Ryobi dual chem charger p113 What does it mean when the red light keeps flashing red? It says that its testing. But my other battery goes to a flashing green after testing. The one that i am asking about just stays flashing red(testing) Can you please help me

SOURCE: 18 volt ryobi battery charger...green & yellow lights come on wha

talked to Ryobi and they are vague. It can either mean that the battery is bad, or the charger is bad and another one that maybe the contacts of the battery are dirty or not seating fully in charger. What I would look for in this instance first unplug the charger and look into charging slot to make sure the terminals of the charger are not bent and they come out into the cavity where battery would go. If not gently pull terminal into opening and retry. Sorry I couldn't be of more assistance

SOURCE: The Yellow and Green light both come on and stay

http://oneworld1.inetu.net/manuals/ryobi/hp1442m_1802m_874_eng.pdf
It sounds like your battery is bad. If yellow and green are on for more than 15 minutes it probably a defective battery pack. See page 8 in the manual.

SOURCE: Green & Yellow light on 14.4V charger

It sounds like your battery is bad.

If both yellow and green LEDs come on, this indicates
a deeply discharged or defective battery pack.
Allow the battery pack to remain in the charger for 15
to 30 minutes. When the battery pack reaches normal
voltage range, the red LED should come on. If the
red LED does not come on after 30 minutes, this may
indicate a defective battery pack and should be
replaced.
n After normal usage, a minimum of 1 hour of charging time
is required to fully recharge battery pack.