Electronics > Projects, Designs, and Technical Stuff
Arduino based battery analyzer with datalogging
(1/1)
Moragor:
I had some NiMh batteries which performed badly, so I built a battery analyzer to test their capacity and on the long run their self discharge.
The prototype. Every good project starts with a breadboard and DuPont wires, right?
The finished device. It is built on a proto shield for the Arduino Mega 2560. The AA battery holder is connected to an Ina219, the output goes to a replaceable 10W resistor, then through a MOSFET and back to the battery holder. The display shows the main menu where you select the battery type with the tactile buttons bellow the Wago clamp. The button in the top left corner resets the Arduino.
The test display. All shown information is logged to the SD card in CSV format (time as milliseconds).
Testing a AAA battery inside an adapter. The SD module was removed to do a test without logging. A warning is displayed on the OLED screen.
Test setup for a LiPo pack. + goes to the Vin+ pin on the Ina219, - goes to a soldered in pin where the - of the AA battery holder is (MOSFET output).
The OLED screen is removable to replace the resistor which is held by a screw terminal and a Wago clamp. My tests were made at 5 (AA) and 10 Ohm (AAA). I'm limited by the resistors I have, maybe I make a V2 with constant current regulation some day.
The back of the proto shield with the finest botchery this side of the Mississippi.
One day I will remember to clean the flux off my projects.
>Here's the code for the Arduino<
Current comparison to a multimeter. The average difference is 0.3%.
All the batteries I've tested. The blue bars show the measured capacity in mAh, the red stacked bars the difference to the advertised value. The (tiny) green stacked bars show capacity above the advertised value (Eneloop AAA ooc).
For the "normal" tests the batteries rested 12 hours after charging. The "ooc" tests were made right out of the charger. More tests are scheduled in three and six months to test self discharge. (Spoiler: Don't buy Conrad (German supplier) brand batteries, they suck.)
The test in row 31 was made with an electronic load for comparison. The mWh are calculated and therefore in parentheses.
Here's an album with all the discharge curves I recorded: https://imgur.com/a/Vng5Am2
Navigation
[0] Message Index
Go to full version