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View Poll Results: Which would you pick for your house system?
12 V 16 50.00%
24 V 16 50.00%
Voters: 32. You may not vote on this poll

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Old 02-12-2009, 08:53   #1
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12 or 24 Volts?

I'm pretty aware of the advantages of 24V for the house system. Anyone here run 24V and what's your experience? Is it really the "wave of the future"?

For those who have made the conversion, any pitfalls?

I've added a poll.
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Old 02-12-2009, 09:51   #2
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12 volt devices are more plentiful and less expensive. The reason is economies of scale and creating devices for the mass market. It's the same reason there is more and cheaper software for Window's than Macintosh's.

The advantage of 24 volts is smaller diameter wire required (less expense and weight). When the electrons get to the devices at the ends of that wire those devices are more expensive and less plentiful. 24 volt motors are about 2/3 the size of 12 volt motors which might be helpful for a large anchor windlass or the starter motor on a very large engine.

If you are limited to one system or the other, smaller yachts where you do not have lengthy wire runs you are overall better off with a 12 volt system because of the lower prices (with the exception of wire) and greater selection.

Some boats have dual 24/12 volt systems taking advantage of the good points of both.
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Old 02-12-2009, 09:56   #3
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Had a 22 foot rib that was 24 volt with a big ford mermaid inboard. The problem is having to check out aux equipment that you want to fit. For example the Icom & Lowrance had to have an extra circuit and dropper box to reduce it down to 12 volts. However the Garmin GPS ran much better on 24 (acutally 27 volts when the engine was running) and deffinately didn't like anything below 11.5v.

Odd things like finding 24v light bulbs with the correct fitting was a problem which needed trips to motor factors rather than chandlers.

However it did allow much smaller starter cables to be used, but even then they were 3/4 inch.

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Old 02-12-2009, 10:54   #4
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US? It's a 12-volt world thanks to a US Navy purchasing contract standard written around 1940. In the EU you might be happier with 24 volts. But in the US? 24 volts is going to be sand in your shorts every day and night that you are on that boat.
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Old 03-12-2009, 03:28   #5
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Not sure about the US but almost every big truck in this country (Australia) is 24 volts and lights and bits like that are easy to find. The physics suggests that 24 volts is better and lot of marine equipment can be switched from both 12 to 24 volts. My boat is based on a 12 volt system. In hindsight.. and with a few more bucks, 24 volts might have been better. That is the reality most of us face I think. Its a bit like VHS and BETA I think.
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Old 03-12-2009, 04:57   #6
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12 volt for me, cost and supply.
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Old 03-12-2009, 10:19   #7
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Colin, you might find 24V light bulbs in a major truck stop in the US but they won't be at the chandlery or gas station the same way that 12v parts are. "All" routine vehcile power systems in the US are 12V. You may find big rigs that run higher, and aircraft that run higher, but if you want to just drop by a store and pick up a light bulb...it had better be 12 volts or 120 volts that you're looking for here. Anything else and you'll probably have to go to a bulb store, monday to friday, nine to five.
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Old 03-12-2009, 10:42   #8
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Bulbs aren't the reason I voted for 12V--they are cheap compared to the other stuff.

For example, I searched Defender.com for Macerator pumps. Three 12v pumps to choose from from $106 to $125. One 24v pump at $158. In most chandleries, you can pick a 12v off the shelf, but will have to special order the 24v.
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Old 03-12-2009, 22:24   #9
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Bulbs aren't the reason I voted for 12V--they are cheap compared to the other stuff..
You are right and they may last longer but 24V is the future and Raymarine, if they survive, is moving toward 24V.

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For example, I searched Defender.com for Macerator pumps. Three 12v pumps to choose from from $106 to $125. One 24v pump at $158. In most chandleries, you can pick a 12v off the shelf, but will have to special order the 24v.
In OZ most 24V is the same price than 12V and you can pick from the shelf, it is just a question of demand.
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Old 03-12-2009, 22:46   #10
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The deciding factor for me was that the chosen Yanmar was only available as 12v. While it was certainly possible to mount a 24v alternator for house and a 12v for start, it all started to seem like too much trouble to save some wire weight. Above 55' or so it's easier to justify as the engine's all come with 24v options and the required size windlass and bow thruster may require 24v.

Carl
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Old 04-12-2009, 19:05   #11
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12 V - because I have a small boat and my future dream boats (if at all) will be small too - max 36-40ft. In a bigger one probably 24 - since some eqip may call for 24, then I would stick to just one installation. (I hate boats with 12+24+shore power).

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Old 04-12-2009, 19:20   #12
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Some boats have dual 24/12 volt systems taking advantage of the good points of both.
Exactly. 24v makes sense for something like an electric windlass or other high current device, but not your cockpit electronics or lighting system.
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Old 22-12-2009, 08:54   #13
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well, my 1990 Oyster 55 is a 24V system, even the Perkins main engine has a 24V starter and electronics.

Interestingly the generator (Westerbeake) has a 12V starter and a seperate starting battery.

There is a DC to DC converter aboard for the electronics which need 12V.

So far it has not been a significant problem. The cost of pumps and the like is similar but can take a few extra days to get.

Most of the other boats I looked at in the 48 foot and up range had 24V house systems but not all.

Inverters are definitely easier to deal with at 24V with cable run distances being much relaxed, many of the winches have the same size drive motor but are rated at 50% higher wattage/horsepower.

Most bow thrusters in the size range needed for this vessel are 24V or hydraulic

By far, dealing with the retrofit of the existing 50hz power system is far more problematic!
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Old 22-12-2009, 09:04   #14
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Double the volts and halve the amps, so 24v is great for high draw components.
I guess its hard to justify for smaller boats but I can appreciate why some see it as the future.
In the trucking world there are a lot more appliances at 24v designed for travel use like microwaves and kettles, tvs and media players.
Pulling a 24v supply off 2 x 12v batteries is healthier for batteries and offers a more stable supply.
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Old 22-12-2009, 09:12   #15
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