Topic: jump from a car battery

[puffpd]

Hi,

I wanted to find out ifi can jump start my bike from a car battery?? hooking my bike with a car?

I wasnt sure if i can do this

[750goes]

as long as your car has a 12V system and the bike battery is not completely dead it should be ok..

if bike battery is dead as a dodo........would not recommend as the bike battery could explode....

[rab1dwolf]

I was told that starting the car might cause havoc (fry coils etc) with the electrics on the bike as the alternator does something or other.


anyone else hear this or anyone know one way or the other?  Didnt make much sense to me

[TwoTired]

Yes, it can be done.  Be absolutely certain of polarity Plus to Plus, Minus to minus.  The bike's charging system has no protection circuitry.  Applying wrong polarity can destroy rectifier diodes and melt wiring.

Batteries give off hydrogen gas.  Sparking the posts during connection can ignite this gas. Bang.  

Connect the power source last.

I was told that starting the car might cause havoc (fry coils etc) with the electrics on the bike as the alternator does something or other.

The starter motor on a car can produce huge current spikes.  These have the potential for damaging the rectifier diodes in the bikes charging system.  However, the car's battery and the bike's battery really should damp these out before they can travel to the diodes.  Perhaps if you connected jumper clamps to terminals closer to the starter instead of at the battery itself, you might get these spikes into the bike's system.  The car's alternator is no issue.  It's power is but a fraction of what's in a fully charged car battery.

Cheers,

[oldbiker]

I keep a spare fully charged car battery in my workshop and if the need arises use that to start the bike or the car. Never had any problems. Naturally, if you take such precautions, the need never arises.

[cb650]

Give the starter a rest every so often.   The car battery will last longer than the bike starter and might burn it up.   I dont have the car running either.




            Terry

[cadler]

Yes make sure the car is not running and you should have no problems

[BobbyR]

I do this all of the time and it is not a issue. This is especially true if the car is not running. Think of it this way, the starter motor will draw or pull what it needs from the battery. It is not a "push" like you will find using a car charger with a "start"  feature. The biggest risk you will run is that the car battery will allow you to crank the Bike starter longer than a Bike battery can which can overheat the starter. 15 seconds is the total max you should crank a starter. Then give it a rest.

[k4rider]

Don't start the car at all.  Try the kick starter first!

[dusterdude]

tt,you`re lookin better my man.

[csendker]

I just did it 2 hours ago with a spare deep cell battery from my camper.  No problems.

[n9viw]

I smoked the charging circuit on my bike by starting from a running car (my wife's Jeep CJ-7)- it was a bloody good thing the battery was as new as it was, I just barely made it home. Had to pitch the battery and rectifier, and had to replace about half the wiring. Thankfully, the rect going poof saved the alternator.
I've since started the bike with a car batt, but ALWAYS from a non-running car. I let the two batteries sit connected together for about 5 minutes to poke a bit of charge into the bike batt, then start the bike and let it run on both batts for a bit. Always get the bike batt on a desulfating charger as soon as possible.

[swamprat]

Have to agree with most of the posts.  I had a Suzuki Cavalcade that was jump started off the car battery more that the bike battery.  Always with the car engiine OFF.  Just my 2 cents worth.

[Nobby C]

I have often started various bikes from car batteries.    The trick to not frying the bikes electrics is to connect the negative terminal of the car battery to a good earth on the bike as far from the bikes battery as you can.  I usually use the rear shocks mounting bolts. This allows the frame to "absorb" a lot of the over current. The +ve terminals are connected together as normal. I have never had any problems this way, even with the car engine running.     BTW this is also the best method to use when jump starting cars with all thier electronic circuitry.    Nobby

[cbjunkie]

TT representing the HandyMan's Fractal...

[puffpd]

thanks for the info guys

[rab1dwolf]

how would you know if you toasted the starter?

I assume it would sound different when trying to crank yes?

[cb650]

Or it dont work at all.



            Terry