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Converting a 12v system to a 24v...

Discussion in 'Technical Discussion' started by Bunkysdad, Mar 17, 2012.

  1. Bunkysdad

    Bunkysdad New Member

    Mar 17, 2012
    I currently don't own a boat, but I have an opportunity to aquire an older wooden boat with a 12v system. My idea is to convert the existing 12v house system (but not the engine starter) to 24v to make life easier on the inverter (e.g. higher voltage = lower amps drawn).

    My loose plan is to use a Samlex 24v to 12v Dc to DC converter to power the boats 12v panel (again note, engine starter would still be independent from 12v battery). I would need a 110v to 24v battery charger and a couple of ATS switches to fully automate the system. Batteries would be two 12v connected in series...

    My remaining question is, has someone else tried this before, and if so what kind of AC to DC 24v charger, and DC to DC 24v to 12v converter did you use??


  2. rcrapps

    rcrapps Senior Member

    Sep 8, 2004
    Why again?

    Inverter batteries are usually a different set from house batteries.
    Better inverters run on 12 or 24vdc (or more).
    Better inverters recharge their own batteries.
    12vdc options are more readily available.
    Why make a simple system (old boat) more complicated and expensive?

  3. Bunkysdad

    Bunkysdad New Member

    Mar 17, 2012
    "Inverter batteries are usually a different set from house batteries".

    This will be the case...

    "Better inverters run on 12 or 24vdc (or more)".

    Yes, but 24v is waaay more efficient (less prone to surge tripping)...

    "Better inverters recharge their own batteries".

    Yes, but I already own the inverter - it does not have a charger...

    "12vdc options are more readily available".

    12v won't run my 24v Go-Power inverter...Again, my goal is to have a 24v system (to the inverter), that will easily be reduced to 12v (via inexpensive Samlex dc to dc converter) at the 12v panel. The 12v panel will still be fully operable.

    "Why make a simple system (old boat) more complicated and expensive?"

    I don't really see this task as all too complicated or expensive except possibly for the 24v charger...I'd like to have a viable AC option in the event of no shore power...I'm retired so I think the project aspect might be fun. The key ingredent will be how to charge the 24v batt (actually 2 - 12v in series).


  4. Marmot

    Marmot Senior Member

    May 20, 2007
    So the reason for this scheme is you got a "good deal" on an inverter and want to build a boat around it?

    Listen to what people here are trying to tell you.
  5. Capt Fred

    Capt Fred Member

    Jun 22, 2009
    12 to 24 conversion

    I would also recommend that you leave your system all 12 vdc. I worked on an old Chris Craft that had 32 vdc and someone put in 3 32 vdc to 12 vdc inverters and all 3 were burned out due to them being overloaded. Secondly and more important; I like to have the inverter's battery set charged off the main engines. It does not take long for the inverter to drain the batterys. If the inverter's power source can be charged off the main engines then you don't need to run the genset when under way unless needed for higher power requirements. I have found the 12 inverters to be very reliable and generally anything that is 24 vdc or higher is much more expensive due to product demand. Just things to consider.
  6. C4ENG

    C4ENG Senior Member

    May 19, 2006
    Hi Bunk
    I think you have an interesting project to exercise the mind with.
    My first thought was to change the alternator on the engine, how ever you said you want to keep the 12v start system in place.
    Second thought was a secondary 24v alternator installed on the engine to charge the 24v house bank?
    Third thought, expensive generator installation which defeats the purpose.
    Fourth thought, wind generator?
    But good question, what options do we have to charge a 24v house bank besides shore power?
  7. Capt J

    Capt J Senior Member

    Jul 11, 2005
    Do yourself a favor and listen to everyone else here. 12 volt everything can be found just about anywhere if you need a part of lightbulbs. 24volt stuff is harder to source when traveling and more expensive. Not to mention the entire boat is already 12 volts. Get an inverter that can charge and invert. Also get a battery isolator so you can charge the inverter bank in addition to the engine bank so you don't need to rely on the generator...... OR, if you want to save money.....just run the generator like the boat was supposed to be run and spend 1/2 of the money you're going to spend on batteries, inverter, etc etc.......on fuel.

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