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Old 08-11-2015, 12:39   #16
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Re: Electrical?

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Originally Posted by Paul Elliott View Post
My boat is 44' and has a 12V windlass (and just about everything else). We have appropriate-sized cables from the windlass / control box to the busbars and breakers located just forward of the companionway. This works just fine. There's no way I would opt for the hassle and expense of a 24V system just to have slightly cheaper windlass wiring.
It's not just to have cheaper wiring. It's to have wiring which is lighter and easier to route. But much more than that, it's to reduce the voltage drop (you can size 24v cables more conservatively) and make the equipment run better internally, since there's half the amperage involved for any given operation. The equipment will be more reliable as well as it's much less likely to burn out. With 12v, you get the double whammy of double the amps to begin with, plus greater propensity to voltage sag (in most installations).

I think actually 24v itself is marginal for bow thrusters, which are huge power consumers (and I just wouldn't have a 12v thruster). You wouldn't see 12 or even 24v in electrical propulsion systems, for all these reasons -- 36v or 48v is what is used, and would be that much better for a thruster. Or AC, as one poster above has done.

Many well equipped cruising boats have a combination of light DC power users (electronics, lighting, pumps, etc.) and heavy power users (thrusters, windlasses, winches, etc.). It's true that you won't be able to get absolutely everything in 24v. But it would be the tail wagging the dog to design the whole electrical system for the sake of your 2 amp 12v electronic device which you can't get in 24v. Voltage droppers for small consumers cause negligible efficiency losses. But they also bring a great benefit, as they automatically stabilize voltage, which is really good for electronics.

My biggest problem with DC voltage was with my Icom M802, which unlike the M801E is 12v only. It is a large consumer drawing up to 200 amps.

I solved the problem with a large Victron dropper, which will feed the M802 13.6 volts no matter what the system voltage is on the 24v system. It's actually the same device (more or less) which is built into the M801E.
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Old 08-11-2015, 19:48   #17
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Re: Electrical?

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Originally Posted by Dockhead View Post
......
My biggest problem with DC voltage was with my Icom M802, which unlike the M801E is 12v only. It is a large consumer drawing up to 200 amps........
That conflicts with the ICOM M802 specs....(from the 802 manual)

Quote:
The transceiver requires a regulated DC power of
13.6 V and at least 30 A.
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Old 09-11-2015, 04:16   #18
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Re: Electrical?

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Originally Posted by Dockhead View Post
I think actually 24v itself is marginal for bow thrusters, which are huge power consumers (and I just wouldn't have a 12v thruster). You wouldn't see 12 or even 24v in electrical propulsion systems, for all these reasons -- 36v or 48v is what is used, and would be that much better for a thruster. Or AC, as one poster above has done.


From reading, it seems like 24V works OK, assuming well-matched to the boat and with managed run time, and the next steps up are AC or hydraulic.

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Old 09-11-2015, 05:02   #19
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Re: Electrical?

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Originally Posted by Dockhead View Post

Did you ever have a 6v car?
Almost as much fun as a POS+ earth car !

I shudder to think if one of those old classics beasts had both...
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