Won’t start

Sounds like a parasite battery drain. Try disconnecting the ground cable when the car is not in use and determine if the battery is going dead due to a defective battery or if there is a parasitic drain from some unsuspected load in the electrical system. All lights off, backup, interior, brake? Radio or booster amp still on? These are some things that can be silent battery sappers. Here is a simple test; Using a 12-volt bulb, such as a tail light bulb, determine if there is current draw. Hold the tip of the bulb against a battery post, then touch the cable to the side of the bulb. It it lights, you have a drain somewhere.

I have had trouble like yours in the past. Could not find a short in the wiring anywhere, and had ruled out the battery by replacing it. Unfortunately, I eventually realized that not all new batteries are good. What is wrong with them is hidden from view. I would take the battery back to where you bought it and ask for a replacement. If they refuse, then ask for warranty credit on the years left and get rid of it. When I replaced mine, the problem went away. Sometimes you miss the most obvious problems by trusting that new parts are always good.

If you leave it set for long periods of time, try using a battery tender. You could check for too much amp from the battery, everything off? The generic spec I use is 50 ma, that is .050 draw not even a tenth of an amp. It could be a little higher or lower, but, you get the picture. If too much amp draw, you can pull/replace fuses one at a time, if you pull a fuse on the problem circuit, the draw returns to normal. Sometimes a generator that has a problem, might let the battery drain?