VDO ampmeter on a one wire alt?

[djvw1969]

The way I figure this is to run the wire from the alt to the + side of the amp meter. Then run the - side back to the battery. Take the load for headlights and the ing sw off the - side also. Am I correct?

[Ol'fogasaurus]

https://www.bing.com/videos/search?q=ho ... AF0928AC37

This is on a VW bus where they are adding a volt and AMP meter. I recommend 8 ga. wiring on the long run. I had posted something before but was questioning myself so I looked this up.

An AMP gauge measure the working current flow and direction. A volt gauge measures voltage capacity... more or less. A shunted voltage gauge is supposed to do the same thing (I have been told) but no one has yet proved it to me. An AMP gauge, if you know how to read it will tell you a great amount of what is going on electrically.

Lee

[Ol'fogasaurus]

Even though VW didn't do it I like to add a properly sized C/B in line to protect the long run forward and back.

Lee

[Piledriver]

I almost violently recommend a shunt type ammeter to eliminate the excessive wire run.
Or better, nothing at all.
We already know how long wires work out in the long run.
Wires should be as short and fat as possible... an extra 30 feet does no one any favors, in addition to the existing mess.
...And use a fuse or circuit breaker.

A voltmeter connected at the battery via a relay is more than sufficient to determine charging state-- don't add unnecessary complexity that reduces reliability, you don't need your own version of the F35.

[Ol'fogasaurus]

I agree up to a point. An AMP meter if you know how to read it can tell you volumes about your electrical system. A shunt, if I remember correctly softens up the readings. Do run a CBS any high volt, high AMP wire. Again, a I recommend at least an 8 Ga wire.

[Piledriver]

I agree up to a point. An AMP meter if you know how to read it can tell you volumes about your electrical system. A shunt, if I remember correctly softens up the readings. Do run a CBS any high volt, high AMP wire. Again, a I recommend at least an 8 Ga wire.

~ ALL high current "ammeters"- past ~100mA have a shunt built in, its just in the wrong place for a sane ACVW electrical system.
(You think that tiny little meter movement coil is passing 50-100 Amps? Think again, the shunt is in the ammeter, and its just a voltmeter playing an ammeter, I have worked on that sort of junk for decades)

I maintain my violent opposition to an extra 30 feet of unnecessary wire and useless dash filler.

Run an additional run of fused 8 ga to the fusebox from the battery, run your headlights etc off it via relays?
Good plan.

Stick a voltmeter in the dash wired direct to the battery, via an ignition powered relay so it turns off?
Good Plan. 13.8-14.1v is a full charge.

STILL have to have an ammeter?
Install one with a remote shunt at the battery.

In dash "direct" ammeter and 30 extra feet of wire?
Really Bad Idea.

[Ol'fogasaurus]

I will bow to your superior knowlege. I had my gauge looked at and I was told it didn't have a shunt in it a long time ago but I don't know or sure. It reads 60 amps so it might be what you say.

I'll still argue that an AMP meter/gauge will tell you more than a volt meter/gauge and quicker too. Since I grew up with them in cars (mid 50s and on... about the same time the car companies went to idiot lights as most people didn't have a clue other than the gas gauge and the idiot lights and by that time the lights went on it just meant... Oops, its too late) I got use to reading/using them both for myself and as a erstwhile mechanic (at the time).

I agree with the long run of wire which is why on the next rewire (a shortened pan glass buggy) all the important stuff is not going to be under the dash but in the rear like I would with a rail; e.g., minimal stuff like an idiot light or two. But still, if you have to do it protect it as VW didn't for some reason.