Finally bought a battery hydrometer, need help with results

Check the section on tiny 3-legged voltage regulator CHIPS. In goes a higher voltage out comes a regulated lower voltage. Go to eBay to buy chips the little radiators called heat sinks and tiny diodes if they are needed. This is stuff anyone can do right. All of the battery toys that are no longer battery, here, have the chips stuck inside where the batteries used to go.