azk101
New Member
London so will do the refit in an Essex marina likely
24V or 12V System
- Thread starter azk101
- Start date
melvynpatrick
Active Member
Mine is a 24v boat. I have a beta 50 hp with twin alternators. 12v for starting. 24v for house. I have some 12v stuff. NK 2 and pc but I run that through a Victron 24 to 12 70 ah converter. Everything else is 24v including led lights fridge heater etc. I have a 24v Fogstar drift gen 2 battery. Which is a beautiful thing. I charge from solar and engine alternator through a wakespeed ws500. Rarely have shore power as I’m on a swinging mooring. The boat came with the 24v system. At first I was trepidatious. Now I’m really glad I have it for all the positive reasons above. I see no downsides.
PaulRainbow
Well-Known Member
A lot of the Essex marinas don't have very good local tradesmen or chandlers, so choose carefully.
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Alan S
Well-Known Member
You really need to fit as much solar as you can so plan this carefully. It can be difficult on a mono hull sv, easier on a mobo or cat. Rigid domestic panels are superior as regards efficiency, value for mony and longevity but need careful installation.
ps go for a 24 or 48v system with small dc-dc converter(s) as required.
ps go for a 24 or 48v system with small dc-dc converter(s) as required.
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azk101
New Member
Good to know thanks, will investigate.
If it is this particular boat I would be looking to get a 400W plus rigid panel on the back davits and then I will have to get creative with two more smaller ones somewhere. But yes it seems very tricky without getting a big arch made, which is a future project I am sure.
Neeves
Well-Known Member
The argument is not simple. As outlined if you already have a 12v windlass and don't intend powered winches nor a bow thruster (so your yacht might typically be 35'), then dumping all the existing kit and replacing with 24v seems perverse - unless you have won the lottery. Lots of people sail round the world on a 35' yacht, 50' would undoubtedly be more comfortable - but not everyone have. the funds ro buy the 50' yacht (and the bulk of people here will not own a 50' yacht, nor bother to dream of same)
So unless OPs define what. yacht size they are talking about and the kit they intend to buy - sticking with 12v and using the kit already installed seems perfectly safe - its been used safely for decades. Many bigger used yachts will already have a 12v windlass, maybe 12v powered winches, maybe a 12v bolt thruster - how many are going to dump perfectly good gear. (Sell it second hand - you simply will not get their real value.). I don't know about bow thrusters but powered winches, the winches last for ever, as do the motors. Similarly windlass - if they are serviced regularly they too will last decades.
Now a new yacht and a clean slate, or a preowned yacht with dated gear, or unlimited funds - different story.
There is a right and a wrong but unless the yacht is defined - some of the arguments for 24v imply bottomless pockets - and not everyone is so lucky.
Jonathan
geem
Well-Known Member
The average yacht size in the ARC + this year is 53ft.
Neeves
Well-Known Member
and these people and their yachts are typically of members of PBO?
There is nothing wrong with owners of 53' yachts being members of PBO. But making comments without qualification based on background from owners of large yachts and, possibly, suggesting these comments are valid for small(er) yacht owners seems...wrong
Jonathan
geem
Well-Known Member
The only point I am making is boats have got bigger. There are still plenty of people crossing in small boats. I am currently in the Canaries and there are plenty of boats in the 30 to 40 ft band crossing this year. There are also a lot of large boats over 50ft. Something that was fairly rare 20 years ago.
I hwve no proof, but there seem to be more boats closer to 50ft than 35ft sailing around the world
seeSimon
Well-Known Member
Interesting...how many actual boats is this number please?
Goldie
Well-Known Member
I think there are 86 boats in ARC+ 2025.
Stemar
Well-Known Member
Assuming they're fitted, would it be realistic to keep the 12v windlass and bowthruster, and power them from their own 12v battery via a B2B charger?
Dockhead
Well-Known Member
Well, sure. No one said 12v doesn't work. The OP asked what's better.
24v is enough better that I wouldn't consider buying a boat with high power 12v gear, even a smaller boat. And 12v positively sucks for lithium power systems or high power inverters.
But everyone will have to weigh up the tradeoffs for himself. If you're somehow stuck with a 12v boat with high power gear you can't afford to replace the motors of, then sure - maybe you're stuck with 12v. I did not hear the OP saying that was his situation , but he can speak for himself.
If I were building a custom boat, I would do it in 48v, with a 48v lithium power system.
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jakew009
Well-Known Member
When I redid the electric system in my boat I thought about converting to 24V, but with a 12v engine starter motor, 12V thruster and 12V windlass, it didn’t make any sense.
If I was starting from scratch sure I’d go with 24V for the main consumers. And probably then a smaller 12V battery to power all the 12V electronics that can also act as an emergency backup if the main house battery failed somehow.
My point is you need to look at the layout in your boat and then decide. If the inverter is right next door to the batteries then the cable size is a bit of an irrelevance.
If I was starting from scratch sure I’d go with 24V for the main consumers. And probably then a smaller 12V battery to power all the 12V electronics that can also act as an emergency backup if the main house battery failed somehow.
My point is you need to look at the layout in your boat and then decide. If the inverter is right next door to the batteries then the cable size is a bit of an irrelevance.
jakew009
Well-Known Member
48V is still a bit of a pain in the ass in many ways as there are very few 48V accessories available and many of the typical boat fuses / isolators etc are not rated for 48v systems.
24V is still the sweet spot in terms of practicality for most “normal” boats.
I’ve often thought about a 230V boat - ie. 48V battery bank and big inverter and then just run *everything* else off 230v. Not sure if you can get 230V windlasses and bow thrusters in small sizes, but you could just give them their own batteries and charge of mains chargers.
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PaulRainbow
Well-Known Member
Absolutely.
Neeves
Well-Known Member
You are correct, 40 years ago a race winning yacht might be a J35 - now race winning yachts are 100'. Go to a boat show and you will not find many 'starter' yachts, say like a J24 or the X-79. When we raced ed our X-99 in HK she Wass about middle of the fleet when we bought her, 4 years later she was the smallest (and did not meet stability etc for blue water races.
I expect that the average size of yacht owned by PBO forum members has increased in size but there are still many sailing with yachts less than 30' (but a number own yachts of 50' plus and what works on a 50' yacht might not work on a 35' yacht).
It would be nice to think all PBO members would have the same ideas but reality is different. Many will stretch themselves to buy their dream - and would not dump 12v - its proven to work and they don't need to replace a perfectly satisfactory 12v windlass, bow thruster and powered winch.
The current thinking seems to be discuss this as if the OP has a bulging wallet and ignore the more parsimonious.
The best car might be a Bentley or Rolls Royce - but they demand spare cash,
The best is one you can afford and maybe the OP could have provided more detail (but an absence of detail is not uncommon from an OP). They forget we are good but not prescient
Jonathan
geem
Well-Known Member
Dockhead
Well-Known Member
24v gear is practically universal, so you are correct that you have better choice of gear than with 48v. Certainly 24v is a decent compromise and works well enough. It's what I have on my boat and I have no complaints.
But 48v inverters, alternators, windlasses, thrusters, and winches are reasonably widely available, and if I were building a boat from scratch I would definitely go this way. The cabling will be half the size, alternators run cooler and work better, thruster motor runs cooler and works better, etc. etc. Fuses and contactors are not a problem, nor are BMS's. A single 280AH 48v battery run by a single BMS has 13.4kWH of power in it. 48v lithium power is the standard setup for offgrid solar with a user base orders of magnitude larger than the sailing community.
And then you just run all the low power equipment off droppers. A separate 12v battery for radios and nav gear, as someone mentioned above, would be good practice -- required by GMDSS on ships, by the way. YMMV, but that's certainly the way I would do it.
I think your idea of 230v AC high power gear also has merit. You can get windlasses and thrusters in 230v AC, at least in sizes for my boat, although they are rarer than 48v DC. The cabling is even that much better. You could run your high powered gear directly off an AC generator if you need to -- which is the main reason why this gear was invented in the first place.
Dockhead
Well-Known Member
Naturally PBO members have very different boats, budgets, and priorities. That's normal in any community. We're just exchanging views here. My priorities are not necessarily valid for other people, but may be helpful hearing about for some.
My present boat is a 54' Moody (last 16 years) but the previous boat was a Pearson 365 (decades before that). If I were still sailing the Pearson I would still go with 24v power system (at least), if I were setting her up for extended autonomy. It would be easier on that boat, paradoxically, because winches and windlass were manual, hand-cranked, with no electric assist. And no thruster. But we used plenty of domestic electrical power spending sometimes weeks at a time at anchor, so lithium power and a good inverter would have been great.
As it was on the Pearson, we had a fairly large solar array (for that day and age), 2x 8D lead acid batteries, and a no-name but large inverter, so the use case was really not so different from today despite the now quite old fashioned electrical system.
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