1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. Welcome To LandyZone!

    LandyZone is the biggest Land Rover forum on the net. We have plenty of very knowledgable members so if you have any questions about your Land Rover or just want to connect with other Landy owners, you're in the right place.

    Registering is free and easy just click here, we hope to see you on the forums soon!

Not starting , nearly dead battery.

Discussion in 'Land Rover Discovery' started by ClassikFan, Dec 7, 2013.

< Previous Thread | Next Thread >
  1. pedros

    pedros Active Member

    Joined:
    Oct 10, 2011
    Posts:
    287
    Likes Received:
    1
    The Disco is a big old lump to start. If you do put jump leads on, it surely will take a bit of time and some revs before the Disco battery will have a proper go at starting. The batteries these days also don't tend to give much warning before packing up. One minute fine, the next time- click click...nothing.

    One thing I'd advise is getting a good quality battery if you need to, not the cheapest. False economy.
     
  2. trax

    trax . Events Planner

    Joined:
    May 4, 2012
    Posts:
    10,639
    Likes Received:
    113
    Location:
    Oxfordshire
    jump starts are to start the engine with the other cars battery, not a way to do a fast recharge
     
  3. pedros

    pedros Active Member

    Joined:
    Oct 10, 2011
    Posts:
    287
    Likes Received:
    1
    Yes, it's a way to start the vehicle, not charge the battery. But it still holds true that you have to give it some time connected or it won't work, especially with crappy jump leads.
     
  4. discodrivercumbria

    discodrivercumbria Well-Known Member

    Joined:
    May 29, 2011
    Posts:
    3,317
    Likes Received:
    339
    Location:
    South lakes
    with a good set of jump leads, you don't even need a battery there! just onto the terminals would do! i personally wouldn't though!
     
  5. ClassikFan

    ClassikFan Active Member

    Joined:
    Apr 11, 2013
    Posts:
    328
    Likes Received:
    7
    Location:
    Surrey
    OK battery has been on charge for 4 or 5 hours and is now fully charged, remains to be seen if it will hold the charge for long but I will find out in due course.

    Suggestions that the root of my trouble could be either the alternator or starter motor will have to be investigated, unfortunately the car is out on the road not the drive making it harder to work on in the dark so will have to wait till next weekend.
     
  6. thebiglad

    thebiglad Well-Known Member

    Joined:
    Jan 18, 2008
    Posts:
    7,382
    Likes Received:
    30
    Location:
    Central France
    Hi CF, did you measure the voltage on the battery (after it had rested for at least 1 hr), after charging it? If you did, what was the result?

    Dave
     
  7. ClassikFan

    ClassikFan Active Member

    Joined:
    Apr 11, 2013
    Posts:
    328
    Likes Received:
    7
    Location:
    Surrey
    12.5 volts but my meter is a bit vague.
     
  8. thebiglad

    thebiglad Well-Known Member

    Joined:
    Jan 18, 2008
    Posts:
    7,382
    Likes Received:
    30
    Location:
    Central France
    Well assuming that reading is accurate, it's at the very bottom end of acceptable.

    I would leave it on charge overnight and then check it. Irrespective of what your charger might say, it won't be fully re-charged after just 4 hours.


    Dave
     
  9. Thor1950

    Thor1950 Well-Known Member

    Joined:
    Aug 1, 2012
    Posts:
    39,247
    Likes Received:
    3,938
    Location:
    Land of the midnight sun
    a long slow charge is better than a high fast charge
     
  10. brian47

    brian47 Well-Known Member

    Joined:
    Jan 24, 2013
    Posts:
    8,876
    Likes Received:
    5,370
    Location:
    Bridgend, Mid Glam. Somebody's got to live here.
    The only reliable method of determining the state of charge of a lead-acid battery is by measuring the specific gravity of the electrolyte. The SG for a fully charged cell should be around 1.26. The specific gravity rises in an almost linear fashion from about 1.1 for a fully discharged cell. Battery hydrometers are fairly cheap and readily available.

    Sadly, with the advent of sealed, gel and maintenance free batteries this method isn't always an option.

    The terminal voltage isn't a reliable indicator because of the one of the most useful characteristics of the lead-acid battery; its ability to maintain a near constant voltage over the bulk of the discharge period.

    During discharge, the terminal voltage remains almost constant at about 2.0 volts per cell, dropping to 1.8 volts at the very end of the discharge cycle. While it's on charge, the terminal voltage will remain at about 2.2 volts per cell, rising to 2.4 volts at the very end of the charge.

    The only other method of "guesstimating" the charge state is to monitor the charging current during the recharging period. The actual charging current will depend on the capability of the charger, but generally the current will be very high when first connected falling to a steady level for a number of hours. When a significant drop in the charge current is noted, the charge cycle is nearing or reached the full charge.

    Lead-acid batteries are generally more suitable for slow charging over 8-12 hours rather than fast charging, although that will depend largely upon the design of the battery.

    A "drop test" whilst not reliably indicating the state of charge of the battery, it will often show a battery which is nearing the end of its useful life.
     
    Last edited: Dec 9, 2013
  11. ClassikFan

    ClassikFan Active Member

    Joined:
    Apr 11, 2013
    Posts:
    328
    Likes Received:
    7
    Location:
    Surrey
    This is all good info, but the battery is not a problem. There is something more to it. Hope it is just a loose connection. These dark nights leave no time to try and fix it so it is off to see my friendly LR mechanic tomorrow.
     
  12. ClassikFan

    ClassikFan Active Member

    Joined:
    Apr 11, 2013
    Posts:
    328
    Likes Received:
    7
    Location:
    Surrey
    Official diagnosis is that the starter motor has failed. New one coming tomorrow, hopefully that will be the end of this little episode. At least it chose to fail outside my house and not in the middle of nowhere!
     
  13. ClassikFan

    ClassikFan Active Member

    Joined:
    Apr 11, 2013
    Posts:
    328
    Likes Received:
    7
    Location:
    Surrey
    All fixed, no sign of any current drain, so we have a clean bill of health again.

    :)
     
< Previous Thread | Next Thread >