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I braved the freezing garage today and fitted my voltmeter.

it is in place of a very early vacuum gauge so I didn’t need to cut the dash.

the feed is off the ignition switch and the light feed from the adjacent Rev counter bulb feed ( a bit bright tho !!)

i will be removing the ammeter and replacing it with an oil temp gauge when I get around to fitting my Ali sump with its temp sender boss. 

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Hamish - appears that your overdrive switch is UP to engage, the opposite to the majority, I seem to think (certainly the opposite to what I found both on my TR2 and 4VC).

Ian Cornish

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1 minute ago, ianc said:

Hamish - appears that your overdrive switch is UP to engage, the opposite to the majority, I seem to think (certainly the opposite to what I found both on my TR2 and 4VC).

Ian Cornish

Yes you are correct Ian 

it’s how the car was when I got it,  all I have done is fit a momentary switch for the logic box.

to me flicking the switch up is to go faster  !?!?!

 

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My TR came to me in 1975, with the original egg shaped switch mounted so up is overdrive engaged.  I have not changed it.  It catches my brother out when he drives the car, same way as his one does to me.

I have a plug in combination voltmeter, air temp and usb thingy plugged in my cigar lighter socket. Cost under a tenner.

Peter W

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Edited by BlueTR3A-5EKT
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8 minutes ago, Z320 said:

Hi Hamish,

what in your opinion is the benefit of a voltage gauge instead a ampere gauge, please?

Ciao, Marco

My only knowledge is ammeters seemed to be matched to dynamos

and voltmeters to alternators 

ammeter shows the usage and the volt meter the storage potential and the rate that the alternator is putting out. 
 

it’s changed on a whim tho as I’m no expert 

I expect to see 13-14+ when running

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11 minutes ago, Hamish said:

My only knowledge is ammeters seemed to be matched to dynamos

and voltmeters to alternators 

ammeter shows the usage and the volt meter the storage potential and the rate that the alternator is putting out. 
 

it’s changed on a whim tho as I’m no expert 

I expect to see 13-14+ when running

 

Mine sits around 13.

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In my personal opinion, but I could be wrong, an ampere meter tells you very fast about a problem while a voltage gauge with "12 Volt" from the battery still tells you everything is OK.

Just an idea...

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IMHO both types have some merits. An ammeter is more of a diagnostic tool as it shows the actual current flowing into and out of the battery, from which you can assess the state of the battery by how quickly it recharges after starting. It also helps to show whether the charging circuit is working correctly. It would be obvious instantly if the fan-belt snapped, for instance.

A voltmeter cannot do that - it can only tell you the average voltage coming from the generator (of whatever type) when the engine is running or the state voltage of the battery when it is not. It doesn't tell you whether the battery is actually taking charge current nor whether some load is causing a drain.  Most voltmeters are slow-acting so cannot respond to fast changes of load.

The wiring for a voltmeter is -arguably- safer, since there is no need for high-current wiring behind the dash. 

You pays your money and takes your choice...........

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33 minutes ago, 2long said:

Don’t know much about electrickery but that’s a cool looking dash and the illuminated gauge looks great.

Cheers

Dan

Thanks Dan

;)

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11 hours ago, Z320 said:

In my personal opinion, but I could be wrong, an ampere meter tells you very fast about a problem

while a voltage gauge with "12 Volt" from the battery still tells you everything is OK.

Just an idea...

12 hours ago, Hamish said:

My only knowledge is ammeters seemed to be matched to dynamos

and voltmeters to alternators 

ammeter shows the usage and the volt meter the storage potential and the rate that the alternator is putting out. 
 

it’s changed on a whim tho as I’m no expert 

I expect to see 13-14+ when running

 

I am thinking of doing this change myself.  The old ammeter only goes to 30amp, and the alternator can put out 45. Also one can wire the alternator direct to the battery and eliminate some of the high current wiring behind the dash. I don`t drive watching the ammeter all the time, and in the event of something sudden happening, like a fan belt breaking, I am more likely to see the big red light on the dash which is a more visible and instant warning. The volt meter gives you a better idea of the condition of the battery if you bother to check it before starting the engine, and you can tell whether the battery is charging from the voltage.

I think ammeters are old school, dating from the days when feeble dynamos could barely keep up with the electrics on the vehicle and it was necessary to know if you needed to turn your heater fan off for a few miles to let the generator put a bit more juice back in the battery, or your ancient regulator box was starting to play up.

I also think Hamish is right as it was around the early seventies when alternators became the standard fitting on most cars that voltmeters (sometimes labelled as battery condition gauges) started to become the normal fitment. As the alternator removed the need for a voltage regulator box it also removed some of the need for an ammeter.

I would say if you still have a dynamo and control box, keep the ammeter. If you have moved into the 20th century with an alternator fit a voltmeter.

Ralph

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What I didn’t realise is that the small gauges seem to be lite by a couple of external common bulbs and the gauges have slots in them to let in the light !

no wonder they are so dim. 
and I think one of the bulbs is out. 
There are a lot of wires in there ! 
 

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1 minute ago, Hamish said:

What I didn’t realise is that the small gauges seem to be lite by a couple of external common bulbs and the gauges have slots in them to let in the light !

no wonder they are so dim. 
and I think one of the bulbs is out. 
There are a lot of wires in there ! 
 

Mine are newer gauges, in the main recovered from a spare Vitesse dash I had, so all have individual lights, but you don`t get that nice glow behind the dash. I used to have a Sunbeam Talbot 90 that had red lamps in the footwells that came on when the heater was used to make it feel cosy. It does mean though that the voltmeter I buy will match the rest of the gauges. 

Ralph

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What I didn’t realise is that the small gauges seem to be lite by a couple of external common bulbs and the gauges have slots in them to let in the light !

Hi hamish, problem with dim small guage sis that teh plastic 'Yellows' with age, doesn't help with illumination.

I very much like your dash also, very business like.

John.

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I also I need to understand the wiring diagram ( and be able to read it with 2 pairs of reading glasses on !!)

if I can fully isolate any of the wires to/from the ammeter ?

as it’s my intention to just join them all together 

but that does leave that high power electrickery live behind the dash. 
 

I have my alternator and I have modded my regulator box to suit. It has some fat brown wires that look similar to the ones on the back of the ammeter ?

are there wires that go to the ammeter and back purely to make the ammeter work or once out of the ammeter do they supply things behind the dash ?

I think there is already some add on in there for the elec fan/override switch/fan on light.

it’s a bu@@er not being able to see close up anymore without glasses especially whilst upside down under the dash. 

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11 minutes ago, Hamish said:

are there wires that go to the ammeter and back purely to make the ammeter work

Yes Hamish - on the 3A the high current charging wires come from the generator via the control box pinA  to the ammeter and then back out again to the fuses and battery. As standard there is nothing else taken direct from the ammeter behind the dash - the feed to the ignition-switch and lights comes from the control box. 

You could just join the ammeter wires together and leave them behind the dash, provided you insulate the joint properly of course as you say because they will still be 'live' and carrying all the battery charging current.

Alternatively you can eliminate them completely and make the joint in the engine bay - just disconnect and insulate both ends of both the old ammeter wires and put in a new linking wire of the same size between the places they came from.  

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I’ll have to have another look and come back to you guys for advice on this one as I have a number of wires on the back of the ammeter.

so thank you. 
 

H

PS just for info my car was Tony Thompson’s so there will be very good and safe reasons for any deviation. 

Edited by Hamish
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Just now, Hamish said:

I’ll have to have another look and come back to you guys for advice on this one as I have a number of wires on the back of the ammeter.

so thank you. 
 

H

That will be feed for the overdrive for one and possibly a direct feed power supply for a charger socket.

Stuart.

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Hi,

I have a different view on that.

An ampere meter is a very useful instrument – but the issue of lots of questions and complaints from standard customers.

Some examples wanted?

“Every time I open the door (when the interieur light became standard) the ampere meter shows negative – there must be a problem”

“with the engine off I can’t keep the radio switched on – because this discharges the battery”

“When I use the cigarette lighter I always have a massive current problem, this damages the battery”

“With my new radio I always have a positive current (because "he" connected it direct on the battery)”

“with a stronger alternator I need a stronger ampere meter (no, the charge of the battery rules the current, not the alterator)”

With a voltage gauge you have NOT ONE of this complaints!

With the cars more comfortable, more people able to own one and less interest in the technique the producers needed to get rid of them.

So the swoped the ampere meter to a voltage gauge and “the problem” was very easy solved.

Brilliant!

Todays consumers you better not even discommode with any move on the water temperature gauge.

Edited by Z320
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1 hour ago, David Owen said:

What is wrong with having both?  To me it is a positive redundancy.

I am planning on fitting a hard “wired” oil temp gauge and the distance sump to dash works best to replace the ammeter. Which is why the volt meter is the other side of the steering wheel after removing a manifold vacuum gauge. 

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29 minutes ago, Hamish said:

I am planning on fitting a hard “wired” oil temp gauge and the distance sump to dash works best to replace the ammeter. Which is why the volt meter is the other side of the steering wheel after removing a manifold vacuum gauge. 

 

Ahh.  Thanks. 

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A bit late to the party here but I also swapped my ammeter for a voltmeter by connecting the wires together behind the dash. 

With cold weather, lots of short trips and sometimes a few weeks between drives, I like that I can check battery condition just by looking at the gauge. 

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