First thing when I’m ready to get the Hercules 20V battery going is check its status. Pull the pack off the tool, check the status, and then plug it in. The fuel gauge will display the current charge level.

Pressing the fuel-gauge button show you the current charge level.
Understanding Charger Indicators
It’s also a time saver as you can have the battery appear to be fully charged while it is actualy depleted.
You avoid guessing about the power level when you check it with the fuel-gauge button.

When you physically check the power, you don’t have to guess at its strength.
When you are aware of your battery’s condition you simply slide it on and attach it to 20V charger. The pack must seat firm in place for the connection to work. If not it will just sit there and won’t try to do anything with a loose fit.
The charger is well lit with various colors indicating status which makes troubleshooting simple.

These gauges are there so you can see what’s going on in the unit.
If you notice a flashing green light, then the battery is charging. You’ll also notice a solid red light in this state. Together, this indicates power are moving properly into the pack. So when these two lights is on there’s no cause for concern.
How long does it take? That will vary by pack size. For example, it only takes about 30 to 45 minutes to top off one of the smaller 2.0 Ah pack.

It also gives you time to take a breather. Expect roughly 60 to 75 minutes with the standard 4.0 Ah pack. Be patient with larger packs. It will take about 75 to 90 minutes for your 5.0 Ah battery to charge fully.
An extended charge gives you an extended run time. Rapid-charge models will cut down on the charging times more considerable.

Solid green means your battery is 100% charged. The green light stops blinking only when it is solid green.
So once you see a solid green signal, you know your pack is ready for deployment. Grab it out of there and head back to work.
No further waiting is required.
Once the battery is fully charged, there’s no need to wait any longer. Things can goes wrong in the process. When there’s a problem, you’ll see it on the charger with a blinky-red light. That typically means that it’s not charging because of bad contact. How do you solve that?


Take out the battery and reinsert it, ensuring a good fit. That’s usually enough to clear the problem. Charging will resume as normal. The red light will no longer blink. Simple, and you save some good batteries from the trash can.
It’s important to know what all your lights mean so you’re not frustrated by it. Is it just charging or has the battery failed? No guessing required with the green/red LED indicators.
Once you know what those are telling you, the system works well. When something makes sense and is easy to follow, you can be confident in your tools. You can save time by checking the gauge before checking anything else. You should of checked the gauge first.