Electrical questions

[howie123]

1. Car had been starting fine. One day I had a dead battery, just a faint glow from the headlights, nothing else. I tried to charge the battery with a small maintainer/charger with no luck. I took it to Batteries Plus, they tried to charge it but could not get over 5 volts so could not do a load test. I bought a new battery and installed it. I am running a 6 volt positive ground alternator. With the old battery the amp gauge would jump to about 15 amps at about 5 MPH and then gradually drop to about 2 amps. With the new battery I started the car and let it idle about 5-10 minutes. The amp gauge jumped to about 15 amps while idling. I took about a 7 mile drive and it stayed between 13-15. It would drop to about 8 with the headlights on low beam and 2 on high beam. I am not sure I should be driving it until I get this figured out. Any ideas would be helpful.
2. I have an old reproduction ahooga horn that I rebuilt. Without the car running it is very weak. With the car running and the alternator charging it sounds good. Is this normal? I don't remember how it acted with a generator. Could these be related problems? Thanks Howie

 

[Ted in MN]

Sounds like the ground strap of the battery isn't making a good connection with the frame. Remove strap and grind off rust from the frame and reconnect.

 

[Tom Wesenberg]

When you buy a new battery it's a good idea to put it on a small charge (3 to 6 amp charger) for several hours to make sure the battery is up to it's peak.

Your horn sounds typical. Are the bushings oiled and the commutator clean. My friend's horn was real weak until I layed some sandpaper on the commutator while it was spinning. All of a sudden it started speeding up and now it blows much better than my horn.