Main battery draining after disconnecting auxiliary?

[Captain Le Bleu]

I have a 2018 Wrangler Sahara 3.6L and ESS stopped working, so assume the auxiliary battery is shot. I removed the wire from the negative pole on main battery and removed fuse 42. I also turn off the ESS via button every time I start the engine. I plan on getting new batteries, but with what I’ve done, will my main battery be draining until I do? Will I eventually have a dead battery to contend with? New to the Jeep world so asking of those more experienced.
Thanks

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[Htfan]

Welcome to the forum!

You didn't provide much information about the age/voltage of your existing batteries. I'm assuming from what info you did post, it's time to replace both batteries immediately unless you decide to eliminate the AUX permanently. Then only get a new main battery, but upsize to an H7.

I have a 2018 Wrangler Sahara 3.6L and ESS stopped working, so assume the auxiliary battery is shot. I removed the wire from the negative pole on main battery and removed fuse 42. I also turn off the ESS via button every time I start the engine. I plan on getting new batteries, but with what I’ve done, will my main battery be draining until I do? Will I eventually have a dead battery to contend with? New to the Jeep world so asking of those more experienced.
Thanks

 

[etoften]

The ESS not working is a good indication of a battery system that is fading. Mine did the same thing. Unfortunately the two batteries being tired together from the factory usually means the aux battery drains the life expectancy of the main. But you would expect a 2018 would be on its third battery by now or a dying second at least. There are a bunch of ways to check it. You could simply not hit the ESS button and see if it works as expected. If it doesn't you should be at least thinking about a battery at some point. Then consider your driving needs. If this is a daily driver you rely on i would say check the battery date. If its over three years old swap it at the first sign of an issue. If it's a second vehicle and you have jumper cables or a NOCO to get you home one time I would roll on till it showed a more definite sign of failure. Just remember all batteries tend to fail in years 3 to 5 despite any warranty they come with

 

[VKSheridan]

Assuming the auxiliary battery is failing and the source of your discharge, disconnecting it will reduce that portion of discharge. Your keyless entry, radio and other PCM’s that remain energized after vehicle shutdown will still draw power which *could* drain your main battery in a week or two. The alternator can have some parasitic draw as well. Regardless, I wouldn’t replace the auxiliary battery as the main can handle the load fine if you don’t use ESS all the time. It can handle the load decently if you do use ESS often…..

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