DIY - Integrated Jumper Cables

[NathanF]

While installing my battery tender plug, it occurred to me what a pain it was to get to the battery. Thinking it would not be fun to be in the middle of nowhere with the sun setting and a dead battery, I decided to make some integrated jumper cables. Here's a description of the setup:

Battery:
Negative - 6ft or so of 10 gauge stranded wire from negative battery terminal to alligator clip. The wire is coiled up and tucked in the rear compartment.

Positive - 2ft or so of 10 gauge stranded from positive battery terminal to butt connector. Separate, normally disconnected 6ft alligator clipped wire with one soldered end that slips tightly into the butt connector while jumping. This is coiled up and also tucked in the rear compartment.

Misc notes:

All connections are crimped AND soldered so they shouldn't pull out by accident.

The butt connector on the positive lead has the metal recessed in plastic so it cannot touch anything by accident. But just to be sure, I also encased the entire positive lead in vinyl tubing I had lying around, and have a plug to seal it when not in use. (Plug not pictured below) This should make it more or less impossible for a fray or short to occur by mistake, either by rubbing or something metal falling into the connector while touching ground.

Safety stuff:

The positive lead is not fused, which creates a possibility for a fire starting short. This is why I'm using thick wire, encased in tubing, just to make sure there is no possibility of accidental short. Still, you might not want to do this mod.

10 gauge wire is NOT rated to carry the kind of starting current seen with our motorcycles. However, I jumped both my Ninja from a Honda Rebel and vice versa without issue. During and right after the jump, my Fluke infrared thermometer showed zero increase in temperature on any of the connectors, battery posts, or wire. Nevertheless, the wire is not rated for this, and you proceed at your own risk.

Do not use this setup to jump a larger bike, or something even more crazy like a car.

Do not leave the jumper connected more than a few seconds for the initial jump.

Do not use to jump a bike that has other problems starting. Running the starter motor off of these jumpers for more than the 1-2 seconds it takes to start a healthy bike could easily result in fire.

Pic of the finished product:

[Snake]

Great DIY! I have often wondered what I would do if my battery whent dead and I needed a jump. Jumper cables for cars are just way too big and a PIA to get on the tiny battery terminals. Push starting the bike is also a PIA.

[Alex]

/linked from main DIY thread

[headshrink]

Yes!

Just a reminder to those that may not know... you will want to turn the car/truck lights ON when you do this.

[setasai]

Nice. After getting the battery tender, I wired it so that I can charge the battery without removing the seat. Along with the tender came jumper wires that I connect to the same port that I keep in the rear trunk as well.

[Snake]

Originally Posted by headshrink

Yes!

Just a reminder to those that may not know... you will want to turn the car/truck lights ON when you do this.

Why do you want to turn the cater lights on? Just wondering. I know you don't want to have the cagers engine running but I have never heard of leaving the lights on. Please educate me.

[g21-30]

You should still consider inline fuses (as close to the battery as possible) on both jumper cables. Why you ask? What if you reverse the leads when connecting to the external source?

Since you already have the Battery Tender leads connected, why not use them?

[warlord]

Originally Posted by g21-30

You should still consider inline fuses (as close to the battery as possible) on both jumper cables. Why you ask? What if you reverse the leads when connecting to the external source?

Since you already have the Battery Tender leads connected, why not use them?

QFT... also what about just push starting the thing? I've seen people push start heavier bikes. It seems like it would make a lot more sense then lugging around something you don't need.

[Jinx250]

My only question is why did you need a negative wire? Every bike I've ever jumped I've used the frame as the connection for the neg. Usually the brake pedal. Also, in one of the moto rags a while back, they had a write up on jumping, and said that you shouldn't connect both leads to the battery like you would for a car, but didn't go into detail on why not.

[headshrink]

Originally Posted by Snake

Why do you want to turn the cater lights on? Just wondering. I know you don't want to have the cagers engine running but I have never heard of leaving the lights on. Please educate me.

For basically the same reason you keep the engine off. I don't know how big the risk is, but it is an extra safety measure. I THINK I originally read this in my manual, but I may be wrong about that. Anyways, some old-timers confirmed it, so I know I'm not totally nuts

Oh, forgot to mention I have had the occasion to do this, and it works like a champ.

[Snake]

Thanks for the reply Bob. That does make sense to me now. It reduces the amount of current going to our tiny little battery. Car batteries can put out 800+amps.

[DarC]

+1 for push starting....

[NathanF]

To answer everyone's questions / comments:

Originally Posted by g21-30

You should still consider inline fuses (as close to the battery as possible) on both jumper cables. Why you ask? What if you reverse the leads when connecting to the external source?

Since you already have the Battery Tender leads connected, why not use them?

The SAE automotive connector cable that comes with the battery tender is thin gauge wire (14 or 16 I think) and has an inline 7.5 amp fuse. Starting current is way, way more than 7.5 amps and would blow that fuse instantly.

You could cut the fuse out or put a jumper in its place, but again, we're dealing with really thin gauge wire that was never intended to do anything but do a 1.25 amp (at best) charge. Sounds like a fire waiting to happen, at least more so than the beefy 10 gauge wire I have. It's possible it would work fine, but I wanted something more robust and safe.

You make a good point about about reversing the leads. I suppose adding some really high amperage fuse (50 - 100 amps?) would add some safety, but it would also add cost, and could fail during the moment of high starting current even though the wire is safe. I think just being extremely careful should be sufficient.

Originally Posted by Jinx250

My only question is why did you need a negative wire? Every bike I've ever jumped I've used the frame as the connection for the neg. Usually the brake pedal.

Well, clearly a negative wire is needed unless you plan to push the frames of the bikes up against each other.

But you were probably asking why do a permanent lead right to the negative, rather than just a length of wire with alligator clips on both ends. Well, the answer is that either way works. It's just that I was already there running the positive leads, and it's only like 1ft, so it just made sense to connect straight to the battery. No worries about having to find a good connection point, or get a bad connection due to oxidation or rust.

Originally Posted by Jinx250

Also, in one of the moto rags a while back, they had a write up on jumping, and said that you shouldn't connect both leads to the battery like you would for a car, but didn't go into detail on why not.

The only reason they say not to connect both leads to a battery when jumping is the risk of gas from a non-sealed battery igniting if you spark right next to the battery posts. Because this is a permanent connection, and you're nowhere near the battery, that piece of wisdom does not apply here. It would technically apply to the other bike you are jumping to or from though.

Originally Posted by warlord

QFT... also what about just push starting the thing? I've seen people push start heavier bikes. It seems like it would make a lot more sense then lugging around something you don't need.

Push starting is great when you're on a hill, or even nice flat pavement. But when you're a few miles up a bad gravel road for a break stop and it doesn't start, I'd prefer to have jumper cables. Or if you've ridden 300 miles, are exhausted, and likely to drop your bike trying to push start.

If you don't do that sort of thing, or don't go far from home, it may not be worth taking up the space. It's really minimal though, so for me I'm very glad I have it.

Originally Posted by Snake

Thanks for the reply Bob. That does make sense to me now. It reduces the amount of current going to our tiny little battery. Car batteries can put out 800+amps.

I'm a little bit dubious about the benefits of turning the lights and such on. That sounds like one of those car/motorcycle myths that makes sense (an argument from inference,) but isn't actually grounded in evidence or reality (an argument from empiricism.) There is a lot of stuff out there that sounds logical but really isn't necessary, or makes such a small difference to be negligible. I could be wrong though!

Not starting the engine is definitely good idea though, since the charging current of some cars' alternators is much higher than what our motorcycles and their batteries expect to see.