a fully charged battery is 12.6v. most modern vehicles in temperatures over 40F will crank down to the mid 11 volts. When a battery shows it has sufficient Voltage... but it falls on it's face when applying a large load like cranking the engine (not to be confused with a low amperage draw like headlights or dash lights etc) That's a Direct result of a Sulfated battery & it will need to be replaced. Sulfation is nothing but a fancy electrical term for corrosion. Corrosion creates resistance... So for example... easy numbers... say something takes 200 amps normally... it the battery is internally sulfated (or has sulfated battery terminals) that battery might think it's trying to do something that's 250 0r 300 amps.. not tha actual 200... It's also a two way street.. if the sulfated battery or terminals make the amperage struggle to get out... it also makes it harder for the charging system to recharge it. Voltage & Amperage are different. so you can have what appears to be a fully charged battery... but it can't produce enough Amperage for the job.... internal sulfation is the reason all batteries need to be replaced every few years. FYI... only a discharged battery sulfates... a battery kept fully charged almost never sulfates. this is why we use trickle chargers or maintainer chargers on vehicles or toys that won't be used for months... the Battery tender compensates for parasitic drain as well as natural discharge. ( batteries will self discharge ove time even with no load) Hope this helps.
a fully charged battery is 12.6v. most modern vehicles in temperatures over 40F will crank down to the mid 11 volts. When a battery shows it has sufficient Voltage... but it falls on it's face when applying a large load like cranking the engine (not to be confused with a low amperage draw like headlights or dash lights etc) That's a Direct result of a Sulfated battery & it will need to be replaced. Sulfation is nothing but a fancy electrical term for corrosion. Corrosion creates resistance... So for example... easy numbers... say something takes 200 amps normally... it the battery is internally sulfated (or has sulfated battery terminals) that battery might think it's trying to do something that's 250 0r 300 amps.. not tha actual 200... It's also a two way street.. if the sulfated battery or terminals make the amperage struggle to get out... it also makes it harder for the charging system to recharge it. Voltage & Amperage are different. so you can have what appears to be a fully charged battery... but it can't produce enough Amperage for the job.... internal sulfation is the reason all batteries need to be replaced every few years. FYI... only a discharged battery sulfates... a battery kept fully charged almost never sulfates. this is why we use trickle chargers or maintainer chargers on vehicles or toys that won't be used for months... the Battery tender compensates for parasitic drain as well as natural discharge. ( batteries will self discharge ove time even with no load) Hope this helps.
Thank you for teaching me all that. Much appreciated. Very informative.