AMP Gauge reading in Car

[Lateral]

Hi Guys

I have what I hope is a simple question.

I want to install a number of gauges in my 12 volt Type 1 beetles (I have 2) including an Amp gauge.

I think the alternator in one of my cars puts out 45amps and the other I think puts out 75amps...

I have the following questions:

1. What gauge range would I install (-30/+30) or something else?
2. What would the gauge be displaying at idle and under load?

Thanks for any help and info you can provide.

Regards
Greg

[Ol'fogasaurus]

First of all, not everyone is enamored with an amp gauge... but I am. I grew up with them and know how to read them so I am comfortable with them in my car. Supposedly... a bussed volt gauge is supposed to work the same as an AMP gauge (some may even be just that from what I have been told) but I have not been convinced that is true... yet.

That being said, the highest reading automobile AMP gauge I have seen only goes to 60 AMPs on either side of "0". Here in the states a generator is 30 AMPs and an alt is (roughly) 55 AMP. If you do use an AMP gauge I also recommend you add a appropriate sized fuse or circuit breaker as VW did not use one for protection on the long run from the charging system to the gauge and back. I have done that myself.

Lee

[Lateral]

Thanks Lee

[Ol'fogasaurus]

Lateral, I think I probably used the wrong word; bussing is probably not be the right word but shunted should be: Shunt: A conductor having low resistance in parallel with another device to divert a fraction of the current. Shunt circuit: A closed circuit in which the current divides into two or more paths before recombining to complete the circuit. http://en.wikipedia.org/wiki/Shunt_(electrical) Page down and look at; Use in current measuring. Also look at; Current measurement techniques. Everything I looked at seems to be directed toward digital reading not analog.

For some reason I have a problem with the words bussing and shunt when talking about low draw gauges.

All the ammeters I looked at on Amazon ended up being positive flow only and did not cover negative flow (draw on the battery or a draw that reflects over draw or shorts. Sorry 'bout that.

Lee

[Piledriver]

A non-shunt style ammeter should be avoided like the plague due to the long wire run already present in the car.

ALL the cars power other than the starter current must go through the meter...

Your vw already has way too much voltage drop, add a separate circuit for your headlights and run them off a relay direct off the battery for "enlightenment".

VW actually more or less designed this into the later cars, but taking the headlight and ignition switches out of the actual headlight circuit on my 74 914 was ~akin from swapping from well used sealed beams to HID.

Also not any automotive gauge has to be somewhat ruggedized, the display heads needed for an accurate shunt style meter will be beaten to death in your car unless you buy the right kind.

[Ol'fogasaurus]

Like I said, I did put some protection in where VW did not and did run larger wires. I currently don't have the AMP or Oil gauges in place as I need to move them from the dash to somewhere else as when the hood comes off the dash is part of the hood. It did work well for many years before I pulled it with absolutely no problems what-so-ever and the amp gauge read as accurate as a volt/OHM (both digital and analog) meter read.

Lee

[Lateral]

Thanks guys

[Ol'fogasaurus]

This is how I solved the problem. One side is a switched (ignition) set of circuit breakers and the other side is running hot. The idea was to have the separation, in case of a problem out on the dunes, incase of one circuit fail and not take out the other side.

Lee

[Lateral]

Thanks Lee