What cause Parasitic draw

Computers, entertainment presets, USB ports, all of those are normal these days. If you think you have excessive battery draws, then have it checked by your favorite shop. I have seen bad alternators cause so much that they will kill a battery in a few hours.

There's a way to test for a voltage drop across a mini fuse , I would go a step further and go to the pos. terminal , You have to wait for timers and such to draw down after an hour , To trace it yourself is a PITA even if you know what you're doing

If you don't drive the vehicle much, leaving it sit for as little as 3 weeks can kill the battery. This is normal for a modern vehicle with all the computers and other electronics constantly drawing power even after the ignition is turned off. Jim

3 weeks? Even with a new battery I'm lucky to get even a full week out of my rig. I've had it checked and even checked it myself and that's as good as it gets. I think the battery is just too small for everything it has to keep up with. I'm thinking about putting in an auxiliary battery with continuous duty solenoid and switch.

Yesterday I ran my 08 Grand Marquis for the first time since the last week of October. It's been getting colder here and since I don't use the car much I run it to keep the battery charged and things moving. It's not stored in a heated garage or anything. Just parked in my driveway. It did crank over a bit slowly, but started and ran no problem. As the weather gets colder I'll run it more frequently, every 2 to 3 weeks. The battery isn't new either. I bought it in June of 2017. It's a Motorcraft battery. I buy AC Delco batteries for my GMs and Motorcraft batteries for my Fords. I don't buy aftermarket batteries. OEM batteries are more expensive but it's been my experience over the years they're better. I once had a Delco battery last 10 years. I only replaced it because it was 10 years old and I was selling the vehicle. It was still good but I didn't want the new owner to possibly have a dead battery shortly after buying the vehicle. It was 10 years old after all. Most aftermarket battery cores that I get back at the auto parts store where I work are around 4 years old. Batteries that come with a new vehicle are only rated for 3 years. My friend has a 2019 Ford Escape with the original Motorcraft battery still in it. I told him to be prepared to replace it this Winter. He wants to see how long it lasts, so we'll see. The last Delco battery I had in my 03 S 10 Pick Up lasted 8 years. I bought it in July of 2016 and it died back in August. Jim

Sometimes the convenient lights will stay on without you knowing it. Lights like the glove compartment light and trunk light. I had a glove compartment light stay on with my Buick LaSabre. You can start by eliminating fuses to things that you really don't need. Get a tester that will test your battery under load and also your charging system. They are pretty cheap. Jim