Truck sat for two weeks and batteries were dead when I went to start it. I jump started it fro another vehicle and got it running. I have a few questions. The ground terminal on the drivers side battery has corrosion. I cleaned it off a year ago and it came back. What causes the corrosion? Do I need to replace both batteries or should I have them tested to see what the condition is? Is there any place that stands out that sells batteries for a good price?

 

Corrosion on battery terminal is pretty common. Use those felt circles and a spray can of battery terminal protectant.

Running a standard lead battery dead can sometimes kill them, but not always. Get them load tested (it's free). But, if they're more than 5-6 years old, it's probably time for a replacement anyway.

Every couple of years or so, Consumer Reports does a battery test. The top three are usually Diehard, Interstate, and Autozone. IIRC, Optima finally broke in to the top 5 in the last review.

I always buy Autozone.