Jump to content

Ammeter v clock


iana
 Share

Recommended Posts

My car currently has an ammeter installed and I’m not sure of the benefits of one with an alternator (I thought they were more useful with dynamos) so was thinking as part of the work I’m doing to remove the ammeter in its entirety and install a clock. 

Is there any real benefit in retaining the ammeter?

Link to comment
Share on other sites

Not really and as you say you are running an alternator. Personally, I'm not a great fan of them.

Additionally, the ammeter has to handle some significant amperage - if your wiring is old or perhaps not up to scratch then the ammeter will test it !!

I tend to advocate a volt meter / battery indication gauge; there are some very nice Smith units about - the current used by a volt / battery indicator is far less and simpler; an earth and a ignition side connection.

You can purchase period gauge holders and many have 1, 2 or 3 instrument options - ideal for a volt meter and a clock, without cutting an extra hole in the dash !!

Regards.

Richard.

Link to comment
Share on other sites

You cannot mistake the wiring and easy to track the route - it's thick !!

I was going to suggest looking at the WSM, but it is probably an after market fitting ??

You will likely find one wire going to the solenoid, another to the fuse box and certainly an earth. There may be another wire, but cannot off-the-top-of-my-head think what that wire is or where it goes to - in fact it may just be the three I mentioned.

Different cars have different ammeter wiring set-ups.

Regards.

Richard. 

Link to comment
Share on other sites

It’s an aftermarket job, under the dash is easy to follow as it’s got a woven sleeve on the cable. I think it’s a battery disconnect and then remove back to source and put it on eBay.

Link to comment
Share on other sites

I like an ammeter, it tells you the state of your charging system, it's immediate, the battery's charging or it's not. A volt meter tells you the state of your battery. You can figure out the charging system's not working from the volt meter dropping but by the time you notice it's too late!

The trouble with the usual ammeters is the size of the cable required, all the current goes through the ammeter, so a heavy cable is required and dangerous to have behind the dashboard. I eventually took mine off and sadly replaced it with a volt meter.

On my old mini I had a shunt ammeter, a volt meter sits across a tiny high wattage resistance. The volt meter reading is proportional to the current going through the resistance and the dial calibrated to current. It was a Smiths but they don't make them anymore. 

I've just bought a new ammeter device from Germany it has an encapsulated coil and the battery cable goes through it, haven't tested it yet, it has an LCD but it might be useful.

Doug

Link to comment
Share on other sites

11 minutes ago, dougbgt6 said:

I've just bought a new ammeter device from Germany it has an encapsulated coil and the battery cable goes through it,

I rather hope it's not actually a coil, because that won't work. A coil (toroidal inductor) with a cable through it will act as a transformer of sorts and can be used to measure AC currents fairly accurately. It's also how strobe lights work because they're only interested in the spike of current - which is AC. But to replace a conventional ammeter you need to measure DC current.

The device used to do that is called a Hall probe. It still has the magnetic toroid to "capture" the field around the wire, but inserted in a gap in that toroid is a small piece of semiconductor material with a current passing through it in one axis and a sensitive voltage measurement circuit across the other axis. The magnetic field "bends" the current so that the electrons are concentrated on one side and a voltage is produced, proportional to both the sense current and the magnetic field, which is, in turn, proportional to the current in your big fat wire.

Link to comment
Share on other sites

This is what Im intending to do, Ive got the fascia plate in the polished aluminium which Id like to change to black either crinkle finish (if I could find the paint) or satin black, what would I need to do to key the surface, a good sanding, and a primer plus a couple of top coats or would I be better covering in vinyl?

image.png.7771ba699f51301ed6c20ac31ab36c47.png

Link to comment
Share on other sites

For an aluminium panel, I'd go with: good sand down, wipe with thinners, coat of etch primer, two coats normal primer, allow to set, light rub down, then the crinkle finish applied as per own method derived from the instructions but tested on scraps first. The last lot of crinkle finish I bought needed some variation from what the tin said (IIRC, fewer, lighter coats, longer apart). The paint is VHT brand, available from Frost, eBay, Amazon and others.

Alternatively, covering in black vinyl from Park Lane gives quite a nice finish.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...