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Jump starting a car from a bike

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by huplescat, Mar 1, 2010.

  1. I've searched Google, I've searched Netrider, but there seems to be no mention of this anywhere. Yes you can jump start a bike from a car, but it seems no-one else is batty enough to want to do it the other way around.

    I'm guessing the answer is "not unless you want to blow up the bike", but I have a dead car sitting in the driveway collecting possum poo that needs some battery love and it'd be a lot easier if I don't have to call in help from someone else to jump it.

    So any ideas?

  2. your not gonna get enough power from a bike battery.

    you'll surley just **** it and have 2 non working vehicles.
  3. where do you live mate?
  4. +1

    If it's near where I ride I could drop in a charger for to you to borrow overnight if it's just a case of a flat battery.

    (Otherwise they are pretty cheap from a discount auto parts store.)
  5. Haha yeah, that's what I figured :) Oh well, worth asking anyway. I don't want to do anything to risk the bike as it's my only transport right now, as well as my beautiful darling precious baby.

    Not far from you, Balwyn. I have a mate coming over on Thursday night and can probably pinch some juice from him though. I was just thinking of trying to get it started sooner so it can be limped to a mechanic (they offer a free car wash with every service so I don't have to deal with the possum poo). Not in any real hurry though, it smells like dog and isn't fun to drive.

    Thanks for the offers of help though :) Much appreciated.
  6. I did it a roundabout way. My housemate's car had broken down. Not wanting to risk the Tiger's electrics, I threw my superdooper multi-charger into my topbox and gave his battery a 5 minute charging using the Tiger's battery as a power source (I had the Tiger's engine running to keep that charged up). That meant I could control the charging rate, etc, etc. Worked a charm.

    Not sure if you can do it directly tho.

    Useless trivia: The reason jumpstarting works is because when you charge a dead battery, all the charge clumps around the electrodes of the battery. So while most of the battery is completely flat, the area immediately around the electrodes is fully charged and so you can start the car.

    (Same reason for why if you crank and crank and crank the engine til it goes flat... you end up flattening the area around the electrodes. If you wait a few minutes the charge equalises across the battery, recharging the area around the electrodes, and you can try to start the engine again)
  7. piffle

    ever opened up one of those portable Jump start kit's? you should take a look.

    The battery will do it fine, just ensure you follow the same rules you would always follow when jump starting, that is assuming of course you have
    a.) Good leads
    b.) Preferably ones suitable for use on EFI engines.
    c.) Common sense.
    d.) an understanding of how to jump start in the first place
    e.) how dead the battery is
    f.) that the battery in the bike can produce enough CCA to turn over the car.
  8. If the car battery has been dead flat for long it will probably be heavily sulphated up (and possibly terminally cactus). If the car not in great nick it may also take a bit more cranking to stir it into life so while in theory a decent bike battery in good nick could start a car (small one - little hope on a V8) it will struggle and you risk flattening the bike one.
    Best bet is to take up the offer of a charger at high current for a few hours to help break up the sulphation then leave it on low overnight. If that doesnt work nothing would have, least of all a bike battery.
  9. I'm actually just assuming it's flat as it hasn't been started in 3 or 4 months :) The car isn't too stuffed, it just overheats very easily and I'm thinking it's a thermostat or sensor issue that I could probably fix myself but can't be arsed so it's going to the mechanic. Well that and it's a year over the last service date...

    Although it's a little car (94 Ford Laser) it has an auto choke and can be a little temperamental when it's cold so probably will take the bike battery down with it.

    So yeah I'm not going to risk the bike and just get my mate to lend a hand tomorrow night. He probably has a battery charger too so I might get him to bring it along just in case it's needed.

    Thanks for the info though, I've learned a few things from this thread :)
  10. Take the battery out and drop it into a battery world shop, they will test and charge it up for you if its not stuffed.
    Whoops should have checked the last entry date, So is it working OK?