1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Charging your battery which Amps to charge on

Discussion in 'Electrics, Vacuum, Ignition and ECU' started by johno2004, Oct 22, 2012.

  1. johno2004

    johno2004 Senior Member

    Messages:
    644
    Likes Received:
    0
    Joined:
    Dec 7, 2007
    Your Mercedes:
    SLK32 AMG
    Hi

    Got home from 10 day hols today and battery totally flat due to alarm draing battery.

    I purchased a new Ring Smart Charge and it has 4 charge settings it has 2amp 4amp 8amp and 12amp. The default is 2amp is that the correct setting for my battery as i dont want to charge incorrectly and damage battery.


    Thanks
     
  2. television

    television Always remembered RIP

    Messages:
    164,074
    Likes Received:
    310
    Joined:
    Mar 14, 2005
    Location:
    Daventry
    Your Mercedes:
    2002 SL500, 216 CL500, all fully loaded
    4 amp is a nice rate to start for 10 mins, take it up to 6 for a few hours, say 10 and as the battery charges the current will fall away on its own,,when around 1 or 2 amps its charged
     
  3. EmilysDad

    EmilysDad Senior Member

    Messages:
    9,234
    Likes Received:
    2,760
    Joined:
    May 8, 2012
    Location:
    Bury Lancs
    Your Mercedes:
    ML350
    Isn't it a 'smart charger'?
    Its name suggests to me that it will monitor the battery and charge & float charge as needed
     
  4. Frontstep

    Frontstep Senior Member

    Messages:
    7,396
    Likes Received:
    1,279
    Joined:
    Apr 22, 2007
    Your Mercedes:
    T210 320cdi
    I use an old wheelchair charger its very good.
     
  5. television

    television Always remembered RIP

    Messages:
    164,074
    Likes Received:
    310
    Joined:
    Mar 14, 2005
    Location:
    Daventry
    Your Mercedes:
    2002 SL500, 216 CL500, all fully loaded
    I have some golf trolley chargers also good :D
     
  6. OP
    johno2004

    johno2004 Senior Member

    Messages:
    644
    Likes Received:
    0
    Joined:
    Dec 7, 2007
    Your Mercedes:
    SLK32 AMG
    Yea thats right but in the instructions it says choose the right amp setting for your battery.

    On mine model in the manual under heading chargge rates it has a chart and model it has this: voltage 12v default charge rate 2A available rates 2/4/8/12A Maximum rated battery 25_300ah
     
  7. Frontstep

    Frontstep Senior Member

    Messages:
    7,396
    Likes Received:
    1,279
    Joined:
    Apr 22, 2007
    Your Mercedes:
    T210 320cdi
    I have a golf trolley without a charger that the Youth has other plans for, not that I have ever played a round of golf in my life despite being dragged to some very nice courses.
     
  8. EmilysDad

    EmilysDad Senior Member

    Messages:
    9,234
    Likes Received:
    2,760
    Joined:
    May 8, 2012
    Location:
    Bury Lancs
    Your Mercedes:
    ML350
    If the battery is charged & you just want your charger to keep your battery charged while you're away I'd just leave it at its default 2 amp.
     
  9. television

    television Always remembered RIP

    Messages:
    164,074
    Likes Received:
    310
    Joined:
    Mar 14, 2005
    Location:
    Daventry
    Your Mercedes:
    2002 SL500, 216 CL500, all fully loaded
    You are welcome to one :D:D
     
  10. wireman

    wireman Senior Member

    Messages:
    2,632
    Likes Received:
    3
    Joined:
    Sep 20, 2005
    Location:
    lancashire
    Your Mercedes:
    nice 201 2.5D 1993 & very nice 129 SL500 1994
    You can safely charge a fully discharged (1.8V/cell) lead acid battery at 1/10th of the Ah rating for 15 hours, for a 60 Ah that's 6A. To compensate for the inherent inefficiency of the LA battery 150% of the stored Ah must be supplied to charge the battery, for my example 90Ah.

    Typically on charge each cell has a PD of 2.35 Volts, that's 14.1 Volts at the battery terminals.

    You can leave a battery permanently connected to a constant voltage charger at 13.8 Volts, the current will be quite low and to fully charge at this voltage will take a very long time.

    You should not for any length of time charge at a terminal voltage in excess of 15 Volts, if the voltage is over 15V reduce the current, such that it is lower.

    The battery's case temperature should not be allowed to exceed 40C, pref 30C.

    Its all plus or minus a yard or two, the temperature of the plates inside is the limiting factor, too warm and they buckle or blister, loosing their fill material, reducing storage capacity and shortening the battery's life.
    Too much charge current in a battery nearing full capacity will cause gas build up on the plates, thus reduces the active area of wet/conducting plate and causes severely injurious hot spots on the plate surfaces.

    I would avoid the 12 Ampere setting, the 8A will be fine. Your charger will monitor the battery and adjust itself accordingly.

    Do make certain sure that the charger is disconnected at the mains before you disconnect the chargers battery leads, one small spark will ignite the oxygen/hydrogen atmosphere around the battery, BOOM... Been there, done that.
     
    Last edited: Oct 22, 2012
  11. television

    television Always remembered RIP

    Messages:
    164,074
    Likes Received:
    310
    Joined:
    Mar 14, 2005
    Location:
    Daventry
    Your Mercedes:
    2002 SL500, 216 CL500, all fully loaded
    I had a friend who had a bus, he always charged his batteries before any runs and test them out by just flashing a starting handle across the terminal, he did this one time too many for when I called in to see him he was sitting on the floor in the garage wondering where his battery had gone
     
  12. television

    television Always remembered RIP

    Messages:
    164,074
    Likes Received:
    310
    Joined:
    Mar 14, 2005
    Location:
    Daventry
    Your Mercedes:
    2002 SL500, 216 CL500, all fully loaded
    The reason I said 4 amps was, if the battery is still connected you do not want a higher voltage going through the car electrics if the battery is dead flat as its internal resistance will be too high
     
  13. OP
    johno2004

    johno2004 Senior Member

    Messages:
    644
    Likes Received:
    0
    Joined:
    Dec 7, 2007
    Your Mercedes:
    SLK32 AMG
    I have left it on 2A the default since 4 this evening and its got to 90% so gonna leave it on 2 now till it reaches Float stage as i wont be using car tomz anyway. I supose a nice slow charge is better than fast one.

    I have fully read all the manual now and it has a 7 stage charge and says its safe to leave on indefinitely so ok for me just to leave it on 2A
     
    Last edited: Oct 22, 2012
  14. television

    television Always remembered RIP

    Messages:
    164,074
    Likes Received:
    310
    Joined:
    Mar 14, 2005
    Location:
    Daventry
    Your Mercedes:
    2002 SL500, 216 CL500, all fully loaded
    That very good, and the safest way of all,,if the battery was dead flat it can require a higher setting to start it off
     
  15. OP
    johno2004

    johno2004 Senior Member

    Messages:
    644
    Likes Received:
    0
    Joined:
    Dec 7, 2007
    Your Mercedes:
    SLK32 AMG
    I had driven the car arround for about 2 hours after jump starting so there was a fair amount of charge in it
     
  16. Xtractorfan

    Xtractorfan Senior Member

    Messages:
    6,084
    Likes Received:
    155
    Joined:
    Nov 16, 2007
    Your Mercedes:
    S class
    The lowest setting for an overnight charge is always best, the longer the charge the healthier the battery, fast charges tend to warp plates, and boil the battery..
     
  17. cleverdicky

    cleverdicky Senior Member

    Messages:
    2,385
    Likes Received:
    2
    Joined:
    Feb 25, 2009
    Your Mercedes:
    MB
    You can now get very good 'pulse' chargers which are meant to do a better job of recovering any bad cells.
     
  18. Frontstep

    Frontstep Senior Member

    Messages:
    7,396
    Likes Received:
    1,279
    Joined:
    Apr 22, 2007
    Your Mercedes:
    T210 320cdi
    Thanks I adapted a charger to fit, but the youth now has his nose in a book earning how to write C++ programmmes !!!!
    When he realises those doey eyed girls want him it will all change I suppose.
    Aah to be young, or maybe not !
     
  19. wireman

    wireman Senior Member

    Messages:
    2,632
    Likes Received:
    3
    Joined:
    Sep 20, 2005
    Location:
    lancashire
    Your Mercedes:
    nice 201 2.5D 1993 & very nice 129 SL500 1994
    When he realises those doey eyed girls want him it will all change I suppose,

    /*That's when the C++
    {
    do{ }
    while( )
    }
    /*statement will help him.
     
    Last edited: Oct 23, 2012
  20. Frontstep

    Frontstep Senior Member

    Messages:
    7,396
    Likes Received:
    1,279
    Joined:
    Apr 22, 2007
    Your Mercedes:
    T210 320cdi
    Oh no there every where
    I learnt basic on punched tape which went to I think Harris College in Preston I am now suitably confused.
    We know someone who writes those PS3 X-Box things for a Liverpool firm far to confusing for me.
     

Share This Page