New mower battery dies after 5 mins – what gives?

Hey guys, my Ryobi 40V mower battery won't hold a charge. It was working fine last season but now it dies after like 5 mins of cutting. I've tried charging it overnight but no change. Any idea if it's the battery or the charger? I'm about to drop $200 on a new one but want to be sure.

Before you buy new, check if the charger has a light that changes color. If it stays green even when dead, it might be the battery's BMS (battery management system) tripped. Try pressing the button on the battery 3 times – that resets some Ryobi batteries. Also, if you have a multimeter, test the voltage. Should be around 40V fully charged.

Wendy's right. I've seen this a lot. Also, clean the contacts on both the battery and charger – corrosion can cause a bad connection. Use a little rubbing alcohol and a q-tip. And check the fuses inside the battery if you're brave enough to open it (be careful!). If it's the cells, you might need a new battery, but try a slow charge at 2A if your charger has that option.

Thanks guys! I tried the button reset and cleaned the contacts. No luck. I don't have a multimeter but I'll borrow one from my neighbor. If it's below 35V I guess it's toast? Any recommendations for a replacement? Should I stick with Ryobi or switch to EGO?

If you're replacing, check the cycle count on your old battery – if it's over 500, it's probably time. Ryobi's good for price but EGO has better runtime. Since you already have Ryobi tools, I'd stick with Ryobi to keep compatibility. But if you wanna switch, go ahead – just remember you'll need new charger too.