Stubby wrote:
I bought a 9.6v Ryobi from Home Depot but hardly use it. The battery
does not seem to charge because it lasts only a minute or so now. The
yellow light on the charger has never come on, just the red "charging"
light. How can I tell if the battery is bad or the charger? TIA.

You can test it with a voltmeter. A 9.6v battery has 8 cells of 1.2 V
each. If shortly after charging the voltage drops below 9.6, cells have
shorted.