I bought an amp meter but the directions are very vague, only mentioning a few American automakers and how the meter may hook up with them. I know some people have them, so where should I route my + and - wires for a reading ??

 

1987 GL-10 Turbo 5 speed.

 

Thanks,

Chad L

The gauge gets wired into the thick single wire that is "bolted" to the back of the alternator. If its like what I'm used to you have to cut that wire connect one wire to one side of the cut wire, and one wire to the other side of the cut. Make sure to use wire equal or larger in size than what you cut. Run both wires to your gauge and hook them up. This is where I usually screw it up. Hook up the wire that goes to the alternator to the + on the gauge and the other to the -. If you start the car and it reads - then switch the wires.

 

Also, when running the wires make sure there is no chance for them to get pinched. If the wires short against the body BAD things can happen.

 

Keith

Keith, I'm sorry that connection will only show + current flow.

The correct point is between the main wire feed from the fusible link box and the battery.

This will show discharge and charge as the case may be.

BTW

The alt. output goes to the fusible link box and then from there to the battery through this wire.

 

Hope this helps

Skip's correct, you want to connect the ammeter in series between the battery and the rest of the car (but exluding the starter). Find the heavy wire (about 10ga on most cars) leading from the battery, break it, and make the ammeter's connections there. This is often easiest to do if you disconnect it from the battery, connect one lead of your ammeter to that lead, and one to the place where you disconnected the stock lead.

 

If you connect the ammeter to the alternator's output, the ammeter will only show how much current the alternator is generating at any given moment (unless the alternator has a bad diode, but that's an exceptional case).

 

Be sure to use the same, or preferably one size heavier wire when you connect the ammeter. Most ammeter "kits" ship with either 10ga or 12 ga wire, which may or may not be heavy enough for your particular application. Wire is cheap, don't scrimp.

 

Also, be doubly certain not to route the ammeter's leads near sharp edges, or use wire loom wrap to protect them. If it shorts, you'll have a fire, guaranteed: it's unfused, in most installations, unless you install an additional fusible link between the battery and the ammeter lead.

 

The ammeter, wired in this fashion, will show the current flowing into and out of the battery, which is what most people want to see (Is it charging? Is there a current drain?) It will not, typically, show how hard your alternator is working, because a properly regulated alternator carries the load of all the car's combined current needs, plus the current to recharge the battery after it's been started.

 

The shunt style ammeters are a lot safer to wire, they don't carry all the current up to the gauge then back to the rest of the car, but I don't see the shunt style ammeters sold much outside of OEM channels.

 

A shunt style ammeter is the only ammeter installed in OEM applications, and have been for at least forty years.