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Battery Problem

Discussion in 'Technical and Troubleshooting Torque' started by kennyc, Feb 28, 2010.

  1. Hi All

    I recently fully drained my battery by leaving the lights on overnight (silly I know but shit happens sometimes). Problem was, the NRMA couldn't get it charged again and I was told by both the NRMA mechanic and the bike shop mechanic where I got a new one, that the bike batteries are designed now so that once you've fully expended the charge in them, they're pretty much f#*ked, reason being that they're a sealed unit and unlike the larger car batteries, they are not designed to be drained and recharged in the same way.
    Has anyone had similar experiences and if so, did you have any problems getting it charged up again (I actually tried to clutch start it but no luck, probably because the battery was, according to the mechanics, already cactus).
    The battery was about 18 months old.
  2. Lead acid and Gel batteries are not happy if completely flattened. Standard automotive batteries are not designed to go below 50% of charge. Lower and you can damage the plates. You could try a gentle charge with an automotive charger overnight but with a battery 18 months old even if you get it going again its charge capacity has been reduced so in the colder weather when cranking the engine is harder it will probably let you down.

    The best bet is to replace it as you have done.
  3. The main damage to the plates is the formation of lead sulphate. Stick it on high charge initially to try to dissolve the salt and then leave on low overnight. Battery life is measured in charge cycles, by letting it go flat you have used up a couple of its lives but assuming a quality battery like a Yuasa, it should recover OK.

    Clutch starting can often make the situation worse (if battery completely flat) because too much current is applied and may buckle the plates. Better to put it on a dedicated charger.
  4. If we had the positive karma function back, you'd both a point fellers :)

    Kenny, what they said.