I recently noticed my wipers changing speed, so I scrolled to voltage on the dash. At times voltage was as low as 11.8 V. The odd part is that if I backed off the gas the voltage would rise to 13.4 or so. I'm old enough to remember accessories run by engine vacuum and this is what it acted like...
I installed to a magnetic drain plug on first oil change. A bit more insurance and It collects particles too small for the filter. You will find a small amount of metallic "dust" on it when you do your oil change. This is normal wear.