I have an ammeter in my 62 Lark wagon. It is part of the gauge package and I don't want to change it. I am installing a 1 wire alternator. It is recommend that I run a 10g wire from the starter solenoid to the ammeter and then a 10g wire from the other ammeter post to the alternator. The gauge is not marked which post goes to the battery. I have conducted a small experiment. Isolating the ammeter, I connected one post to the + pole of a 9V battery and connected the other post to the - battery post. The ammeter showed a slight discharge which is probably what I want since the battery was not being charged. Can I assume that the post I have connected the + terminal to should go to the starter solonoid? I do not want to fry the ammeter, they are a major pain to find and replace. Thanks Warren
Some early cars had an ammeter that was only rated for 20 or 30 amps since they were originally used on cars with few electrical requirements and a generator instead of an alternator. I will typically run a "shunt" so that part of the ammeter current is carried through the shunt instead of it all going through the ammeter. In your case, where you are running one wire from the ammeter to the starter solenoid and another from the other ammeter post to the alternator, the shunt would be a second wire from the solenoid directly to the alternator. The ammeter is then in "parallel" with the shunt. I will typically experiment a bit with the shunt wire size, as it has to have some resistance in order to still allow the ammeter to show charge or discharge.
I'd be much more concerned with the change in charging system output. Factory ammeters are usually sized to OEM output, which if it's a generator car is probably only 30 amps, maybe 40 if you're lucky. Almost any modern alternator is capable of at least twice that and that amount will fry your ammeter. I'd suggest switching it out to a voltmeter, either in place of the dash unit or under the dash. Leave the OEM gauge disconnected. Stay away from home-made shunts, those can be a recipe for disaster...
Found two diagrams showing how to hook up the ammeter with a one wire alternator. Not much supporting info though. I would take what Ebbspeed and Crazy Steve said about amp ratings for the ammeter though. As far as the needle pointing this way or that way when you know it is charging that is as you asked, wires on the correct posts of the ammeter. Backwards it shows the current flowing in the wrong direction as all an ammeter dies is tell you current flow and how much is flowing.
To start with wiring isn't something I know much about but I've always stayed away from ammeters. The possibility of the gauge shorting out and letting all the smoke out of the wiring under the dash or worse concerns me. I think I remember somewhere a discussion about installing an insulted coiled wire between the 2 posts on the ammeter and then running the hot wire through the coiled wire similar to a pass through gauge like the one on my '39 p/u before I changed it to a volt meter. Is this a possibility or am I misinformed?
Home-made shunts can work fine with no more risk than what an ammeter inherently has. Your coiled wire is a shunt, effectively reducing the amount of current that flows through the ammeter.
If the ammeter will take the current, you won't fry it, it;ll show discharge, or charge. Simple as that. i/e if you fry it hooking it up backwards, youd fry it if hooking up correctly
Buick, at least in 1950 ,didn't call it an ammeter. Called it a "charge indicator". I simply connected the wire from the alternator to the same post as the one to the starter, effectively bypassing the ammeter. Then installed a volt meter.. Ben
Somewhere on your alternator the output current should be stamped. If the output current of the alternator is larger than the maximum reading on your alternator don't use it unless you use the shunt as mentioned above.
This is great input. I have a 65 AMP alternator. In 1963 when Studebaker switched to alternators, they used a 35 AMP unit. I have read about the shunts and like the idea as well as putting inline fuses on both sides of the shunt. How do I determine which size fuse and shunt to use? Sorry about so many questions, but I really don't want a fire. Thanks Warren
Shunt wire sizing and length is something you need to experiment with. If you have an extremely accurate ohmmeter that can read fractional ohms, you can measure the resistance of the ammeter, and then in order to cut the current through it in half use a piece of wire with the same resistance. It's much better to use a longer piece of wire of a larger gauge than a short piece of a smaller gauge wire, as heat is always created when current flow causes a voltage drop across a section of wire. A longer section of larger gauge wire will have more surface area to dissipate the heat. I wouldn't put fuses in the shunt, because if there is a surge and a fuse blows, you have all of the current flowing through that ammeter that you're trying not to burn up.
Remember The ammeter should only see the power going to the battery not the out put from the alternator. Unless the battery is discharged It should not over power the meter. This is just my thought but most ammeter fails come from shorts in the system not the meter. I had a car with a 20 amp meter that I wanted to keep I jumpered a switch accross the gauge to be used after start up for maybe a minute.
My 1963 Lark and my 1964 Daytona came factory with an alternator - maybe we just need to check the 1963/64 wiring schematic. Let me know - I have the factory manuals......
I have the 62 and 63 wiring diagrams and I have the shop manual, but no where on the instrument or in the documentation does it indicate the + post on the ammeter that goes to the battery. I guess the only way was to do it daily at the factory or mark the wires which I couldn't do because this is an upgrade in my 62. I've decided how to wire it, just don't know the ammeter polarity. I've tried to attach a scan of my new wiring schematic, but it doesn't seem to work. Using 10 gauge wire every where, I run a connection to the 10 AMP shunt and from the shunt to the alternator. I build a parallel circuit from one side of the shunt to the ammeter and back to the other side of the shunt with 10 AMP fuses on both sides. Warren
I have a 63 dash out with the wiring still attached - it's storage - I'll try to remember to take a picture when I get home.
The red wire goes to the battery. If you can, does it come off the post to the drivers side or the post to the passenger side? Thanks Warren
Actually the white wire with the red trader goes to the alternator. Hard pics of one in storage that also had a small fuse to. Pic of my stock 63 with prestolite. Had another dash which is the same just didn't have the fuse. Red wire on back of dash meter is on drivers side - white wire with red trazer on passenger side of dash meter.
Thank you Stillrunners, that is exactly the info I need to finish this puzzle. Thank you everyone for your input, it is valued and used. Hopefully we have prevented any fire here. Warren
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