Gauge clusters - Which years got a Oil Temp gauge in the cluster?

[Herald1360]

An ammeter shows you directly whether the battery is being charged (dynamo or alternator supplying all of the electrical loads with some capacity left over to charge the battery) or discharged (more electrical load than the dynamo or alternator can cope with).

A voltmeter simply shows the battery voltage though the charge status can be inferred from this- roughly speaking, over 13.5V or so, the battery is probably charged and happy, less than about 12.5V, time to be concerned if it persists for more than a minute or two.

[Alan Drover]

The problem with an ammeter is the need for heavy duty high current carrying wires and I wouldn't fancy that with my 70 amp alternator. That's why I have a voltmeter.
My 1955 Series 2 Morris Oxford had an ammeter fitted as standard along with an oil pressure gauge.

[GVO418J r.i.p.]

The problem with an ammeter is the need for heavy duty high current carrying wires and I wouldn't fancy that with my 70 amp alternator

Not really -- even back in the day the Rover P5 had a remote ammeter shunt and much lighter duty wires to the ammeter/dash.

In the P5 it was a large chunk to be fair, but I imagine modern tech. has such things down to a normal relay size now.

At the end of the day the 2 instruments [ammeter/voltmeter] do differing jobs and with the advent of reliable high output alternators the voltmeter took over as the instrument of choice since it does the battery condition extremely accurately when there is no load on the battery, plus it crudely shows the alternator is charging when the vehicle is running and it's cheaper to fit

[NoBeardNoTopKnot]

...Not really -- even back in the day the Rover P5 had a remote ammeter shunt and much lighter duty wires to the ammeter/dash.

In the P5 it was a large chunk to be fair, but I imagine modern tech. has such things down to a normal relay size now.....

I did wonder, I searched up shunts - could find no diagrams. You've focused my search: found a P5 diagram, shows what you speak of clearly. Looks like there's under 2A going thru' ammeter. Thanks:

[Herald1360]

It took me a while to find the battery(ies) on that! Two 6V by the look of it (like my early 2A diesel, though probably not as big!).

It'd be interesting to know the technical details of the shunt and ammeter!

[Alan Drover]

OT maybe but the Morris Oxford Series 2 ammeter was fed direct from the control box without a shunt. I checked this in my BMC official workshop manual for the car.

[NoBeardNoTopKnot]

Perhaps so. gv04 put me on the scent. See Smiths ammeters on eBay; terminals come no larger than equiv. fuel-gauges, thus can't be moving much more current. The shunts must be very high current, near dead-short resistors.

[NoBeardNoTopKnot]

Nice looking gauge.
Let us know how you get on.

Sorry, dreadful pic; you get the idea. Looks like it coulda' been  factory, which is how I like mods. Sensor/sender was a simple swap-fit. was spec'ed for a early 60s Morry Minor - not the late. Many pre 65 run TC 12V format gauges. eg Farinas have them at 2 o'clock. Done.