Still have a battery drain, ideas?

[forester2002s]

Could be faulty diodes in the alternator.

Do a search on this forum. There should be plenty of posts about failed diodes.

[fgf]

Some test info: '96 Legacy, EJ22 engine, key off & removed

mA meter between -battery post and post clamp.

65 mA steady current after 1 minute (to let ECU settle down)

= 1.5 Ah/day = 47 Ah/month

Group 35 batteries used in the '96 typically list ~ 40 Ah capacity, so could discharge battery in a month...

Leaving my UltraGauge (OBDII viewer) plugged in doubled the draw - apparently it keeps checking to see if the key has been turned on yet - so only 2 weeks to discharge battery.

Got bitten when I didn't start the car for several weeks followed by a sub-zero cold snap (discharged batteries freeze easily)...

[Boxer Medic]

This might help out some. It has helped me learn by watching it be done methodically and competently.

Edited January 13, 2018 by Boxer Medic

[Bushwick]

Wanted to update to possibly save someone else the headache in the future.

 

You definitely NEED BOTH wires going to the alt (constant 12v+

AND the "dummy light" wire

). 12v+ constant *can* be attached to the right-side (if looking down at engine from front of car orientation) terminal and will allow alt to charge but needs a key-on activated relay to avoid draining battery at engine off. After getting both wires in proper orientation and connected, no drain and car can sit w/o being dead overnight.

 

My mistake for thinking they could be run as a 1-wire set up as-is. Connector plug was cut to get the Tribecca alt to work before, and once reverting back to the factory-style alt, saw it was charging with right-side getting fed 12v+ constant and assumed it was correct. Since the drain can take days to leave battery dead to months in warmer weather, and alt was testing OK with good diodes; like chasing a group of wild turkeys.

Edited February 11, 2018 by Bushwick