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Sunseeker Electrical Charging 12V system

Discussion in 'Technical Discussion' started by Ken O’Connell, Sep 24, 2019.

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  1. Ken O’Connell

    Ken O’Connell New Member

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    Evening all

    Just wondering is anyone up to speed on the charging system on Sunseeker Manhattan 56 2004 with twin CATS

    How is the 12 volt system charges from the alternators ? Having wiring diagrams just trying figure out.

    Many Thanks in advance

    Ken
  2. Capt J

    Capt J Senior Member

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    I'm not familiar with that Sunseeker, but a 2007 62' Predator I've run for years. The generator battery bank is 12 volts, it gets charged from either the generator alternator and it has it's own charger. Your boat is probably the same. On a 2019 66' Manhattan, every battery bank is 24 volts and they use DC to DC converters to step it down from 24 to 12 volts for electronics and things of that nature.
  3. Pascal

    Pascal Senior Member

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    Most boats generators are 12v charged by their 12v alternators and a 12v Charger

    House and mains are 24 volts charged by their 24v alternator and 24v Charger

    Usually the few 12v systems (VHF, stereos...) are powered from one of generator batteries
  4. Ken O’Connell

    Ken O’Connell New Member

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    Hey Guys
    Thanks for the feed back
    There is a 240 volt 12 volt charger which does charge the battery
    The problem is when using the boat at sea which engines running the 12 volt system goes down after an hour
    The generator probably does charge the system when running but that isn’t the case when at sea so the 24 volt alternator from the CATS should charge the 12 volt system some how
    Will look again at the drawings and post.
    Many thanks again from this side the pond ☘️☘️
    Ken
  5. Pascal

    Pascal Senior Member

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    I don’t understand what you mean by
    When you have 24v Mains, 24v house and a 12V system for the gennys and 12v loads, you usually need to run one of the gennys to keep the 12v systems charged

    What voltage is the house and the mains? What is the 12v system used for?
  6. Ken O’Connell

    Ken O’Connell New Member

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    Mains voltage to the boat from shore is 240 volt
    When I run the generator and turn on the charger it works for the 24 and 12 system from the 240 volt from the generator
    My question is should the 12 volt system not charge from the alternators when the engine is running at sea?
    Many thanks
    Ken
  7. Pascal

    Pascal Senior Member

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    Unless SS set it up with a converter, your 12v system will not be charged off the 24v alternators on the engines.

    ASS-uming the engines are 24v
  8. Capt Ralph

    Capt Ralph Senior Member

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    I think I understand this,, should you run the 12 v charger while the gen-sets 12 v alternator is running/working also? I feel the same for the 24 v charger when the mains are running, turn the chargers off.
    This scenario has been asked before and then a mixed bag of answers.
  9. Capt Ralph

    Capt Ralph Senior Member

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    But it seems you have a problem with something going down in an hour? Can you start over on that with some detail?
  10. Capt J

    Capt J Senior Member

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    Your boat is designed to have the generator running at all times when the boat is not connected to shorepower. The generator alternator will charge it's own batteries (12 volt bank), the battery chargers also should be on at all times. The house batteries usually have the bow thruster coming off of them and the boats alternator will not keep up with the bow thruster/house bank and the engine bank when docking and using the thruster(s).
  11. Capt Ralph

    Capt Ralph Senior Member

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    I warned you about a mixed bag.
    What does the ships manual say?
  12. Capt J

    Capt J Senior Member

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    The ships manual is absolutely useless at least for the 2007. For the 2019 it's pretty good, but on that one they use all 24 volt, then 24V DC to 12v DC step down converters.
  13. Ken O’Connell

    Ken O’Connell New Member

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    Hi Guys

    Thanks for all the positive feedback and help
    Yes it would appear that the 12 volt system only charges from the 220 volt shore charger and the alternator in the generator so the generator must be on which is stupid I think considering there would be 2 engines generating 24 volt which should be used

    I tested it today and checking the voltage across the 24 volt system port system which is 2 x 12 volt batteries in series, when I checked the voltage across one of the batteries there is 13 volts ish so a charge. I will put a link between this and the 12 volt battery system with a VSR voltage sensitive relay so it will only charge and not draw from the 24 volt system.

    Keep you posted on how it works out or any feed back appreciated

    Many thanks

    Ken

    Mod Edit: Oversize pics removed
    Last edited by a moderator: Sep 26, 2019
  14. Capt J

    Capt J Senior Member

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    Is there a reason you don't want to run the boat as it was intended with the generator on? That is how the boat is designed for all of the systems. It's possible at cruise speed to fill the generator with sea water if it is not running. Sunseeker put an electrically controlled valve on the new boats for this reason.

    You can get a battery isolator that has one lead that steps down the 24 volts to 12 volts. I've seen it on other boats.
  15. CSkipR

    CSkipR Member

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    I've always run the boat with generator running and the charger on and as Capt J mentioned we also have a battery isolator that steps down from 24v to 12v.
  16. Ken O’Connell

    Ken O’Connell New Member

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    Thanks for that Capt J
    I do often run the generator when at sea but sometimes the kids maybe swimming on the back platform for a couple of hours so don’t want the fumes going back when they are. Also it’s just a touch I wasteful and uneconomical to run a generator to simply charge the 12 volt system when not using anything else to have the stereo on or something small. Will
    Look into the step down isolator and VSR. Many thanks again for all help and info :)
  17. Pascal

    Pascal Senior Member

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    Pretty much all boats with diesels and enclosed Salons are designed to run the genset most of the time. Fridges and freezers, ice makers need power and most modern boats are just too hot without AC

    Yes you can setup boats to rely less on gensets. But you need larger battery banks and an inverter.
  18. cleanslate

    cleanslate Senior Member

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    I agree. I like peace and quite when at anchor at times. I like to shut my generator down for a bit. But my refrigeration etc is dependent on the generator. My main engines / systems are 12 volt only so while under way I do run with the generator off for a few hours at a time, at times. My mains charge the batteries . Or my 120volt charger will too.

    Perhaps you can add another alternator 12 volt only to one or both mains to charge the 12 volt system . Most engines usually have another spot/ braket mount and pully groove for another drive belt .
  19. Sea Gull

    Sea Gull Member

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    This is the salient point. If you are at anchor and don’t want to run the genset, you also definitely don’t want to run the mains. The issue therefore is not how to charge the batteries but how to get them to last longer. The answer is a bigger 12v bank.
  20. Capt Ralph

    Capt Ralph Senior Member

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    Currently planning on 48Vdc Lithium Ion Sulfide banks for a 75' Hatt project. Side by side inverters making 230Vac tide to an auto-transformer for balanced 115Vac devices.
    It will run at least 2 A/Cs plus the boat thru the night. Auto small 12 gen start up for fast recharges and auto gen shut down.
    Victron putting the details together for us.

    This Fall the 30kw gen-set comes out of the cockpit and we start the 48V battery farm.
    You have to trust the long term life expectancy on these fancy batteries or the up front cost will drive you crazy.
    New 20 & 12 NLs already installed forward.

    Still trying to sell that fine running 30 from the cockpit.

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