My battery will not charge. ( Ryobi 18.0v) When I put it in the charger both amber and green light stays on. I have a second battery that charges just fine?

From your description the battery is probably faulty. If the batteries are still quite young it is possibly just one cell and while Ryobi don't refurbish batteries there are companies dotted around that do.

If it is a nicad battery, Ryobi told me just a couple of days ago they no longer supply nicad replacements and expect everyone to upgrade to lithium, which means also buying a charger.

When the battery is charged the green will be steady on and the red will go off. Flashing green is an indication that it is charging.

hope this helps?

I have used alot of battery type drills and other action tools . Ryobi is on the lower end of the market as opposed to Milwaulkee and Dewalt . But my experience with battery operated tool charging equipment is that if the light is green and it's blinking , I would say it's charging . When the light goes off or stays on . I would say it's charged . Leaving the battery or batteries in the charging unit for 24 hours will not hurt the battery . My solution here is put it in the charger , and check it 12 hours later !
Electrician by Trade

red is charging, green is done, amber is either hot or bad battery ive seen that with both symptoms when on with the green. dont run your battery down to the limit and always keep the battery charged this will prolong the life of the battery, dont store dead batteries in other words.

see if your charger is under warranty and have it replaced..yours is bad..

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.

I hooked a 12 volt car battery charger to the battery for about two min. Then I put it in it's own charger,the yellow & green lights came on for about 5 sec. then the red light came on . About 30 min. later the green light came on and the battery is fine.

try pitting battery in charge and wiggle the battery a little to see if the green light comes on, sometimes the make contact and then loose it when you let go of the battery.if still same problem charger is probbly dead.

For others with the same problem (flashing red light won't go off)...make sure you FIRMLY PUSH the battery down onto the charger and engage the latches. Simply resting the battery on the charger will not work.

Just was on a website for Ryobi drills and it states that if the yellow and green light stay on for more than 15 minutes the battery is fried. Couldn't find the link but if you do a search for Ryobi Drill 18 volt you should find the same info. It was as product review from Australia I think.

I also have a problem with the charging of Ryobi batterys. They seem to charge AOK with the green light coming on but the charge does not last at all. Not sure if the problem is with the batteries on the charger.