willysmjeeps.com

Every year I go to get my jeep ready for the year, it is always dead. I usually unhook the batteries from the wires and just leave them in the jeep. Sits in a garage, non heated. Yesterday I tried to light the lights and would not even turn lights on. Starting to charge the batteries again. So do I have a electrical leak? I have just put new harness on the jeep last year but still does it? Any help?

You don't say what part number-type you have.
Sealed? Or the type where you have to check and add distilled water to the cells once in awhile?

Did you measure the voltage when "dead"?
A disconnected battery sitting for a year is going to lose some charge all by itself.
You said the batteries were disconnected from the harness --- so the harness is out of the picture, disconnected it can't "leak" the charge.

Batteries don't take kindly to freezing.

Suggest charging them up and take them to most any auto parts store where they'll test them with a load for free.

Good luck!

Batteries can and will discharge over a period of time. Leaving batteries in an unused vehicle outdoors or in unheated storage facilities will accelerated these inactive discharge rates. I was raised not far from you in South Jersey, Williamstown. I had three cars when I finished high school and anytime I parked one for several months of winter my dad taught me to always pull the battery, take it to a warm area like the basement and at least once a month hook it up to a 2 amp trickle charger. Well the same applies today to both vented & unvented batteries but life is more convenient now-a-days. We have access to battery maintainers. These are much like a trickle charger but they are fully automatic and only function when the battery charge level begins to drop. Here's an example: https://www.amazon.com/Battery-Tender-0 ... 4302&psc=1

A simple battery draw check is to remove the chassis negative cable from the negative post closets to frame ground or the positive cable from the positive terminal closest to the starter with all switches off and then touch the cable terminal to the battery post. If a spark jumps as it gets close to the post you have a system draw someplace in the jeep. Another way is to remove one cable and put a voltmeter in series with the disconnected circuit. While on the volt meter topic I prefer the voltmeter to the amp meter for monitoring the condition of my battery and the operating condition of my jeep's electrical charging system. You can leave the jeep completely stock and add a volt meter at the bottom edge of the dash for this purpose.

I wonder what happened.