Apparently I’m not the only one who’s tried to charge a Milwaukee RedLithium cell and had the charger flash red/green. Here’s what happened.
The following is by my understanding.
My wife got me a drill/impact wrench set from Milwaukee tools maybe a year ago. It revolutionized my handyman chores.
I recall having to charge the cells before using the drill and the impact drill. When I slid one cell into the charger, the indicator went solid red, which means it’s charging. You want that.
Then, when charging is finished, the indicator light on the charger turns solid green: you want that, too.
Such happened with the first cell. However, with the second, the indicator light flashed red/green when I slid it in. You don’t want that; the manual seems to suggest that it means either the contact isn’t good, or there’s a hardware problem either with the cell, the charger, or both.
Since the set was brand new, I didn’t want to think it was already defective. I played around a bit, slightly changing its geometry in the charger. After a couple of minutes of this, the indicator turned solid red: charging. I wanted that.
Holding the cell in place in the charger, and my breath, I continued to watch the indicator light, wondering if it would start to flash. It did once, but by readjusting the position of the cell I was able to bring it back to solid red. Eventually, I could let go, and the indicator remained solid red. A few minutes later, I checked back: solid green. I wanted that:)
Charging time doesn’t seem very long, anyway. I didn’t time it, but it seems maybe it took half an hour(?) from near-dead to full charge. That’s a very loose guess.
Best of luck:)