Quote Originally Posted by z28-50 View Post
FYI, I have NOCO Genius 10.

It has a power supply mode.

Copy and paste from the user guide.

Converts to a DC power supply for powering any 12VDC device, like a tire inflator, oil changer, or as a memory retainer when replacing a battery.

When selected, a red LED will illuminate.13.6V @ 25°C | 10A | Max 12A.

I have mentioned this before about noise being induced and corrupting tunes.

When I was tuning mid 90's Camaro when we used battery chargers/tenders, noise could be induced in the 5V corrupting data.
A standard battery charger is a 2-phase half-wave rectified, so it's choppy, on, off, on, off; cars use 3 phases in their alternators and a full wave rectifier.

Full wave rectifier will flip over the negative sine wave to positive where a 1/2 wave chops it off, so it's a pulsating DC, not smooth or clean, as you mentioned.

A good battery can act like a capacitor and absorb this, like an electrical shock absorber, but a questionable battery could spell trouble.