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Charging 12 volts with 6 volts

Discussion in 'The Hokey Ass Message Board' started by moprr71, Jan 23, 2013.

  1. moprr71
    Joined: Jun 5, 2010
    Posts: 34


    I have a 52 buick that is 6 volt system and I'm going to run air ride 12 compressor. I'm not going to convert the car to 12 volt and I want to keep it as original as possible. I was thinking about running 2 6 volt batteries in series In the trunk and charge off the generator. My question is, is there a way to charge the batteries off the gen individually? Can I switch the gen to either battery? I'm still going to run the 6 volt battery for starting under the hood. Any help or advise is greatly appreciated.

    Posted from the TJJ App for iPhone & iPad
  2. Original as possible and air ride?:confused:

    I would rethink the 6 volt idea. HRP
  3. Agreed. Too much trouble. If you want the 6v look leave it there and hide the 12v battery in the trunk

    Sent from my iPhone using Tapatalk
  4. diodes...and lots of them...and wires...lots of them.
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  5. I think he's thinkin 2 much :eek:
  6. Model T1
    Joined: May 11, 2012
    Posts: 3,310

    Model T1

    I think while you are thinking this is the best idea.
  7. Nothing wrong with creative thinking,,but not all ideas are piratical. HRP
  8. moprr71
    Joined: Jun 5, 2010
    Posts: 34


    If it can't be done than ill defiantly use a 12 v battery. I know that in the past I would jump start a 24 volt system with a 12 v truck. You just put the cables on one battery at a time. The batteries still remain 12 v each so it wouldn't hurt anything. We would actually use 2 trucks, one on each battery. I'm just thinking that if I had 2 6v batteries that I could charge one at a time with a batt selector switch( like in a boat) while going down the road.

    Posted from the TJJ App for iPhone & iPad
  9. Thunderroad312
    Joined: Nov 18, 2012
    Posts: 159


    Two 6v batteries in series, have the generator rewound for twelve volts, and get a 12 volt regulator. Take your power tap that feeds the car and connect it to the first battery, you will have 6 volts to run the old stuff. Anything you need 12 volts for connect it to the second battery where you have 12 volts. Been done many times. In the old days I have seen where guys would do a motor swap, but didn't want to re-wire the car and would actually drill into the top of a 12 volt battery in the middle and run a screw into it to pick up 6 volts out of a 12 volt battery to run accessories. I'm not saying I would, but two batteries in series is a clean way to do it if you must.
  10. moprr71
    Joined: Jun 5, 2010
    Posts: 34


    That exactly what I wanted to know. I've had people tell me that it couldn't be done. I'll be wiring it up this weekend or next week. I'll post the results. Thanks

    Posted from the TJJ App for iPhone & iPad
  11. Dale Fairfax
    Joined: Jan 10, 2006
    Posts: 2,585

    Dale Fairfax
    Member Emeritus

    Find a J.C. Whitney catalog and look for a series parallel switch. Two six volt batteries in parallel to power up the car and charged by the existing generator. Using a starter solenoid to direct 12 v to the generator. You won't be able to run the compressor continously but long enough to pump up your bags.
  12. Mr48chev
    Joined: Dec 28, 2007
    Posts: 27,225


    Another possibly simpler and less expensive way might be to add an internal regulator alternator to the engine on it's own bracket and wire it so it's only function is to charge the 12V battery that is in the trunk to run the compressor.

    I'm with the others who say that if you bagged the car you already pissed away the "all original" thing and should just go 12V and be done with it. The car has already been hacked to put the bags in and will never be all original again.
  13. moprr71
    Joined: Jun 5, 2010
    Posts: 34


    I like the idea of a Gm one wire just for 12v. The car is in original condition and I don't see it necessary to convert to 12v just for bags. I shouldn't need to do any cutting for the install so when I sell it I can put it back to original.
  14. LONG
    Joined: Aug 20, 2011
    Posts: 292


    or just run a marine deep cycle batt in the trunk. I have a 52 that I am bagging right now. I am converting to 12v.
  15. Cantstop
    Joined: Jul 11, 2005
    Posts: 239


    this probably would be easyest any other way would require massive amounts of diodes and/or relays.
  16. d2_willys
    Joined: Sep 8, 2007
    Posts: 4,098

    from Kansas

    This is what I would do too! You can probably just use a 53 up 12 volt gen and reg instead of rewinding, but either way is fine. Biggest drawbacks of the 2 battery system is the extra room for the second battery, and when one goes dead, trying to correctly determine the culprit. I did think of one other thing that might mess you up, the starting relay for the "gas pedal" start. The relay coil gets returned through the ARM terminal of the gen. If the old gen is different from the newer 12 volt units, then it might have to be rewound. Good luck
  17. Morgan91
    Joined: Sep 12, 2010
    Posts: 560

    from Australia

    It's not that hard to change it to 12v, just change the fuses and globes and change the regulator. Compressors draw a shit load of amps and will flatten even a good 12v battery pretty quickly without any amps coming from the alternator/generator
  18. Kerrynzl
    Joined: Jun 20, 2010
    Posts: 2,284


    It is possible, and simpler than you think!

    I don't know much about the “Ins and Outs” of air ride suspension , but 12 years ago I had a similar scenario with a MK1 Lotus Cortina with the pathetic Lucas Starter Motor.
    With any decent compression or ignition advance and these starters would struggle unless I put 24 volts to it.

    What I was put 2 batteries in series with a Ford Solenoid between them.[ 2 small batteries fitted perfectly into a plastic “marine” battery box ]
    The battery with the ground strap was wired normally to run ignition etc but when I hit the starter button there was a wire to the solenoid that connected that starter motor in series with both [ 24 volt ]

    Now here is the tricky bit, I wired 2 heavy amp relays [ 5 post ] to connect the batteries parallel, but I wired them “Reverse Post” so the relay switched them off [ I used a fusable link here as a failsafe measure ]
    These relays were also wired to the same starter button.

    Push the starter button and the 2 relays switched off and the solenoid switched on ................. 24 volts to the starter motor [ series ]

    Release the starter button and the 2 relays switched on and the solenoid switched off ................. 12 volts to both batteries getting charged. [ parallel ]

    This worked fine until I fitted a Denso reduction starter to save weight [ a few years later ]
  19. 56C3B6
    Joined: Mar 2, 2010
    Posts: 36

    from central NY

    They make a device called a battery isolator. It's for charging multiple battery banks from a single charging source. Commonly used on campers, boats, fire apparatus. Might save a lot of headaches.
  20. nali
    Joined: Sep 15, 2009
    Posts: 828


    This works for small amperes. Considering the fact that an air compressor needs about 20 Amp, it won t work unless you use a HUGE electronic circuit.
  21. raengines
    Joined: Nov 6, 2010
    Posts: 227

    from pa.

    me thinks this isn't gonna end well, not a good idea
  22. Diavolo
    Joined: Apr 1, 2009
    Posts: 810


    If you want to show off your mad skillZ.

    less than 1 amp a piece, get a piece of plexiglas and mount 50 of them in parallel, then you will need a place to store that energy. If you don't want to use a battery, you could rig a stack of slow discharge capacitors but the amount of resistance you would need would mean you have a trunk full of capacitors. Then there's heat to deal with so you will need huge heat sinks and fans. Probably should run them off 6V because you aren't going to have a lot of 12V left after all the circuitry.

    Or, just convert to 12V and hide the battery...
  23. Use it to charge a 12 volt battery, run the compressor off the battery.
  24. Bryan G
    Joined: Mar 15, 2011
    Posts: 176

    Bryan G
    from Delmarva

    I would try the 2-6v idea, just for the fun of it. I would study what Kerrynzl talks about, among others. If I were smarter I'd think of something with two regulators and a relay to constantly switch off between the two systems, but this is starting to make my head hurt.
  25. john walker
    Joined: Sep 11, 2008
    Posts: 1,106

    john walker

    mount a separate 12V generator/regulator setup or mini alternator connected only to the isolated 12V battery
  26. Dan10
    Joined: Aug 14, 2007
    Posts: 386

    from Joplin

    Run a 12V alternator off the driveshaft. It will be hidden and should be enough to charge a deep cycle battery.
  27. flynbrian48
    Joined: Mar 10, 2008
    Posts: 6,480


    Converting to 12V, assuming your wiring is in good condition, a HUGE assumption, is no harder than swapping the bulbs, and swapping the 6V gen for a 12, or switch to a one wire alt. Put whatever music you want in the glove box, pull the fuse for the stock radio, and you're done. The gas gauge, if it works, will still work on 12V. I ran the stock gauge in my '48 pontiac untill I put the LT1 in it, it worked fine. The heater will live just fine on 12V too, I'm still using a 6V heater in the aforementioned '48 Pontiac convert for 10 years now.

    Does the Buick have a long, narrow 6V battery and you want that look? Just drop a 12V tractor battery, available at every farm supply store, in it's place.

    Why you'd go to the trouble of bagging it, without doing the VERY simple coversion to 12V seems a bit backwards. I don't get the idea of having a car set on the rocker panels and keeping it look "original".


  28. Kerrynzl
    Joined: Jun 20, 2010
    Posts: 2,284


    I don’t know your motives here but if you’re going to add a 2nd battery , you’d actually be better off adding a 12 volt battery [ and removing the 6 volt battery while you’re at it.] and you won’t need to fabricate a battery box / mount for the 2nd battery
    Converting all the bulbs to 12 volts would take up less brain cells than hooking up all the electrical relays and solenoids wiring .

    Just a note here about my Lotus Cortina twin battery system. [ posting # 18 ]

    When I first tried this, I had two batteries in series using a 24 volt internally regulated alternator off an Isuzu truck , and I took all the 12 volts off the first battery [ the one with the ground strap ]
    At the end of a days racing it struggled to start and eventually developed a miss at high rpm.
    When the batteries were checked the 2nd battery was fully charged but the 1st battery was getting flat, so to charge them both evenly they must be hooked up parallel.
    [ that is why I made a 24 volt on demand ,but 12 volt on default system ]

    Personally ,even though electrics is very simple for me! I would recommend converting to 12 volt [ this involves replacing bulbs and modifying or buying generator components ]
    Every component that you add is increasing the chances of failure

    Your starter motor will love 12 volts going through it, plus there are so many other benefits like sound systems , navigators, radar detectors, cell phone chargers, brake controllers etc etc.

    You can also keep the original battery and a box of bulbs to convert it back later when you sell it [ or offer them to the buyer ]

  29. moprr71
    Joined: Jun 5, 2010
    Posts: 34


    I would love a phone charger and a better radio. If I don't have to change the heater blower motor and anything major, than I probably will. The gas pedal starter system still works, will I need to change out anything for that? Also the dash clock, fuel , amp gauges etc still work will it be easier to use a resister for those? I agree that 12v is better but the 6 volt works fine.

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