Thanks. That was my guess. How long before one crosses the line?
That answer varies with the particular vehicle in question, the age of the battery and any parasitic loads on the system, but generally speaking I don't even use a trickle charger on any of the motorcycles except in the middle of winter I might connect one for a day to each of them if they've day for at least a month already.
And I just got eight years out of the battery in the Harley, and have had similar longevity out of other batteries in the bike fleet.
Batteries are happiest with a full charge. If you are doing a long term storage then a trickle charger is in order. Three weeks is not long term. If you are not going to use the vehicle for more than a month then a trickle charger would not hurt. Make sure it has a self regulating feature so you don't overcharge. The worst thing you can do to a battery is to let it sit for several months then charge it and then let it sit for several more months. HTH
A good trickle charger like the Battery Tender is nice to have. Many Corvette owners use them and still have their original batteries after 7 years (although I'm not sure I would trust one that old away from home.) They definitely help prolong battery life.
2014 Deep Cherry Red GC 4X4 V8 QDII
2012 Crystal Red Cadillac CTS-V Coupe
2011 Crystal Red Chevy Corvette Z06/Z07
"If you are leaving your vehicle dormant for more than 21 days you may want to take steps to protect your battery. You may:
• Disconnect the negative cable from the battery.
• Anytime you store your vehicle, or keep it out of service (i.e. vacation) for two weeks or more, run the air conditioning system at idle for about five minutes in the fresh air and high blower setting. This will ensure adequate system lubrication to minimize the possibility of compressor damage when the system is started again."
This is a different type of battery than used years ago, it can be damaged by some trickle chargers. It has low inherent discharge rate, but the Jeep is alway drawing some current, hence the suggestion to disconnect the battery. There may a service/storage/ship mode somewhere in the settings that does the same thing.
When left unattended for more than a week, sometimes the parking brakeshoe will fuse itself to the hub. You may want to park without the parking brake set or be prepared to rock the Jeep back and forth to break it loose..
2011 Grand Cherokee Overland V8, 2009 Liberty Rocky Mt V6, 2000 Grand Cherokee Laredo I6, 1979 CJ7 I6 Quadratrac