Ammeter hook-up

W

woodrow

Senior Member
Working on a 1914 Model T Speedster. The car is 12 volt with an alternator. I would like to put in an ammeter---which I've now done but I haven't hooked it up yet. There are two terminals on the back side of the ammeter but, being dumb on things electrical, I don't know where to connect them. If I were forced to guess I'd say one to the back of the alternator and the other to ground---but I don't want to mess up. I'd appreciate your comments. Thanks
 
I'm no electrical expert, but the ammeter on a standard T goes between the generator and the battery. Is your ammeter made for AC? Standard Ford ammeter for a DC generator may not work with the alternator.
 
You need to know the output of the alternator which normally put out more than 20-30 amps, as most 6 volt gauges are - I've seen 60 amp gauges which I'm assuming are for higher output generator/alternators but I believe you might want to hook up a voltmeter instead.
 
What you really need to do is put a VOLTMETER in there. Youll need a separate switch to turn the meter on and off as the key will only turn it on if its on BATT; MAG takes that line out of the circuit. A VM goes from + to ground to read anywhere on the system. An ammeter needs to be in line. A OEM meter can handle 6 volts/20 amps, but a 12V/40 amp alternator will need to be connected parallel to a shunt. ws

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This car will be run on battery. It will run on mag but not that well. For me to try to understand electrical stuff is about like trying to drink from a fire hose so I do appreciate your patience. You're probably right on the volt meter but I already have the ammeter. Thanks, I appreciate the help.
 
Sounds like you should wire it "Battery-ammeter-ignitionswitch" If the alternator is wired directly to the battery the ammeter will not likely read a charge but if it is wired to the coil side of the switch it might? Might max out if the battery is a little low right after starting, probably bad for the amp meter and even the switch.
If you wire it to ground (like you first suggested) you will have a dead short with lots of sparks and the ammeter will stop working and likely melt so try to avoid doing that.
 
Type of ALT would be good to know and how its sensor monitors the system. Regardless, because an AMP is wired in series between the ALT and BATT, it creates in-line resistance between the ALT and BATT, thus reducing (be it fractional) the amount of the AMPs created by the ALT that are reaching the BATT. As mentioned by others here, I would instead use a VOLT meter and source its input from the point where the ALT connects to the BATT. This would show the amount of VOLTs at the BATT connection .... then you know if the ALT is doing its job.

Also, strongly recommend a circuit breaker or fusable link (of AMP rating slightly less than ATL's max output) in that main route, next to BATT. My Delco 10 SI ALT puts-out 63 AMPs max so I use a 60 AMP circuit breaker with reset button adjacent to the seloniod.
 
Put a voltmeter in and be done. Also, 15max, the Alternator puts out DC current as well as the generator. Good Luck.
 
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