QUOTE(Roman Catholic @ Sep 22 2019, 02:56 PM)
Sorry too burst your bubble but what you wrote is incorrect. A weak battery can and will cause a car to stall too. It happened while I was in the car and it happened to a good friend of mine Cikgu Ali. Cikgu didn't believe initially when I warned him about it when he came to see me about his battery, and sure enough happened to him also while on his way home. Well, I had to help him with my car's battery so that he could drive home. Modern cars with so much electronics in them is now highly dependant on a healthy battery too. 😊
Perhaps the correct question every car owner should ask is when should they change their battery before it dies out ? For some its 80%, for some its 60% and some its 40% State-of-Charge but at stage, one is pushing ones luck a little to far. Penny wise but definately pound foolish.
Thats the thing, cars dont stall if the battery is weak only if the motor is weak as well in which the voltage of both are too low to supply the required amps. I do know that electronics need the right voltage, but its also to do with amps. Draw too much amps and the volts decrease.
When the engine on, the motor produces DC, ideally at 12V but you do need more volts to recharge the battery so it can go to as high as 15V and is allowed to vary. If the motor is too weak, it will not be able to sustain a good voltage. Thats why the voltage guide for checking battery health for voltage isnt determinate when the engine is on but rather when the engine is off when the battery is fully charged.
If the battery drains too much when the car is off it will mess with the electronics.
But if the car can stall just because the battery is too weak, but the motor is fine, than something must be wrong in the design. Given the same electrical connections, the higher voltage always wins the flow.
Sometimes things plugged into the cig slot can cause interference, especially if they have switching voltage setups like USB chargers (feedback interference back on the 12V circuit from switching 12V to 5V) which can mess with the cars electronics especially if a voltage on the line is weaker.