If you have been reading my blog you will have noticed I made two Arduino based NIMH AA battery testers around 2 years ago. One was the first Arduino project I made but it needed some improvement and as I had mentioned in one of my previous posts I’m really running out of things to make; I don’t want to end up with a load of gadgets I’ll never use. So I decided to revisit some of my earlier projects and either scrap / repurpose them or improve them. The second tester I made does not really need further improvement as I have already done that and it only gets used once in a while. It is sufficient for my needs so I’m not that concerned about it’s shortcomings. This one however I have plans to turn it into a 12V lead acid battery tester but for now I decided to improve the display layout and make better use of the limited 16×2 LCD.
I had already changed the voltage reference from the inaccurate voltage divider method to a TL431 2.5V reference IC so in preparation for the conversion into a 12V SLA tester I have released an updated version of the NIMH tester code with the improved display layout I plan to use for the 12V version. The project page is here.
So next update I will probably show the completed 12V SLA battery tester although I have also been working on a 24V LiFePO4 version of it too which is complete and working but again needs further improvement. That will be shown in a future blog post when I feel the code is release ready. The pump control timer I mentioned before will get a full project page too when I get round to it. The priority now is to convert the AA tester into a 12V battery tester as I have a ton of them to test.
The 12V version is now complete and has been tested with an 17.5Ah SLA battery. Not going to bother posting a full article but the schematic and code can be found on the project page in the text above.