Originally Posted by Bob Dillon
The alternator shows charging at 14.6 volts at idle. When I kill the battery this way, a 10-minute hit with my crappy little Chinese charger brings it right back up.
The battery is a 6-month-old Delco that has passed the load test at my local buddy'* garage.
I know it'* weird. It seems like there would be safety (fire) issues to discharge a 600-amp battery in 10 minutes, but everything else works and no smell of smoke nor fried wires I can see.
Let me restate my Twilight Zone BS from a different angle.
Voltage (14.6) and capacity are not always the same. Had you charged the battery up when it was load tested... or did it come straight out of the car without any messing with it... just as it would be when you run to the grocery store?
- If there are any battery cable issues in the charging path, it LIMITS the current going IN to the battery.. can limit a 200 amp alternator to a 2 amp charging device (ie trickle charger).
But if you want to chase a mystery power drain, you need to verify that it is actually pulling current to the max while in ACC. That will take either a very high current capable meter (you would torch a little volt ohm meter) ... or ... you can put a 12v load in series with one of the battery cables while in ACC.
- Unhook a cable
Put the key in ACC
Hook a test light from the battery terminal to the unhooked cable
Does it glow BRITE? (Something is drawing a lot of current)
Does it glow at all or very dim? (Just normal drain)
You can drain a fully charged battery in 10 min. with a WHOLE bunch of current draw.
You can drain a poorly charged battery in 10 min. by listening to the stereo.
1993 Red SSE - Bone-Stock except for High Perf. Power Antenna-Original Owner. Less than 130K - Love of my Wife
'05 Magnum R/T Hemi - Bunches of classic VW Beetles... and one "not quite stock."