When I took the Hitachi lithium-ion charger from the suitcase what I noticed were little red lights before. I assumed that it will be something simple, but that tiny LED shows five different states of the battery according to its different rhythms of blinking. I started the test by plugging in the charger without a connected battery.
Right at the moment when I connected it the red light started blinking in a steady beat. Like this the charger signals that it is ready and waiting for a battery to charge. It is totally normal that the red light blinks when no battery is attached.
There is no reason to worry about that.
I placed the battery pack in the charger and set it in position. Right when the battery touched the metal pins, the behavior of the light totally changed. The red light stopped blinking and shined all the time.
I left it on the charger and watched as it pushed energy into the old cells.
How to Read Your Hitachi Battery Charger Red Light Indicators
The charging lasted around an hour for my half empty battery. I checked it often to see when the light would change, and finally it did that. The steady red light turned to blinking in a medium beat.
When the red light blinks in a medium rhythm, the battery is fully charged.
What surprised me were signs that there are two more rhythms of blinking that signal problems. One of them is a red light that blinks in a slow beat. The temperature is too high or too low.
The charger will not start the process until the battery reaches normal heat. That happened to me after leaving the battery in the car during a cold morning. I brought it inside and waited around twenty minutes so that it warmed, and then the light became solid red.
The final pattern of light is one that you do not want to see. Fast, very fast red blinking shows that the charger found a fault in the battery itself. It is a bad battery.
Do not toss it right away, there is a trick to restart that you can try.
That can restore the link between the charger and the battery. I tried that with an older battery that gave the fast error, and it actually worked.
It started to charge normally.
The whole system depends on that one red LED, so notice whether it shines all the time or blinks and what rhythm, and that tells you everything about the situation. When I first used Hitachi tools, I would just leave the batteries on the charger and assume that they were ready. It made no sense when I would take a battery that I thought was fully charged, only to find that it was almost dead.
I noticed that I removed them too soon… During the solid red phase, instead of waiting for the medium blinking. That is a common mistake.
Now I know that you need to wait for the blinking rhythm after the solid red goes away.
