u/Binford_Tool

I have a set of M18 CP 2.0 batteries that are around 5 years old. Started noticing an interesting issue that fully charged batteries would die quickly when the impact driver was under load (the drill seems fine). The battery indicator would show empty and then jump to two bars as soon as I put it on the charger. Thought it might be a cell imbalance issue but they were all at 3.96 volts on a full charge. Depleted both batteries and each cell is showing 3.68 volts. I think the cutoff is 2 volts per cell from my research online. Just want to confirm my suspicions that it's probably a faulty circuit board?