Help! My circular saw battery won't charge!

Hey everyone, I've got a problem with my cordless circular saw. The battery is dead and it won't charge. I've tried plugging it in and the charger just shows a red light. Anyone else had this issue? Any tips?

Sounds like a classic battery issue. First, check if the contacts are clean. Sometimes dirt or oxidation can prevent charging. Use a pencil eraser or a bit of contact cleaner on the terminals. Also, make sure the battery is fully seated in the charger. If that doesn't work, it might be a cell problem inside. You could try a multimeter to check voltage, but if it's a cheap battery, might just be time for a new one.

I've always stuck with the same brand for my cordless tools, and I've never had a battery issue. What brand is it? If it's a lesser-known brand, you might want to consider upgrading to a reputable one. My Dewalt batteries have lasted years. Just my two cents.

It's a Ryobi, actually. I've had it for about a year, so it's not that old. I tried cleaning the contacts and still no luck. The charger itself is fine because I have another battery that charges perfect. So it's definitely the battery. Should I open it up and try to replace the cells? I've seen videos, but not sure if it's worth it.

@DIYDave330 If it's a year old, it's likely within warranty. Check the date code and contact Ryobi. But if you're out of warranty, opening it up is risky. Those lithium-ion cells can be dangerous if punctured or shorted. If you don't have experience with battery rebuilding, might be safer to just buy a new one. I've rebuilt a few, but you need the right spot welder and cells. Otherwise, save yourself the hassle.