# Car Battery Went Bad After 20 Months

**URL:** <https://boards.straightdope.com/t/car-battery-went-bad-after-20-months/722256>\
**Category:** In My Humble Opinion\
**Created:** [June 11, 2015, 3:03pm UTC](https://boards.straightdope.com/t/car-battery-went-bad-after-20-months/722256 "2015-06-11T15:03:19Z")\
**Posts on this page:** 1\
**Page:** 3

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**Author:** ![GusNSpot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gusnspot/32/436_2.png) [@GusNSpot](https://boards.straightdope.com/u/GusNSpot)\
**Post date:** [June 15, 2015, 3:29am UTC](https://boards.straightdope.com/t/car-battery-went-bad-after-20-months/722256/41 "2015-06-15T03:29:27Z")

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> [@excavating\_for\_a\_mind](#):
>
> Actually, ALL AMMETERS measure voltage, not current. They measure a voltage drop across a (usually high resistance) shunt; the value of the resistance and the value of the voltage determining the amount of current. At least that was what I was taught in Electrical Engineering.

Didn’t you actually mean “usually low resistance)” shunt ???

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