Electronic Ignition Conversion HELP
You may have an intermittent, or a bad battery, hard to say.
Do you think your battery is "up?" It might just be "that much dead?"
But I asked you to also check the charging voltage, IE the voltage at the battery while running.
At this point I think I might be inclined to scare up a temporary "known good" battery (??out of your wife's car??) and substitute it long enough to find out if you have a battery or charging problem
The .5 V for now is OK