Hello,

How does one keep a stable voltage to a Dry Cell while the vehicle Voltage Regulator/Charging system fluctuates between 12.8 and 14.8 volts?

I have a PWM, when the voltage drops, the current drops.

14.8v is about 49 amps
12.8v is about 32 amps

When I start the engine, I get 14.8 volts. Over a period of time, it will fluctuate down to 12.8v. Once it gets down to that level, it stays there. I kill the engine and then quickly start it back up. I get 14.8 volts with 49 amps. The time it takes to go from 14.8 to 12.8 varies. Sometimes 5 minutes, sometimes an hour, and all in between. Thought that head lights being on would the difference. It is vary random. Sometimes it will drop down to 13v, but will recover back up little or a lot. But once it hits 12.8, 12.9, it stays. I have never seen it drop fast.

Your knowledge would greatly be appreciated.

Have a Good Day!