I bought a 18v lithium Ryobi Drill and Impact Driver set close to 8 years ago.
Included 2 1.3AH and smart charger.
I rotate the batteries, 1 is in use, 1 is on the charger. Has been this way the whole time. Lots of drill use and decent amount of impact driver use.
3 years ago bought a string trimmer that my yard is a bit too big for, and started mowing a friends yard last year since she can no longer due to health issues.

About 3 weeks ago pulled one battery off the charger and nothing. Put it on the charger and check the lights and the defective indicator is flashing.
Today pulled the other battery off the charger and same thing.
I am guessing they have met the end of their life. Pretty decent run as much as I have used them and I paid $85 for the kit.
I can buy 1 4AH battery for $85, or a 2 pack 1.5AH for $60.
So I figure I will just buy the new Hammer drill kit that gives me a 30 minute charger (currently have a 1 hour charger), 1 4AH battery, and of course the hammer drill. My current drill the chuck is starting to slip a bit so a new drill is not a bad idea plus I do not have a hammer drill.
Then Home Depot usually has a solid sale on their Ryobi tools come fathers day so I'll just buy a couple more batteries.

I happen to have several Ryobi one 18v tools as well. A couple of my batteries did the same thing. I just so happened to buy a Ryobi hedge trimmer at a pawn shop, it came with a couple of batteries and a charger. Long story short, the batteries charged just fine on the newly found charger. Old charger iz poop. May be your same problem

I believe most have a rating somewhere between 500-1000 charge cycles.

Lithium batteries have a limited number of charge cycles. Each time you charge a lithium battery, you decrease it's total capacity a little bit. The total number of charge cycles you get out of a lithium battery is a moving target. Fully discharging and recharging a battery decreases the total capacity a little more than discharging and recharging it a little. The battery takes a charge easiest between 40 and 70% of it's total capacity, so this is the range where recharging does the least damage.

Lithium batteries also have a shelf life. As the batteries age, the total capacity also decreases. The amount of power stored in the battery affects the shelf life. A fully charged battery degrades faster than a partially empty one. However, a completely empty cell suffers damage as it self discharges. Accordingly, keeping the battery at about 40% is optimal for storage--enough juice left in the cell to allow for self-discharge, empty enough to keep the battery aging happy.

If both batteries are coming back defective, it's probably because you let them self-discharge past the safe limit that the charger is looking for. Lithiums have a very low self-discharge rate, but if the the batteries were already pretty close to empty when stored, and the total capacity has been degraded overtime, it might return too low of a voltage for the charger to consider safe.

Get the Rigid tools at HD instead. If you register them, the batteries have a lifetime warranty.

My own experience is the more you use them, the longer they last. Batteries that sit die.

I am a DeWalt user the most, Milwaukee a close second. but truly think that if they sit, they shit!!

Mine get weekly use and I run them dead. With lithium they just stop.
My old NiCd stuff would get weak and slow so you knew they were going.

I have had them for 7 years so I don’t find them to be a bad run at all for under $100.

quote:

Originally posted by jejb:
Get the Rigid tools at HD instead. If you register them, the batteries have a lifetime warranty.

Then I would have to replace all my tools. No thanks.

Yes, rechargeable batteries have a limited number of charge cycles / service life.

Looking like BigSwede and I had the same issue, the charger not the batteries.

I went to the Depot today and they had the hammer drill kit with 2 1.5aH batteries for $99.
Figure I have made it almost 8 years on 2 1.3aH batteries. Save $20 and have the lighter batteries.
Charged up the new batteries and put an old one on the charger for giggles just to see.
Been on there for a bit and the defective error light has not come on just the charging light.

Looking forward to giving the hammer drill a go. I have a few things I need to mount in my shop that has concrete walls.
The hammer drill is a lot heavier than my old drill. Seems a bit better made. Likely needs to be to withstand the hammer action.