Charging Issue 1987 300tdt

[southherogrease]

I've had my 87 300tdt (195k) for about 5 months and love it, but...

A couple of weeks ago, it wouldn't start after sitting at work for 12 hours. My indy mechanic found the battery discharged, swapped it out while charging the dead one and found no apparent issues. The original battery tested o.k. so he put it back in the car. I had been having tach fail/abs light stuff going on, so he replaced the OVP relay at the same time.

I drove it for a couple of days without issue and then it wouldn't start to pull it into the garage. I charged the battery up and then started driving it again, recording battery voltage with a multimeter (see numbers below if you think it would be helpful). A couple of days later, same problem. I haven't driven it since then because on that last drive home the right front turn signal assembly abandoned ship.

Any thoughts? Thanks.




Sun @1345hrs 13.49v coming off the charger
no driving
Mon@620 12.79v before start
13.87v running, before leaving for work
12.8v after 17 mile drive to work (avg 40 mph, few/no stops)
@1615 12.9v before start
12.85v after 17 mile drive home
Tues @630 12.3v before start
11.95v after 17 mile drive
@1605 12.19v before start
11.44v after 17 mile drive WON'T START