My battery is not charging well, I am only showing 12V when charging rather than 13.4V. What is wrong?
• There are numerous causes for this. Most of the time the problem is fairly trivial. Going from cheapest to most expensive, try the following: See also charge light diagnosis below. • Check the ground connections, possibly install a new ground from alternator to battery rather than using the engine block/transmission as conductor. Forget trying to find the bad connection with an Ohm meter: Say your alt. puts out 50 Amps, you’ll get a drop of 1 Volt for each .02 Ohm!!! Most VOMeters are not accurate enough in this range. So, those tiny little resistances that have build up over the years REALLY add up. Use a THICK (10 or less Gauge/”AWG”), multistrand wire. • Check the alternator wiring harness. Same reason as above. • Clean all related connectors (sand paper, file). • SOLDER ALL crimped connectors • Check for an unusual drain (unlikely but possible) • Check/clean/replace the alternator brushes (easy, see wear limits in Bentley). • Check the battery water level (use distilled water) NO
