I was changing a battery in a friend's (A) truck over the weekend when another friend (B) advised leaving the truck running while doing so. I thought what? I followed his advice and sure enough, the truck stayed running with no battery in it. Installed the new one with no issues with the truck still running. Friend B then explained by doing it this way the vehicle doesn't lose any of it' pre-sets (radio, seats, mirrors). Learn something new every day...The truck is kind of rare. It is a one-owner 03 Denali with a 6.0L, custom paint, factory fiberglass widebody box with DOT mandatory roof/fender marker lights, Quadrasteer, Flowmaster duals, and 20" factory wheels.
It's a little hard on some of the electronics i've been told but i've done that with parts cars where the owner wanted to keep the battery for some reason
Not great for the alternator without the battery to smooth out the charge, but for a short time, not a huge deal. I've limped cars home several times with no battery in them. Also, high risk of shorting something as the terminals are still hot with full alternator amperage behind them. When I worked at AutoZone, they had a tool for us (when changing a customer's battery, don't think it was for sale) that was just a 9v battery connected to an OBDII plug, this would keep just that circuit energized with just enough power to retain memory functions. But can only supply less than an amp, so not enough to damage anything if it shorted (there was also a plastic sleeve to put over the positive terminal). Something like this: https://www.amazon.com/Connector-Ba...&qid=1610990105&sprefix=9v+obd,aps,186&sr=8-1 Always a good idea to check the owners manual on modern cars about changing the battery. Late '90s Subaru factory security systems had to be reset after a battery replacement via a button buried in the wiring harness above the driver's feet. Most Hondas have a security code for the radio, and if the battery dies or is removed, you need that code to get the radio to work (can be pulled if it's unlocked, and should be written on a card in the owners manual book).
I don't remember having to reprogram any of those things when I changed the battery in our '13 Escape. I wonder if those settings are stored in the key fob since the car sets those devices depending on which fob it detects? I don't remember having to program radio presets either. The one thing I was concerned about is that the "battery minder" system needs to be reset with Ford's diagnostic tool so that the car knows it has a new battery installed and uses the correct charging algorithm. Apparently it varies the alternator's output based on age of the battery in the name of improving fuel economy by reducing alternator drag. I never did have anything changed and the new battery has survived for a few years now.
I had an '86 325E that did that with the factory radio. Super annoying because it would only happen often enough to forget where the code was written down. Haha.
He jokes but my comanche had a bunch of labels on the dash for speedometer corrections for oversized tires and the CB radio codes
