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Power Brick
For usb and misc electronics.
Charges via solar panels.
thoughts
2025-11-09
the buck converters we're using are really not that efficient, if you accidentally leave the lever in the on position it will slowly drain the batteries. these old li-ion cells don't hold power that well either, usually have to charge the device the day of if we want to take the old camera with us.
2025-02-14
Lipo batt scare me. Fire.
oops: could not find "/physical-objects/power-brick/Sodium Ion nail penetration test".
Sodium Ion seam a lill less scary.
Less holding power, less flat engery discarge, but i'm ok with that.
At least they don't create fire if they fail.
Main thing this needs to be useful is a larger solar panel. More watts.
The 3 peuny 4watt pannels take forever to charge this thing.
inside
diagram
sorry for the handwriting.
Fuses keep circutry safe.
Diode keeps the batteries from discharging into the Buck Converter and solar panels.
Battery Managment System (BMS) keeps the LiIon batteries happy.
Made from
- 18650 LiIon batteries recyled from a drill battery
- 3 LM2596S adjustable buck converters
- 2 amp fuse
- 20 amp fuse
- switch
- brass hardware (screws and stuff) for conecting to the batteries - this was like $20 >:(
- springs for the brass
- 1/4 inch ply-wood
- wood scraps
- toothpicks (as dowels)
pictures from making of the box
links videos that helped make this thing
The switch is needed because LiIon batteries cannot be charged and discharged at the same time.
Phones and the like run off of the charging cable while the LiIon battery charges.
This is the dc to dc buck converter that was used.
Can also limit the current allowed through.
Shows how the circutry of the BMS works.
