Originally Posted by pwilletts
it seems we cannot live w/o air conditioning...I see that a lot of boats have it but not many have a genset to run it offshore.. would prefer not to use the Honda solution...what type of electrical set up will power AC w/o a genset..I assume it involves a big alternator/ big inverter and isolated switching??
From your phrasing, I'm assuming shore power
is not regularly available to you in your current boating
lifestyle. Therefore I suspect you would need a generator if you don't want to prematurely wear out your primary engine charging
batteries. [Unless you are motoring most of the time anyway...]
But I say this based upon how our boat is set up- which I'll share here for perspective on a thoroughly tested and proven setup:
The previous owners used our boat in the tropics for 15 years and therefore installed 3 independently controlled and regulated air conditioners [A/C: 9k BTU fore cabin, 18k BTU pilothouse, and 18k BTU in the master cabin. All are raw water
cooled using a single
pump and plumbing
Since the A/C units each have a dedicated circuit breaker and thermostat, we can run 1, 2, or all 3 as needed. [Note: when at the dock
in winter we use them for heat since our current
power rates are cheaper than putting hours on our generator or Esbar heater...]
Using shore power, running all 3 A/C units requires a 50 amp [or two properly paralleled 30AMP services] 115VAC [split 230VAC feed] to handle the A/C load as well as the normal boat loads [water heater, battery charger
, etc.] A 6.5kw generator would also handle them and the boat, but we have a 10kw generator instead. [We were told it cost the same as the 6.5 at the time the previous owner's installed it...]
Back to your question: Could we run one of these air conditioners at a time from our 2800 Watt 115VAC/125A 12VDC inverter charger? Yes. [On paper anyway- I have never had the need to attempt it...] Our 900 AH 12VDC house bank would likely handle it for a few hours. However, the energy/time required to recharge the batteries outweighs the benefits for me. Therefore we choose to run the generator when away from shore power when A/C is needed, and let it take care of other needs during that run period. [Charge batts, etc.] The need for air cond is rare where we currently cruise
[55N-61N] but we do exercising the units on those hot days when the pilothouse [AKA solarium
] starts climbing through the mid-90°s F due to the sun.
I don't mind running our generator as it is very quiet and surprisingly fuel
efficient. [Fisher-Panda running a 3 cyl Kubota diesel.] Yes, we can hear the gen hum in the pilot house, but the blower from the AC on high drowns that out. And outside our split exhaust
arrangement makes it difficult to tell if it is running unless you wander over to the exhaust
area and lean over to hear it blowing bubbles... Any neighbors would never know it was running... but neighbors are rare for us... We have had kayakers approach and not realize they were approaching the running gen exhaust until they were within ~10 feet of the boat...
I hope this helps provide some prospective from another vessel's point of view.