12 volt 24 volt system question

Discussion in 'PSI Superchargers Tech Questions' started by Danny Humphreys, Jun 25, 2009.

  1. Danny Humphreys

    Joined:
    Aug 4, 2003
    Messages:
    489
    Likes Received:
    0
    i run 2 batteries in series for 24 volt to go to the starter. i pull all the 12 v electronics off the first positive post to run the 12 volt stuff. I've been running 2 5 pole relays that switches the charger back and forth between the two batteries with mixed results. I'd like to hook up a 24 volt charger and be done with it, but I'm not sure how that will affect my 12 volt components when the charger is on. I've attached a diagram of my current (no pun intended) setup. My intent is to run the 24 v charger to post A and D to charge both batteries at the same time.

    [​IMG]
     
    #1
  2. Don Onimus

    Don Onimus New Member

    Joined:
    Feb 28, 2009
    Messages:
    1,337
    Likes Received:
    0
    24 volts

    I have a hard time wiring my light switch, but I think DMPE sells something that gives you 24 volts to start the car then you can run 12 volt stuff off of that. Something like that. I think it is on there site, under Electrical. Good luck Don
     
    #2
  3. Mike Canter

    Mike Canter Top Dragster
    Staff Member

    Joined:
    Mar 10, 2004
    Messages:
    4,502
    Likes Received:
    156
    Running a 24 v starter does not effect the 12 volt system we do it all the time on our PM. The 24v chargers at around $300 so maybe the DMPE widget can save you money
     
    #3
  4. hemi altered 378

    hemi altered 378 Blown Altered

    Joined:
    Jul 3, 2004
    Messages:
    864
    Likes Received:
    0
    Danny.....
    couldn't you just put a switch between the B and C posts, like a power disconnect deal. then use 2 small chargers and charge them seperately? just a thought. we used to run the same thing as you, and i just unhooked the B to C post wire and charged with 2 seperate chargers.
    hope this helps,
    Darren
     
    #4
  5. Larry Wycoff

    Larry Wycoff AA/GAS

    Joined:
    Feb 18, 2009
    Messages:
    15
    Likes Received:
    0
  6. jeragsters

    jeragsters top fuel sand

    Joined:
    Apr 12, 2005
    Messages:
    22
    Likes Received:
    0
    You should have a switch to turn on and off your electronics already.When the switch is off [or open] you are isolated from the batteries.

    www.batterystuff.com they have all types of chargers
     
    #6
    Last edited: Jun 25, 2009
  7. PROMOD63

    PROMOD63 Member

    Joined:
    Jun 6, 2008
    Messages:
    359
    Likes Received:
    0
    We run the same setup put a switch between b and c turn if off and charge batteries sepratly we us small chargers from carquest they are automatic and 10 amp and cost around 30.00 we put a small wire and stud set up to a and b and another to c and d it has worked great for 5 years
     
    #7
  8. Danny Humphreys

    Joined:
    Aug 4, 2003
    Messages:
    489
    Likes Received:
    0
    I already have a charger that will do 12 or 24 volt, but at 55 amps which is what Rock batteries says i need. But, I want to be able to do the 24 if i can to make it easier.
     
    #8
  9. Bottlefed

    Bottlefed New to Blowers

    Joined:
    Feb 20, 2008
    Messages:
    375
    Likes Received:
    0
    Do it... the batteries don't care if they are wired together internally or externally they are still just a collection of separate 2v cells.


    If you want to make sure (I have always checked <> I have never been wrong on wiring stuff before.... but I always check.... so I never will be :rolleyes:) to set your mind at ease, just disconnect the 12v "c" terminal from the car while you connect the charger and then connect a voltmeter to the 12v "c" terminal and ground and you will see its measuring 14-15 volts while charging so your car will see the same voltage when you charge with it connected.


    Good luck with it.

    Richard Gavle
     
    #9
    Last edited: Jun 25, 2009
  10. PROMOD63

    PROMOD63 Member

    Joined:
    Jun 6, 2008
    Messages:
    359
    Likes Received:
    0
    You can put a shut off on c to the 12 volt stuff and charge through a and d at 24 volt but 12 volt stuff must be unhooked! My fear would be to accidently leave them on thats why i went the route i went
     
    #10
  11. Mike Canter

    Mike Canter Top Dragster
    Staff Member

    Joined:
    Mar 10, 2004
    Messages:
    4,502
    Likes Received:
    156
    You don't have to shut 12 volts off. That line to the 12 volts will only be 12 volts even with a 24 volt charger attached on on. We do it all the time.
     
    #11
  12. bill

    bill Member

    Joined:
    Dec 25, 2006
    Messages:
    100
    Likes Received:
    0
    i run 48 volts to my starter and 12 to my dash and i bouth 4 cheap 2volt chargers and hooked them in series + to - to get 48 volts and it works great i run 4 lawn mower batterys
     
    #12
  13. JP

    JP Member

    Joined:
    Oct 8, 2005
    Messages:
    229
    Likes Received:
    0


    Correct , also you dont have to disconnect anything because in reality a24 volt setup is just 12 2volt cell together . The 28volts that the battery charger put out will be "distributed" between all cells for proper charge.
     
    #13
  14. Policy Peddler

    Joined:
    Oct 12, 2005
    Messages:
    200
    Likes Received:
    1
    i am first to admit i did not read every post, so if i missed something and this is not relavent then skip it.
    if you have a 24 volt charger hooked to the system, to me that means the vehicle is parked. Then everything is shut off, so regardless if something is 12 volt or 24 volt it does not see the 24 volts because the switch is off. So it does not matter. Just be sure the master ground switch is turned off so no one can inadvertently turn on something.
     
    #14
  15. Bottlefed

    Bottlefed New to Blowers

    Joined:
    Feb 20, 2008
    Messages:
    375
    Likes Received:
    0
    Originally posted on the 25th,

    Bottlefed
    New to Blowers Join Date: Feb 2008
    Posts: 198

    Do it... the batteries don't care if they are wired together internally or externally they are still just a collection of separate 2v cells.


    If you want to make sure (I have always checked <> I have never been wrong on wiring stuff before.... but I always check.... so I never will be ) to set your mind at ease, just disconnect the 12v "c" terminal from the car while you connect the charger and then connect a voltmeter to the 12v "c" terminal and ground and you will see its measuring 14-15 volts while charging so your car will see the same voltage when you charge with it connected.


    Good luck with it.

    Richard Gavle

    You do not have to disconnect anything, instead of seeing the 12v that it would normally it will see the 14-15 volts that your charger puts out well within the safety range of any 12 volt device. So don't worry about anyone turning on the car or leaving the car on to check data loggers, program MSD box's etc.
     
    #15
  16. Joad Donnelly

    Joad Donnelly Member

    Joined:
    Jul 2, 2009
    Messages:
    84
    Likes Received:
    0
    We run the same 24 volt set-up and here is what I found. We tried running a 24 volt charger and it never would give an even charge between the two batteries. One battery would get all the charge and the other one would pull down to less than 12 volts eventually even with running the charger after every pass. Both batteries tested good but they are different ages so I thought that may have had something to do with it. But I decided to just add seperate 12 volt charging lugs to each battery so I could easily charge them and monitor the voltage of each battery independently.

    BTW, the batteries are under the deck lid so by adding the external lugs it just kept us from having to remove the deck lid after each pass for battery access.

    Joad Donnelly
     
    #16

Share This Page