32v.-24v.-12v.?

[SeaEric]

Survey is today on my 46 Matthews even though the buyers still don't have their financing in place. I'm not holding out a lot of hope for this sale, but you never know.

Doing my shopping for the next refit. Many of the older dinosaurs have a 32v. system running a bunch of the house stuff- lights, pumps, etc. in addition to 12v. for other stuff. In doing an electrical redo I'm wondering if it makes any sense to convert everything to 12v and get rid of the 32v. The other thought I had was to move the 32v to 24v which seems to be popular on newer boats.

My concern is in going forward, being able to access 32v. components, bulbs, and such. It may just make sense to do something different now in the context of a much needed electrical upgrade.

What say you all?

 

[Genesis]

If you're doing a COMPLETE rewire going to 24V makes sense.

12V does not if you have big engines; 24V starting motors are far more efficient and do not require as heavy of cabling / distribution.

On a full rewire I'd probably go 12V for primary DC and a separate 24V bank for main engine start if the engines were large enough to justify it.

 

[SeaEric]

The engines are late 70's vintage J&T 671N's 310HP. They are already 12v. start.

 

[Liquid Asset]

If the engines already are starting on 12vdc, then i would convert the remainder of the boat to 12vdc. I do not think I would have a 32vdc system unless I needed it to start engines. Just does not make sense for any other reason.

 

[Brian Degulis]

I would go to 12V for the absolute minimum only where there is no other choice but DC. For the rest of the boat I would go inverter and 120V AC. Simplifies everything requires lighter wiring and with today's inverters reliability is great and electrical losses are minimal.

Brian

 

[GJH]

Converting the whole boat to 12 from 32 is a helluva lot easier said than done. You are talking about a complete re-wire with much heavier gauge cable. It will take a long LONG time to recapture the cost vs. just paying more for 32v stuff. 24v may well be a more viable option, because you will find that for many circuits, the existing wire gauge is adequate.
I've been looking at this latter option myself, and am still unconvinced it is worth the hassle.

George

56MY "Incentive"

 

[Maynard Rupp]

Yup, the reason Hatteras went to 32 volt for their DC is so they could use smaller wires. If you switch to 12vdc. you will need to upgrade all the wires to a heavier wire. Personally I think Hatteras uses much larger than necessary wire for the 12 volt systems. I don't know how big their 32 volt wires are, but their 12 volt stuff is way big, much larger than other brands of boats.

 

[bdewar]

I repowered a 53c with engines that had a 12 volt system. I bought some used engines with 80 hours. If i had ordered new engines they would have been 24v. I still have a 32v house bank (4x8v golf cart batteries) and charger. If i add something new its 12v. Heads and lectra sans are 32 volts. It would cost major $ to change everything to 12v.

 

[SeaEric]

Thanks for the responses and the advice. I think it makes sense to maintain the 32v. in this case. To rewire the whole boat would be a nightmare. I agree that as new things are added, a 12v. alternative could be used on an individual basis. Thanks again for the help.

 

[SKYCHENEY]

I think that is a wise choice. It seems that with the wind, solar, and other electric technology changes recently, we have more supply of odd voltage stuff than before. Hybrid electric vehicles, etc, will only bring more of these types of items. Who knows for sure what the future may hold, but with all of this interest in battery technologies and such, we may find 32v come back instead of dying out. You always have the option of converting later if that stuff does become too expensive or too hard to get.

 

[thoward]

Not sure about your boat but my old 1969 Egg had a buch of solid core wire. When I rewired it completely(engines, 12v, 240V, 120V), I ended up pulling all new stranded double shielded marine wire and it was a long, hard, very expensive process. There was 1 wire in each cabin that would have required the removal of the headliner so those were the only wires on the whole boat not to get replaced. The problem I ran in to is on long 12v runs the wire ended up being very large and almost impossible to run in some instances. A 12V windlass needed its own battery bank up front.

 

[SeaEric]

The survey on my current boat was yesterday. It went flawlessly. So it looks like I am on the prowl for a new (project) yacht. I'm having trepidations about pulling the trigger on the old Trumpy that I have been considering. I'm not sure that I am young enough or have deep enough pockets for that one, although her rich history does intrigue me. The aforementioned electrical gremlins frighten the heck out of me. I spent a half an hour in the engineroom today just looking around at a bunch of scary looking, 60 year old stuff. Nothing like embarking on a cruise to the poorhouse, in style.

 

[GJH]

On the South Carolina ICW the other day, we went by a guy , who later went by us, bringing a 1913 Matthews double ender up from Florida for a three year project. Great looking boat that had been repowered with a 250 HP Cummins. Zipped right along. We hope to get a tour when we go through Norfolk late next week.

George

1981 56MY "Incentive"

Just got back to New Bern, heading up to Mass/RI after a week layover here.

 

[SeaEric]

Yes, She is the 75' "Nymph" which was recently sold. She was the former Maryland Port Authority boat, which the State replaced with a Trumpy called "Mary Lynn" a number of years ago. The "Nymph" has been terribly altered over the years and I understand that her new owner has obtained many original photos and is planning to return her to original condition. She is quite amazing in the way she runs. You may have noticed that she slides along easily at around 8 knots and leaves almost no wake. Its' the darndest thing you've ever seen. I wish her new owner all the best in his project.

 

[partgypsy]

I am going through a similar situation with my refit. The builder (Chris Craft) used 10 & 12 gauge on most of the boat's house wiring. Possibly because mine was built alongside many 12 v boats. I started by locating a wiring diagram & identified as much at the wiring as possible. A new low voltage breaker panel was in order and I have installed seperate boards for 12 & 32 v. As mentioned in previous posts, I'm not in a hurry to throw out the 32 v electric toilets and winch etc. There is a much wider selection of 12v (& 120vac) lights and the existing wiring is used for 12 v as long as I know the load on that circuit is not higher than allowed.
Other factors in favor of higher voltage is that lighter gauge wire is easier to work with, costs less and is... ummm... lighter!
I am still puzzled why Detroit Diesel chose 32 volts for their system instead of a multiple of 12 volts.

 

[GJH]

Sorry to high jack the thread here for a moment. Yes Eric that's exactly right! She moved along pretty good at 12knots too. The partner in the project that I chatted with on the radio as we cruised along, a fellow named Sam Wright, also said it was uncanny how straight she backed down due to the canoe stern. However, he noted one of the key modern upgrades they were going to add were bow and stern thrusters.

The work is going to be done in Suffolk, VA.

If I could figure out how to get my 2mb photos of her down to the 98k limit here, I'd attach some.

Back to thread: I don't think Detroit Diesel was the one who made the 32v decision, but rather Hatteras and Chris Craft. 24 and 12 volt starters are available. As someone noted 48 volts is popular in the solar/off grid market, so maybe 8 volt batteries and things in "multiples of 8' will be around a while yet.

George

 

[SeaEric]

George, Yes, Sam Wright. His son was the buyer this time. Sam has done a few previous projects includung a 44 Elco that I sold him a number of years ago. "Nymph" is in good hands.

I'm shopping for 8v. batteries for the 32v. bank. Any recommendations? Personally I prefer budget batteries and then replace them every 3 years or so, rather than the expensive Rolls type. Interstate maybe?

 

[krush]

I would go to 12V for the absolute minimum only where there is no other choice but DC. For the rest of the boat I would go inverter and 120V AC. Simplifies everything requires lighter wiring and with today's inverters reliability is great and electrical losses are minimal.

Brian

That's what I would do. 12v motorized stuff isn't very efficient anyway, so with new more efficient inverters it may be a wash in using more power.

Though, it's nicer to do a 24v bank for the inverter because you can use smaller wiring to the batteries for the same power. Use an inverter with an automatic Generator control to charge the batteries and you are set!

 

[SKYCHENEY]

George, Yes, Sam Wright. His son was the buyer this time. Sam has done a few previous projects includung a 44 Elco that I sold him a number of years ago. "Nymph" is in good hands.

I'm shopping for 8v. batteries for the 32v. bank. Any recommendations? Personally I prefer budget batteries and then replace them every 3 years or so, rather than the expensive Rolls type. Interstate maybe?

Eric
I was told Interstate no longer makes the 8v195's. You could go with golf cart batteries since you don't use them to start your engines. The main drawback to GC's is that the large amp draw of starting can melt the terminals. If you don't start with them, then you have no worries. GC batts are available almost anywhere, even Sams club.

 

[SeaEric]

Sam's Club? Cool, I like the sound of that. I'll check it out. Thanks Sky!