Battery is 100% charged but it will die soon

I’m almost positive I need new battery, but thought I would ask before spending $100. I have a Toshiba A15-1292. When I unplug the power it will run off the battery, the battery icon says it is 100% charged and I have 2+ hrs remaining, but within a few minutes I get the “critical battery level” message and it will die. When I plug it back into AC power the battery charge light comes on (and will remain on for over a hour), but I will have the same problem with it dying as soon as it is unplugged. Do I need a new battery?

Yep, it looks like you have a bad battery. I’ve seen this battery problem many times before. Here are behaviors typical for a dying laptop battery:
1. The battery charges normally (according to the battery icon) but as soon as you unplug the laptop, it dies almost momentarily.
2. The battery charges normally. When you unplug the laptop, it discharges normally until some point and after that point starts discharging very fast. For example it might take 10-15 minutes to discharge from 100% to 80% and then it discharges from 80% to 0 for 2-3 minutes.