TVRs wonderful electrics

[magpies]

I've been chasing the reason my voltmeter drops when switching load on. The gauge shows just over 13v with no load and drops to just over 12v with everything turned on!

New battery (even though the old one tested ok) and change of alternator and still the same.

I then checked the alternator output voltage and that is 14.1/14.2v no matter what load, then checked at the battery (in the boot) and that is the same!

so looks like there will be some dirty connections - will have to see if I can borrow a thermal camera

[phillpot]

magpies said:

I've been chasing the reason my voltmeter drops when switching load on.

T.A.D.T.S.

[Penelope Stopit]

This method will give you a true reading

[glenrobbo]

phillpot said:

magpies said:

I've been chasing the reason my voltmeter drops when switching load on.

T.A.D.T.S.

They certainly do! As Alanis Morrisette will confirm ( "Jagged Little Pill" ).

[Steve_D]

Penelope Stopit said:

This method will give you a true reading

Small correction if I may.
Your relay coil should be connected with pin 85 to ground.

Steve

[magpies]

phillpot said:

magpies said:

I've been chasing the reason my voltmeter drops when switching load on.

T.A.D.T.S.

must be that They All Are Wired Incorrectly too

[Penelope Stopit]

Steve_D said:

Penelope Stopit said:

This method will give you a true reading

Small correction if I may.
Your relay coil should be connected with pin 85 to ground.

Steve

Thanks. Will you kindly explain why, before doing so please note that the relay in the diagram does not have a diode across the winding
I can't be any fairer than this can I

[v8s4me]

magpies said:

I've been chasing the reason my voltmeter drops when switching load on......

If it works leave it alone until the winter. If the sun shines, DRIVE IT!

[Maffe]

Well it´s a feature!
Looks like the electrics work just perfect with in TVR specifications for you

[Steve_D]

Penelope Stopit said:

Steve_D said:

Penelope Stopit said:

This method will give you a true reading

Small correction if I may.
Your relay coil should be connected with pin 85 to ground.

Steve

Thanks. Will you kindly explain why, before doing so please note that the relay in the diagram does not have a diode across the winding
I can't be any fairer than this can I

True the relay will work either way round unless there is a diode inside but the presence of a diode is often not marked on the relay so it is best to use the correct (DIN72552) pin connections at all times.

Steve

[magpies]

I'm only a little worried as last year in the heat of Le Mans the fuse/relay box started to melt. Since then I've fitted a modern Focus one so thought I'd fixed the problem but obviously not. Some time in the near future I'll take the dash out and remove the redundant wires and reterminate the rest. As well as sorting out the heater system.

[MisterTee]

Mine does that too Mick - can be quite entertaining watching the needle flicker in time with the indicators!

Andy

[v8s4me]

At one time my fuel gauge used to flick up and down with the indicators. Passengers used to love that "feature". I fixed that and now the gauge doesn't move from 3/4 full until it is down to the last gallon then suddenly it hits the deck.

[MisterTee]

Now that's far more entertaining!

[Penelope Stopit]

Steve_D said:

True the relay will work either way round unless there is a diode inside but the presence of a diode is often not marked on the relay so it is best to use the correct (DIN72552) pin connections at all times.

Steve

Good point. There is nothing worse than purchasing a standard relay and later finding out it has a diode or resistor in it when not wanted
The proof reading department will spot my error and alter the final product as required
I was undioded whether to reply or not but in the end couldn't resistor it

[magpies]

magpies said:

I'm only a little worried as last year in the heat of Le Mans the fuse/relay box started to melt. Since then I've fitted a modern Focus one so thought I'd fixed the problem but obviously not. Some time in the near future I'll take the dash out and remove the redundant wires and reterminate the rest. As well as sorting out the heater system.

Just in the process of doing this

[Penelope Stopit]

Ok, if you start a new topic and post plenty of images of what you've got we can go from there

Perhaps a topic titled magpies on a wire would do

Edited by Penelope Stopit on Thursday 22 November 20:35