jdege

You can kill a Li-Ion battery by overcharging, or by charging at low temps. Which is why quality battery chargers have protective circuits to prevent that. I'd have expected Ryobi's chargers to have such. Do they not?

Just checked on my Ryobi lawn mower, today, in prep for the season, and the battery was dead. Again. So now I'm on my third 40V Ryobi battery. I'm not sure whether the batteries are flawed or the charger is simply stupid. Or maybe it's planned obsolescence. I'm not aware of any lithium chemistry that isn't good for hundreds of charge cycles. But I only mow a couple of dozen times a year, and I'm seeing them fail after two or three years. I mow, I put the battery in the charger, and then pull it out again when I mow the next time. But after a couple of years of this the battery is dead and won't take a charge. It's the charger too stupid to stop charging when the battery is full? Does it lack temperature sensors and not shut off when it's too cold or too warm?