Switching from 12V to 24V

[rom]

Originally Posted by tarian

My boat is full 24 volts with a 24 v to 12 v converter $70 it takes any 12 volt I need. I dont need 12 volt starters , why would I, I have a 24 volt one connected to the 2 starter batteries, my house is separate, this makes a fail safe easy to understand system , with one 12 volt panel.

If I understand correctly you have 2x 24VDC battery banks. One is the house and the other one starter. And the starter on your engine(s) is 24V. Great setup ! I like the house+safety better than house+start, but that's a detail in this conversation.

Now to to OP if you are building from scratch why over complicate your design either go full 24 volts with two battery banks and run a separate 12 volt supply for any 12 volt gadgets. or go full 12 volts to save yourself grief, the only real advantage of 24 volts is smaller wire ,size ,less voltage drop and more powerful winches etc , but you boat does not really need these , but you choice , but I rewired my boat and stuck with the 24 volt system because it was there , if a choice I would have went 12 volts , just for the convenience of hunting down parts and equipment , not hard but more time consuming.

That's an interesting experience. What is your boat ?

[john61ct]

Originally Posted by Thalas

if you have more than 500W of solar, that 24v would have advantages in generation.

WRT wiring, going from 12 to 24 only affects SC **output**, and they're close to the bank anyway.

Does not change anything between panels and SC.

But for SCs like Victron that have a max Amps output, going to a 24V bank doubles the Watts per SC. Not a big cost saver in the big picture though.

[Thalas]

So for modern cruising boats where there tends to be a 110v outlet in each berth, are they using a single inverter near the battery bank and running both 110v wire and 12/24v wire around the boat and into each berth?

[tarian]

Originally Posted by rom

If I understand correctly you have 2x 24VDC battery banks. One is the house and the other one starter. And the starter on your engine(s) is 24V. Great setup ! I like the house+safety better than house+start, but that's a detail in this conversation.

That's an interesting experience. What is your boat ?

Hi I sail a 42 ft 1977 moody aft cockpit, ketch , with a Perkins 4236 engine 85hp at full revs,
Wired for 24 volts. i,e starter, fridge, instruments,fans, lights, 1500w windlass

[coopec43]

Originally Posted by Thalas

So for modern cruising boats where there tends to be a 110v outlet in each berth, are they using a single inverter near the battery bank and running both 110v wire and 12/24v wire around the boat and into each berth?

I have one 24V/3000W inverter installed near the battery bank and then take 240V to the microwave and to the HWS and to the galley via extension cords (Three wire Live/Neutral/Earth with three pin plugs).

When I got the household electrician to check what I had done he said "no problems" but he said he wouldn't have used extension cords.

I also have a safety device in the system to trip out to prevent anyone getting a shock. There is 24V running to each berth (but not 240V)

Clive

[rgleason]

Boats generally aren't regarded as scientific, but you get into trouble if you don't treat them that way!

I agree with you about knowing where you are headed and having an integrated & designed system.

Will I have a de-salinator? (I think so, but not sure of size)
Will I have an auto-helm? (I think so)
Will I have radar? (I don't think so)
Will I have solar? (Yes but what size?)

In this list, I think you may eventually end up with a radar (fog, nightime) unless your use is very different from most people, but perhaps you are not doing long trips and at night? I see you think you'll have autohelm.

[KeelMe]

We use a 24V/12V system. Our main engine and generator use 12V starters, our main engine has a 12V alternator, our generator produces 24V and also has a 12V alternator. We have a small 12V starting bank, a medium 12V house bank, and a large 24V house bank. Our inverter, windlass, reefer, pressure pumps, and water maker run on the 24V system. Our navigation, lights, and fans run on the 12V system. The 12V starting bank is charged by the alternators and has a trickle charger; the 12V house bank is charged by the alternators and has a 120W solar panel and a 10A charger; the 24V house bank is charged by the generator and has a 20A charger. The 12V systems can be charged by the 24V system via a dc-dc converter and the 24V system can be charged by the 12V system via a dc-dc converter.

[rgleason]

You have redundancy on rudendancy!

[coopec43]

Originally Posted by rgleason

Boats generally aren't regarded as scientific, but you get into trouble if you don't treat them that way!

I agree with you about knowing where you are headed and having an integrated & designed system.

Will I have a de-salinator? (I think so, but not sure of size)
Will I have an auto-helm? (I think so)
Will I have radar? (I don't think so)
Will I have solar? (Yes but what size?)

In this list, I think you may eventually end up with a radar (fog, nightime) unless your use is very different from most people, but perhaps you are not doing long trips and at night? I see you think you'll have autohelm.

I will definitely keep an open mind about radar although I really don't think I want to sail in foggy conditions or in shipping lanes. People I would sail with prefer the South Pacific (and I'm not against that). I've been told radar will pick up a line of breakers which could be very helpful.

Your advice is very much appreciated.

Clive

[noelex 77]

Originally Posted by Thalas

So for modern cruising boats where there tends to be a 110v outlet in each berth, are they using a single inverter near the battery bank and running both 110v wire and 12/24v wire around the boat and into each berth?

24v is our primary means of power so this is naturally distributed throughout the boat.

We don’t use 230v for much. In our old boat we only had a single point where 230v was available and that was fine. In the new boat we have 230v available everywhere (from a single 2500w inverter). The thin wiring makes 230v distribution easy and having this in many locations avoids using extension cords when, for example, using the sewing machine, but 99% of our 230v use is in the workshop, galley and for the washing machine. Most of the 230v outlets see little use and are perhaps overkill for our usage pattern.

We only use 12v for a couple of devices so this is only available in one spot via a single 24/12v converter. We had some large conduit installed by the boatbuilder so it is easy to lead any future wires wherever they are needed. However, if we find we need 12v at another location, rather than running a separate 12v cable it would generally be more sensible to use the 24v system and add more 24/12 converters where they are needed. The converters are not expensive.

[CatNewBee]

Our Lagoon had a 12V and a 240V parallel installation in all rooms, central 2000VA inverter, Onan generator, A/C, dual power watermaker 12V/240V.

After the refit we now have 12V and 240V installation parallel, 2000VA plus 5000VA inverter, separate 240V for the galley induction hob, separate 240V for the convection oven.
we addaed 1650W solar with 60V / 96 cells panels and a Victron 100A MPPT controller.

Radar is essential, even not in foggy conditions, we run it most of the time on passages with safety sector / safety zone collision warning set up, many smaller vessel do not have AIS transceiver, radar helps make them visible on the chart.

We also had a longer days and nights passage with sudden thick fog and no visibility in complete darkness. Using the radar in good conditions and knowing how to gives us a lot of peace of mind doing an instrument only blind navigation in a zone with some traffic of large vessels with AIS (easy) and fishing boats in stealth mode with nothing on. There were no fog horns out there to hear.

[coopec43]

24 Volt Electrical Systems | West Marine
https://www.westmarine.com/WestAdvis...trical-Systems
Jun 12, 2018 - The justification for using 24 volt equipment on your boat gets more compelling ... 24V systems require two 12V batteries in series, which increases the weight and ... be listed as FCC “Class B”, meaning that they produce very little interference.

"The justification for using 24 volt equipment on your boat gets more compelling as the size of the DC loads increases. Items like windlasses, large watermakers, bow thrusters, and large inverters draw so much power (and may be located far from the batteries) that using adequately-sized 12V wiring becomes impractical".

Clive

[rgleason]

Coopec43

I will definitely keep an open mind about radar although I really don't think I want to sail in foggy conditions or in shipping lanes.

You will decide on your own.

My experience was after 5 years without, navigating in fog many times, the fast ferry in heavy fog, showing up close on our stern quarter, convinced us it was a safety item we could not be without. (Plus some other unexpected dense fog where an immediate right turn at the proper time was needed.)

Both my wife and I agreed it at that time that w/o radar was not really an option.

It would be nice to save the $$ and loose the weight on the stern and simplify, but the advantages outweigh the disadvantages in our case.

[tarian]

Radar is a funny one , one of those essential items everyone tells you you need but most of the time its switched off.
Ran sailing on Utube a Swedish couple have sailed from Sweden and are now in Alaska via Hawaii , no radar , no real regrets but are using AIS , most long passages if your out of the shipping lanes you will not expect to see many small boats out there,

[rgleason]

Yes, I think it is more of a coastal device, but very useful anywhere for weather fronts and all ships if you don't have ais, and if you do, those without. If you leave it on all the time it is a big power draw. So just like night watches, small boats with small batteries can turn them on from standby regularly to get the "picture".