Battery

[SD-MAC]

My X5M has been in my garage since mid December and not started or on a trickle charger. Our roads are wet and salty so I don't want to drive it. If I pull out in the drive and let idle for 10 to 15 minutes, is that enough to charge the battery?

[jjt4806]

All depends on how dead the battery is.
Most likely, no - 10 minutes is not enough to do much of anything.

[secretariat]

I don't think these batteries charge by letting the car sit idle. I think you have to drive it on highway cruising for 30 or 40 miles. Just my opinion.

[ajob]

Don't ever store an engine after a 10 minute cold start!

The engine won't get warm enough and you'll fill the cylinders, turbos and exhaust with water vapour (fuel + oxygen = water + CO2) that will condense inside the engine and promote rust.

It's better to protect a 10k+ $ engine and its battery with a 50 to 100 $ trickle charger. Just make real sure it has an "AGM battery type" setting. ("Ctek" is a good brand, there are many more!)

For best longer storage moisture protection you may add a couple 2 lbs bags of 2 Sta-Dri (reusable moisture remover) in the engine compartment and inside the car. Recondition every two-three months by drying 6 h in conventional oven at 250 °F (120 °C). Aircraft piston engines are cleverly protected by sticking a silica gel filled plug at the end of the exhaust, but for an X5 M you need four of these...