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Re: Voltmètre or Ampmeter?
[Re: Toucan]
#610374
31/12/19 09:02 AM
31/12/19 09:02 AM
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Joined: Feb 2016
Posts: 3,678 East Harling, Norfolk UK
RichardV6
Talk Morgan Addict
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Talk Morgan Addict
Joined: Feb 2016
Posts: 3,678
East Harling, Norfolk UK
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As already mentioned ammeters, which measure the current both going into and out of the battery (hence centre zero scale) generally went out of use when higher current alternators took over around the late 1960's. If you know what to look for they offer more immediate information on your cars electrical performance than a voltmeter. Downside is that all the battery current has to pass through the instrument or its shunt which is usually integral to it. This is an extra link in the chain involving higher current handling cables so generally not practical with modern car alternators putting out 50 + amps for reasons of reliability and cost. Higher current ammeters with remote shunts are available, the ones on my boat measuring up to 500 amps, but not practical for use on cars.
A voltmeter on the other hand is very easily fitted without interrupting any of the existing car electrics, allowing an approximate guide to battery state of charge before engine started and also if it is being charged to some degree afterwards.
Richard
2018 Roadster - Red/Magnolia - "Morton" 1966 Land Rover series 2a SWB 1960 Velocette Venom
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Re: Voltmètre or Ampmeter?
[Re: Toucan]
#610387
31/12/19 11:08 AM
31/12/19 11:08 AM
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Joined: Jul 2015
Posts: 921 Shropshire
MDS61
Talk Morgan Regular
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Talk Morgan Regular
Joined: Jul 2015
Posts: 921
Shropshire
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I love instruments within the car to tell me "stuff".
However, as soon as one of these does something - out of the ordinary, I can go into a blind panic!
The missus modern however, does not even have a temp gauge, yet I never worry about the car over-heating....."knowing stuff - is important - but can worry you?"
Honesty means doing it right, even when no one is looking!
2004 Roadster S1 3.0 V6 - "Seve"
Mark
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Re: Voltmètre or Ampmeter?
[Re: John V6]
#610389
31/12/19 11:17 AM
31/12/19 11:17 AM
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Joined: Dec 2019
Posts: 32 Touraine, France
Toucan
OP
Just Getting Started
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OP
Just Getting Started
Joined: Dec 2019
Posts: 32
Touraine, France
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JohnV6, l didn't find the one with Voltmeter,alll found were with Ammeter, including the one within the instructions booklet provided with the car and hopefully gone to me. Could you provide a link or send me the right one via MP?
BTW, thanks all of you who answered, it helps. I didn't know the link between Ammeter and dynamos / Voltmeter and alternator. Seems that factory improvement was not synchronized with documentation update.
Toucan 1981 4/4 Kent
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Re: Voltmètre or Ampmeter?
[Re: Toucan]
#610391
31/12/19 11:26 AM
31/12/19 11:26 AM
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Joined: Dec 2009
Posts: 27,141 Devonshire
+8Rich
Member of the Inner Circle
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Member of the Inner Circle
Joined: Dec 2009
Posts: 27,141
Devonshire
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If you click on the Blue Voltmeter link on my earlier reply you will see the link to the diagram from gomog they call it a volt gauge , Lorne is the owner of that very useful site. The diagram is for an 1988 model but the first one with a voltmeter I could find.
Regards Richard
1999 Indigo Blue +8 2009 4/4 Sport Green prev 1994 Connaught Green +8 prev
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Re: Voltmètre or Ampmeter?
[Re: Toucan]
#610410
31/12/19 12:38 PM
31/12/19 12:38 PM
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Joined: Jul 2007
Posts: 19,605 Suffolk
John V6
Member of the Inner Circle
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Member of the Inner Circle
Joined: Jul 2007
Posts: 19,605
Suffolk
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JohnV6, l didn't find the one with Voltmeter,alll found were with Ammeter, including the one within the instructions booklet provided with the car and hopefully gone to me. Could you provide a link or send me the right one via MP?
BTW, thanks all of you who answered, it helps. I didn't know the link between Ammeter and dynamos / Voltmeter and alternator. Seems that factory improvement was not synchronized with documentation update. GoMog has an 84 car http://www.gomog.com/allmorgan/Wiring44Diagram1984.jpgand a 74 car http://www.gomog.com/allmorgan/wiring44diagram1973.jpgBoth as you say show ammeters
JohnV6 2014 Brooklands Edition Roadster "Brookland's Belle" #5 of 50
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Re: Voltmètre or Ampmeter?
[Re: MDS61]
#610524
31/12/19 09:33 PM
31/12/19 09:33 PM
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Joined: Dec 2011
Posts: 1,943 Seattle, USA
Button
Talk Morgan Enthusiast
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Talk Morgan Enthusiast
Joined: Dec 2011
Posts: 1,943
Seattle, USA
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I love instruments within the car to tell me "stuff".
However, as soon as one of these does something - out of the ordinary, I can go into a blind panic!
The missus modern however, does not even have a temp gauge, yet I never worry about the car over-heating....."knowing stuff - is important - but can worry you?" +1 - My '63 +4 has a ammeter as well as a voltmeter. Not sure what the ammeter does except scare the hell out of Me. As I have an Alternator I pay attention to the Voltmeter and not the ammeter. My Son In Law (auto electric mechanic) says the ammeter is "TROUBLE". Remove it!!!!!!
Button
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Re: Voltmètre or Ampmeter?
[Re: Button]
#610726
02/01/20 08:15 AM
02/01/20 08:15 AM
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Joined: Feb 2016
Posts: 3,678 East Harling, Norfolk UK
RichardV6
Talk Morgan Addict
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Talk Morgan Addict
Joined: Feb 2016
Posts: 3,678
East Harling, Norfolk UK
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My '63 +4 has a ammeter as well as a voltmeter. Not sure what the ammeter does except scare the hell out of Me. As I have an Alternator I pay attention to the Voltmeter and not the ammeter. My Son In Law (auto electric mechanic) says the ammeter is "TROUBLE". Remove it!!!!!! Having both gives you the fullest picture on battery charging and electrical consumption but OTT on a car. Basically ammeter gives instantaneous info whilst voltmeter gives trend (cause and effect). Your SIL is right though in suggesting you remove ammeter unless it's kept for originality. The shunt within is necessarily a very low resistance so mechanically robust, but the extra cabling and connection's on what is the main power feed to all but starter add a degree of unecessary unreliability.
Last edited by Richard Wood; 02/01/20 08:16 AM.
Richard
2018 Roadster - Red/Magnolia - "Morton" 1966 Land Rover series 2a SWB 1960 Velocette Venom
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