Battery dead, use a car to jump?

utgunslinger13 · May 15, 2009, 03:32:59 PM

Quick question. I've been doing some wiring that I would like to check that its done right but my battery is dead. The bike doesn't run and the battery is almost a year old. Would I hurt anything hooking jumper cables from my car into the bike so I could check the wiring I have changed?

Anything to look out for or be aware of if I do it?

Thanks,

Nick

sledge · May 15, 2009, 03:45:47 PM

As long as it is a 12v battery and you keep the polarity the same you wont do any harm whatsoever, if there is a short the fuse will pop.

scottpA_GS · May 15, 2009, 04:04:12 PM

As long as you dont start the car you will be fine

sledge · May 15, 2009, 04:37:13 PM

Quote from: scottpA_GS on May 15, 2009, 04:04:12 PM

As long as you dont start the car you will be fine

Why?..... The bike will only pull as much current from the car as it needs to start. In effect a jump start is like fitting a larger capacity battery, it wont do any harm at all.

gsJack · May 15, 2009, 05:42:05 PM

I've jumped every bike I've owned many times from a car battery riding year around here in NE Ohio. Play it safe and turn the car off while jumping a bike. Get a good connection and it spins like crazy and starts almost immediately with the big car battery. Here's some thoughts on why not to keep the car running:

http://www.shadowriders.org/faq/jumpstarting.html

Better safe than sorry, you will use very little of the cars battery jumping a bike.

ATLRIDER · May 15, 2009, 05:53:18 PM

Quote from: sledge on May 15, 2009, 04:37:13 PM
Quote from: scottpA_GS on May 15, 2009, 04:04:12 PM

As long as you dont start the car you will be fine

Why?..... The bike will only pull as much current from the car as it needs to start. In effect a jump start is like fitting a larger capacity battery, it wont do any harm at all.

I agree with Sledge. The car and bike have 12v systems and the bike's electrical system is only gonna draw what it needs.

utgunslinger13 · May 15, 2009, 06:25:24 PM

Not sure if this makes a difference but I'm not trying to start the bike, I just need juice in the wires to check turns headlights etc. Will it be ok just to hook the car to the battery so juice goes to the accessories?

Thanks,

Nick

allaussiegrown · May 15, 2009, 06:28:30 PM

yes, there inst any difference except a car battery is much bigger so it has more draw. Your bike will draw the amount it needs. But if you turn the car on it may cause a current too large for the bike.

Car batteries and jump starters work fine for me.

ATLRIDER · May 15, 2009, 06:29:56 PM

Quote from: gsJack on May 15, 2009, 05:42:05 PM
I've jumped every bike I've owned many times from a car battery riding year around here in NE Ohio. Play it safe and turn the car off while jumping a bike. Get a good connection and it spins like crazy and starts almost immediately with the big car battery. Here's some thoughts on why not to keep the car running:

http://www.shadowriders.org/faq/jumpstarting.html

Better safe than sorry, you will use very little of the cars battery jumping a bike.

I made my post at same time you posted. I guess it doesn't hurt to play it safe.

ATLRIDER · May 15, 2009, 06:30:45 PM

Quote from: utgunslinger13 on May 15, 2009, 06:25:24 PM
Not sure if this makes a difference but I'm not trying to start the bike, I just need juice in the wires to check turns headlights etc. Will it be ok just to hook the car to the battery so juice goes to the accessories?

Thanks,

Nick

I say go for it. It's only 12v

scottpA_GS · May 15, 2009, 07:03:19 PM

Yes... YES!!! its FINE!

But like GSjack says.... Why risk it? Leave the car ignition off... plenty O juice just being connected. DONT START THE CAR! Not worth the risk...

Anyone read the great link he posted?

werase643 · May 15, 2009, 07:08:30 PM

for testing yes.... no need to have car running....except to waste gas

running a bike and a car at same time with the batteries in parallel...
you get dueling volt regs...the bigger one will win.....CAR 1 bike 0

simoniz · May 15, 2009, 07:44:46 PM

I've done it before with no ill effects. 12V is 12V, regardless. And if you are just testing the lights and horn, you will be OK.

sledge · May 15, 2009, 11:19:12 PM

The car's alternator is rated for 1400 watts. The bike's regulator can dissipate a maximum of 700 for (very) short periods before it cooks itself. It's a tug of war, and the bike regulator ALWAYS loses.

The above statement is where he trips up.....so the car can deliver 1.4kw of power, so what? doesnt mean the bike needs or will draw that sort of power to start nor will the bikes regulator see it when its connected to a running car, unless the bike has 28, 50w headlamps and they are all turned on!. The only difference is that the volts are coming from the car not the bikes battery but thats not an issue, volts are volts, it doesnt matter where they come from or how they are generated they are all the same. Its simple Ohms law, the current flow in the bike will depend on electrical load. You can "force" extra voltage into a circuit but the circuit will never draw anymore current than it needs.

I work in a Power-station that has the ability to generate up to 2000Mw at full chat, thats 2000,000,000w. The average house connected to it draws 2-3kw.....so why arent they all catching fire when the lights are turned on?

Its the same principle, each house only takes what current it needs and that in turn depends on the electrical load at the time.

People simply dont understand exactly what Volts, Amps and Watts are, what purpose they play and what effects they have on each other.......... You could jumpstart your GS from a Supertanker without issue so long as the voltage is around 12v DC.

utgunslinger13 · May 15, 2009, 11:28:11 PM

lol sorry didn't mean to stir the pot here, just wanted to make sure I wouldn't fry anything.

And jump starting from a supertanker would be AWESOME.

Big Shot · May 16, 2009, 02:11:40 AM

Quote from: utgunslinger13 on May 15, 2009, 11:28:11 PM
lol sorry didn't mean to stir the pot here, just wanted to make sure I wouldn't fry anything.

And jump starting from a supertanker would be AWESOME.

Agreed... And should be the next challenge in the picture game!

ATLRIDER · May 16, 2009, 07:35:51 AM

I was thinking the process thru and correct me if I've got it wrong. When you jump from a car, even if it's running, it's putting out 12-15v. The voltage has already been rectified to DC and regulated down. You turn on the bike's key and push the starter button, current is being used up for the lights, starter, ignition system. This current from the car never goes thru the bike's reg/rectifier. Voltage generated by the bikes charging system comes through the 3 stator wires, into the reg/rectifier, through the battery and out to satisfy the electrical systems needs. So, since ur jumping directly from battery-to-battery isn't the reg/rectifier being bypassed on the bike altogether since it's ahead of it in the power cycle?

Jared · May 17, 2009, 05:02:24 AM

Quote from: ATLRIDER on May 16, 2009, 07:35:51 AM
I was thinking the process thru and correct me if I've got it wrong. When you jump from a car, even if it's running, it's putting out 12-15v. The voltage has already been rectified to DC and regulated down. You turn on the bike's key and push the starter button, current is being used up for the lights, starter, ignition system. This current from the car never goes thru the bike's reg/rectifier. Voltage generated by the bikes charging system comes through the 3 stator wires, into the reg/rectifier, through the battery and out to satisfy the electrical systems needs. So, since ur jumping directly from battery-to-battery isn't the reg/rectifier being bypassed on the bike altogether since it's ahead of it in the power cycle?

Repeated jumping off a running car can do some damage..... Charging voltage from the car will usually exceed the bikes charging output ...the regulator/rectifier basically "consumes" the excess voltage the bikes charging system normally makes. Give it too much (say from a car..) and they can fail.

Just don't start the car ( haven't we done this topic a few times.....?) and you'll be fine.

ATLRIDER · May 17, 2009, 01:11:31 PM

Hey Jared,

Just ran out to my car 00' Honda Odyssey and checked the charging voltage. 14.45v @ Idle. Started the 93' GS and get 14.20v @ Idle. Output is virtually the same. Any excess voltage above what the system is designed to run gets dumped to ground by the regulator. Anyway, can't hurt to play is safe by keeping the car engine off, just don't see the hazard of leaving it on.

Jared · May 17, 2009, 05:38:33 PM

Quote from: ATLRIDER on May 17, 2009, 01:11:31 PM
Hey Jared,

Just ran out to my car 00' Honda Odyssey and checked the charging voltage. 14.45v @ Idle. Started the 93' GS and get 14.20v @ Idle. Output is virtually the same. Any excess voltage above what the system is designed to run gets dumped to ground by the regulator. Anyway, can't hurt to play is safe by keeping the car engine off, just don't see the hazard of leaving it on.

I have a few spare RR's...let me know when you need one.

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Battery dead, use a car to jump?