Jumpstart terminals.

[Pete]

Fox can't because of how he needs to access his battery.
Most owners manuals tell you not to jump your bike. Using "normal" jumper cables can allow to much current flow and might fry your electrical system. A homemade set of 10-12 ga jumpers will limit current to your bike.

Wouldn't they just overheat and melt? A wire isn't going to limit current flow....well without burning in half and stopping it.

 

[itsbob]

Fox can't because of how he needs to access his battery.
Most owners manuals tell you not to jump your bike. Using "normal" jumper cables can allow to much current flow and might fry your electrical system. A homemade set of 10-12 ga jumpers will limit current to your bike.

Why would current be a problem when everyone involved is 12v? I thought this was a problem when bikes had 6v batteries, and if you jumped from a car you "overspun" your starter. (solution there was not to have the car running at the time, and you could still safely start off of a car battery).
I'm honestly asking, not trying to argue..

 

[desertrat]

Why would current be a problem when everyone involved is 12v? I thought this was a problem when bikes had 6v batteries, and if you jumped from a car you "overspun" your starter. (solution there was not to have the car running at the time, and you could still safely start off of a car battery).

I remember being really impressed with how fast a 12v system got a 6v cigarette lighter heated up.

 

[Pete]

I remember being really impressed with how fast a 12v system got a 6v cigarette lighter heated up.

A 12V battery installed on a 6 volt system on a 1949 vintage fire truck in the Avera Georgia volunteer FD will also blow all the lightbulbs on the truck, when you flip them on to check it. And there are a lot of lightbulbs to change.

 

[Pete]

Why would current be a problem when everyone involved is 12v? I thought this was a problem when bikes had 6v batteries, and if you jumped from a car you "overspun" your starter. (solution there was not to have the car running at the time, and you could still safely start off of a car battery).
I'm honestly asking, not trying to argue..

Current and voltage are proportional. 6V and 12V do not mix A car not running still has the same voltage as a car running does....well maybe the car running will be pushing 2 extra volts to charge the battery.

Running 12V through a system really can mess up stators, rotors, windings, lighbulbs, coils, condensers, points and anything else electrical. Very bad juju.

Never ever use one to boost the other.

 

[aps45819]

Wouldn't they just overheat and melt? A wire isn't going to limit current flow....well without burning in half and stopping it.

They do get a little warm But that's their resisting carrying the current

Most jumper cables are 0 - 000 ga. They can carry a LOT more current than a set of 10 ga wires.

If your battery is dead because something is shorted to ground vs a bad charging system, limiting the current available is good unless you want to do some welding.

 

[itsbob]

Current and voltage are proportional. 6V and 12V do not mix A car not running still has the same voltage as a car running does....well maybe the car running will be pushing 2 extra volts to charge the battery.

Running 12V through a system really can mess up stators, rotors, windings, lighbulbs, coils, condensers, points and anything else electrical. Very bad juju.

Never ever use one to boost the other.

Maybe I don't remember right, and just assumed.. but I thought my 82 Silver Wing had a 6V battery. When I tried to jump it (it HATED any weather below about 50) it would 'sound' normal with the car off. The car running it sounded like the starter could launch the bike into orbit.

Now with the current bike (12V) I've had to jump it using BG's truck. Running or not, the starter reacted the same. When it wasn't running it didn't seem to be getting enough juice from her system through the cables and into the bikes system, I had to jump it with her truck running. I HOPE I didn't do any damage *fingers crossed*, but I haven't had to jump it since.

 

[Pete]

They do get a little warm But that's their resisting carrying the current

Most jumper cables are 0 - 000 ga. They can carry a LOT more current than a set of 10 ga wires.

If your battery is dead because something is shorted to ground vs a bad charging system, limiting the current available is good unless you want to do some welding.

But what I am saying is the "wire" has little to no resistance at all. It will allow all the current available to pass until it melts in two. A bigger wire with more mass can carry more current before it heats up to the point it melts.

The only way a smaller cable limits current is by burning in two thus stopping all current flow altogether.

 

[itsbob]

Next question is, and I don't want to find out with a dead bike.. Can you bumpstart a bike with EFI??

 

[Pete]

Maybe I don't remember right, and just assumed.. but I thought my 82 Silver Wing had a 6V battery. When I tried to jump it (it HATED any weather below about 50) it would 'sound' normal with the car off. The car running it sounded like the starter could launch the bike into orbit.

Now with the current bike (12V) I've had to jump it using BG's truck. Running or not, the starter reacted the same. When it wasn't running it didn't seem to be getting enough juice from her system through the cables and into the bikes system, I had to jump it with her truck running. I HOPE I didn't do any damage *fingers crossed*, but I haven't had to jump it since.

I would say you were lucky you didn't have to buy new starters. 6V and 12V don't mix well. 12V to 12V is fine. Your car battery and 12V automotive system provides many more amps because it has to provide more power for stuff. A bike is considerably less. You can jump it and the bike will draw whatever current it needs, should be little problem unless you leave it hooked up a long time. Remember you are in effect "charging" your battery and powering your bike with an automotive charging system designed to provide much more amperage. Like filling a shot glass with a fire hose. You could damage a battery by over/too rapidly charging it, or overloading the smaller cables running off the battery throughout the bike.

 

[Pete]

Next question is, and I don't want to find out with a dead bike.. Can you bumpstart a bike with EFI??

I have when rolling, shut the bike off, cycled the engine switch and poped the clutch and started it, sure. I have an EFI light, it is orange until the EFI pump reaches pressure, then it goes out and it is OK.

I don't think you can if the battery is totally dead. The pump feeding the throttle body would have to function at least to get pressure.

 

[itsbob]

I have when rolling, shut the bike off, cycled the engine switch and poped the clutch and started it, sure. I have an EFI light, it is orange until the EFI pump reaches pressure, then it goes out and it is OK.

I don't think you can if the battery is totally dead. The pump feeding the throttle body would have to function at least to get pressure.

That's what I'm thinking.. I've done the same with a good battery, pulled out stalled, and just let the clutch back out, I've never attempted to bump start with a dead battery.

 

[aps45819]

You'd at least have to roll far (and fast) enough for the alternator to power the efi pump
...and you'd have to be in gear while you do it.

 

[Roughidle]

I created a set of bike jumper cables using plugs at one end that match my battery tender cable ends. The other ends have clamp ends from a standard size battery charger. Just a lil' food for thought as everyone's needs/bike designs may differ.

 

[Dougstermd]

They do get a little warm But that's their resisting carrying the current

Most jumper cables are 0 - 000 ga. They can carry a LOT more current than a set of 10 ga wires.

If your battery is dead because something is shorted to ground vs a bad charging system, limiting the current available is good unless you want to do some welding.

you still will not limit the current until the wires melt

 

[aps45819]

you still will not limit the current until the wires melt

The wires heat up because of their resistance to the current flow

 

[aps45819]

I don't think you can if the battery is totally dead. The pump feeding the throttle body would have to function at least to get pressure.

Just sent this to the Cycle World service colum

Is it possible to push start a bike with a dead battery if it has EFI?
Some of my friends say no but my theory is it's possible if you developed enough speed to allow the bike to go through the start up sequence.

 

[Pete]

Just sent this to the Cycle World service colum

In theory you may be correct but my fuel pump takes aproximately 4 seconds to build up pressure to exstinguish the light, and that is with a full charge on the battery. So you would have to push the bike fast enough to provide 12V off the alternator for 5 seconds before you even tried to light it off.

In other words you would have to push the bike at least 25 MPH with the clutch out, transmission spinning the motor, thus spinning the alternator, for 5+ seconds. Can you do that?

 

[Dougstermd]

The wires heat up because of their resistance to the current flow

and as they heat up more current can flow causeing more heat causing more current to flow...


eventually the wire will melt. That is the how a fuse works.


you will only draw what current the bike requires across the cable. If you have a dead short the smaller cable will get hot quicker

 

[Pete]

The wires heat up because of their resistance to the current flow

Actually you are partially right. If you take two 3 foot pieces of wire, one 10ga. and one 00ga and check the resistance down to the .000 (micro) ohms on each you will read almost identical readings because wire has very little internal resistance. The real answer is "hole flow" in that the larger wire, with more mass, has more current carrying capability because it has more atoms for the electrons to hop from/to. The smaller wire, having less mass and atoms, will overload and melt because of the flow of electrons. Read: the bigger the wire the less the resistance to electron flow.
Electron flow through the atoms that make up the wire cause heat. In a large wire there are more atoms for the electrons to move through spreading the load out evenly over the conductor using up to 50% (typical rating approved) of the available holes or valences, in the small wire nearly every hole/valence will be used causing extreme heat due to the increased resistance caused by smaller wire.

In the end, by using a smaller wire you limit the amps traveling very very little, but you do cause a significant fire hazard because of the overloaded wire.