Another 12V & 24V question

[johnno]

I suspect this has probably been covered before (although I can't find it), but what are the merits of choosing 24V over 12V for DC power on a boat?

A lot of boat reviews I've read talk about 24V as if it is a better choice without elaborating why.

What is the availability of 24V equipment like when compared to 12V?

Any assistance greatly appreciated

John

[Deering]

Higher voltage allows the usage of smaller electrical conductors and smaller motor windings to transfer the same amount of power with the same voltage drop. Less weigh, less cost, and motors last longer due to less heat.

[cyclops]

Anybody know if all 12vdc is also available as 24vdc. -------- You are probably in a cruiser with a kitchen and AC before you get into 24 vdc. A boat interior designer would be VERY usefull on this question.------------- Things like this is what makes getting larger boats still interesting.

[Deering]

It's pretty easy to pull a 12v leg off of a 24v system to feed the 12v stuff. Much wider variety of 12v accessories than 24v. But the auto industry is starting to make the shift to 24 or even 48v systems, so with that will come more gear.

[johnno]

Thanks for the responses - that's certainly given me some more to think about

Kind regards

John

[marshmat]

You might also take a look at gear designed for off-grid residential. A lot of home wind/solar systems run at 24 or 48 V, and there's certainly gear available for them. Also take a look at stuff designed for upscale RVs and buses, most of which are 24 V. The idea behind higher voltage is that power loss in a wire is proportional to the square of the current- twice the voltage means half the current for the same total power transferred, thus 1/4 the power loss in the wire. You can then use lighter wires and more efficient motors etc.

[FAST FRED]

"It's pretty easy to pull a 12v leg off of a 24v system to feed the 12v stuff."

However if it is not done correctly it will shorten the life of both batts by about 80%.

Google Vannier and see how it is done corectly.

24v is fine for the start system and many of the instruments , autopilot , and GPS ect are EZ in 24.

What gets hard is light bulbs and RV or boat kitchen toys.

Simplest is a cheapo inverter and just run a 120v blender, bread maker , vacume cleaner .
About $200 will get a 1500w unit that will recharge your computer run the TV an dish , along with most of the other house stuff.

Some filks have used 2 inverters , one just for a florescent light circuit, to get away from those pri$y 24 v bulbs.

FAST FRED

[DGreenwood]

24 V Isn't difficult to achieve. I have had no problems getting equipment including light bulbs of all sorts. (I don't know about flourescent)
I recommend 24 V for lighter weight wiring harness and overall efficiancy of all equipment. On a new build you come out way ahead...going back and retro fitting is another story.

[ABoatGuy]

24V equipment is readily available for almost everything except car stereos and anything RV oriented. A DC-DC convertor can solve that problem.