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A project log for Smart Battery Tester

An intelligent test device that tests batteries by discharging them to measure capacity

adam-oakleyAdam Oakley 11/29/2015 at 00:440 Comments

After putting this project on the shelf for months, I've put some work in and the project is in a reasonably finished state. There's more that I want to do with the software so I may work on that and post updates. I have posted the current source code and uploaded a few pictures. The source code is not pretty. It needs better documentation, but it does the job.

As for what work I have done, most of my effort has been put towards 3D printing the case for this project. The case was a big headache. I spent a decent chunk of time modeling the case in Autodesk Inventor and I was pretty happy with the design. I designed some 3D printed buttons that make use of standard tactile switches. These buttons feel very satisfying and I like that the parts are very cheap.

Albert and I ran into quite a few problems actually printing the case out. The case is fairly long because it has to hold all the circuitry and a big heatsink. The long case is very difficult for us to print because with ABS plastic on a print this large we get warping issues. Aside from that Albert's printer broke before we could print out the project case properly. The printer had all sorts of feeding issues, from the nozzle getting clogged and also from the extruder failing midway through prints.

Albert put a lot of effort into repairing his printer and now it's working again, but not fully. We managed to print out my case with some minor warping. The warping made it difficult to fit things in properly but I managed to make it work. I soldered everything together and closed up the case.

As it happens right when I finished assembling the load tester, my home's alarm system began complaining about a low battery. I removed the sealed lead acid battery and tested it with my load tester. The tester worked great, and reported that the alarm battery had a remaining capacity of 93mAh. The battery was originally 4.5Ah so it's clearly worn out now and needs to be replaced.

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