and never underway.

[The Yacht Rigger]

I run this exact Termodynamica unit on my Leopard 43, just to cool two cabins at night when on anchor though. During the day it cools the saloon (I can open and close vents). We turn it down to 50% output at night, so it's only drawing about 400w.
This is running off a 600Ah 24V lithium bank, so plenty of juice there. I recharge with 2400w of solar, and 2x 185A 28V alternators if needed, so no issue getting the batteries back to 100%, even if it's cloudy.
It's very high quality, well made, nice interface, cold air. Not as powerful as my previous 120V unit, but the ability to run variable speed and dial back the amp draw is amazing.

We're currently exploring other models too.

[more]

Originally Posted by SailingHarmonie

An alternative solution.

We can AC our 53 foot boats sleeping cabin with a 464 A-hr 24V AGM battery bank. We have an 8kBTU AC unit, powered by a Victron 3kW inverter/charger. Starting with full batteries, that goes for about 8 hours or so, depending on duty cycle. When the batteries drop to 65% SOC, our 3.5kW DC generator starts automatically, runs for 90 minutes, then automatically turns off at about 93% SOC.

In our years of cruising we have run our AC at anchor exactly once, and never underway.

We can AC our 40 foot boats sleeping cabin with a 400 Ah 12V lifepo4 battery bank. We have an 9kBTU AC unit, powered by a Victron 3kW inverter Starting with full batteries, that goes for about 8 hours or so, depending on duty cycle. When the batteries drop to 15-20% SOC, in boat this summer be so hot i take hotel or go home.

i now buying used SO 54 and install inverter chiller 50-60000 btu

size of battery newer is problem this is so easy and cheap upgrade 400AH lifepo4 not enough,no problemos double size this is only couple thousand €.

problem is every day for example 17.00 battery must be full and in morning 07.00 minimum 40%


for info AC unit, chiller don't spend any energy ,i spend energy because switch on AC-chiler unit. also not i 100% guilty. big chunk is guilty sun,hot sea and boat builder becouse isolation is week.

this summer if you put pan on deck easy you can slow cook meet,eggs.

but if i put only ac in sleeping cabin i think 5-6000 btu is enough .
in reality i dont know how many btu i need but expert in Croatia say 16000 btu for small 40-45 ft sailboat with small window for room need 5000 btu ,main saloon 16000 btu. with shade deck this number can be lowered.
decision inverter chiller or example termodinamica VRT8E1 working in range 35000(1500W cons+ pump + fan)-4800 btu(400w consumation + pump + fan)

or VRT12E1 55000 btu(2600w+f+p) 12300btu (700w+p+f)

but also i think put under bed this ALUMINIUM CONNECTOR RADIATOR
https://www.yachtboatparts.com/radia...wpm-1786-p.asp

this year is simply crazy ussualy we have 1 week hot, but this summer we have 2 month over 30°C and italian greek friend say you are lucky in greece/sicily is over 40°C