Hi Team

How do I wire up a aftermarket volt meter?

thanks,
wes

+ positive side to key on source and ground -. the back of gauge should have a + and - symbol

Good Choice over the AMP. METER....VOLT Meters are easy to install unlike AMP. METERS that have burned many a vehicle under the dash.

You should have a "ACC" terminal on your fuse panel..... connect the + wire of the gauge to it and ground the - wire to the dash.

I agree, volt meters are the way to go.

Have an original ammeter on a 66 with the optional guage package. It works, so it's possible that the ammeter could start a fire. How does this work? Plan to put an oil/tem/volt guage package even though all the original guagues seen to work fine. So sould I unhook the ammeter or are there precaustions I should take? Thanks

Amp meters are connected in SERIES with supply and indicates an increase or decrease of current (charge or drain) in the circuit. Therefore it can allow a significant amount of current to flow thru the wire if it's shorted. (read as potential for FIRE) However, FACTORY wired ampmeters rarely cause problems. Their circuits are designed to be well insulated and properly routed.

Volt meters are in PARALLEL to the supply and indicate amount of voltage present at the connecting point. Requires very little current to operate and can quick-fused to prevent heating the wiring if shorted.

Us old timers are used to ampmeters and some prefer them. They do give an actual status of the supply circuit and the alternator (gernerators in the old days). Obviously, if the current meter (ampmeter) indicates a constant negative flow of current, things won't go well for very long.

Voltmeters are a relatively recent addition to cars. They are cheaper to incorporate, easy to fuse for safety and easier for the average person with little to no electrical knowledge to understand. A volt meter can also indicate that the alternator is not funtioning or putting out 13.9 to 14.3 (nominal) voltage. If it is only showing 12 volts or less when the engine is running, it too is a good indicator that something is amiss in the charging circuit and you will be walking soon. An HEI distributors like to see a solid 12 volts at all times, not 11 or 10. However, a bad battery can still show 12 volts on a voltmeter in an unloaded condition.

Both gauges can co-exist and function just fine. No need to remove or disconnect either if they are wired and funtioning correctly. However, if their function and indications aren't clearly understood, you're better off with an idiot light. That's why they were invented. No offense intended to anyone, just MHO. My wife's Jeep has gauges. She has no clue how to interpret them for a potential problem and doesn't want to learn. But if a bright RED light comes on, she know's she has a problem. (either in the car or from the cop behind her ;-))

/h

Thanks for the information Herb. All original wiring with the 66 guage package that included the ammeter and it seems to work fine as far as indicating a charge or draw. Have deceided to carry an fire extingisher also, just in case. So think I go ahead and add the 3 guage set-up and keep the original guages operating also.

Sounds like all good decisions Jim. Don't worry about a fire from the original amp gauge wiring. It's just not a major issue. If it were, there wouldn't be any original cars around after 30+ yrs with original amp gauges. Just be careful when monkeying around under the dash not to short anything. Like I said earlier, us old farts are used to them and I've never seen a fire caused by an amp gauge. Not saying there haven't EVER been any, but I know of none.

I took a second look at my gauge and it is a ammeter, should I get a voltometer instead?

thanks,
wes

YES........ I would. easy to hook up and safer.

Volt meter = easier to hook up, not as useful
Amp meter = requires more care when installing, more useful readout

I've always prefered amp meters since I can tell at a glance if the electrical system is working properly or not. Heck, my old pickup has a factory amp meter AND an aftermarket amp meter and I haven't burned it down yet. The factory gauge has unhacked factory wiring and the aftermarket gauge was wired carefully with large gauge dedicated wiring.

I've never had a problem with any of the amp gauges in any of my vehicles. I find the volt meter in my daily driver only moderately useful since it is difficult to tell if it is reading at, above or below 12 volts. I rarely even look at it. If it wasn't for the additional warning light in the daily driver I'd never really know when the electrical system is experiencing a problem. However in my truck or Chevelle, I often consult the amp meter to see how things are doing and know what I need to know at a very quick glance.

I took a second look at my gauge and it is a ammeter, should I get a voltometer instead?

thanks,
wes

I wouldn't. Just make sure it's wired correctly and use it. Like I said, I've never even heard of a car fire that could be attributed to an amp meter that was wired correctly. In the 60's, there were a lot of teenagers wrenching on these cas (I was one) and even they didn't burn them up with amp meters.

If you want to use an amp meter, simply wire it per the instructions (they are usually VERY specific and most often make specific since different cars accomplish their power systems in different manners), use large gauge dedicated wiring and route that wiring in such a way as to protect it. Be sure to use rubber grommets where the wires pass through the firewall and zip tie the wires securely to the body structure and/or other wiring harnesses to keep it out of harm's way. Make sure the connections at the gauge are secure and well separated from each other and from any metal body structure and other wiring terminals.

Of course these tips apply to ANY automotive wiring project...

I would use a voltmeter, see reasons here.

http://www.autometer.com/tech_faq_answer.aspx?sid=1&qid=5

I have a amp meter installed on the '68, and early on I did have an incident where the leads behind the gauge touched. Plenty of sparks and smoke!

Towed the car home and easily replaced the wires. But it was my fault for not securing the wires properly. That was 10 years ago, and I'm still using the same Amp meter, checking the connections from time to time, but quite satisfied with it's accurate readings and health of the battery/charging relationship.

The caviat with the amp meters is what everybody else is stating....Make sure all is tight, insulated and safe.

From what I've read, the factory amp meter on the 60's Chevelles (and probably most other cars of the era) weren't true amp meters, but more of millivolt meters, reading the difference in voltage from one side of the horn relay to another. This difference is proportional to the current draw, so with the right scale on the gauge (or a less-distinct Charge/Discharge), the gauge would read in amps, without having all the current pass through it.

Aftermarket amp meters are actual amp meters, all the current that flows through your car goes through the ammeter. That's where the risk of fire starts. You have to have some pretty thick wire to handle the total current flow on some of the cars out there, with some heavy electrical loads (think electric fan, electric fuel pump, A/C, maybe a compressor for airbag suspension, stereo, etc.). Yeah, I know the alternator will run most of it, but in case of an alternator failure, where's that current going to come from? Yup, the battery, through your ammeter.

Basically, if it's a factory ammeter, I'd say you're okay, but if I had to add in an aftermarket gauge, I'd go with a voltmeter.

thanks for all of the help!
-wes