What tools should be carried in a modern car?

So why would a jump start cause a bigger spike then?..

So not voltage regulation in the alternator that that can cope with that?..

Well I've been jump starting other peoples cars for years now with none of the problems. I'll try running the car I have with the battery disconnected and see what a storage scope has to say about that then;!...

Or take the output of the alternator to a 12.8 volt load bank we have a switched one here up to 200 amps..

Yep from the battery..

Kicks in?. That comes up to speed as it will normally do when the cars started;!..

See the other post on this...

In article , Dave Plowman (News) scribeth thus

Does it?, no solid state voltage regulator then?...

AKA a battery box.

Which for the last decade has built in surge suppression.

Chris

Why does it have twin batts then, is it 24 volt overall?..

In article , johannes scribeth thus

I had to do that on a Mini from central London to Cambridge once years ago. Some first gear starts which it did very well and a Lot of carefully timed and speed matched gear changes;!...

and a lot of anticipation of what the traffic was doing up front;!..

You run an alternator with the battery disconnected and you will fry your electronics, they kick out around 48 volts 3 phase

En el artículo , SteveH escribió:

Transformers only work on AC. Your Pious's batteries are DC.

I really don't care about the technicalities of it.

I'm just surprised there's no way to use the hybrid battery to power up the car if the very small 12v battery is dead.

No the batteries are connected in parallel gives a greater capacity

Nope, Bosch charge you extra for that. Jaguar actually fit it as a separate part.

Turning the headlamps on & off should get you one you can see without breaking anything

Try switching it out with the battery disconnected.

I think its possibly a concern that the power supplies if not isolated could make the bodyshell live at 480 volts

Many alternators won't put out anything unless connected to a battery. The field is excited from the battery via the warning light. Of course if you started the engine then disconnected the battery you could well get very high volts. But why would you?

Right.. So the alternator is a Three phase generator with a rectified output. Now from what you've just said the battery is a dump for that what the alternator is generating. OK so how then does the alternator control itself or the said output from same is controlled or else surely the battery will be over charged if there is no current /voltage limiting on the unit?.

You cannot just use the battery to dump excess power without some sort of regulation can you?..

It may well under total discharge conditions take most all of the alternator output but what happens when the battery is fully charged?.

This going to rise to the 48 volt output is it?...

In article , Dave Plowman (News) scribeth thus

Well very possible to have a duff connection on the battery leads which of course might just be "made" better by a set of jump leads applied. Joint then plus added jump battery may start the car. Leads removed joint now free to be intermittent again then what happens?.

Are you suggesting that the volts are now going to go waay North of nominal because the battery is disconnected?...

Literally just across each other?..

Wonder what happens when you get a duff cell on just the one?..

In the best reporter fashion perhaps you should add 'allegedly' ? I can give you one possible version.

Car breaks down due to faulty ECU. Battery run flat trying to re-start. AA called. They try jump starting but doesn't work. Car taken to garage who diagnose faulty ECU. Owner believes (either genuinely or fraudulently) it was the jump starting which caused the failure and sues the AA. Who, of course, just settle out of court as the easiest way. Then mandate the fitting of surge protectors.

I'd love to know how an LED or two could confirm that the snubber network on these surge protectors is actually working as it should.

RAC through Tesco vouchers. Costs about the same in voucher value.

MBQ