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What are the options today for 32 volt systems on older yachts?

Discussion in 'Technical Discussion' started by Wally Young, Jun 2, 2019.

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  1. Wally Young

    Wally Young New Member

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    Is it better change the system to 36 volts (batteries) and use a voltage reducer to achieve the 32 volts required foe the circuit where needed?
    Will the starter motors on the old gm diesels take 36 volts?
    Engine generator's need to be rebuilt/replaced anyway, to 32 or 36 volts.
  2. Pascal

    Pascal Senior Member

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    36v isn’t going to work unless you replace the charger and alternators. Why fix something that ain’t broken? The only downside to 32v is that it s harder to find some items like LEDs, pumps etc. so why bother stepping down to 32v? Makes no sense...

    You could keep the engines 32V and convert the rest of the boat to 24v with a dedicated house bank and charger. Usually the wiring is thick enough to go from 32 to 24v. You could keep the bilge pumps on the start batteries at 32v
  3. Lepke

    Lepke Member

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    I have an 83' boat some previous idiot converted to 12v. I long for my older 32v systems. But now it's hard to find items that run on 32v natively. Maybe because it's all made in China. I ended up installing relays to shorten the power paths and went to an inverter system that lets me run 120/240 ac 24/7. So now only items that absolutely have to run on dc are 12v. Winch, cabin lights, reefer, etc., are all 120/240 ac.
    In the days of 32v, I never had to replace a bilge pump, blower, etc. Items lasted my time with the boat. Now, before installing relays, the 12v stuff (except nav and radios) lasted about a year or two even after installing wiring 2-3 steps above chart recommendations. That, too, maybe because it's all made in China.
  4. Capt Ralph

    Capt Ralph Senior Member

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    I shop and stock 32Vdc options. Sell off my excess to friends down under.

    If you have no spares and a pump fails, you may have a problem.
    If you can maintain a spare level,, like you should even if 12 or 24Vdc, then you should have no problems.
    4 x 8V batts in two banks we use for the ship. You can tap off the third battery if you need 24Vdc.
    17 years ago I thought 32V was going to be a problem. 41 year old boat and us are still all happy with 32Vdc systems on board.
    Probably the only concern, Most LED thingies are listed at 32Vdc max.
    Damm things are to expensive for us anyway, not a worry here.
    Please find all my previous threads on this topic the last 15 years I've been on YF.
  5. Capt Ralph

    Capt Ralph Senior Member

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    BTW, some PNW boats are still most 48Vdc. Most of my spares (most again NIB) come from Canada on e-bay.
    I still have a brand new Raritain 32V charger converter in inventory. Cost more in shipping that what I paid for it.
    Outback makes a great 32Vdc inverter.

    Stay 32V.
  6. Ormond Bert54

    Ormond Bert54 Senior Member

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    I have stayed with the 32V. I have a Newmar 32V to 24V step-down inverter for my 24V system. My 24V items are toilets, windlass, LED lighting and some bilge pumps.
    I have a 12V system from the battery bank for the generators.

    If I have an option to buy 32V or 24V items, I generally buy the 24V because they are easier to find when it comes time to replace them.
  7. dwelch

    dwelch New Member

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    1968 Roamer , still 32 v , redid everything year 2000 , rewired entire boat , by Neptunus in St. Catharines Ont , left engines / 32 , and a couple bildge pumps , installed a couple ac pumps as well as 12v , I have used for 30 years , 2 x 12s and a 6 volt . x 2 banks for engines / 24 for thrusters and heads and winch ...12 for most other house , all fine on my 51 yr old girl
  8. rtrafford

    rtrafford Senior Member

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    Split away to 24v, but left the engines on 32. Set them up with 36 volts, and they love the power. Next step will be to shed a 12 and turn the 36 to 24 for the engines, swapping out the starter solenoid with a 24. I am told the starter will run on 24 with the new solenoid. Add regulators to the alternators, and there shouldn't be much left. But I've been on the 36v for the engines, and they have no issue.
  9. v10builder1

    v10builder1 New Member

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    I would appreciate you letting us know how well the 32V starters (the motors themselves, with the solenoids replaced with 24V units as you say) work at 24V.

    What charging voltage are you applying to your "36V" system with your engine alternators and/or your shore powered chargers? You would need to charge the set of three 12V batteries you have in series at about 41.5V to get to 100% state of charge. Are there any 32V fuel control solenoids, relays, or electronics on your engines that you are now operating at 36-41.5V?

    Previous threads have stated that (readily available in the US) 8V "golf cart" batteries make 32V (4 x 8V) sets easily.

    The 32V to 24V converter such as Ormond Bert54 describes in a post above provides ample power for 24V electronics and lighting circuits (lower amperage circuits - 32V wiring sizes are probably adequate) and eliminates any issues with charging, starters, solenoids, pumps, or other high amperage draw components (all that equipment is left at 32V), and is a simpler, significantly more reliable way to go forward. Less expensive in the long run. Carry a spare converter on-board, possibly.
  10. rtrafford

    rtrafford Senior Member

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    The 32 volt starters love the voltage, which sits between 39 and 40.5 volts. That extra voltage foes away immediately under load as the cells cannot hold it. The starters would love for me to leave their system at 36 volts. They spin freely, crank extremely well. I have several hundred hours on the setup.

    I am using 2 12 volt smart chargers, one for each 36 volt setup, tying each battery to an output. The chargers have 3 outputs of 12 volts. I'm using Odyssey series 31 batteries.

    The DD's have a separate 12 volt feed for the gauges, and the shutdown solenoids are essentially coils that will function on the 36 volts as well as the 24 volts. I've gone ahead and converted the power source for the shutdown to 24 so that all that remains is the starters and alternators.

    The boat is still equipped with a 32 volt constavolt attached to the 36 volt system as original. It was to be removed until I arrived at the boat one morning to find that somehow the 12 volt charger circuit had been interrupted, and the batteries were flat dead (longer story avoided here). I then discovered that the new smart chargers would not pick the banks up from dead zero. I assume this is a fluke of the particular smart chargers that were purchased and implemented. So I energized the 32 volt charger, and it picked all of the batteries right back up and allowed me to then shift back over to the 12 volt chargers and shut down the old unit. Put a smile on my face, and I left the installation intact as a backup.

    I was in the process of refitting the entire boat, so this all allowed me to shift all ship systems to a new 24 volt house structure, including a new Lewmar thruster and bilge pumps/alarms. I always had in my mind that the conversion would eventually include the engines, but I wanted to retain the 32 volt system in the event that I was overlooking something and needed the voltage. However I wanted to structure the temporary 32 volts system with new batteries that were both reliable as well as providing the flexibility to become 24. The moment I hit the start button on the DD for the first time, I knew it was a good decision. So good, in fact, that I have been slow to complete the conversion, although it's planned for later this summer.
  11. rtrafford

    rtrafford Senior Member

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    Also note that even with the 36 volt setup you can create a 24 volt takeoff for house systems if you need to pull your house from engine batteries. I did not want my house on these engines given their hunger for amperage when starting. The engines won't keep the 36 volt bank at charge without some work to the existing alternators, but as nothing else is on these banks I don't really worry about them and typically just let the 12v chargers run all of the time. Basically my alternators never truly engage, and they like the constavolt sort of sit in reserve. The house has its own 24 volt bank, and the thruster has its bank as well.
  12. Pascal

    Pascal Senior Member

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    Glad it s working but if you do a full refit the price of a couple of starter and alternators isn’t worth the hassle.

    I recently repowered my old 32v Hatteras 53 and converted evrything to 24v incl all new wiring. I ended up ordering the factory reman C-series in 12 volts since the price difference with 24v was ridiculous and with short cable runs to each engine there were no real benefits to 24v

    I am big fan of dedicated banks for house, mains and gens anyway
  13. rtrafford

    rtrafford Senior Member

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    Pascal, my refit was predicated on removal followed by replacement. Install a new <bilge pump>, run new properly colored wiring, then remove the old <bilge pump> along with its old wiring. Wash, rinse, repeat. The engines are simply the last in the line of the process, and if not for the failure of the old Rolls batteries, I never would have needed to build a 36 volt system at all. Problem is they failed, and I needed batteries to maintain a system that was not yet obsolete.

    As far as the 24v, knowing 12v LED lighting is far better for dimming, I would have considered an all-12v, but the bow thruster really wanted a 24 volt basis for load and durability.
  14. Capt J

    Capt J Senior Member

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    I have no issues with dimming 24V LED's. All of the ones I have used DIM fine. I converted an entire boat to LED with 65 LEDs (scandvik wafers mostly) about 4 years ago. They all dim perfectly and I haven't had to replace a single LED yet.
  15. rtrafford

    rtrafford Senior Member

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    When you use COB LED bulbs in light fixtures, the 24 volt variety doesn't dim well. The chips in LED tape for toe kicks, etc dim just fine. I'm assuming the chips are in the Scandvik units as well, but the COB style bulbs provide a much nicer quality of light.
  16. Capt J

    Capt J Senior Member

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    Yes the Scandvik's have the chips as part of the bulb. I haven't had any issues with them dimming from candle light brightness to fully lit. I've been very happy with them and have used them on several yachts. It might be your dimmer and not the COB bulbs. Some dimmer switches made for incandescent or halogen bulbs simply aren't capable of lowering current enough to dim LED enough.
  17. rtrafford

    rtrafford Senior Member

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    I buy a lot of lights for professional reasons. I am told by manufacturers that the Cob 12v has the desired dimming range whereas the Cob 24v sims slightly and tends to flicker. I’ve had these conversations with the manufacturers themselves.

    Cob gives you the quality of light, but stick with 12v. I made the error.