Jump Starting Question
- Thread starter timbob
- Start date
Don't worry, I borrowed a multimeter. The battery is showing a miserly 2.78 volts, and is improving by 0.01 of a volt every 5 minutes with a booster battery connected. Will borrow a proper battery charger off a mate and charge it up overnight.
This was just a quick query, so mods can delete the thread if you like.
This was just a quick query, so mods can delete the thread if you like.
I wouldn't be worried about the battery. That will be the least of your problems now.
The reverse current will most likely have fried a considerable amount of the car's electrics. The alternator, ignition and fuel injection computers, the stereo, and any components of the dash that have LED's in them come to mind first.
Hopefully the car had a reverse current protective diode on it in the primary fusible link. If so, it'll just be a matter of replacing the fusible link.
There's also the distinct possibility you've blown all the diodes in the charging car's alternator.
Not good, mate. Not good at all.
The reverse current will most likely have fried a considerable amount of the car's electrics. The alternator, ignition and fuel injection computers, the stereo, and any components of the dash that have LED's in them come to mind first.
Hopefully the car had a reverse current protective diode on it in the primary fusible link. If so, it'll just be a matter of replacing the fusible link.
There's also the distinct possibility you've blown all the diodes in the charging car's alternator.
Not good, mate. Not good at all.
Sorry, just re-read the first post. Nothing will have happened to the dead battery. You effectively connected to the same point (electrically).
I'd be checking the running car's battery and alternator, though. Because if you connected up like you say, you dead-shorted the charging car's battery.
Mind you, if you connected up like that, you'd have smoked the jumper cables, too.
I originally thought you'd connected -ve (dead) to +ve (good), +ve (dead) to -ve (good)...
I'd be checking the running car's battery and alternator, though. Because if you connected up like you say, you dead-shorted the charging car's battery.
Mind you, if you connected up like that, you'd have smoked the jumper cables, too.
I originally thought you'd connected -ve (dead) to +ve (good), +ve (dead) to -ve (good)...
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Okay, you've scared me now!
The good car seems fine - nothing has blown up on it, and it's showing ~14v across the battery whilst idling, so the alternator is doing it's job fine still.
I connected (in this order, it makes a difference):
-ve dead battery to +ve good battery (-ve terminal is coloured red on the dead battery, stupidly!)
then -ve good battery to an earth point on the dead car.
I have nothing in the dead car at all - no dash lights or anything, but the battery is dead. It's barely showing a couple of volts. Does that mean I've fried the electrics? Surely if I had, there would have been burning, smoke, fried cables etc.??
The good car seems fine - nothing has blown up on it, and it's showing ~14v across the battery whilst idling, so the alternator is doing it's job fine still.
I connected (in this order, it makes a difference):
-ve dead battery to +ve good battery (-ve terminal is coloured red on the dead battery, stupidly!)
then -ve good battery to an earth point on the dead car.
I have nothing in the dead car at all - no dash lights or anything, but the battery is dead. It's barely showing a couple of volts. Does that mean I've fried the electrics? Surely if I had, there would have been burning, smoke, fried cables etc.??
Soldato
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- Cheshire
I think you should be ok, however if you had connected the -ve good to +ve bad then you could have done some damage 
Fog
Fog
Soldato
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- Glocestershire
Some muppet connected a battery backwards to my old VW Polo (he also managed to leave the ownners manual under the bonnet) and the only thing he killed was the radio.
Soldato
- Joined
- 5 Jul 2003
- Posts
- 2,843
- Location
- Cheshire
Oh yes!!! I've seen the cables burst into flames before now
Fortunately you didnt complete the circuit so there should be no harm done
Fog
Fortunately you didnt complete the circuit so there should be no harm done
Fog
I only asked, as after I noticed (stupid, stupid me!) my error, I changed them round. Still with the negative lead on the dead car on an earth point. Then I remembered speaking to a friend about jumpstarts a while ago, and he had thought that you were supposed to connect -ve to -ve and +ve to +ve, so I turned off and hooked them up briefly like that, before checking in an old haynes, and seeing it said "use an earth", and reverting to that method.
I'm positive (haha) that I did this after realising my mistake, and having the correct terminals, but in my "after-reading-MickeyD's-post-panic", I couldn't remember if I did this before or after noticing the crossed cables mistake.
But it didn't blow up, cables weren't hot, no smoke, no sparks, no flames, no nothing. So I'm hoping it's ok!
I'm positive (haha) that I did this after realising my mistake, and having the correct terminals, but in my "after-reading-MickeyD's-post-panic", I couldn't remember if I did this before or after noticing the crossed cables mistake.
But it didn't blow up, cables weren't hot, no smoke, no sparks, no flames, no nothing. So I'm hoping it's ok!
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