Battery charging Help required

Discussion in 'Tech/Mech General' started by Heyupluv, Jan 29, 2011.

  1. Heyupluv

    Heyupluv Read Only Funster

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    Fiat flat battery
    Questions,
    To charge the engine battery from a normal 2 / 4 amp battery charger.

    Can it be done, like the Motorhome dealer suggested....connecting the battery charger to the Jump start terminals at the front underneath the bonnet of the motorhome while the battery is still connected to all the electrical equipment........will it do any damage e.g. alternator..or anything else....AND WOULD IT CHARGE THE BATTERY
    or
    Can the battery charger be connected direct to the battery while the battery is still connected to all the electrical equipment........will it do any damage e.g. alternator..or anything else.

    The reason for not disconnecting is so I do not loose the radio code or effect the immobilizer.

    I could put some small croc clips and wired to a smaller battery....to keep the codes while the battery is charging.....as the battery would need to come out to be charged and my luck I would most likely knock off one of the wires to the spare small battery while I was taking out the engine battery!

    Is it possible to to take a small battery connected at one end to the battery + - with the wires at the other end to a cigarette/cigar plug and while the ignition is switched on.... would it keep the immobilizer and radio codes still intact...:Eeek: or would this do any damage....also what size wire would be needed to do this type of connection,:Doh:
     
  2. Geo

    Geo Trader - Funster

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    Connect up either to the batt direct or the jump start terminals it will make no difference
    with a 2-4 amp charge its going to be a longish job but it will charge sufficiently to start engine then go for a run your alternator can charge 10-15 times quicker
    For future reference for a couple to five quid on flebay you can buy a code saver plug in device with 9 volt battery, you need to know that the cig socket works without ign on, if not make it so it does always better and safer if the ign is off when working electrics
    Geo
     
  3. jonandshell

    jonandshell Funster

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    Connecting a charger to a connected battery won't do any harm. Have done it many times over the years on numerous vehicles from cars to tanks! Just ensure the lights and ignition are off otherwise the battery charger will only be supplying them and not charging your flat battery! It might be worth also pulling the habitation main fuse in case your split charge relay activates and diverts some of the current from your charger to the leisure battery......

    There are devices on the market which plug into your cigarette lighter socket and maintain the radio memory if you wish to disconnect your battery for charging-

    http://cgi.ebay.co.uk/Computer-Memo...0805993&cguid=9f28064e12d0a0aa15137163ff72246
     
  4. scotjimland

    scotjimland Funster Life Member

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    Hi Mel
    I asked the same question some time back and was advised similarly .. then read the Honda manual which instructed to disconnect the battery to prevent damage to the ECU ..

    This may be overcautious but as it only takes a few seconds to re enter the radio code and it only needs one voltage spike to do irreparable damage to the ECU, it is a risk I wasn't prepared to take for the sake of a few minutes work with a 10mm spanner.
     
  5. Heyupluv

    Heyupluv Read Only Funster

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    That you for the information and your reply Geo:thumb:.....I will look on ebay for the code saver:BigGrin: I will check to see if the cig lighter is on / live when the ignition is off....there are two on my dasboard one of a higher rated not sure if that is off the habitation battery !! or the cab/ engine battery DOES ANY BODY KNOW......it is a 130 2008 multi jet fiat...thanks again

    Mel
     
  6. Heyupluv

    Heyupluv Read Only Funster

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    Thanks Jonandshell...I was never sure has I was told many years ago charging while connected damaged the diodes/ rectifier in the Alternator....maybe tooooo long ago and things have changed ...thankyou

    Mel:thumb:
     
  7. MikeandCarolyn

    MikeandCarolyn Read Only Funster

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    So many coincidences-as this post was being posted I was busy making up a lead to connect a CTEK charger,via our EHU on the side of the house,to the Volvo 15mtrs away on the hardstanding,where it lives whilst we are away.I'm fed up with coming home after a few weeks to a flat battery and having to put the M/H in behind the Volvo and then swap them round next day after charging the thing !!
    Think I got a tads off the point :Smile: which is that my local garage advised that using a 'smart' charger like the CTEK there would be no problems with leaving it on for a long time without removing the battery from the vehicle.

    Mike.
     
  8. jhorsf

    jhorsf Read Only Funster

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    Your small charger connected to the battery with battery in situ and still connected will do no harm leave ign off and charge for 2 or 3 days if an auto charger .Keep your eye on aldi lidl they do a small charger every so often as a special offer that can be left on for a long time and is fully auto they are about 12 pounds I think and work well
     
  9. aba

    aba

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    a local garage to us at work recently connected one of those booster packs to jump start a newish vauxhall and this blew the ECU they mentioned it to vauxhall and they replied "oh yes its a common fault £350 for a new ECU"
     
  10. chatter

    chatter Read Only Funster

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    You can buy jump leads that have a unit built in which protects the elec brain etc, t also protects everything if you were to connect the leads incorrectly but they dont come cheap, my ex son-in-law has some seeing as he is/was a mechanic i assume he got them from one of the firms that provide tools to garages. - but they are out there
     
  11. jonandshell

    jonandshell Funster

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    As an electric forklift engineer, I suspect all those myths of blown ECUs, alternators and the like are due to leads being connected with incorrect polarity and the guilty parties covering up their mistakes!
    I will accept, however, that a completely knackered battery lacks any capacitive effect and a start-charger might cause ECU problems if used in this case. A healthy, albeit flat, battery acts as an electrical 'buffer', absorbing any electrical 'spikes' which can cause data corruption on the EPROMs (chips) in a poorly-designed ECU.
    Some manufacturers do insist on time delays in between the connection/disconnection of battery leads too, just consult your handbook. Some Peugeot cars fit into this category for example.
    A trickle charger should be fine in any case.
     
    Last edited: Jan 30, 2011
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