Silverfox gave me his solution on how he keeps his batteries topped off and I decided to follow his idea and create my own battery refresh charger.
Thanks Silverfox for the idea. I hope you don't mind me spilling the beans and sharing your idea with everyone else.
The basic concept is to use a mechanical timer like the one you use for your christmas tree every year. The one with pegs for every 15 minutes. The timer output feeds a bunch of slow chargers. Since many chargers and other electronic devices have a AC brick leaving the brick plugged in all time when it's not being used is wasting electricity. The timer turns on the brick and chargers once a day and thus tops off the batteries replenishing the ~2% internal loss.
I have batteries lying around all over the place and this is my problem. I don't like to keep the batteries on the chargers and I don't have that many chargers.
As such I have created a simple board that holds single AA battery holders and power series resistor. Hooking the holders up to a surplus wall wart with 5V or 3.3V output will with the correct resistor provide the necessary charge for the 15 minutes it will be turned on each day.
Below is a picture of the plexiglass, copper tape, battery holders and power resistors (15 ohms).
The picture didn't come out that well and you will have a hard time seeing the engraved plexiglas.
After assembly the top side of the battery holder is shown below.
The bottomside image.
The wall wart I have has both 3.3V and 5V output and I plan on wiring both to a switch on the panel so that I can power the batteries from either one.
This will take several weeks to determine the time needed each day and which voltage works better. Ideally, over an extended time of several months this system should keep the batteries near full charge.
My plan is to make one or more of these to park my batteries after I put them in a regular charger. Once the battery has a full charger I will park them here to keep them topped and to keep them at full charge status.
If there is interest in this as a kit form I would be willing to make a run of these for CPF.
The battery holders cost 75c or less and the 3W 15 ohm resistor in surplus is 10-15c each. Add in the plexiglass, copper tape, some wire, solder, switch, wall wart power supply and mechanical timer. I would suspect the total cost would be under $20.00.
I'm actually going to put a AC strip after the timer and put my laptops on this timer as well. That way the laptop will get topped off and not be dead next time I go to use it. Heck... I might be plugging a lot of items on this timer.
Thanks Silverfox for the idea. I hope you don't mind me spilling the beans and sharing your idea with everyone else.
The basic concept is to use a mechanical timer like the one you use for your christmas tree every year. The one with pegs for every 15 minutes. The timer output feeds a bunch of slow chargers. Since many chargers and other electronic devices have a AC brick leaving the brick plugged in all time when it's not being used is wasting electricity. The timer turns on the brick and chargers once a day and thus tops off the batteries replenishing the ~2% internal loss.
I have batteries lying around all over the place and this is my problem. I don't like to keep the batteries on the chargers and I don't have that many chargers.
As such I have created a simple board that holds single AA battery holders and power series resistor. Hooking the holders up to a surplus wall wart with 5V or 3.3V output will with the correct resistor provide the necessary charge for the 15 minutes it will be turned on each day.
Below is a picture of the plexiglass, copper tape, battery holders and power resistors (15 ohms).
The picture didn't come out that well and you will have a hard time seeing the engraved plexiglas.
After assembly the top side of the battery holder is shown below.
The bottomside image.
The wall wart I have has both 3.3V and 5V output and I plan on wiring both to a switch on the panel so that I can power the batteries from either one.
This will take several weeks to determine the time needed each day and which voltage works better. Ideally, over an extended time of several months this system should keep the batteries near full charge.
My plan is to make one or more of these to park my batteries after I put them in a regular charger. Once the battery has a full charger I will park them here to keep them topped and to keep them at full charge status.
If there is interest in this as a kit form I would be willing to make a run of these for CPF.
The battery holders cost 75c or less and the 3W 15 ohm resistor in surplus is 10-15c each. Add in the plexiglass, copper tape, some wire, solder, switch, wall wart power supply and mechanical timer. I would suspect the total cost would be under $20.00.
I'm actually going to put a AC strip after the timer and put my laptops on this timer as well. That way the laptop will get topped off and not be dead next time I go to use it. Heck... I might be plugging a lot of items on this timer.
