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Discussion Starter #1
Here is my situation, my bike sits outside and I never really winterize it because I can usually get a ride in every couple of weeks. With my family coming here for the holidays I haven't had a chance to ride since late November.

Long story short my battery was weak and I know that she will need a little "coaxing" to get going again. I brought the battery in and somewhat nursed it back to health ( 12.9 volts for the last couple of days) and think that it may get me through the next season.

Now the question.

Will it hurt the electrical system to use the battery in my jeep, cold, to get past the tinkering needed to get the bike fired? After in runs for a couple of minutes, and I know that it will fire right back up, I will shut it off and put the bike battery back in and then go for a ride. Will the cold auto battery hurt the system if I do this?


Thanks
 

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Dave,
I'm not sure if I'm reading you correctly, but if I do understand what you're proposing, I'd have to say DON'T TRY IT! Simply jump the bike from the Jeep battery without the Jeep's engine running, it should start OK this way. The Jeep's alternator is too powerful for the bike's electrical system and could cause problems if you jump the bike with the engine running. You'd also run the risk of a short if you try to run the bike's engine using jumper cables from the Jeep's battery to the battery leads on the bike. Only run the bike with a battery installed in it!

Brian
 

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Brian is right. Leave the battery in. If you have to jump it, jump it with the bike battery in place. You can destroy the ignition circuitry if you run the bike without a battery in place. The voltage regulator requires the load of the battery to regulate properly, and if the battery is not there, you can kill the $400 ignition controller.

Jumping a bike is just fine, but make sure that your jeep is not running, and that the bike battery is still correctly installed in the bike. If you do those two things, you should have no trouble.

--Justin
 

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tubes_rock said:
Brian is right. Leave the battery in. If you have to jump it, jump it with the bike battery in place. You can destroy the ignition circuitry if you run the bike without a battery in place. The voltage regulator requires the load of the battery to regulate properly, and if the battery is not there, you can kill the $400 ignition controller.

Jumping a bike is just fine, but make sure that your jeep is not running, and that the bike battery is still correctly installed in the bike. If you do those two things, you should have no trouble.

--Justin
tubes_rock,

I'm wondering if it really matters if the motor in the Jeep is running or not? Once the cables are connected, current from the Jeep battery will rush to motorcycle battery because of a difference in voltage. I know that a fully charged 12volt battery has enough current to arc weld for about 5 minutes with. I know it's not the same, but I'm thinking that a battery alone is capable of at least 70 amps, so I'm wondering what dfference the alternator is really going to make?

John
 

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John,

I completely agree, that the jeep running should make no difference at all, and that in all likelyhood, whether the jeep is running or not should have no bearing on the bike.

That being said, I've heard stories of people doing damage to their bikes (or other equipment) by jumping it with the engine running. I can't figure out how or why. perhaps it's because of the increased voltage on the wrong side of the voltage regulator? Or that the voltage regulator doesn't expect to see 14V at the battery when the engine isn't running? Or maybe the person just had it hooked up wrong, which is probably more likely.

So, because I can't verify the circumstances that have supposedly wrecked people's things, jumping the bike with the jeep off is the safe bet. You'll have a harder time wrecking something with 12V than you will with 14 or 15!

So, I chime in with the safest bet when giving advice on jumping a bike! I agree though that the jeep running shouldn't hurt anything.

--Justin
 

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tubes_rock said:
John,

I completely agree, that the jeep running should make no difference at all, and that in all likelyhood, whether the jeep is running or not should have no bearing on the bike.

That being said, I've heard stories of people doing damage to their bikes (or other equipment) by jumping it with the engine running. I can't figure out how or why. perhaps it's because of the increased voltage on the wrong side of the voltage regulator? Or that the voltage regulator doesn't expect to see 14V at the battery when the engine isn't running? Or maybe the person just had it hooked up wrong, which is probably more likely.

So, because I can't verify the circumstances that have supposedly wrecked people's things, jumping the bike with the jeep off is the safe bet. You'll have a harder time wrecking something with 12V than you will with 14 or 15!

So, I chime in with the safest bet when giving advice on jumping a bike! I agree though that the jeep running shouldn't hurt anything.

--Justin
Jumping a bike with a running vehicle won't hurt a thing.

High voltage being on the wrong side of the regulator?
Doesn't the regulator keep the current at around 14v give or take a few
on both?
The battery is the load. If the battery on the bike is low, it will only draw
and load off the car what it would from the bikes charging system.

I'd be willing to bet people who have had troubles had something wrong,
like you said.
Jumping a bike with a running vehicle is no different than
jumping it with a fast/high amp charger (starting mode) and that is done
all the time.
 

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Discussion Starter #7
navillustoo said:
Dave,
You'd also run the risk of a short if you try to run the bike's engine using jumper cables from the Jeep's battery to the battery leads on the bike. Only run the bike with a battery installed in it!

Brian
Thanks for the replies people. Brian, this is what I was looking for. What I am trying to avoid is running the bike battery back down trying to start a bike that has been sitting dormant for a month. Like I said, I know that she will need a little petting and talking too at this point and was basically thinking to use the jeep battery (cold) to bring it back to life instead of the bike battery.

Now another question,

Will it hurt to go ahead and connect the cables to the jeep battery ( jeep not running) even though the bike battery is showing 12+ volts? I would just really hate to drag it back down trying to crank a somewhat tempermental, cold natured bike that is probably going to protest starting because she's mad, anyway...

Thanks again folks!

p.s. Good to hear from you again Brian, I hope that all is well on the homefront
 

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Jumping a bike with a good battery in it won't hurt a thing. By jumping a bike with a known good battery from another known good battery, you are essentially just putting the two batteries in parallel, and that is done in all sorts of things, and for all sorts of reasons. It's perfectly safe so long as you follow the standard rules for jumping a vehicle. Go right ahead!

--Justin
 

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DavidT said:
navillustoo said:
Dave,
You'd also run the risk of a short if you try to run the bike's engine using jumper cables from the Jeep's battery to the battery leads on the bike. Only run the bike with a battery installed in it!

Brian
Thanks for the replies people. Brian, this is what I was looking for. What I am trying to avoid is running the bike battery back down trying to start a bike that has been sitting dormant for a month. Like I said, I know that she will need a little petting and talking too at this point and was basically thinking to use the jeep battery (cold) to bring it back to life instead of the bike battery.

Now another question,

Will it hurt to go ahead and connect the cables to the jeep battery ( jeep not running) even though the bike battery is showing 12+ volts? I would just really hate to drag it back down trying to crank a somewhat tempermental, cold natured bike that is probably going to protest starting because she's mad, anyway...

Thanks again folks!

p.s. Good to hear from you again Brian, I hope that all is well on the homefront
Why don't you spend less than $50. and buy a good battery tender and then you can keep the battery on a full charge all the time, if bike sits outside cold weather can pull the battery down and get a waterproof battery tender like this http://www.cruisercustomizing.com/detail.cfm?model_ID=8&Category_ID=120&manufacturer_ID=282&product_ID=10061&sblid_name=Battery_Tender_Waterproof_____for_Honda_Shadow_Sabre this would solve your problem and extend the life of your battery (either old or when you get a new one.
 

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Discussion Starter #10
Thanks again guys

Yes Eldorado, I probably will get a battery tender ahen I have to replace mt battery next time around. The only reason that I have never gone that route before is I usually do get a couple of rides a month in, even duringthe winter. In this case the holidays and visiting family kept it from happening and my bike has ended up sitting for five or six weeks now without a ride... very unusual for me!
 

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I understood that you could ruin the voltage regulator if you jumped the bike with a cars engine running. This is the reason as I understood it;

The regulator in these bikes is a shunt type regulator. It takes the excess voltage and runs it to ground and can only dissipate 700 watts max. Not a problem with the bikes charging system as the regulator was designed to handle that.

A cars charging system can supply more current than 700 watts (easily) at a high enough voltage that the regulator in the bike sees it. If there is enough current available at the regulator, it can be damaged. If the vehicle that is doing the jumping is not running, the bikes regulator won't even know it's there. This would be the safest way to jump the bikes battery.


There are a couple variables that add into this that make jumping not so straight forward.

The battery being charged is consuming current. More current when it's down, and less as it charges up. (Reducing the current available that the voltage regulator sees, at least at first).

The jumpers and the connections made at either end of the jumpers will limit the amount of current traveling from vehicle to vehicle. (Limiting the amount of current that the entire bike sees).

Now I don't know if I had smoke blown up my... errr.. Lemme just say I don't want to test the theroy. If my bike needs jumped, it will be from a vehicle without the engine running just for peace of mind if anything.

Take it for what it's worth. It didn't cost anything, so maybe it's not worth anything either. :roll:
 

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zikzak said:
The regulator in these bikes is a shunt type regulator. It takes the excess voltage and runs it to ground and can only dissipate 700 watts max. Not a problem with the bikes charging system as the regulator was designed to handle that.

A cars charging system can supply more current than 700 watts (easily) at a high enough voltage that the regulator in the bike sees it.
Actually, most cars have 50 to 60 amp alternators.
Some of the larger pickups have larger alternators up in the 90 and 100 amp range.

700 watts at 12 volts is 58 amps, still inside a normal car alternators range.
700 watts at 14 volts is 50 amps, again, inside a normal car alternators range.

When we talk about jumping it off, I don't know about anyone else,
but that's exactly what I am talking about, jumping it off.
I'm not talking about leaving it running and let the vehicle charge
the bikes battery.

Jumping a bike from a running vehicle won't hurt anything.
Trying to charge the bike with a running vehicle, yes, it could hurt something. You are trying to dissipate a LOT of heat.
For a short time (jumping and removing cables) there isn't going to be
enough to do any damage. Leaving in on and charging, yes,
it's going to build up heat, heat is resistance, and resistance causes loads
to go high, and something can blow.

The thing for everyone is probably "do what you feel comfortable with".

In either case, car running or not, the bike being started is not going
to load the cars battery down hard enough that it is going to matter
if the car is running or not.
If you feel comfortable doing it one way, do it that way.
If you don't, do it the other way.
 

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litnin said:
zikzak said:
The regulator in these bikes is a shunt type regulator. It takes the excess voltage and runs it to ground and can only dissipate 700 watts max. Not a problem with the bikes charging system as the regulator was designed to handle that.

A cars charging system can supply more current than 700 watts (easily) at a high enough voltage that the regulator in the bike sees it.
Actually, most cars have 50 to 60 amp alternators.
Some of the larger pickups have larger alternators up in the 90 and 100 amp range.

700 watts at 12 volts is 58 amps, still inside a normal car alternators range.
700 watts at 14 volts is 50 amps, again, inside a normal car alternators range.

When we talk about jumping it off, I don't know about anyone else,
but that's exactly what I am talking about, jumping it off.
I'm not talking about leaving it running and let the vehicle charge
the bikes battery.

Jumping a bike from a running vehicle won't hurt anything.
Trying to charge the bike with a running vehicle, yes, it could hurt something. You are trying to dissipate a LOT of heat.
For a short time (jumping and removing cables) there isn't going to be
enough to do any damage. Leaving in on and charging, yes,
it's going to build up heat, heat is resistance, and resistance causes loads
to go high, and something can blow.

The thing for everyone is probably "do what you feel comfortable with".

In either case, car running or not, the bike being started is not going
to load the cars battery down hard enough that it is going to matter
if the car is running or not.
If you feel comfortable doing it one way, do it that way.
If you don't, do it the other way.
litnin,

There are quite a few things I don't know about these charging systems, and I am still having a problem understanding why some people think that boosting from a another vechicle that is running is somehow bad.

I don't have a schematic for the system, but I'm wondering why hooking up a battery (which is just another term for the boosting vehicles power supply) to the motorcycle system will somehow damage the charging system.

1) I'm thinking that replacing a bad battery doesn't cause any problems, (IE: raising the voltage of the power supply) is there a threshold that if the voltage of the new battery is above somehow discharges into the regulator? I was thinking that the job of the diodes was to prevent current from flowing out of the battery to ground, wouldn't those same diodes prevent the same thing from happening with a booster battery connected? .

2) Those numbers about alternator output are usually only valid at somewhere near peak RPM and aren't even near that at an idle.

3) Wouldn't the charging system on the boosting vechicle stop charging once it sensed the system voltage was high enough to warrant it? In other words, once the system voltage increased, would the alternator still be putting out maximum current?

I'm finding it difficult to believe that it's damaging to boost a vehicle, because we've done almost countless times.

I'm not presenting an argument, just wanting to know if there are any errors in my thinking. There may very well be a valid reason why we shouldn't jump a bike with a running vehicle, but I really need someone to tell me why. I heard so many 'theories' about electricity over the years that I have to take the route those people from Missouri do. SHOW ME.

Don't take this to be a negative assessment of anyone's skills or knowledge, it's simply an attempt to improve my own.

Also, for my part, if I suspected the battery wasn't any good I would replace it, regardless of the condition of the rest of the motorcycle. The only exception to that might be if I was going to ride it straight to the scrap yard.


Thanks,

John
 

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Olivereaman said:
litnin,

There are quite a few things I don't know about these charging systems, and I am still having a problem understanding why some people think that boosting from a another vechicle that is running is somehow bad.

I don't have a schematic for the system, but I'm wondering why hooking up a battery (which is just another term for the boosting vehicles power supply) to the motorcycle system will somehow damage the charging system.
It won't. You and I are on the same page.

It's just one of those myths that someone heard or mis-heard somewhere
down the line and it's spread and stuck.
It's nothing different than the "high octane makes more power" type of
mis-information.

Olivereaman said:
1) I'm thinking that replacing a bad battery doesn't cause any problems, (IE: raising the voltage of the power supply) is there a threshold that if the voltage of the new battery is above somehow discharges into the regulator? I was thinking that the job of the diodes was to prevent current from flowing out of the battery to ground, wouldn't those same diodes prevent the same thing from happening with a booster battery connected?
Right!
People are affraid that a running vehicle (alternator output) will hurt the
charging system on the bike.

Olivereaman said:
2) Those numbers about alternator output are usually only valid at somewhere near peak RPM and aren't even near that at an idle.
That is correct.
An automobile alternator, if in good and properly functioning condition,
will put out close to make voltage, however it won't allow max
current draw at idle.

Olivereaman said:
3) Wouldn't the charging system on the boosting vechicle stop charging once it sensed the system voltage was high enough to warrant it? In other words, once the system voltage increased, would the alternator still be putting out maximum current?
Well, sort of.
A vehicles system never stops charging.
It's charging rate is reduced, but since something in the vehicle is always
using electricity, the charging system is always charging.
It's not charging to it's max potential, but it is charging.

Olivereaman said:
I'm finding it difficult to believe that it's damaging to boost a vehicle, because we've done almost countless times.
I agree.
 

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This I can tell y'all is no myth, I fried my car's computer by jumping another vehicle with it. Ever since, I either use a battery booster or a car's battery with the engine off. The cost of a rebuilt computer for a single jump was definitely not worth it!

Brian
 

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navillustoo said:
This I can tell y'all is no myth, I fried my car's computer by jumping another vehicle with it. Ever since, I either use a battery booster or a car's battery with the engine off. The cost of a rebuilt computer for a single jump was definitely not worth it!

Brian

Yep, ECM's are VERY susceptible to voltage spikes.

They are a lot more resilient in current vehicles than they were just
5 or 10 years ago, but they are still pretty touchy.

On an ECM vehicle, the best way is to not actually jump the vehicle,
but hook the cables up and just let your battery charge, don't actually
try to start the vehicle.
Let the vehicle with the good battery charge the dead battery.
The dead battery vehicle, should not have the key on.
This will drastically reduce the likely hood of a voltage spike killing the ECM.
It takes longer this way, but much more safe.
 

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litnin said:
navillustoo said:
This I can tell y'all is no myth, I fried my car's computer by jumping another vehicle with it. Ever since, I either use a battery booster or a car's battery with the engine off. The cost of a rebuilt computer for a single jump was definitely not worth it!

Brian

Yep, ECM's are VERY susceptible to voltage spikes.

They are a lot more resilient in current vehicles than they were just
5 or 10 years ago, but they are still pretty touchy.

On an ECM vehicle, the best way is to not actually jump the vehicle,
but hook the cables up and just let your battery charge, don't actually
try to start the vehicle.
Let the vehicle with the good battery charge the dead battery.
The dead battery vehicle, should not have the key on.
This will drastically reduce the likely hood of a voltage spike killing the ECM.
It takes longer this way, but much more safe.

Now ya tell me! :lol: I wish I had known that before I made the mistake. It was a '90 Olds 88(which I'm still driving with 208,000+ on the odo)3800 V6. I was jumping an '86 Ford Ranger. I blamed it on the Ford! :lol: Expensive lesson. Bought 900 amp battery boosters for each vehicle so I wouldn't make that mistake again.

Thanks for the info!

Brian
 

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litnin said:
navillustoo said:
This I can tell y'all is no myth, I fried my car's computer by jumping another vehicle with it. Ever since, I either use a battery booster or a car's battery with the engine off. The cost of a rebuilt computer for a single jump was definitely not worth it!

Brian

Yep, ECM's are VERY susceptible to voltage spikes.

They are a lot more resilient in current vehicles than they were just
5 or 10 years ago, but they are still pretty touchy.

On an ECM vehicle, the best way is to not actually jump the vehicle,
but hook the cables up and just let your battery charge, don't actually
try to start the vehicle.
Let the vehicle with the good battery charge the dead battery.
The dead battery vehicle, should not have the key on.
This will drastically reduce the likely hood of a voltage spike killing the ECM.
It takes longer this way, but much more safe.
litnin,

I think that some vehicles must be more sensitive to voltage spikes than others.

I had an 89 Ford F-250 that had an alternator brush hang up. When it reached the point of failure it made so much voltage that it burned out almost all of the light bulbs, the headlights went to at least double their normal intensity for about 1 second and the ones that still worked didn't last much longer, but it never damaged any of the EEC components. There must have been a voltage regulator built into the EEC system. It actually burned the copper brush wire in two.

A couple years later we had a Ford LT 9000 with a Leece-Neville system do the exact same thing, that time though there wasn't a good component left anywhere, it ruined wires, switches and the whole nine yards...... Right down to the fuel shut-off on the Cummins engine. All junk!!. And just that quick!

John
 

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Olivereaman said:
litnin,

I think that some vehicles must be more sensitive to voltage spikes than others.

I had an 89 Ford F-250 that had an alternator brush hang up. When it reached the point of failure it made so much voltage that it burned out almost all of the light bulbs, the headlights went to at least double their normal intensity for about 1 second and the ones that still worked didn't last much longer, but it never damaged any of the EEC components. There must have been a voltage regulator built into the EEC system. It actually burned the copper brush wire in two.

A couple years later we had a Ford LT 9000 with a Leece-Neville system do the exact same thing, that time though there wasn't a good component left anywhere, it ruined wires, switches and the whole nine yards...... Right down to the fuel shut-off on the Cummins engine. All junk!!. And just that quick!

John
Yep, that's a definite truth. A lot of newer vehicles are coming with
automatically resetting circuit breakers on on the ECM for such very
problems. They are very quick reset and can trip and reset
without the engine shutting down. Pretty neat technology.
If they reset so many times, back to back, within a given amount of time,
the ECM will go in to fail safe mode and either shut itself down
or limp itself along. This prevents problems if the spike is reoccuring
event.

I've seen several ECM's fried because of jumping a vehicle.
You can't just jump them like you could an old 65 Chevy.
Sometimes technology is a bitch... other times it's a blessing.
 
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