these are not theory they are facts i am a retired harley master tech.with 25 years experience.all batteries 6 or 12 volt produce 2.1 vdc to 2.12 vdc per cell all batteries are wired in series thus producing the voltage of a battery 6 volt has 3 cells 12 volt has 6 cells.specific gravity is the comparison of gravity of the earth itself or density. a solid or liquid. sulphuric acid is very dense and is diluted with distilled water to a specific gravity level. shall i continue with the class?specific gravity is checked at 77 degrees with a correction factor of .001 for every 3 degrees in temp difference s.g.+.84= cell voltage.when charging a battery the max temp of the battery should not go past 120 degrees. check it with a heat gun,put your hands on the case of the battery if it's hot when charging give it a break for a while or this is also a sign of a bad cell .050" difference of gravity between cells indicates a bad cell and the battery is toast. the main thing is keep connections clean & tight use a electrical contact grease on the posts and connections, keep the battery case clean a dirty battery will self discharge faster than normal.normal self discharge rate is.5 to 1 % every day so if your truck is not a daily driver keep a trickle charger on it. bikes tend to sit a lot now days people buy them to show off on the weekends.they can't understand why the battery went dead.replaced a lot of really good batteries that went bad simply because of neglect.i get 6 years out of my batteries in all of my vehicles because i keep up the maintenance also the fluids will absorb water from sitting or running for a short time only. the worst thing you can do to a motor is start it up in the drive way run it a few minutes and shut it off the condensation immediately starts in humid condition's especially.take it for a drive that's what it was made to do be driven. after 25 years of listening to whining customers and tryin to beat it in their heads i know my stuff.bike or truck
