Quote Originally Posted by rsnald View Post
parang disagree ako dito pre... mas accurate na indication ng battery charging yung ammeter... pag positive yung reading while you're revving, that means your alternator is providing current,while you're on idle, sometimes makikita mo naglalaro between positive to slightly negative value, meaning your electrical components in your car is drawing current from your battery and/or alternator.

a battery's voltage does not really indicate it's reserve power. subukan mo kunan ng voltage ang diskargadong baterya na size A or AA, babasa pa rin yun na around 1.5V kahit mahina na sya. what would really indicate its reserve power is the ampere reading or the amount of electrical current it can deliver.
kaya ang makikita mong reserve power ratings sa mga car batteries, measured in ampere-hours, not voltage-hours, and battery chargers are also rated on how fast they charge based on amperage w/ matching voltage. imho. i could be wrong but that's how i understand it...hth
You are absolutely 100% totally correct... Ampere is the best way to measure how much you are charging. Voltage will only tell IF it is charging but not by how much you are charging . In short more ampere means more "juice" in your battery. More volts just means that there is a juice going into your battery but doesn't indicate how much. This is also related why batteries are rated in "Ampere-Hours" since this will indicate how long they can last.

Using digital voltmeter can be annoying. Unless this is a digital voltmeter with averaging function. It kinda looks weird seeing the numbers go up and down very fast hehe. I think this is why we have a charging light indicator sa gauge eh.. This is to indicate if the battery is being charged or not... Try removing your alternator terminals for fun lang.. Hindi mawawala ung red battery ilaw sa gauge kc it's not charging... FYI lang... Very very old cars have an analog meter for the battery voltage reading para makita kung charging or not.. later models 88 and up to today may indicator nalang nilagay with a battery symbol... It usually lights up when u start ignition but not the starter yet..