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Asus Battery Drains While Laptop Is Off

Tags:
  • Laptops
  • Power
  • Battery
  • Light
  • Asus
Last response: in Laptop Tech Support
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October 15, 2013 10:11:27 PM

I have an ancient Asus A3A, just to experiment with. While turned off, the power light comes on for a few seconds and the CD drive whirs. Light then goes out.This drains the battery within 2 weeks, unless the charger is connected. Everything works OK, except for this discharging. The battery is non-genuine. I've tried the usual power resets suggested on many forums, but to no avail.

When the battery is removed, there is still 14V across pins 1-8 of the battery, so the protection circuit is not active. Pin 7 is, I believe, the temp sensor, and pin 2 is the isolation s/w.
Can the battery be fixed or reset with some trick?

Thank You.

More about : asus battery drains laptop

October 21, 2013 3:35:01 PM

This is a partial answer, but there is still a slight drain. The original problem caused a 60mA drain on the battery.

I took the laptop apart and disconnected everything from the mobo, except for the CPU and GPU. The battery/power isolators are two TPC8107. These tested OK (spec idle draw is 10uA) for breakdown. Lots of SMD chip caps. Too hard to extract, but these should be OK.

Nothing looked burnt. I re-assembled the machine, and booted then shutdown. No more heavy drain, nor blinking lights. The drain is now 1point9 mA, so battery will hold a charge for 3 months while in the laptop.

1.9mA still seems a bit big considering there are no wake-up nor charge functions. Drain should be a measly 20uA.

Anyway, this exercise proves that a wonky or even just badly connected peripheral can cause a heavy battery drain. No doubt, all caused by incompetent design.
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