A/C underway

AZtoVA

Well-known member
Joined
Nov 5, 2016
Messages
102
Fluid Motion Model
R-23 (Sterndrive)
Vessel Name
Scarlet Lady
Hello Tugnutters, After 8 months on the hard and replacing a cracked muffler from frozen water in it, we have our 2014 Cutwater 30s in the water! This weekend we moved it from the yard to the slip in the Chesapeake. Wow, there are a lot of systems on the boat I need to learn about despite reading a lot and checking this forum weekly. Todays question is about A/C underway. I have an Onan Genny and a batterycharger/inverter. What is the best way to run AC in the Cabin while underway? With the Genny on? Can it run off the engine? Use the inverter?

Thanks,
Ed
 
The generator is best. The inverter battery will not keep up with only the engine alternator charging it.

I put a second, smaller ac on my boat to provide limited underway cooling with the inverter and engine alternator. Look around Shearwater-sailing.com or run the generator


Stuart Bell
Ranger 25: Shearwater
(561) 352-1796
 
The inverter will not handle it. Use the generator, under 15 knots, per Andrew Custis. I limit myself to 14 knots on the generator.

I found I was going through a lot of impellers at higher speeds, likely from air in the pickup, from the stepped hull. Be aware, the generator can really only handle one a/c, when there are other loads, including battery charging. You may find you will need to reset the breaker ON THE GENERATOR periodically. Once all batteries are charged, the generator can fairly well handle two a/c's, but charging can take hours. Make sure you burp your strainer by allowing all trapped air out, before starting the generator. Also you may need to do the same for the a/c, strainer so the pump primes.
 
Thank you gentlemen! I did find out that the AC on my boat will not even work with the inverter on...unless I dont know how to do it right. I put the Genny/shorepower switch to off and turn the inverter on. the AC will not come on. am I doing this wrong
 
Yes, don't try to use the inverter, no way can it handle the load. Put the inverter switch to the top position, charge. Put the power switch to off, start the generator. Wait a couple of minutes for warm up. Switch the power switch to generator. Then turn on one a/c only, along with the a/c pump.
 
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