Switch to 24V or 12/24V Hybrid Electrical System

I read all these posts just to get to the last one by MYTraveler. That's the question I want to post; my bow thruster and windlass ( already purchased) are 24v DC and I want the rest of the boat to be 12v. All my past boats were 12v and I understand it and am comfortable with it. I planned to have a pair of AGM batts in the very deep v-berths to power these two devices and charge the AGM batteries with a dedicated 24 v charger that receives its 110v ac from the generator. My questions: Shore power, two 30A hookups or one 50A? AC power, 110v only or combination of 220v and 110v? How do I do a combination of both voltages? Other batteries onboard are starting battery for generator, assuming genny's alternator will charge it, single diesel main engine, possibly a single 4D starting battery with an engine driven 100 Amp alternator to charge it, (already installed) and three 8D batteries for house bank; how do I charge those? I know some people install another alternator to charge house bank but I'm thinking at 170 horse power on this completey new Lugger might be a bit much on it...not sure.
Could sure use some insight.

Single 50A with a 230v panel and in addition to that 115v panel.
You use one of the legs of the 230v or a transformer (my boat has one).

N4712 said:

Single 50A with a 230v panel and in addition to that 115v panel.
You use one of the legs of the 230v or a transformer (my boat has one).

Click to expand...

This is how our DeFever is set up too. We also have an adaptor for the cord that allows 50A 220V to come in on one leg from a 30A 110V dock post.

Yep, it works both ways if I just want to leave a battery charger on I can just hook it up to the 30A plug and I got 230v. If you have a lot of HVAC's I would consider a second 50A inlet for those. We have found that very hand when we have all the AC's running and also have a large house load.

Wil said: "solar panels (on the pilothouse roof of a KK42 for instance) and wind generator would extend the time intervals where the very quiet little DC generator would be needed."

It's a very interesting "thought problem" but I don't know why you'd bother. You mention the KK42, and I know of a local KK42 that has 500 watts of solar panels that operates for 6 months of cruising in the PNW, and that averages 0.5 hours of genny runtime/day. There are bigger fish to fry for the new boat owner (speaking from experience ) than to worry about converting the entire boat over to 24 volt IMO. The only thing that we have that is 24 volt is the bow thruster and it has it's own charging system and AGM setup.


Jim
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Great responses, thank you. But what about charging the 3 battery house bank? Will the 100 Amp alternator, after it replenishes the starting battery of its start up drain, can I use it to slowly recharge the house bank while underway?

It might help to think about electrical power as being easily converted. DC to / from AC, 12vdc to 24vdc, etc. and watts = volts * amps.

So the question is, how many watts are you using - on average - and how do you replace them (shore power, alternator, generator, solar, etc).

And the answer - in general - is reduce usage first. LED bulbs, low power entertainment systems, alternate cooking and heating fuels, more efficient refrigeration, et cetera.

And to reduce usage you have to be able to measure and record that usage. And that's where every boat and operator is different. Do you use AC? Water maker? Satellite TV? Electric hot water heater (our Insta-hot in the galley is a high priority item!), ice maker, and the list is truly infinite in variety.