Thread: 2nd battery not charging

Originally Posted by I Love My Landy!

Good morning all,

Just to report back. I had an auto electrician test the current getting to the (pretty flat) battery. Results: 10 amps at fast idle; 2 amps at fast idle with headlights on high beam and heater on. The voltage from the alternator dropped below 12.8 volts as well. He suggested that the alternator may be struggling, but on inspection of the alternator he noticed that the wiring from the alternator to the starter motor was a bit thin. He made me up a new wire (120 amp) for me to try. I haven't taken measurements of the current since, but i have noticed that the battery charges faster and the volt gauge on the dash reads a bit higher.

Thanks again,

Edward

Something else to consider is the negative cable from the body to the battery. I assume all your other earth connections are to the body? The body is more or less isolated from the chassis and the current path is via that cable from the body to the neg terminal on the battery. Perhaps you should consider spending another $10 to complete the current path with new larger wire.

This is something young guns forget when fitting way too large sound systems to their cars.