Gen Sets .

[svBeBe]

Originally Posted by Capn Morgan

In theory I can run the aircon while motoring as the alternator keeps the batteries from going too far down. This is without the genset. In reality, the inverter shut off a couple of times as there was an overload when the AC compressor started. Still, for what it's worth, the system works.

I am going to sound pompous and rude, but people reading what you have written above need to hear the another side of the story:

"The system works" until it does not work anymore. The inverter cutting out is probably because of low voltage and it is delivering low voltage to the A/C...low voltage to the A/C will damage it over time...low voltage can cause electrical motors to stay in their start cycle, which, over time, will ruin them.

Misuse that works for some people can be problematic for others.

I respectfully suggest that you should seek some expert advice on what you are doing before it costs you dearly.

Bill

[Capn Morgan]

Originally Posted by svBeBe

I am going to sound pompous and rude, but people reading what you have written above need to hear the another side of the story:

"The system works" until it does not work anymore. The inverter cutting out is probably because of low voltage and it is delivering low voltage to the A/C...low voltage to the A/C will damage it over time...low voltage can cause electrical motors to stay in their start cycle, which, over time, will ruin them.

Misuse that works for some people can be problematic for others.

I respectfully suggest that you should seek some expert advice on what you are doing before it costs you dearly.

Bill

No offence taken Bill; perhaps I should have noted that the inverter is not meant to run the aircon like that. The system works for what it is supposed to work but not to start a compressor on its own. That was just experimenting and you are absolutely right about it.

[OceanPlanet]

Originally Posted by Gordon

Boy, you guys have thrown open another area for me to look into. We have eight months to get this sorted before boat handover. Now I am researching AC water makers, this will be on another thread. Still unsure what would be the best option re the gen set. We will be running 230/240 v and 50Hz. And being a catamaran want to keep weight to a min.
Thanks for the input, it all helps and experience counts. We have only been coastal cruisers and managed on our previous boat with solar, 600Ah house bank and a Victron Pheonix 3.0Kw inverter/charger and no where near the extra power requirements.
Cheers Gordon.

Gordon,
What size engine(s) are you looking at, if going conventional power? If they aren't too big, and your batteries have a decent CAR (Charge Acceptance Rate), then you may consider adding high-power alternators to one or both of the engines. Not quite as efficient as a genset, however not bad at all if the engine(s) can be loaded up enough. The added alts, brackets & cabling are a lot lighter than a genset and take up less space.

The caveats are a bit more fuel use (depending somewhat on battery CAR, etc.), perhaps louder when charging, and some engine mfg's don't like added alt pulley/loads on the crank bearings (may void warranty, although I've never heard of this causing a problem).

An example is a client of mine with an 55ft cat who added one APS 250A x 14V alt to each of his engines. This allowed charging at over 400A continuously. He could run his A/C (in 2 of his 3 cabins) all night long, using up about 540Ah from a 720Ah Genasun lithium bank and recharge completely in about 1.25hrs in the morning.

This is a bit of an extreme example (using A/C off the dock without a genset), however it gives an example of what can be done. I don't think I'd try this with conventional batteries though. Takes too long to top them off and not enough load on the engine(s).

Good luck with the new build!
Bruce