FWIW, you can get a decent DMM (digital multi meter) from Sears for $50-75. The model I own (I'll get you the number when I get home) can measure DC current up to 10A for brief periods of time.

You can use the amp meter to determine if there is a constant current draw (10A or less) on the battery.

You might also just disconnect the power antenna...it may be frozen up and not shutting off it's little motor.

edit-I've never seen <$20 meter that would measure any current other than milliamps.

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