Don't know about that but watch out for central locking.....A chap I worked with some years ago was helping someone on a cold wet night and had engine running and doors closed. Some time during the starting operation his car locked him out. Then it stopped raining and by the time he got back in his wiper blades had worn away on the dry screen
lots of cases have been documented where bmw has charged the owners of their cars around the £3k mark for a new loom etc and ecu because they didn't trip the switch they needed to trip to enable the car to be jump started or to enable the car to be used to jump start another vehicle
the guy i bought my last sierra had to pay out for his so i think i'm pretty sure it's not as uncommon as people would have others make out
On a ERF EC11 HGV, you have to have the heater, wipers and full beam on. If you don't it blows the big f*ck off fuses if you try to jump start it and its a ERF dealership callout to sort it.
Funny how we used to jump start Landrovers and lorries like that. And you don;t arc weld anything putting the terminal back on unles you're a girls blouse and pansy about doing it.
Explain. Thats what voltage regulators are for. The ignition system alone will be drawing sufficient current to prevent this. It isn't running without a load.
When you remove the jump leads there's an arc.
Following up my own post but Conor reminded me, you disconnect the lead from the earth first.
The small explosion I had with the tractor battery was when I disconnected the crocodile clips while everything was still live. Presumably the battery was duff, so gassing occurred immediately, the dynamo on the tractor probably hadn't cut in because it sensed over voltage from the welder/charger so the battery was still being fed a high current when I took the clips off. The inevitable spark then setting the hydrogen and oxygen in the cell off. All this in hindsight, I just wondered what the hell had happened at the time and wondered why my tie dyed Levis were disintegrating.
AJH
The handbook for my E39 describes how to jump start it and makes no mention of such a switch. Indeed, it provides terminals under the bonnet for jump starting in case you can't access the battery direct - it's in the boot.
It would make sense to link the positive terminals at the battery, and make the chassis or negative connection elsewhere on the body. If you were worried about the battery blowing up from a spark. But the chances of this happening are *remote in the extreme*. I've yet to hear of it happening in a jump start situation - unless someone links positive to negative etc or shorts the leads - a common occurrence.
But as I say, disconnecting a battery while still on charge in a battery charging area of a garage often resulted in blowing them up.
The regulator circuit relies on being fed a control voltage off a low impedance source. Remove that source after the alternator has been excited means the voltage may go sky high. On older alternators, at least. I've seen over 50 volts. It's possible modern ones don't, though, although all still warn about running the engine with the battery disconnected.
Why? You're simply breaking a circuit. Makes no difference which is first.
aha! perhaps you aren't meant to jump it from the boot then?
Do you actually enjoy being gratioutously offensive? Try learning a little physics and reading - the word "can" seems to have slipped under your radar.
So what? Try figuring out the difference between removing a connection and attempting to connect to a dead short.
Any explosion is more likely to be internal arcing in the battery as well due to sudden high current demands. I've seen enclosed battery compartments go bag from accumulated H2 but never one in the open air.
Makes no difference - the terminals under the bonnet are simply in parallel. Or rather the positive one is - the negative one is the body.
In news: snipped-for-privacy@davenoise.co.uk, Dave Plowman (News) decided to enlighten our sheltered souls with a rant as follows
I always disconnect the earth lead first just incase I have a mad spanner arcing out moment.
Just seems more logical.
Cos you normally attach the earth clamp to the engine & hence the sparks firther away from the battery. & if you drop it or touch it against the bodywork it doesn't cause agreat big spark, unlike the other lead.
What dead short?
What in, a Ford Anglia? They've been solid state for a while you know.
3 pins. Voltage In, Regulated Voltage Out, Gnd.
I agree its not ideal for long periods but a whole few seconds isn't going to matter.
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