Q: I replaced the battery and alternator in my car is still lose charge and battery light still on

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I replace my alternator and my battery my truck light battery still on and I lose power driving and it cuts off

My car has 163893 miles.
My car has an automatic transmission.

It sounds like you may have a failing voltage regulator. When the voltage regulator is not working properly, this may result in the alternator allowing too much power to be delivered to the battery resulting in damaging wires and prematurely sometimes destroying the battery. In other cases it may result in the alternator not supplying enough power to the battery, resulting in undercharging the battery or not charging it at all. In some cases when a battery is too weak or damaged, it may no longer hold a charge for any length of time, in which case the alternator may be doing its job, but the battery is just simply too weak to hold a charge. In either case, I would recommend having an expert from YourMechanic come to your location to diagnose your vehicle’s charging system.

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