Parasitic battery drain?

I have a '97 Maxima SE that appears to have a parasitic battery drain problem. My wife drives the car short distances, leaves it for several
hours, then the engine won't turn over when she tries to start it. I replaced the battery; it worked for a few days before the problem repeated itself.
The battery does appear to be getting charged by the alternator. Measuring AC volts from the alternator, I get about 330 mV of ripple output; I've heard that this should be less than 500 mV, so this reading seems fine. Measuring voltage from the battery while the engine is running, I get about 14V. After shutting off the engine the battery at first reads about 12.5V, then drops slowly, by about 10 mV every 15 seconds or so. About 8 hours after making the 12.5V measurement, the battery reads about 12.1V. If it drops to 11.98V the car won't start.
An ammeter connected in serial with the negative ground cable shows a fluctuating 85-95 mA current with the vehicle shut down, doors closed, etc. I pulled each fuse while checking this leak in order to determine what might be causing it. Removing the BCU fuse drops the leak to about 10 mA. The interior lights and trunk light only add to the baseline drain. When the BCU fuse is left in place, the only fuse from the interior that affects the reading is "Room.L" which drops it to about 75-85 mA. There's also a fuse in the engine compartment, "FL.30A Power Window" that drops it by about 3 mA. Other than that, no other fuses appear to affect the baseline leak.
Is there anything I can do to further diagnose the BCU current drain? Is this amount of drain normal? I've heard that most modern cars shouldn't draw more than 30-50 mA at rest. The car is completely stock with no added electronic components, no phone charger, etc. Are there any components connected to the BCU that I can test? Pulling all the fuses I could find with the BCU fuse in place didn't seem to change anything much; is there anything else I can disconnect?
I know that a faulty alternator diode can cause battery drain, but because most of the drain stops after the BCU fuse is removed, I don't think the alternator is the source. Is it worthwhile having the dealer check the alternator? There is a recall for the alternator on this MY, but I don't think my VIN corresponds to the recalled vehicles.
Any comments or suggestions would be appreciated -- thanks!
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Well it sounds like your wife is driving the car TOO SHORT a distance and time for the battery to get charged up suffciently. Based on what you are saying the draw is in mA - which is OK, but the battery needs at least a good 1/2 hour of 40 mph driving to get fully charged. This can happen to older batteries and even newer ones, especially when it is cold.
The alarm, the ECU, the clock all draw some minute currents while in standby mode. Remember that the starting process takes lots of energy and it is not being replenished. So try my suggestion, have your wife verify how long she rides the car and how often she starts and restarts it in what time frame.
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Did you ever get your parasitic battery drain solved? My daughter (at college) has a 96 Maxima, and she often goes out of the dorm to find her call dead. She may not drive it for days at a time. The auto repair guys can find no drain on the battery. We now have placed a new battery in it, and the car continues to go dead.
Share some of you lessons with a fellow struggler please?
Thanks, Kevin
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wieserk wrote:

You need a good mechanic. If the battery is dying, then there is a draw. You need someone to measure it, and then start disconnecting circuits one-by-one until they find it. Maybe just be a stuck relay.
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