Installed Mains Battery Charger overheating

Discussion in 'Tech/Mech General' started by ronrumbol, Sep 7, 2009.

  1. ronrumbol

    ronrumbol Deleted User

    I have an Elnagh Marlin 59 motorhome on a Fiat Ducato chassis registered in 2000.
    I have had some problems with the charging of my leisure battery and have just replaced the battery and had to replace a 50amp strip fuse. It now appears to be charging from the alternator ok but on connecting the van to a mains hookup, the built in mains charger seems to get very hot and now smells hot if you know what I mean. It never used to get hot or smell.
    Any ideas anyone?
     
  2. hilldweller

    hilldweller Funster Life Member

    Joined:
    Dec 5, 2008
    Messages:
    26,475
    Likes Received:
    25,167
    Location:
    Macclesfield
    What make is it ?

    Has it got a cooling fan that has stopped working ?
     
  3. pappajohn

    pappajohn Funster Life Member

    Joined:
    Aug 26, 2007
    Messages:
    29,484
    Likes Received:
    16,967
    Location:
    YO11 2BD
    Has it got a cooling fan that has stopped working ?

    thinking just the same thing Brian....
     
  4. Wildman

    Wildman Read Only Funster

    Joined:
    May 30, 2008
    Messages:
    15,458
    Likes Received:
    8,598
    Location:
    Ilfracombe, Devon
    for the 50 amp strip to blow a serious overload has occurred, possible short in the charging transformer changing the charge rate, that would account for all of the symptoms. Until sorted do NOT try to charge whilst on hookup or you will burn out the 50amp strip and maybe bugger the new battery as well. If it is something as simple as a fan it could be a cheap fix. Seriously needs looking at by someone who can check the charge rate and charging voltage from the zig unit. smells hot, then insulation on transformer is melting, good way to start a fire. Make sure insurance is up to date.
    Good luck
     
  5. ronrumbol

    ronrumbol Deleted User

  6. hilldweller

    hilldweller Funster Life Member

    Joined:
    Dec 5, 2008
    Messages:
    26,475
    Likes Received:
    25,167
    Location:
    Macclesfield
    No obvious signs of burning. Have you measured the voltage on charge ?
     
  7. ronrumbol

    ronrumbol Deleted User

    Have just made the following measurements:
    Voltage across battery with terminals connected 12.70v.
    Voltage across battery with terminals disconnected 12.69v.
    No current with everything switched off.
    Across terminals with mains charger switched on but not connected to battery 0.12V.
    When connected to battery started at 12.97v and gradually increased to 14.08v.
    I also checked the A/C voltage across the terminals which was 30.00v and the current was measured at 7.75amps.
    I was surprised at the A/C current.
    Any thoughts please?
    I have switched it all off as I have to go out but I will resume tomorrow and will see how hot it gets but won't leave it for obvious reasons.
     
  8. scotjimland

    scotjimland Funster Life Member

    Joined:
    Jul 25, 2007
    Messages:
    28,934
    Likes Received:
    25,574
    Location:
    .
    Hi

    The AC readings I presume were on terminals inside the charger ?

    The other readings look typical .. nothing untoward, do as you suggest and monitor for a couple of days ..

    Just a thought, if your old battery was knackered it's possible the charger hasn't been working hard for a while .. it may just have been dust burning off .. ?

    jim
     
  9. ronrumbol

    ronrumbol Deleted User

    Hi Jim,
    No the readings were at the terminals that connect to the leisure battery.

    Ron.
     
  10. scotjimland

    scotjimland Funster Life Member

    Joined:
    Jul 25, 2007
    Messages:
    28,934
    Likes Received:
    25,574
    Location:
    .
    Hi Ron

    I'm puzzled, why did you measure on AC ? ..

    If you want to measure the charging current, set to DC Amps.. that is assuming the meter has a big enough DC Amp range.

    Jim
     
  11. pappajohn

    pappajohn Funster Life Member

    Joined:
    Aug 26, 2007
    Messages:
    29,484
    Likes Received:
    16,967
    Location:
    YO11 2BD
    more likely working too hard pushing volts/amps into a very high resistance....
     
  12. ronrumbol

    ronrumbol Deleted User

    Sorry a slight misunderstanding. The current measured was DC not AC.
     
  13. camper69

    camper69 Read Only Funster

    Joined:
    Nov 22, 2007
    Messages:
    109
    Likes Received:
    0
    Location:
    North Bucks

    I have the same charger in my motorhome. It also runs quite warm but I think it is normal.


    Derek
     
  14. Andy - V8 Diesel

    Andy - V8 Diesel Read Only Funster

    Joined:
    Sep 3, 2008
    Messages:
    280
    Likes Received:
    0
    Location:
    Manchester
    Maybe charging all the time and not cutting out when the battery is fully charged.

    over charging the battery ?

    Battery cells damaged and creating problem for the charger?

    Teat your battery and also the charge output of the charger.


    love nad light Andy
    ..
    .
    ..
    .
    .
    .
     
  15. ronrumbol

    ronrumbol Deleted User

    Thank you all for your advice and thoughts on the matter.
    While I have a little knowledge of electrics, I am by no means an expert and what concerns me is the fact that I measured 14volts dc and 30volts ac across the battery terminals with the mains charger switched on.
    Firstly, does anyone know if there should be ac voltage across the terminals?
    Secondly, since the battery condition on the motorhome main control panel shows it as fully charged, I was surprised to measure a dc voltage of 14volts and a dc current of 7.75amps flowing. Shouldn't the charger's voltage and current reduce as the battery becomes fully charged?
    Any thoughts anyone please?
     
  16. camper69

    camper69 Read Only Funster

    Joined:
    Nov 22, 2007
    Messages:
    109
    Likes Received:
    0
    Location:
    North Bucks
    ronrumbol

    How good is your meter. The charger should maintain a charge of 13.8 volts when the battery is fully charged. Not a million miles from 14v

    Derek
     
  17. scotjimland

    scotjimland Funster Life Member

    Joined:
    Jul 25, 2007
    Messages:
    28,934
    Likes Received:
    25,574
    Location:
    .
    A good point from Derek

    If you don't already have, buy a hydrometer, it is the only way to really know the state of charge .. panel meters and measuring voltages are only a guide .. take SG readings after the battery is off charge and has rested for a few hours, otherwise you will get false 'high' readings.


    100% Charged = 1.277
    90% Charged = 1.258
    80% Charged = 1.238
    70% Charged = 1.217
    60% Charged = 1.195
    50% Charged = 1.172


    NOTE: Use your battery manufacturer's specific gravity chart. If your manufacturer does not have one, use the above chart as an approximation.

    If only one cell gives you a low reading, while the other cells in the same battery give you normal readings, this is an indication of a bad cell in your battery




    Jim
     
  18. ronrumbol

    ronrumbol Deleted User

    Thanks Jim.
    Unfortunately my battery, which is brand new, is sealed so I can't measure the specific gravity.
    Ron.
     
  19. hilldweller

    hilldweller Funster Life Member

    Joined:
    Dec 5, 2008
    Messages:
    26,475
    Likes Received:
    25,167
    Location:
    Macclesfield
    Red herring time -- some meters will read a voltage on the AC range even if it's DC. Also the voltage will be wrong.

    7.75 amps is good, 17 would be better but maybe it's just a low current charger.
    14V fine - it should go as high as 14.6V then drop back to 13+.

    I'd power up and keep watching very carefully and see what happens - don't leave it just in case. At 7.5A it will take ages to charge a flat battery - 12 hours sort of time.

    If the voltage goes to 15V ( how accurate is your meter ? ) then you have a problem.
     
  20. ronrumbol

    ronrumbol Deleted User

    Thanks Brian.
    I will take your advice and just leave it on all today but keep monitoring it.
    My meter is a digital one which I think is accurate.
    Regarding the ac voltage, I have thought about it and remember in the past if I select ac voltage range by mistake it does show roughly twice the dc voltage. As you say that was a red herring.

    Ron.
     
Loading...

Share This Page