A/C System: 12V or 230V system?

[xiam8992]

Starting to think about investing in a A/C unit for my 38ft sailboat. I have two cabins plus a decksaloon. 12v or 230 v, what would be the pros and cons?
Of course, the A/C would run from a (to be installed) power generator. Consequently, I guess it would be a good idea to find a generator and an A/C unit aligned to each other. What do you think?

[coopec43]

Have you read this article? (I'm not recommending it)

https://www.panbo.com/dc-air-conditi...ator-required/


Guidelines for selecting air-conditioning for your boat

http://www.southerncalmarine.com/products/air-conditioning/guidelines-for-selecting-ac/0854b-
mas-guidelines-select.pdf


Powering an Air Conditioner from 12v DC sources

Powering an Air Conditioner from 12v DC sources - Coastal ...

www.coastalclimatecontrol.com › images › PDF › comparison_of_air...

PDF
provide a refreshing blast of cold air for the operator in summer, or be a demister if in heat mode. A Climma Compact 4.2 will draw, on average, between 35 and 40 amps at 12v DC, including the water pump and inverter loss. ... Either install a dedicated 12v DC system, or a 110v AC system running through an inverter.

[a64pilot]

Voltage is irrelevant to efficiency. In fact I’d bet money that a DC airconditioner is a BLDC motor, and as such runs off of AC power, just like our DC fridges do.

Search for the most energy efficient AC you can find if your really concerned about that, most likely will be an inverter AC, and very likely it’s going to really cost, don’t be lured into a tiny one that won’t actually cool anything though, it takes a 6K to cool our stateroom with the door shut.
However if you realize that it’s going to take a generator to run one, then efficiency isn’t really as important.
However just for a comparison, my $1,300 6K Webasto pulls 4.5 amps all in, in reality, installed on a boat at 120 VAC, so figure 45 amps if run off of a battery bank with an efficient inverter properly sized.
But a Honda suitcase generator will easily run my 16K Webasto with a soft start and do it in Eco mode and even have enough amps to charge my bank at about 30 amps too.

Also don’t buy into the 20 to 30% duty cycle either, if it’s that cool your better off opening the boat up and allowing the breeze in.
Last year or maybe it was year before that, we came back to FL from the Bahama’s late Jun, early July and weren’t hot at all until we hit FL and the ICW, then it was sweltering hot, but in the trades breeze it was quite comfortable.

[xiam8992]

Originally Posted by coopec43

Have you read this article? (I'm not recommending it)

Thank you, that was quite interesting

[xiam8992]

Originally Posted by a64pilot

Voltage is irrelevant to efficiency. ...

Thank you

[xiam8992]

@a64pilot and @coopec43:
Thank you again for your input. This is where I stand at the moment:
- Sooner or later I will need to replace the original Volvo engine and I will not replace it with another diesel engine. Assuming that I won't be able to charge the engine batteries with solar or wind I will end up with a generator.
- Having a generator, I will rather go for a 230V A/C unit. I will look for an efficient and, maybe even more important, reliable, sturdy A/C.
- Technology: I assume a split system with one compressor unit and three vaporizers will suit my needs best.

- Which brand? I will start looking at the market leaders like DOMETIC or WEBASTO. Any other ideas?


Stefan