Using jumpleads on a motorbike

383Ger

Hi,
Having run the power down on my bike battery yesterday I want to hook it up to a car battery via jump leads later this eve to recharge. What is the procedure here so I don't ruin my battery? I vaguely recall someone told me before that unlike two cars, that a car to a bike could only be connected for a short while. Any help appreciated, thanks.

KamiKazi

I've jumpstarted my bike before, no hassle.

Positive lead to the positive terminal on the battery, negative lead onto the engine somewhere - anywhere it can get an earth.

I wouldn't leave it charging from a car though, get the bike started and go for a nice long spin to charge the battery.

Cuddlesworth

Different amperage on the batteries, connect it up but don't start the car. You should be able to start the bike pretty much straight away.

KamiKazi

Cuddlesworth wrote: »

Different amperage on the batteries, connect it up but don't start the car. You should be able to start the bike pretty much straight away.

Didn't do any harm to my bike, car wasn't revving mind, just idling.

paddy147

Why dont you just bump start the bike by pushing it in 2nd gear and then letting out the clutch and pressing the start button to fire her up,and then go out and ride it and that will recharge the battery as you are riding the bike.

That would be the safer and more practical thing to do.;)

KamiKazi

paddy147 wrote: »

Why dont you just bump start the bike by pushing it in 2nd gear and then letting out the clutch and pressing the start button to fire her up,and then go out and ride it and that will recharge the battery as you are riding the bike.

That would be the safer and more practical thing to do.;)

Have you ever tried push starting a heavy bike with a dead battery?

I have and it SUCKS

extra-ordinary_

KamiKazi wrote: »

Have you ever tried push starting a heavy bike with a dead battery?

I have and it SUCKS

It does! I had a CBX 750 back in the mid-90's that I used to do couriering on. It had a snapped alternator chain for a few months. Had to bum start it many times everyday. The things you do when you're young and mad!:D

Cuddlesworth

KamiKazi wrote: »

Didn't do any harm to my bike, car wasn't revving mind, just idling.

Depends on the bike and the battery and the car. But the fact is the charging unit of most cars will force far more amperage into the bikes electrical system then it can handle, namely the charging unit which is not fused between the battery. I don't know exactly what this will do(as I have never taken apart a bikes electrical system), but at a guess I would say you would have the charging unit on the bike fry and the most of the fuses blow.

KamiKazi

Cuddlesworth wrote: »

Depends on the bike and the battery and the car. But the fact is the charging unit of most cars will force far more amperage into the bikes electrical system then it can handle, namely the charging unit which is not fused between the battery. I don't know exactly what this will do(as I have never taken apart a bikes electrical system), but at a guess I would say you would have the charging unit on the bike fry and the most of the fuses blow.

That's why I said the car was just idling, and take the bike off the leads as soon as it starts

Cuddlesworth

KamiKazi wrote: »

That's why I said the car was just idling, and take the bike off the leads as soon as it starts

That might not work on some cars, as the power draw of both the bike and the engine could kick the charging unit into overdrive. Considering the fact that its should not be necessary to turn the car on in the first place, its not a good idea to risk it.

You can see the logic there, yes?

KTRIC

In all the new bikes I've had it said no push starting in the owners manual.

Hotblack Desiato

KTRIC wrote: »

In all the new bikes I've had it said no push starting in the owners manual.

Says that on cars too. It's to stop unburnt fuel entering the catalytic converter - standard bike exhausts have small catalysts now. As we've no emission testing here, and a lot of people remove the standard pipes anyway, it's nothing to worry about.

On a car though you could fail the NCT due to a damaged catalyst and then have a €1000+ repair bill

Hotblack Desiato

Cuddlesworth wrote: »

Depends on the bike and the battery and the car. But the fact is the charging unit of most cars will force far more amperage into the bikes electrical system then it can handle, namely the charging unit which is not fused between the battery. I don't know exactly what this will do(as I have never taken apart a bikes electrical system), but at a guess I would say you would have the charging unit on the bike fry and the most of the fuses blow.

Sorry but that's wrong

Provided the car is 12V then there isn't a problem. (a 24V truck or bus would be another story!) The car's regulator will limit its alternator to 14.4 - 14.5 volts, no matter what the car engine's revs are - that's the same maximum voltage the bike's alternator puts out. So given that the voltage is the same and the load (resistance of bike battery) is the same, the current will be the same as if the bike alternator was doing the charging. Ohm's law.

I once tried to jump start my bike from my wife's previous car - 1.0 Opel Corsa - the car battery would just about turn the bike over but not start it. So I disconnected the leads, started the car, let it idle, reconnected the leads and then started the bike with no problems. Odd that a battery which could start a one litre 3-cylinder car could not start a one-litre 3-cylinder bike!

What can cause problems is starting up the car with the jump leads connected to the bike - this can cause large transient currents which could possibly damage electronics on the bike, they should be somewhat protected but why take the risk.

If you are going to start the car, do it before you connect the jump leads. Also do not have the car running faster than idle when connecting or disconnecting the leads, this minimises the current flowing so you don't get huge sparks.

Thinkingaboutit

Not the slightest problem.

Maxav

ninja900 wrote: »

Sorry but that's wrong

Provided the car is 12V then there isn't a problem. (a 24V truck or bus would be another story!) The car's regulator will limit its alternator to 14.4 - 14.5 volts, no matter what the car engine's revs are - that's the same maximum voltage the bike's alternator puts out. So given that the voltage is the same and the load (resistance of bike battery) is the same, the current will be the same as if the bike alternator was doing the charging. Ohm's law.

I once tried to jump start my bike from my wife's previous car - 1.0 Opel Corsa - the car battery would just about turn the bike over but not start it. So I disconnected the leads, started the car, let it idle, reconnected the leads and then started the bike with no problems. Odd that a battery which could start a one litre 3-cylinder car could not start a one-litre 3-cylinder bike!

What can cause problems is starting up the car with the jump leads connected to the bike - this can cause large transient currents which could possibly damage electronics on the bike, they should be somewhat protected but why take the risk.

If you are going to start the car, do it before you connect the jump leads. Also do not have the car running faster than idle when connecting or disconnecting the leads, this minimises the current flowing so you don't get huge sparks.

+1 I,m a spark and this is a PERFECT explanation!! Well done that man!!:)

gsxr1

I have 2 linked 750amp batteries in my Van.

Jumped modern sports bike of it a few times. (EDIT without starting the van)


You will be grand.

keithm1

it is possible to fry stuff in the bike caused by a spike from the cars altenator
if you can jump the bike without starting the car do so

hedgeh0g

ninja900 wrote: »

Sorry but that's wrong

Provided the car is 12V then there isn't a problem. (a 24V truck or bus would be another story!) The car's regulator will limit its alternator to 14.4 - 14.5 volts, no matter what the car engine's revs are - that's the same maximum voltage the bike's alternator puts out. So given that the voltage is the same and the load (resistance of bike battery) is the same, the current will be the same as if the bike alternator was doing the charging. Ohm's law.

I once tried to jump start my bike from my wife's previous car - 1.0 Opel Corsa - the car battery would just about turn the bike over but not start it. So I disconnected the leads, started the car, let it idle, reconnected the leads and then started the bike with no problems. Odd that a battery which could start a one litre 3-cylinder car could not start a one-litre 3-cylinder bike!


What can cause problems is starting up the car with the jump leads connected to the bike - this can cause large transient currents which could possibly damage electronics on the bike, they should be somewhat protected but why take the risk.

If you are going to start the car, do it before you connect the jump leads. Also do not have the car running faster than idle when connecting or disconnecting the leads, this minimises the current flowing so you don't get huge sparks.

"If you are going to start the car, do it before you connect the jump leads."
Is it a good idea for cars to car jump starting as well?

bbbbb

keithm1 wrote: »

it is possible to fry stuff in the bike caused by a spike from the cars altenator
if you can jump the bike without starting the car do so

Yes, this happened me. Fried the alarm on the bike jumpstarting it off an idling car. Same might have happened using the battery only, who knows. (note I had previously jump started successfully without damaging the alarm off the same idling car)

In this scenario, should you disconnect an alarm (or any other extras) if possible, to protect them?