Situation:
- 2001 Jeep XJ last driven 8 days ago
- Power steering leak, so prefer not to drive right now
- Going on trip for 3-4 weeks (not taking Jeep)
- No time to buy a battery charger

Goal:
- Start up fine when I return in 3-4 weeks

Question:
- Better to start the vehicle now and let it idle for 15 minutes, or just wait to start it until come home?

 

Start it and run it until it warms up, then shut it off.

Disconnect the battery ground cable. You'll just have to reprogram the radio when you get back.

 

If there's no concern about parasitic drawing of power, you're probably fine to just leave it. If you're at all worried about parasitic draw, fire it up and take it for a short drive (or rev it up a bit in neutral).

If you want to be as sure as possible that the battery will be charged when you return, just pull off the negative battery cable while you're away.

Bottom line - you're probably fine just leaving it until you get back. 4 weeks vs 5 weeks isn't a big enough difference to concern yourself with.

 

Another thought - you'll have plenty of time to buy a battery charger when you return, so whatever you do you should be fine.

 

Open the fuse box under the hood. If there is a fuse marked IOD, remove it. That fuse powers the PCM memory and radio memory. My 2000 doesn't have one, but the later models do. IOD = Ignition Off Draw.

 

You could get a float charger, either solar or hard wired...

 

Has it ever died from sitting before? If not I wouldent worry about it.

 

Wow... great tips everyone! Thank you.

Yep, it's died before while sitting. But the battery wasn't as new as this one.

 

I'll check... thanks. For this purpose, is that the same as pulling the ground cable off the battery?

(If so, learn something new everyday!)

 

If you don't have a parasitic draw, the memory is still drawing enough to lower the battery voltage enough to not allow a start after more than a month. On the newer jeeps of all kinds they installed this fuse so that wouldn't happen. Because you are time limited, I'd just pull the cable and be done with the whole thing. But that's me. I think the memory draw is about .075 amps. You wouldn't think that little bit would hurt anything, but it does.