Cell Phone Li-ion battery tester

Li-ion Battery Tester

While working at Macalegin Electronics I discovered that many times we need to verify the charge on a cell phone battery. We have a multimeter but is a little cumbersome to use especially when testing several batteries at once.
So I had the opportunity of designing and building a Li-Ion Battery tester for quick and easy battery charge indication.
It consists of one green LED, one red LED, and adjustable leads.
When the leads come in contact with the battery the LED’s will light up as follows:
Green only – the battery charge is ~80% to 100%
Green & Red – the battery charge is between 0% and ~80%. If the green LED is noticeably brighter than the red LED, then the battery charge is between ~65% and ~80%. If the red LED is noticeably brighter than the green LED, then the battery charge is less than ~10%.

Adjustable Leads
Internal Circuit
Li-Ion Battery Tester – EveryCircuit
[iframe width=”560″ height=”360″ src=”https://everycircuit.com/embed/6522073815973888″][/iframe]
To adjust the input voltage: Select the power source in the top right corner, then select the wrench in the bottom bar. then use the wheel in the right corner to change the voltage.


Pinewood Derby – Propeller powered

A week ago my brother invited me to join him for an Anything Goes pinewood derby race. I have great memories of building these cars with my Dad and wouldn’t pass up an opportunity to relive those moments.
First I designed my car in Sketch-Up, and then built the car from a standard derby kit. (see image below)
The hardest part was building the propeller motor stand. I made that part separately and the glued it into place. Before I could glue it I had to drill holes and feed the wires for the motor through the holes.
Then to power the motor I used an old iPhone 4 battery I had laying around. To make the battery easier to use I soldered a new connector on the battery so I could easily plug it into the car and the battery charger. To finish the simple circuit, I added a switch so I wouldn’t have to disconnect the battery to turn it off.
And finally, to finish things off I added some tungsten weights to a cardboard cover painted to match the car.
I say the finished product always looks better than the sketch.