{"id":374,"date":"2013-11-12T14:02:42","date_gmt":"2013-11-12T14:02:42","guid":{"rendered":"http:\/\/www.megalithia.com\/?p=374"},"modified":"2017-03-30T18:36:35","modified_gmt":"2017-03-30T18:36:35","slug":"how-to-measure-battery-capacity","status":"publish","type":"post","link":"https:\/\/www.richardmudhar.com\/blog\/2013\/11\/how-to-measure-battery-capacity\/","title":{"rendered":"how to measure AA battery capacity"},"content":{"rendered":"

Poundland in the UK sell batteries branded by Kodak, but the cheapest ones are zinc chloride. I thought ZnCl has gone out of use decades ago, but it is surprising how often people are penny-wise and pound foolish. Particularly in pound shops \ud83d\ude09<\/p>\n

\"Cheap<\/a>
Cheap Poundland batteries are in fact twice as dear to use…<\/figcaption><\/figure>\n

So I am looking to make something to track the discharge of a battery. This is also useful to qualify NiMH and NiCd batteries – these fade with time and it is good to know what sort of capacity is left.<\/p>\n

\"...as<\/a>
…as the expensive ones!<\/figcaption><\/figure>\n

Every minute it reports the voltage and current from the batteries running through a 2.5V torch bulb, the third bulb is maintained at 2.5V to provide a reference. It transmits the signal using radio to a datalogger. I got a camera to take a picture every 15 minutes, as a video the results are reasonably clear. A picture tells a thousand words – the Zinc Chloride batteries are crap<\/p>\n