guysandiego

I have OEM rated batteries -- Less than a year old --- What is safest and best for the batteries? No previous battery problems -

Should I disconnect them? 1 or both

Should I disconnect and use a battery tender? which battery?

Should I remove them? 1 or both

Should I remove and use a battery tender?

I will be out of town for 5 weeks -- Anything else I should be considering?

220S

5 weeks is nothing, you should be fine. The E63 has one battery so can't help on that issue but I've always stored cars with the battery hooked up and on a battery maintainer (not a tender.) That way there's no issue with codes, etc., from disconnecting the battery.

If you've got hard concrete flooring you could pump up the tires to 50 psi just to be on the safe side. But again 5 weeks isn't long and modern tires don't flat spot as easy as they used to in the past.

Big thing to be concerned with is rodents. Be sure that you don't have mice or rats, etc., around that might get in the garage. They can destroy a car faster than anything.

slownrusty

I used to have my E55 sit typically for 6 weeks at a time (when I was travelling extensively for 1 1/2 years) and I would always put the battery charger on the main battery in the trunk for a couple of hours when I got back home. After 6 weeks the battery was very low on voltage but after a couple of hours it was easily back up to 12V and plenty powerful to start the car at that point.

Interestingly during this 1 1/2 year period, I never had low tire pressures or an airmatic "settle"

Hope that helps.
Yasin

mpwr

I don't use my car everyday, but when garaged I use a CTEK battery tender which maintains the battery at 12 volts all the time, also try to seal the exhaust tips to avoid rodents. Hope that helps.