So last week my Mirage did not want to start and when I checked the battery (Motolite Enduro, a local brand in the Philippines) it only had 10.6V volts. I removed it from the engine bay, charged it with my Ctek MXS 5.0 battery charger, and was fully charged successfully. I left it for 3 days in the charger and was at step 7 (maintaining good battery voltage) until I removed it, washed the terminals with baking soda solution, and gave it a nice cold bath to remove any dirt in it. This is a maintenance-free battery, btw. I left it to air dry for a few hours and when I tested the voltage again, it seems to have stayed at 12.6V so I though everything was good.

I then decided to install it in the car but it still did not start. I forgot to bring my voltmeter with me so I did not know what the voltage was when I installed it in the car.

Then I had no choice but to buy a new battery today. I went with Amaron and when the delivery guy installed the batt, the car started just fine. I still wanted to test the voltage of the old battery but I didn't get the chance to because it was traded-in during the purchase of the new battery.

Questions:

1) With all these observations, does this mean the old battery was really dead? I mean it is already a month shy of 3 years old. We live in a tropical country (Philippines) and people say 3 years is already a long time for a battery life.

2) Is it worth refilling a maintenance-free battery in hopes of reviving it? I kept thinking "what if" I did this instead of buying a new battery. I'm reading that this is not worth it because you're simply prolonging the inevitable for a few more weeks or so, but still!

3) I guess a voltage test doesn't give you the whole story, does it? Does one need to do a load test to determine if a battery is really in a good state?