Jumper Cable Attachment

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ian

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I am using the unswitched, fused, directly wired to the battery outlet for my MP3 and GPS for the Battery Tender. I wonder if this would work to jump the bike using another MC. Battery is in a PITA placd to get to in emergency. I have a 10 amp fuse in line. TIA Ian, Iowa

 
The amperage draw while boosting the bike would toast your 10 amp fuse (if your lucky, and unless your running some serious wire, could melt the insulation on the wire)

 
So, if you fused it differently for charging and had wire of at least the gague as coming out of a charger??

 
The amperage draw while boosting the bike would toast your 10 amp fuse (if your lucky, and unless your running some serious wire, could melt the insulation on the wire)
What he said. The whole electrical system is designed with starting in mind. Look at the battery cables sometime. That is the minimum gauge needed for starting duty. Anything less severely lessens the current available for duty. Rule of thumb when thinking electricity-you can never have too heavy a wire.

 
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So, if you fused it differently for charging and had wire of at least the gague as coming out of a charger??
...,er, I meant coming off the batter to the starter, not coming off a charger (which needs significantly less than to start the bike)

 
The only way this would work is to run wires from the accessory socket to your battery approximately the gauge of the wire that goes from your starter relay to the starter - BIG - and an appropriate fusible link-type fuse. And you still might have issues with the accessory socket not handling the current. Starter motor current is something like 100 amps, over 10x what a typical accessory socket circuit is deisgned to handle.

A few years back, BMW started putting a jumper post down near the starter on their R-bikes with a plastic cover over it. If you want an external jump point, doing something like this might be the way to go. It would be fairly easy to wire such a post into one of the panels near the battery. You'd only need to do it for the positive lead - you could attach jumpers to a frame spot for the negative connection.

Given that getting to the battery is not an onerous job (with practice, it now takes me a minute or two), I'd just leave well enough alone. And perhaps put in a new battery every few years on schedule rather than waiting for the inevitable click-click at the worst possible time.

- Mark

 
What Radman said, only I would add to go up a size or two on the wire depending on the length of the jumper cables. The ones on the bike are sized based on the number of amps they carry over the distance. Jumper cables will probably be longer. I would stay away from the socket as I think it would add in resistance that would drop more voltage due to the higher amps carried under starting conditions. Voltage drop is proportional to amps times distance. Good luck.

 
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... Rule of thumb when thinking electricity-you can never have too heavy a wire.
That's a bit over the top. Bigger doesn't mean better unless the application calls for it.

Which, of course, in this case, it does. Like everyone said. The starter draws serious current. A 10 A fuse would pop like an old flashbulb. A larger fuse would only push the weak link to the wiring. Larger wiring would only push the weak link to the connector. The Powerlet plug and socket can only handle up to 20A. And 20A is nowhere near the starter current.

What you CAN do is use the outlet to pass low current to CHARGE a battery. If I were looking for a solution, I would put plug it in to a charger (that 10A still may not be enough), wait a little while, unplug it, then try to start it. Don't try to start it with the plug plugged in!

-BD

 
I had a BMW R1200C before I got my FJR

the battery was located under the tank, I had to pull the tank to do anything to the battery. I got a 50A 2 prong plug and cut a set of jumper cables and inserted one half of the plug at the far end of the clips, on the bike I ran about a 1 1/2' with the other end of the plug.

now if I had to jumper the bike I would just pull the side cover and plug in my jumper cables.

I have move this over to the FJR so I don't need to take anything apart, just pull the cable out of the bag and plug them in.

 
Dog, why quote and piss on my post, then agree with my conclusions? You think I'm advocating using 00 gauge cable for speaker wiring or something? Sheesh....

 
If you want to jump the bike with a quick connect use a AMP (brand name) connector rated for 100A or more, wire it to the battery with HEAVY cable.

They use these connectors to recharge fork lifts and what not, they are polarity protected (can't plug them in backwards)

Of course you then need to carry your own jumper cables, was a great idea on the race bike with an undersized 5 A-h battery from a little scooter.

 
I keep a set of cables under the seat of my FJR. One end has battery clips and the other end has a cigarette lighter plug.

The intent of this cable is simple.... It's a way to recharge the battery from an alternate source without exceeding the capabilities of the cables, fuses, or cigarette lighter plug.

Plug it in, wait a while, remove cable, try to start.

On the other hand, just bump start the thing and get on down the road.

 
Thanks guys. Aah for the old bump start days. I may just haul my small battery tender along. Seems the older I get, the more my tools outweight my travel clothes. Ian, Iowa

 
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