Alternator and Amp Gauge Question

Linusrp · Post by **Linusrp** » Tue Dec 27, 2005 7:26 pm

I have a question for you electrical engineers out there. I am considering a 60 AMP alternator swap with my stock alternator but I don't want to burn up the AMP gauge. It has a 30+ or minus scale. It normally sits around the +5 mark when I am driving, but drops significantly when I turn on the lights at night, especially with the radio on. I know this is a normal response which is why I am considering the upgrade. Will adding the 60 AMP alternator cause any damage or should I not concern myself? With the cost of these lately I don't want to replace the AMP. It is only two years old. Thanks for the help.

Post by **spl310** » Tue Dec 27, 2005 9:18 pm

If things go along with no problems, then you should be OK - that is until there is a load on the system that causes the alternator to exceed 30 amps output. Then the excitement will begin. Either a smoked alternator or a nice little electrical fire.

If you upgrade the alternator, do yourself a favor and put a bigger amp meter in.

Linusrp · Post by **Linusrp** » Tue Dec 27, 2005 9:36 pm

I figured as much Sid. Thanks for the confirmation. I put in two in-line fuses a while back to prevent either problem with the current alternator, one to the AMP meter and the other off the alternator. I hate to go away from the stock gauges but also hate the power drain on the stock alternator. I guess I have what's called a dilemma. Thanks again.

TR · Post by TR » Tue Dec 27, 2005 11:37 pm

You can run some items like headlights, cooling fans and car stereo through a fuse (and relay) directly from the battery. Then run the remaining portion of the car through a 30A fuse (25A Quick Blow to be safe!) through the amp gauge. You will not get an indication of the amount of draw for the items that are not routed through the gauge, but with that alternator, do you need to?

shifty · Post by **shifty** » Wed Dec 28, 2005 1:50 am

Does running circuits directly off the battery mess with the alternator's ability to recharge the battery?

TR · Post by TR » Wed Dec 28, 2005 1:08 pm

No...As long as the system is charging, there is enough juice for the battery and all the ancillaries no matter where the power is coming from or going...

I wrote battery, but the power can be pulled from any source that does not go through the amp gauge.

spyder · Post by **spyder** » Thu Dec 29, 2005 8:53 am

What I did was add another 10 gaage wire from the alternator output post to the battery positive post. What this does is split the charge current between two wires so you do not stress the old wires, the meter will also not move as much.

hport · Post by **hport** » Sun Jan 01, 2006 9:21 pm

If you install a 30 amp fuse on the alt output wire you will be fine. The stock alt. / amp gauge wiring will support 30 amps. I have a 60 amp self energized GM style alternator on my roadster, it works better than stock and the gauge will stay right around zero no matter what the load ( a true 1 wire system ). You need a good battery to even out the spikes in the system, which is what kills most gauges and wiring. The electrical devices pull from the battery, and the alternator is there to keep it fully charge at all times. So if the battery gets weak or the load is excessive the gauge will go positive when the alternator tries to recharge the battery. If the load is sized correctly, you have a good battery, and a fused (30a) alternator output you will be very happy.