Question for the electrical gurus out there
Seasoned HDF Member
Joined: Jul 2011
Posts: 27,096
Likes: 4,673
From: Frozelandia, Minnysota
Those small lithium jumper batteries are the best thing since kickstarters. I've used them a few times, never had a problem. Just disconnect them quickly when a vehicle starts, car and bike charging systems will fry them if left on too long. If the battery you're jumping has an internal short, a jump won't work, and newer style batteries sure get that a lot more than old "add water" batteries did. I took the negative cable off my 1200 sportster and tried cranking it off an Li jumper by itself, and it turned it over. That's a bigger cylinder and higher compression than a lot of cars have.
Banned
Joined: Jul 2009
Posts: 7,406
Likes: 834
From: Straight Jacket Memories and Sedative Highs
I have only jumped one bike, and we had to rev it up. Might not have to on all of them. I am fairly sure every auto I have jumped, has been with RPMs raised.
Wow, take a deep breath.
I said if you want to be extra cautions you could leave the ign off and let the battery charge for a while, sorry it got you so bent out of shape, and don`t worry, I won`t need any help from you at any time.
Cheers
I said if you want to be extra cautions you could leave the ign off and let the battery charge for a while, sorry it got you so bent out of shape, and don`t worry, I won`t need any help from you at any time.
Cheers
Why do people with mechanical aptitude, click on electrical threads?
Seasoned HDF Member
Joined: Feb 2007
Posts: 6,081
Likes: 1,127
From:
The running car has a voltage regulator, and 10 feet of line drop. Not sure why there is a fear of running the donor car.
I think we got some paranoid people here.
Who waits 10 minutes on side of road to charge the dead vehicle? I hope I never run into you if need help, cause it would be hard to bite my tongue.
What makes you think you are going to over voltage the dead vehixle, when the running vehicle is not blowing itself up?
I think we got some paranoid people here.
Who waits 10 minutes on side of road to charge the dead vehicle? I hope I never run into you if need help, cause it would be hard to bite my tongue.
What makes you think you are going to over voltage the dead vehixle, when the running vehicle is not blowing itself up?
Reviewed bike condition (visually and with my handheld voltage meter) and used my homemade jumper cables from starter lug to starter lug for positive and muffler clamp to muffler clamp for ground (-) to charge their battery with my bike running for a few minutes.
Basically introduced a float charge.
Then shut my bike off and started theirs with jumpers connected.
Every time each person was very thankful.
I would then disconnect jumpers and check their voltage with my digital voltage meter.
One time the individual had a bad regulator(no charge at higher RPM) and required multiple jumps to get to a safe location.
At no time did anybody seem upset that assistance was being offered and at the same time additional damage was not introduced into either bike.
Each time folks were very happy someone took the time to care.
.
Road Warrior
Joined: Nov 2007
Posts: 1,800
Likes: 307
From: Houston, Texas
If the battery is just a little weak, it doesn't matter on jumping. If the battery is completely drained on the other hand, don't jump it. I made the stupid mistake of shutting of at the handlebar and forgot to turn the main switch off at work. I drove a company vehicle for a couple of days and didn't realize my mistake until I wanted to ride home. It took a couple of tried to get the bike started so it would keep running on it's own. It would die again as soon as I removed the cables. Then I road home ( 1 hour ) and everything was fine. The next day going to work, bike started fine but about halfway to work check engine light and battery light came on. Then went off later. Road home and they came back on and stayed on. ( voltage codes ) I followed the test procedures and everything looked good to me. I road it to my indy and told him what I did and he laughed at me ( I've been using him for ten years and have become friends ). He told me it's common after jumping completely dead batteries and that I should have charged the battery. He found that I had fried both the stator and the charger. Funny thing is I'm still using the same battery two years later with no problems.
Moral of my story - Jumping a weak battery is no big deal using the method of your choice. Jumping a completely dead battery can be costly.
I've even helped push start a bike that had enough juice for the fuel pump but not enough for the starter. Note the word helped. It took three pushing and one on the bike,
Moral of my story - Jumping a weak battery is no big deal using the method of your choice. Jumping a completely dead battery can be costly.
I've even helped push start a bike that had enough juice for the fuel pump but not enough for the starter. Note the word helped. It took three pushing and one on the bike,
Banned
Joined: Jul 2009
Posts: 7,406
Likes: 834
From: Straight Jacket Memories and Sedative Highs
You may have damaged the battery some, its not good to drain them completely, but I also wouldn't expect it to fail either. What I do in the spring is charge the battery the day before, so I am not stressing it, and charge once in the winter.
If i am doing lots of winching, and not running at speed much, I will charge the battery too. I don't like to stress the battery on starts. Being completely dead, you probably are not stressing it. But the charging system may be stressed.
I am not sure how common it is to kill a chraging system that way. I have to admit I am surprised one time was an issue, with a battery that was not bad. Especially the way the Harley has their volt reg, it dumps to ground when not called on. Stator is always spinning, so has to dump or open.
Lots of dead cars are jumped no problem. Not idle. Doing it with a bad battery and you can hear the alternator.
If i am doing lots of winching, and not running at speed much, I will charge the battery too. I don't like to stress the battery on starts. Being completely dead, you probably are not stressing it. But the charging system may be stressed.
I am not sure how common it is to kill a chraging system that way. I have to admit I am surprised one time was an issue, with a battery that was not bad. Especially the way the Harley has their volt reg, it dumps to ground when not called on. Stator is always spinning, so has to dump or open.
Lots of dead cars are jumped no problem. Not idle. Doing it with a bad battery and you can hear the alternator.
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