Well, I tested the battery. The battery tester computer passed it the first time but I noticed that under the heavy load test the voltage got down to 9 something volts. So I decided to test it again without charging it. This time the voltage got down to 7.8 volts and it failed the test.
So it seems like this battery is OK for everyday driving, but as it goes down it loses voltage exponentially. Which makes sense due the large drop from 11.8v to 9.8v in only 9 hours with the PC off.
What a shame. My old battery was fine a month ago and then suddenly got an internal short and had to be changed. The current battery that I swapped in was from another car of mine I don't drive and was very reliable about holding a charge. Now it's going out too. Bummer.
Anyone have any recommendations for a good battery? I think the Optima Yellow Top is my best bet considering I have a big sound system, but it is pricy at $150 and has a not so good warranty. Any other suggestions?
Oh yea, the opus did shut down right at 11.3 volts. I was listening to it last night for about 20 minutes and it suddenly went into it's hibernation cycle. I thought I had bumped the key off of something, but I quickly glanced at my digital voltmeter and it was at 11.3. So I guess that Opus shutdown protection only works when it is running.
Can anyone else confirm this?