I decided that experimenting with this charger was way more important than cutting the lawn, painting the soffits, doing brick repairs on the chimney & stuff like that, so...
I de-soldered enough to get the battery out of a couple of units for some science project time. They do, indeed, work without the battery. Curiously the relay in just one of them clicks in & out while the unit is plugged in. The output voltage remains steady while it's clicking. I didn't dive in to that mystery (yet).
Next, I connected a new coin cell externally with an amp meter in series just to check drain on the cell while the charger is unplugged & idle. The meter did not show any drain, but I'm not sure my meter is sensitive enough or if the test was long enough.
I looked for voltage at the battery terminals to see if a charging current was presented to the battery while the device was plugged in. None was present, so my guess is it does not charge the cell. (It might if a load is present, but I did not test that.)
I'd have to agree with what some of you said about the unit being designed for a few years' work & then it is disposable.
The biggest downside in my view is that the end-user does not have any idea that there is a lithium cell inside, so the lithium goes with the charger to the landfill instead of the recycling center. The second biggest downside from my perspective is that it's one more instance of planned obsolescence in our Throw-It-Away culture.
Thanks Again for the great lessons everybody. These innocent appearing chargers got me to do lots of studying about PSUs. ICs & related components & circuitry. Learning's Good!
Enjoy This Day!
Paul
I de-soldered enough to get the battery out of a couple of units for some science project time. They do, indeed, work without the battery. Curiously the relay in just one of them clicks in & out while the unit is plugged in. The output voltage remains steady while it's clicking. I didn't dive in to that mystery (yet).
Next, I connected a new coin cell externally with an amp meter in series just to check drain on the cell while the charger is unplugged & idle. The meter did not show any drain, but I'm not sure my meter is sensitive enough or if the test was long enough.
I looked for voltage at the battery terminals to see if a charging current was presented to the battery while the device was plugged in. None was present, so my guess is it does not charge the cell. (It might if a load is present, but I did not test that.)
I'd have to agree with what some of you said about the unit being designed for a few years' work & then it is disposable.
The biggest downside in my view is that the end-user does not have any idea that there is a lithium cell inside, so the lithium goes with the charger to the landfill instead of the recycling center. The second biggest downside from my perspective is that it's one more instance of planned obsolescence in our Throw-It-Away culture.
Thanks Again for the great lessons everybody. These innocent appearing chargers got me to do lots of studying about PSUs. ICs & related components & circuitry. Learning's Good!
Enjoy This Day!
Paul