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Greetings -- I am building a jumper cable. I have 12 awg wire an SAE connector that I will connect to 12 awg jumper cables via an SAE pigtail with the correct polarity. I will use a 20A fuse. QUESTION: Can I connect this jumper cable to my PC 8 fuse box or should I connect directly to the battery terminals? Regards, JL
 

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The cables should as short & as thick as possible for the best result.
 

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I recall reading somewhere that motorcycles should not be jump started. Anyone know if this is true?
i was talking with an old biker dude a while back and he said that if you are going to jump a bike it should be from another bike and nothing bigger. im not sure if this is true or not but i had some problems with my 2002 dyna and jumped it a few times and shortly after i was having a terrible charging problems even with a new battery so im not sure if it was the stator going out with it or if it was from improperly jumping it
 

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QUESTION: Can I connect this jumper cable to my PC 8 fuse box or should I connect directly to the battery terminals? Regards said:
I would go direct to the battery unless you do not have that option. I think its advisable to keep the jumper lead as short as possible.

I jumped (with cables) my wife's (new to her) bike from her car tonight. The car has a 12 volt battery as does the bike. The car engine was not running at the time and it started the bike without damage to either vehicle.
 

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I would not run that through your PC8 unless I had some proof that starting the bike draws less than 20A. Of course, blowing a 20A fuse would be a quick way to settle that. Your 12 AWG cable may handle it just fine, but think about the PC board in the PC8 that you're putting that current though.

Houstorm48, the issue with jumping a bike from a (modern) car has to do with differences in how the charging systems work. Bikes have a generator and the output is tied to engine speed. Generally, they output a little low at idle, and use a voltage regulator to "dump" excess voltage as waste heat as the RPMs rise. Cars have an alternator which changes the field current in the armature in order to keep a constant voltage output at varying RPM. If the car is trying to maintain a voltage higher than the bikes voltage regulator wants to maintain you'll get into a do-loop where the bikes voltage regulator is dumping voltage and the car's alternator
is trying to maintain it.. right up to the point where you fry the regulator.

I'm sure there are car/bike combos out there where the car outputs something less that the bikes reg tries to maintain. That's where you get the stories of "I've jumped off a running car before with no issues" when someone dismisses this concern. Since I don't carry a reference of car charging voltages around with me, I stick to the safe bet of jumping off a non-running car.
 

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[QUOTE
Houstorm48, the issue with jumping a bike from a (modern) car has to do with differences in how the charging systems work. Bikes have a generator and the output is tied to engine speed. Generally, they output a little low at idle, and use a voltage regulator to "dump" excess voltage as waste heat as the RPMs rise. Cars have an alternator which changes the field current in the armature in order to keep a constant voltage output at varying RPM. If the car is trying to maintain a voltage higher than the bikes voltage regulator wants to maintain you'll get into a do-loop where the bikes voltage regulator is dumping voltage and the car's alternator
is trying to maintain it.. right up to the point where you fry the regulator.[/QUOTE]

That's an excellent explanation MrF.
 

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Discussion Starter #9
Greetings -- thank you for your very valuable & prompt feedback, including the highly technical stuff. per your recommendations, i will not connect the jumper cables to the PC 8 fuse box. instead, i will run the jumper cables directly to the battery with a 20A inline fuse. I will keep the 12 awg jumper cables short...approximately 8 feet if that sounds reasonable. If i connect the jumper cables to a car battery, the car engine will not be running. I'VE HEARD TELL: connect the jumper cables to a car battery for 5 minutes, disconnect the jumper cables, and then try to start the bike. QUESTION: in this example, will the bike battery get juice from the car battery if the car engine is not running or should the car engine be running? Regards, JL
 

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Hi, guys. I got a set of jumper cables labeled 'Jackrabbit' from Quality chain corp.
the packaging says 10 ga. Comes in a nice zippered pouch.
It's about 10 ft in length and the wire is flexible so it folds up compactly.

Any 12volt battery can be used to jumper to a weak or flat battery. Just don't have the supply battery hooked to a charging system. Leave the car/truck engine off.
I had a car battery in the trunk of my Ural sidecar to replace the under seat battery on the bike.
Yes, your bike charging system can feed a bigger battery. What we have on the bike is limited space and the makers put in the most appropriate battery available to provide starting power..
Don't know you need to have a fuse when feeding a battery in a jumper situation. If your battery has an internal fault it may take more that 20 amps to make the system work. You may have to disconnect the bad battery and just run the bike on the external battery. That's why you do not have the car engine running as mentioned above.
Those handy jumper battery kits can start a bike but using one to continue to keep a bike running can apparently cause the unit to fail. It doesn't like to have the recharge through it's output.
And, yes it's best to have the connections directly on the battery terminals.
 

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Greetings -- thank you for your very valuable & prompt feedback, including the highly technical stuff. per your recommendations, i will not connect the jumper cables to the PC 8 fuse box. instead, i will run the jumper cables directly to the battery with a 20A inline fuse. I will keep the 12 awg jumper cables short...approximately 8 feet if that sounds reasonable. If i connect the jumper cables to a car battery, the car engine will not be running. I'VE HEARD TELL: connect the jumper cables to a car battery for 5 minutes, disconnect the jumper cables, and then try to start the bike. QUESTION: in this example, will the bike battery get juice from the car battery if the car engine is not running or should the car engine be running? Regards, JL
I doubt you'll get much charging just connecting the batteries without the engine running - charging voltage needs to be a couple volts higher than the battery you're charging. I don't think you can hurt anything by connecting a running car to your bike IF the key on the bike is off. But why not just connect with the car engine off and start it up, no waiting.
 

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It all depends on why the battery is flat.

If the battery is flat because it has had a load on it just take your time, EG: hook up the cables and wait a bit, if jumping off a car you should not need to start the car but if you do start the donor vehicle just wait a bit before trying to start the flat one.

If the battery is flat because it is stuffed you are taking a risk every time you jump start it.

A good battery works like a big sponge and will absorb any power spikes, a battery with a bad cell can not absorb spikes and can pass the spikes onto the bikes electrical system and that is a risky thing to do.

By leaving your jumper cables attached all the time you are reducing the risk of a spark and that is a great safety feature.

I should add even ridding your bike with a stuffed battery it is putting your electrical system at risk of a spike.
(when the LI battery in my MT09 failed the bike could not be ridden as the relays were snapping in and out)
 

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I doubt you'll get much charging just connecting the batteries without the engine running - charging voltage needs to be a couple volts higher than the battery you're charging. I don't think you can hurt anything by connecting a running car to your bike IF the key on the bike is off. But why not just connect with the car engine off and start it up, no waiting.
There should be no issue with the bike off. A coworker had to do this after he left the ignition on all day and the battery was too low for the bike to even idle on it's own. It was an older Honda that would drain at idle. We charged it with the car running and the bike off for about 10 minutes, then shut the car off and started the bike. It was enough to get him on the highway where he was running fast enough for the bike to charge it.
 
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