Automotive Electrical System Diagnosis Unmasking Battery Voltage Fluctuations

I measured this voltage using a battery analyzer which shows live output as well as with a fluke meter. Additionally I pulled the live data with ... First, check the battery clamps themselves. Have they been over tightened over the years so they are distorted and cannot tightly grip the ... So, it kinda sounds like your battery is not being charged during acceleration. Or else, something is drawing more current (dropping the voltage) ... It is highly likely that the alternator and/or voltage regulator are the problem. '04 330i ZHP - OEM Clears - ///M Strut bar - CoolantSnitch. The issue i'm having is that while driving i'll notice the battery voltage meter drop and the exterior lights will dim significantly. I replaced the original battery this past January and had no issue until this past weekend in the middle of a 900-mile road trip. While cruising ... The voltage regulator shuts down the alternator as the battery reaches its charge and the gauge gradually drops to battery voltage. When there's ... I got in the car. Checked voltage before and after starting It. Voltage hits 13.7 volts for a breif second after starting then drops to battery ... Does so at idle or while driving down the road. Tail lights ... I placed volt meter on the battery and showed him the voltage fluctuation. Sounds like a bad battery, but I would also check the output of the alternator to make sure it's up to par. You need to see at at least 13.5 ...