Reversed jumper cables

[steve.m]

So this topic is covered in detail on badweb, but figured i'd transplant it here for those of us (me  ) who get in a rush trying to jump our bikes, mix up the jumpers and cook our electronics.

If anyone does this to their Buell, the fix is going to run you 135 bucks at your local harley dealer (115 for a battery, 7 for a new key switch relay, and a buck or so for the replacement fuse...plus tax).  You can save a bit online if you're willing to wait for parts, but i'm not in that patient.

here's the details (post copied from Glukasik on badweb):

Came home from overseas (6 day trip) and no dash lights came on when turned to the on position, and it definetly wouldn't start (05 XB9SX). Tried to jump it from a running car (which I've learned is a no no), while it was dark. Stupid car had a black protector over the positive terminal on the battery, so I tried to jump my bike with the cables backwards. Interesting thing was that everytime I switched the bike to the on position, the fan came on... Not sure if this is some kind of protective thing. I then decided to take my battery home and charge it on a trickle charger. Did so, and took the battery back to the bike. Still nothing, so I broke out my voltmeter, tested, and it was at 12.4. So I started looking at fuses, and found that my 15 amp "Key Switch" fuse was blown. I replaced it, and it blew as soon as I turned the bike to the on position. So I had the bike towed home (Thank you Gieco Road Side Assist) and did some research. I then removed the key switch electric relay (located in the fuse box- there are three of them), put another 15 amp fuse in, reconnected the battery, and turned the bike to the on position, and viola! My lights came back on and the fuse didnt blow! So, I am guessing that all I need to do is replacee the electric relay ($5-$10), and I should be back in the saddle again. I will repost tomorrow, if the dealership has the relay in stock. Hope this post helps someone else.

***********UPDATE*************

I bought the key switch relay (part number 31522-00C) and bike started up like a champ. Can't wait to ride it to work tomorrow.


So there ya have it.  I did exactly as he did, and the bike fired right up.  Good to know the bikes can recover from a blantantly stupid move like this without turning into a money pit.

[Rogue]

That is very good to know.

What is a no-no in jump starting from a car?  The car engine running while you start the bike?  Or just the whole thing of using a car to jump start a bike?

I think I've done this on my VFR (battery died on my '01) and all went well.  But I didn't start the car.  I just hooked up the jumper cables (correct polarity of course!).  

[steve.m]

I think that is a misconception, i've done it a few times with no ill effects.  maybe someone else can comment with more authority.  To my knowledge the only difference would be the amperage, but the moto battery would only pull as much as it needed so...not sure what the ptoential problem would be.  Maybe this is a leftover from the days of motorcycles using 6 volt batteries?

my take, jump start it all you want, just make damn sure you're going + to + and - to - or pay the price (literally).

[scottzilla]

I did not follow the thread at Badweb (I haven't been there since selling my Buell over two years ago) but I fail to see how reversing the cables caused the damage.  Seems to me he had a bad relay and went about diagnosing it.  Unless i'm missing something he is attributing the cables to causing the problem but he had a problem with the dead battery first.

I heard years ago to never jump a bike from a car that has the engine runing.  I have since heard it is ok to leave the engine runing.  However, next time I ever jump a bike I will continue to turn the car's engine off.

[steve.m]

reversing your jumpers on a live battery or dead connects them in series and can blow diodes, switches, relays, starters, ecm's, and so on and so forth.  his problem (like mine) started with a dead battery.  we both compounded the issue by connecting the jumpers in reverse (series) instead of properly (parallel).

Just trust me on this, unless you want to bbq your bike, car, skidoo, etc, don't do it and double check even if you're in a rush.

[Blunder]

Ya, reversing polarity results in blown fuses and maybe other stuff. My son did it to his Nissan and it blew the main fuse. 80A fuses for old Nissans that you need "right now" are not cheap.

I think steve.m is right that the old tale of car/bike battery jumping came about when bikes had 6V systems. I don't think there's a difference if the car is running or not, but if the car battery is a good one then doing it 'dead' couldn't hurt.

[scottzilla]

I didn't know this. Good info.

[steve.m]

I didn't know this. Good info.

just trying to save the buellistas of the world, we're a fading species donchaknow  

[Kyle401]

just trying to save the buellistas of the world, we're a fading species donchaknow  

Dwindling perhaps, but fading?!  

We will not go gently into this good night!
.
Rage, rage against the dying of the light!

[Bueller]

In the days of generators there was no problems jumping with a running vehicle.  With two alternators there is a chance that the one doing the jumping and the one being jumped will be out of phase after the jumped vehicle starts and potentially go to double the voltage.

Best to jump from a car that isn't running.  It may take a while for the charge to build up but it is worth the wait.

There was another one on BadWeb where the guy blew the diode when he connected a battery charger around the wrong way.

[steve.m]

the battery should have an internal diode (likely why mine wouldn't take a charge) and the blown relay had an internal diode as well...also blown.