Briefly that's exactly what happens. It depends on how much stuff you've got running at the time compared to how much load is taken off the alternator as to how high it goes, the regulator controls the field windings, not the output voltage directly hence there's a limit too how fast they can react. If you get the very heavy duty alternators then they clamp the output with some oversized Zeners or transzorbs, but that's money that many manufacturers choose not to spend.
Last time I tried this in a controlled test on the old SD1 (Bosch alternator) the open circuit volts read about 18. With a failed regulator (alternator hard on) and a good fully charged battery you'll see about
15.5v Of course these figures will vary somewhat with different alternators and also what other load is applied.
Yebutt in the one I have personal experience of, and others my stepson told me about, the vehicle had not broken down as such; for one reason or another the battery was flat. Jumping it *did* start it, and it ran perfectly OK. It only stopped exactly as the leads were removed.
I actually hesitated before I posted the warning in this thread because I know it's one of your pet hobby horses; you choose to disbelieve that removal of jump leads can cause damage to the dead vehicle whilst many other much more reliable sources say it can and *does* happen.
I'm happy to keep taking the trivial precautions to limit the likelihood of damaging someone else's vehicle, and I would suggest that it's sensible for others to do the same.
Can't help you there; outside my area of expertise. All I know is that the official AA kit has them, and so do the ones you can buy.
Chris
My guess is it's simply coincidence.
Your guess is definitely wrong in the case of the T4 belonging to my step- daughter's partner. I would stake everything I own on the failure of the ECU on that vehicle being caused by jump starting. It was so clear-cut. The odds on the ECU failing for any other reason at the *exact* moment the first lead was removed are so small as to not be worth considering.
We've done this to death before; as I've said, it's such a trivial thing to follow the proper procedure, *I* will continue to do so.
Chris
Oh I'm not denying the use of a sensible proceeder. Just that a surge protector is likely of any use.
Wot? No angle grinder?
I found the RAC to be OK. But spending the £37 on Autoaid gives you the vouchers to spend elsewhere :-)
Well, I get cover with my bank account - happily pay the monthly fee for the cover they give me.
The battery charge state is monitored electronically from within either the ecu or the alternator (depends on the age of the vehicle and vehicle type)
You get a lower capacity however you will still show a test voltage of approx 12 volts as they are in parallel , if in series you would show a drop of around 2 volts
So your telling me that they have an alternator thats got no regulation at all on it?..
Well its there then!..
If you mean the voltage will rise and fall with doing then yes it will but over a sod all range!..
Is this a high end account - most freebies I've seen get you towed to the nearest garage and that's your lot :-)
Yeah, Lloyds Premier.
£25 a month, but that's for our joint account - the AA cover is equivalent to the top line cover, which appears to be £176 for joint membership, plus I get stuff like mobile cover (worth it when you both have iPhones) and a stack of other stuff on top.Works for some, maybe not for everyone, though, at that money per month.
I took it out when I opted out of the company car scheme at work - obviously you need bulletproof recovery when you do that - and have kept it as it means I can jump in / on any of the 'fleet' and know I have decent cover, even though I'm back in company cars again.
No, it's got no protection against an overvoltage surge. Hence them charging you extra if you want one that has
If you bought a Jag. Most of us don't drive Jags.
That's a lot of money for insurance :-). We sat down and worked out that it's cheaper to self insure on pretty much anything. If it wasn't for my wife, I'd probably self insure for recovery of my car too, but I don't want her stuck in the middle of nowhere for hours trying t sort it out herself, hence Autoaid.
In article , Dave Plowman (News) scribeth thus
Well if they have a regulator of sorts in then yes they do, and of course there will be a limit to what they can produce anyway!..
Even when the reg. is turned hard on, the design of a car alternator makes it inherently self limiting. That's not to say it would stand running at full output forever. ;-)
Flypaper !
Why? Perfectly rational, see explanation.
I had bought a brake lamp bulb at a poundshop, the base was a bit rough with some solder sticking out, it was a hard push to get it into the socket. The rear light assembly is accessible from inside the boot. You just take out the frame and change the bulb. when the frame is in place, the bulbs protrudes through holes and light up the rear cluster.
However, as mentioned, the poundshop bulb had not locked in place, so it fell through the hole and into the red plastic cluster on the wrong side. The holes are too small for getting anything through to get a proper grip. Big problem now: Do I dismantle the whole car or do I live with the constant rattle. That's where the flypaper came in handy, figure it out, patent applied for...
Car: Spare bulbs Torch Footpump Towrope AA membership Credit card Standard tyre change kit Small screwdriver set Small penknife Disposable camera
Bike: Torch Spare bulbs Standard tool kit supplied with the bike Small penknife AA Membership Credit card Disposable camera
Dave
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