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Flat Battery question

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by OscarA, Aug 3, 2010.

  1. I installed a set of those cheapy heated grips and sure enough left them on overnight. Next morning flat battery so off to work in the car instead. Before leaving I chucked the trickle charge on the battery to charge it. Yesterday morning I try and go for a ride only to find the battery is still flat (yes the grips are off) and notice the trickle charge only has the ON light on not the charging light. I play around with the connection thinking perhaps I didn't push it in hard enough or something but still no charging light coming on just the ON light.
    Bugger it I'll push start it and get it going that way, right, wrong.
    I do manage to push start it but it spluttered, backfired and ran like an absolute dog as I rode it around the block and as soon as I stopped, the engine quit.
    No problems I'll jump start it so hook the leads up (leaving the car engine off) and get the bike turning over but still it wont start.
    Frustrated I give up and hook the trickle charger back on and this time I see the charge light come on.
    Left it on all day and last night bingo she starts effortlessly like she's always done.
    Now the question I have is why didn't the trickle charger work the first time, could it be they wont or my one wont charge a completely dead battery and why once I push started her did she run so bad. I have heard heaps of stories about people push starting bikes with flat batteries with no problems.
    I'm now worried if I stuff up again and next time I'm not at home the bike will be almost impossible to start.
    I'm going to give the heated grips the flick and when I upgrade I'll have a proper pair installed professionally.

  2. reads more like a bad connection. Sometimes they can look good and even be tight, but corrosion in between the connections can cause problems.
  3. You might be right iblast, I had trouble starting her just now, took me about 3-5 mins instead of the usual 2-3 seconds. Once started I left her idling for about 10 minutes while I removed the heated grips. I checked the battery connections and they look fine, no corrosion etc. Now that she's warm she starts easily enough. All this started after the battery going flat the other day so not sure what's going on, everything was fine before then.
    If she starts easily enough tonight great if not that slightly overdue service will be booked asap.
  4. Some chargers won't deal with a completely flat battery, so that would be my first thought. I've never had anything fancy in the way of a charger, just a cheapo car job that gets use as a 12+V power source on occasion, but it's not fussy about what you hook it to and will always stuff juice into a battery. Haven't blown or burned one yet.

    Bump starting success depends on the individual model of bike. There are permanent magnet alternators, which will put out some volts when turned, regardless of the state of the battery, and there are a type (can't remember the term) that rely on the battery to excite the field coils. These won't work with a completely flat battery. There are workarounds (like jump starting, or connecting a torch battery into the field circuit) but they are a pain if you're stuck without outside help.

    Then, when you do get the engine running, the flat battery can be so hungry for current that the ignition system is starved and the bike won't run properly. This is particularly the case in a world of hard-wired headlamps, which are big current draws in themselves. Again, it depends on how big and healthy your charging system is and how sensitive the ignition system is to input voltage and available amps.
  5. Pat's not wrong.

    To add to that once completely flat sometimes batteries are just stuffed. i.e they will charge but wont hold it for very long. So this could explain your symptoms.

    You really need to put a multi-meter across your battery.
  6. Thanks guys your input is most welcomed.
    PatB from your post that sounds exactly like the problem I had. I do have another cheapo charger but was reluctant to use it as I thought it might do damage to the battery as the salesman told me when I bought it it's for acid unsealed batterys not sealed batterys which my bike is.
    Iblast the battery this morning had a good charge in it, it was just that the bike wasn't starting easily.
    I'll try again tonight when she's cold and see how good the battery is and how easily the bike starts.
    Thanks again guys.
    I'm hopping those cheapo grips don't become expensive grips.
  7. I've used my old buzz box on at least one sealed gel-cell without apparent ill effects, so I wouldn't worry too much. I'd have a look every few minutes for the first hour or two, just to make sure that the battery wasn't inflating or becoming too hot to touch, but I wouldn't actually expect any problems.

    It's worth remembering that most bike charging systems are still quite crude and will whack a big current through a low battery. At least as much, and maybe even more, than even a primitive old charger like mine. All these current limited/voltage controlled/gentle on your hands trickle chargers are a relatively new phenomenon. Once upon a not so long ago, the cheaparse car charger was all there was and you just had to remember to keep an eye on things and not leave a battery on charge for more than a few hours. Regardless of the manufacturers' puffery, lead-acid batteries have not changed significantly in the last 25 years. Nor have the charging systems on most bikes.

    My batteries seem to last quite well.
  8. Looks like everything is fine the bike has been sitting 24hrs and started straight away.
    I now know my trickle charger wont charge a completely dead battery and my bike can't be bump/push started with a dead battery.
    Not being able to push start a bike, who would have thought!
  9. If you're ever stuck, try taking the headlamp fuse out and then bumping it. The reduced load on the electrical system can make all the difference.
  10. Now that is good to know, thanks a heap.
  11. And don't try to start it straight away. Give the battery a chance to recover a touch. Left the lights on in the car in town once, came back, flat battery, wouldn't start. Ran around trying to find a jump starter without luck, came back later and the battery voltage must have recovered enough to get her going
  12. It's the main reason I don't like hard-wired headlamps.

    Don't forget to check that the H/L fuse doesn't also feed the ignition :D. If it does, pull the connector on the back of the H/L globe instead.
  13. Thought Id add my own question on to the end of this thread, hope you dont mind :)

    I havent had much luck in getting out on the bike since I got it. But in the last couple of weeks, every time I go out to have a ride, the battery is dead.

    Its only about 2 months old, a GS500F, but I dont get to ride it for a couple of weeks, so it could be sitting there for 2 - 3 weeks between rides.

    I jump it from the car, but this is not what i want. I took it for a 20 minute ride today, stopped at someones house, and it wouldnt start. Had to roll it down the hill and jump it that way.
    Stalled about 400m from home, and again, wouldnt start. So it was a really lovely push up hill to the house, during which I dropped it twice.

    One, is it possible to disconnect the battery, or set up a quick disconnect set up that allows me to disconnect without having to undo the battery leads etc?

    two, how bloody far or long do you have to go before your battery will start the bike again? I really wouldnt want to ride into melbourne only to come back from shopping to a bike that wont start, 80km from home.

    three, is it worth getting a battery charger? I see people talk about them on this thread? Do you just set it up after youve finished on the bike for the day?
    Whats the go?

    Sorry if this isnt the palce for this, cheers
  14. your battery might be up the Fubar. Get a new one, or replace the old one if its in warranty. If your Bikes new, I'd call the dealership and say your battery isn't maintaining charge. And if it's a continual problem, I'd get them to check the bike over.
  15. A few possibilities Pebble, as Thera said the battery could be dead, winter is when they tend to go. On the other hand your bike may not be charging correctly due to a faulty charge circuit, regulator is the normal culprit in this case.

    If you have access to a Multimeter once you have the bike started measure across the battery and rev the engine to approximate running revs. You should have about 14 - 15volts across the battery.

    Regarding chargers, a charger is a useful item to have available. A standard small automotive charger will charge it up but should not be left connected for more than a couple of hours. They will overcharge the battery. For long term battery maintenance you can use a trickle charger which is designed to remain connected and always keep the battery at full charge. A trickle charger has more smarts and is generally more expensive.
  16. I'll pick up a trickle charger and see how we go.
  17. When you run a battery flat it never fully recovers, simple lead acid batteries often fitted to bikes are not designed to be deep discharged(run flat)

    The next time you charge it you may get 80% capacity, run it flat again and you mnay get 70% and so on and so on...unti the battery won't take a charge or it will but the next day its flat again.

    If you ride your bike occasionally get yourself a battery tender or similar charger, they have eyelets to go onto the pos and neg terminals of the battery and a discreet plug that you mount to the bike, when you get home from a ride just plug it into the charger and and let the charger look after your battery, not only will you always have a fully charged battery when you do want to ride but it will last a lot longer too. They are available from most bike shops, hardware stores etc.

    Fuel injected bikes can be very finicky with battery voltage, a battery on it's way out can cause some pretty funky problems that can be a bugger to diagnose. Also big V twins are a bugger to push start!
  18. Got myself a trickle charger from Autobarn, and all is well.

    Not too sure what the issue was, but having not one jot of issue.

    Trickle charger is now 1 more thing to add to the list of 'if youre getting a bike, you must also have....'

    Cheers for the help!
  19. A work mate speaks volumes about the benefits of a trickle charger for his bike. It sounds like a great bit of kit for keeping the battery topped up or you can do what I do...and ride the bloody thing.
  20. Maintenance free batteries absolutely detest being run completely flat. You might not be even able to charge them up because they can go open circuit.

    Everything you every wanted to know is here: http://www.batterystuff.com/tutorial_battery.html