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I have a 76 Corvette,that has started to blow ammeters . I installed aluminum radiator with dual electric fans BeCool parts. I also installed a 100 amp alternator. Every time Use the car and run the fans for maybe hour I blow the ammeter.
Does any one make a heavier duty unit? Any Suggestions
Thanks
Callahan
The ammeter is connected in parallel with the charging circuit that runs from the alternator through the horn relay to the starter. A portion of the charging circuit current runs through the ammeter and the ammeter is calibrated to show the total current flowing through the entire circuit. If the ammeter is failing due to over current, it's possible your charging circuit is overloaded as well. But, if that's the case, I'm surprised you haven't blown the fusible link on the charging circuit near the starter.
It's generally recommended to upgrade the wire from the alternator to the starter when installing a larger alternator. See this recent thread for some good info: https://www.corvetteforum.com/forums...lternator.html There are a lot of threads on this site about ammeters that will be worth reading.
If you are not concerned about originality, consider replacing the ammeter with a voltmeter. If you want a volt meter that matches, I think I remember reading that one from a mid 70's Chevy pickup will match pretty well. Not sure if any of the C3s later than yours used a voltmeter.
There's a reasonably new VOLT meter, being sold by one of the major vendors, which matches our gauges. I don't believe they're a supporting vendor here so I won't mention their name. Do a search. Easy to find. I just installed one and it works great. IMO, it's far better info on charging system than my ammeter was. Worth the effort.
Hi
Yes I blew the fusible link first . I could not find another,so I replaced it with a 30 amp in line fuse. I don't about the gauge being original in looks, just in fits in the dash. I will read the information you sent. Thanks
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
I did the same mode as you . My meter worked for quite a while. I eventually got rid of it and went to the voltmeter because I lost the alternator belt and didn't know it. The voltmeter is a much better diagnostic tool
Hi
Yes I blew the fusible link first . I could not find another,so I replaced it with a 30 amp in line fuse.
Sounds like you definitely need to upgrade the charging wire. Small coils of fusible link wire are generally available at most parts stores. The fusible link wire needs to be 2 wire gauges smaller than the wire it is protecting. So, if you have a 10 gauge charging wire, the fusible link would need to be 14 gauge. Likewise if you use a fuse or circuit breaker instead of a fusible link. You need them sized so that they are protecting the wire and not the other way around.
As DC said- you need to upgrade the charging wire-
The ammeter will NOT read correctly (I know you can adjust it to work) but it's easy to swap out to a voltmeter- hit the pink power wire behind the gauges and a ground -DONE.
SEVERAL guys have it for sale to match your year's gauges
This is how I would upgrade-
Larger charging cable-fuses at the battery-fans get full juice- all the stuff is readily available-
My favorite battery fuse- protects and if it blows -unlike a fusible link can be easily changed on the side of the road.
I'd use a 80A for the fans and 200 for the starter/battery cable
$20 on Amazon -fuses are $10 -20 depending who is selling them...
I like the idea of fuses at the battery and I also like the fuse you've chosen. My battery is a fairly large side terminal battery so not sure I'd have room for this. I see they offer a surface mount fuse with 3 circuits which would give a place for the stereo wires I already have connected. Hmmm.
I like the idea of fuses at the battery and I also like the fuse you've chosen. My battery is a fairly large side terminal battery so not sure I'd have room for this. I see they offer a surface mount fuse with 3 circuits which would give a place for the stereo wires I already have connected. Hmmm.
DC
Here you go- an easy way to convert the side posts-
Thanks
I will start with the wire,today.I have ordered a 100 amp SW gauge, lt is 2 1/16 in around I will see if it can be made to fit. if not I will order a voltage
meter.I see the 78 or 79 corvette has one. If I go this route I will need to know how to connect it
A voltmeter is a poor substitute for the ammeter....IF you know how to read one properly. But, if you don't, swap to a voltmeter. It WILL tell you if the system is getting charged. But, that's about all.....
A voltmeter is a poor substitute for the ammeter....IF you know how to read one properly. But, if you don't, swap to a voltmeter. It WILL tell you if the system is getting charged. But, that's about all.....
Technically it's not an ammeter it's a galvanometer and that's why the gauge just says "Battery"
As DC said- you need to upgrade the charging wire-
The ammeter will NOT read correctly (I know you can adjust it to work) but it's easy to swap out to a voltmeter- hit the pink power wire behind the gauges and a ground -DONE.
SEVERAL guys have it for sale to match your year's gauges
This is how I would upgrade-
Larger charging cable-fuses at the battery-fans get full juice- all the stuff is readily available-
My favorite battery fuse- protects and if it blows -unlike a fusible link can be easily changed on the side of the road.
I'd use a 80A for the fans and 200 for the starter/battery cable
$20 on Amazon -fuses are $10 -20 depending who is selling them...
A voltmeter is all you need, forget that meaningless amp meter, and that wiring diagram is RONG!!!! you take that fuse/relay to the Spals directly off the alt output stud with it's own wire leaving the rest of the system alone......my '72 been wired that way for some 20 years now.....even survived an alternader failure....
that wiring diagram is RONG!!!! you take that fuse/relay to the Spals directly off the alt output stud with it's own wire leaving the rest of the system alone......my '72 been wired that way for some 20 years now.....even survived an alternader failure....
Sorry- - I feel the alternator stud is not the right place to pull large amounts of current -
ESPECIALLY when the fans start up- it's a lot of juice- I've read the inrush current on the dual spals I am running are upwards of 70A-
You would NOT jumpstart a car by connecting it to the alternator...maybe once...so why hook the fans there?
Most of the time- if not all of the time- the car is idling when the fans come on- the alternator is NOT making full output- as that happens around 1500RPM(most set ups about 3:1 ratio)
Running back to the battery - stabilizes the voltage and acts as a buffer for the alternator- as when the fans turn on -the battery can easily handle the big current draw- just like when you start your car.
I'm glad it has worked for you but doesn't always mean it's the best way- but please explain why you feel my drawing/diagram is wrong.
Richard
Last edited by Richard454; Aug 22, 2019 at 11:50 AM.
ammeter
