Do I need to change my Amp gage??

[38Plyroadking]

I'm concerned about a fire starting. I have the original 30A amp gage and a late model 65Amp alternator. I think I am running the risk of starting a fire. So, should I change out the gage for a higher capacity gage? And, how do I do that without changing the look of it?

Let me know what you think. Oh yea, its the orignal flat head with HEI.

Thanks

Paul

[Don Coatney]

It is doubtful that your alternator will ever see the need to deliver a full 65 amp charge. If you think it will be a problem then it is possible to re-wire your car using relays so the full accessory load does not go through your amp gauge. Or you could install an after market volt meter under the dash and by-pass your amp gauge completely. Is there a reason you installed an alternator of this large capacity?

[38Plyroadking]

Don,

I have read about doing what you said. The alternator was already in the car, I think, because there is a radio with amp installed, and a heater fan as well as an extra set of running lights. I dont think I'd ever pull that many (65)amps but what if I pull 35-40 amps. Wouldn't that be enough to overheat the wires? Maybe I'm worrying too much.

Thanks

Paul

[greg g]

From what I understand (always open for correction) is that most ammeters work from a magnetic field generated by current passing through the meter, rather than direct connection to a needle. commonly there is a permanet spring which basically zeros the gauge, and an electromagnetic one which reacts to the current passing by it.

If that is the case, over current should not hurt the gauge unless it is strong enough to to effect the tension of the spring by over stretching it.

I have a GM three wire alt in my studebaker truck (12 system) running through the stock 60 year old 40 amp gauge. I does peg the gauge just after start up but then settles back to the center or about 10 AMps positive reading.

A lot depends on the condition of the battery. The alternator's job is to replace the charge used from a fully charged battery after it has had a load on it. It is not there to charge the battery from 0 state, but rather to maintain the battery in a fully charged state. So if you are not constanlty running a full load of high demand accessories, and you battery is kept in good condition, I do not think there is an issue.

Once again, I am only putting forth a opinion based on my understandign of the way the gauges work. If my understanding is based on incomplete or incorrect information, please school me different.

[38Plyroadking]

Thanks Guys. I think your responses answer my concerns. I'm probably over thinking things. I'll just sit tight in the drivers seat (until the weather changes and the salt is off the roads). Then I'll drive the wheels off it!!!

Paul

[busycoupe]

If you are concerned that the wiring leading to the gauge is designed for 30 amps and that it may overheat if much more is put through it, you could fuse the circuit at something like 40 amps. This would protect the wiring, but the downside is that if you blew the fuse everything in the car would shut down. - Just a thought.

Dave

[BeBop138]

If your gauge is a 30 amp and your alt. decides to put out more than 30 amps it could cause a fire, or a lot of smoke. I have a 42 amp alt in mine and my gauge reads 50. My gauge did fail and there was no fire but the car would not charge----had to put the leads on one terminal for a tie point to make it work---basically works like an idiot light.............Lee

[Robert Horne]

I have been using a 12 volt generator in my 38 for many years. The 38 amp gauge barely moves.

[Niel Hoback]

By using an inductive ammeter, I have seen my alternator put out a steady 60 amps with the original 35 amp gauge. This rarely happens and has never caused so much as a warm wire.

I am using #10 wire from the alt to the gauge and back to the neg battery cable connection on the starter solenoid.

Like Greg said, the ammeter only senses the magnetic field of the current passing through it. Poor wiring is infinitely more likely to cause a fire than an overheated ammeter.