Be gone for a month, disconnect batteries or not?

[mr. cob]

Howdy All,

I will be leaving on a month long trip sometime in the future, the Jeep will be in the garage, should I disconnect the main battery, if I disconnect the main battery will the small battery still be active, do I have to disconnect it too?

I am scared to death to disconnect anything for fear of all the computers and electronic stuff going wacko, but I don't think just letting it sit for that long is a good idea either. So any advise or suggestions on how best to handle this sure would be appreciated. Thanks.

Dave

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[Lunentucker]

I don't think sitting for a month in a garage would cause any issues at all.

 

[mr. cob]

I don't think sitting for a month in a garage would cause any issues at all.

Howdy Lunentucker,

Thanks for your reply.

I bought my Jeep new a couple of weeks ago but it was built in August of 2021 so it's already close to a year old and I am sure it has sat for months on the dealer lot with out being started, which is not good. I am just trying to do the best I can to preserve what's left of the batteries before I have to replace them.

Dave

 

[Beemer533]

I got my 21 Mojave in October and I travel constantly, although typically at most a couple weeks at a time. This is the first vehicle I've owned in over a decade where I've even given it a second thought.. That is probably because I had some of those bad batteries and I came home several times to a completely dead vehicle.

That being said, both batteries have been replaced by the dealer and I have not had any issues since then letting the Gladiator sit around for a couple of weeks.

If you are concerned and it works in your situation you could just hook the truck up to a battery tender.

Either way, disconnecting the batteries isn't really a big deal. You might have some odd behavior initially when you hook it back up, but it will clear up.

 

[mr. cob]

I got my 21 Mojave in October and I travel constantly, although typically at most a couple weeks at a time. This is the first vehicle I've owned in over a decade where I've even given it a second thought.. That is probably because I had some of those bad batteries and I came home several times to a completely dead vehicle.

That being said, both batteries have been replaced by the dealer and I have not had any issues since then letting the Gladiator sit around for a couple of weeks.

If you are concerned and it works in your situation you could just hook the truck up to a battery tender.

Either way, disconnecting the batteries isn't really a big deal. You might have some odd behavior initially when you hook it back up, but it will clear up.

Howdy Zion,

Thanks for your reply.

I am one of those people who can weld, machine, wrench, fabricate and hammer just about any mechanical devise into service. That said I am a complete and total IDIOT when it comes to anything electronic or electrical, however I am very good at starting electrical fires.

Dave

 

[JTR178]

Put it on a Battery Tender. They make an adapter now where you can plug it into the OBD2 port. Way easier than installing the adapter with ring terminals on the battery.

 

[dcmdon]

A battery tender is your best choice.

But if you dont' want to buy one or don't have an outlet nearby, then pull the transport fuse.

I'm going to let you do the research on the details of where this fuse is.

, but there is a fuse that the truck ships with disconnected that reduces or eliminates battery drain. The dealer is supposed to put it in during the PDI.

 

[Casique]

Definitely put it on a Battery Tender. That's what I do when I travel for a week or more. Been doing this for a year now with no battery issues...

 

[Mr._Bill]

I would also recommend a battery tender. If you have the 8.4 Uconnect head unit, it takes about 24 hours to return to normal operation after it loses power (disconnected or dead batteries).

 

[BRMoose]

Hey Mr Cob, I’ve left mine at the airport for 3-1/2 weeks at a time with not issues

 

[ShadowsPapa]

Battery tender. Don't disconnect.

And if you did disconnect, there are ways to do and not do it.
But the battery tender is the best choice.
It's a good thing on these when they sit anyway.
Even disconnected batteries lose power over time - and the IBS won't know what's going on and will have to relearn on partially down batteries.

 

[Mball488]

I would say older cars yes. Wont do a thing to them. I deployed for 9 months and had my JTR parked in a storage unit with nothing unplugged due to not wanting things to reset. Pushed the button and with no problem at all it started right up. A note...... I would say if you are in a cold climate results may vary.

 

[ShadowsPapa]

I would say older cars yes. Wont do a thing to them. I deployed for 9 months and had my JTR parked in a storage unit with nothing unplugged due to not wanting things to reset. Pushed the button and with no problem at all it started right up. A note...... I would say if you are in a cold climate results may vary.

Obviously depends on the truck - some have left them sitting for a lot less than 9 months and had it not start. Mine had gotten down to 12.19 volts and it wasn't even a month.
The batteries have constant load on them, and as all such batteries will do, they lose power just over time - a natural process. And letting batteries sit lower than 12 volts for a length of time is bad for them, shortens their life, can cause sulfation to start. So it may have started, but it would have shortened the battery life, at the very least - isn't good for batteries. They should never sit and be allowed to drain down and stay low for any period of time.
The truck is a load on them,
Batteries naturally lose charge sitting, even if disconnected (it's less for AGM, yes, but it happens)

 

[jebiruph]

The guidance in my owners manual is to disconnect the batteries if storing for 21+ days.

 

[ShadowsPapa]

Yeah - lowest common denominator, the book, aimed at consumers.
If when you disconnect they are not fully charged, then you let them sit and the further self-discharge, they are sitting in the end at a low state of charge.

Never let them sit not fully charged.
The book doesn't say that.

AGM batteries require full charging between uses or they will have shorter lives, so if disconnecting, I'd do a full charge of each to 100%

On AGM batteries, in general -
Batteries that are stored for long periods will eventually lose all their charge. This "leakage" or self discharge varies considerably with battery type, age, & temperature. It can range from about 1% to 15% per month.
In systems that are continually connected to some type charging source, whether it is solar, wind, or an AC powered charger this is seldom a problem. However, one of the biggest killers of batteries is sitting stored in a partly discharged state for a few months.
A "float" trickle charge should be maintained on the batteries even if they are not used (or, especially if they are not used)

Ideally, I prefer the keep 'em charged thing. Disconnecting is the consumer thing. If they aren't topped off before sitting, and they lose more charge sitting (even disconnected batteries do this) then they may drop to a point where you lose capacity, sulfation may begin.

Owner can choose -
* Disconnect (I still highly recommend fully charging using an AGM charger before leaving them sitting disconnected as they will lose some, even sitting with no connections. )

* Leave connected - and use a charger that has float ability after topping them off.


Generally, unless these are driven every day for a fair amount of time, they don't get fully charged by the truck itself. Mine never fully charges my batteries - it only did when I was driving it a lot more than I am now.

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