Tender or Batt disconnect

[WelderJay]

I am going on a trip without the JL. Just wanted to get opinions if I should leave it alone, disconnect the batt or put a tender on it. I will be gone 3 -4 weeks. Its the 3.6l ess jlus if that matters.

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[emgeesea]

For that long of time without recharging I would definitely either disconnect the terminals or put a tender on the main battery. (A tender hooked up to the main battery will also charge the ESS battery.) If disconnecting, you'll need to properly disconnect both batteries, as just disconnecting the main battery will leave the ESS battery operating.

 

[UTES]

I am going on a trip without the JL. Just wanted to get opinions if I should leave it alone, disconnect the batt or put a tender on it. I will be gone 3 -4 weeks. Its the 3.6l ess jlus if that matters.

I regularly charge my 3.0 while on trips with no issues.
Hunter

 

[emgeesea]

For that long of time without recharging I would definitely either disconnect the terminals or put a tender on the main battery. (A tender hooked up to the main battery will also charge the ESS battery.) If disconnecting, you'll need to properly disconnect both batteries, as just disconnecting the main battery will leave the ESS battery operating.

I have a CTEK tender installed on my JL, and it does a nice job keeping both batteries topped up. If you do install a tender, I read somewhere (but can't recall where) that due to the ESS system, the negative of the tender should NOT be connected to the negative of the battery, but instead to a ground bolt on the vehicle. There are several ground bolts directly behind the main battery on the JL that are already used by the OEM battery grounding system. I connected my negative there. - fyi

 

[WelderJay]

Thank you for the replies. I have a small Noco smart charger I will leave hooked up on 3.5A. This is the first car I have owned with ess. Just to confirm that connecting the tender to the service batt terminals will charge the ess batt? I read the above post regarding body grounding, but can't find anything about it yet.

 

[nerubi]

My maintainer came with rings and with clamps. For clamps it says to connect the negative clamp to the engine or frame. The rings it says to connect to the negative bolt on the battery. The rings are a more permanent connection method. So is the difference the ability to keep the rings apart from each other easier than putting the clamps on each time? On my VW they have a clamp bar next to the battery for clamps for jumping/charging so I use the clamps on it.

 

[emgeesea]

Thank you for the replies. I have a small Noco smart charger I will leave hooked up on 3.5A. This is the first car I have owned with ess. Just to confirm that connecting the tender to the service batt terminals will charge the ess batt? I read the above post regarding body grounding, but can't find anything about it yet.

Just doing a quick search on battery tender connections, the reason for attaching the negative connector of the tender to the vehicle body instead of the negative terminal of the battery is to prevent possible explosion due to an unintended spark igniting the hydrogen gas that emits from the battery. So, it is a safety precaution, not related to the ESS system, as I had thought. See step 15 in this instruction manual PDF from Deltran:

http://products.batterytender.com/021-0128-man.pdf

My tender is connected as: positive to the main battery positive terminal and negative to a body bolt behind the battery (where the OEM battery is also grounded). I've been using it for about a month on the JL and it seems to work well.

 

[emgeesea]

Thank you for the replies. I have a small Noco smart charger I will leave hooked up on 3.5A. This is the first car I have owned with ess. Just to confirm that connecting the tender to the service batt terminals will charge the ess batt? I read the above post regarding body grounding, but can't find anything about it yet.

Oh, and yes, hooking up to the main battery will also charge the ESS battery. When I first installed my tender on the JL a month ago I contacted the company that makes my tender, CTEK, and confirmed. They responded that the batteries in ESS systems are connected in parallel, and with parallel systems (versus series systems) charging one battery also charges the second battery,

Deltran and other tender manufacturers have also posted similar discussions online about maintaining parallel batteries. -fyi

 

[SouthCo]

For 3-4 weeks I don't think you need to do either option. My 3.6 JLU has sat multiple times for a month without doing either and I've had no issues. But between your two options I'd plug it in to a tender. I have a CTEK and it works well. I use it for times when mine will sit for longer periods...

 

[Gee-pah]

For 3-4 weeks I don't think you need to do either option. My 3.6 JLU has sat multiple times for a month without doing either and I've had no issues. But between your two options I'd plug it in to a tender. I have a CTEK and it works well. I use it for times when mine will sit for longer periods...

I tend to agree Steve, but I've heard that a battery maintained at near its capacity, like a trickle charger might provide, lasts longer. : - )

 

[word302]

I tend to agree Steve, but I've heard that a battery maintained at near its capacity, like a trickle charger might provide, lasts longer. : - )

The thing is your trickle chargers aren't really holding your batteries at full capacity. You need something like the Odyssey battery charger to do that. I hook mine up overnight about once a month to bring my batteries back up to a full charge.

 

[DaltonGang]

This is the one I bought, for my Diesel pickup truck, with two batteries. This will get both batteries up to full charge, then maintain a trickle, to keep them at full charge, all automatically.
https://www.amazon.com/gp/product/B06XK7PM9F/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1

 

[Gee-pah]

The thing is your trickle chargers aren't really holding your batteries at full capacity. You need something like the Odyssey battery charger to do that. I hook mine up overnight about once a month to bring my batteries back up to a full charge.

Thanks for the clarification. That said, would you guess a vehicle battery kept on a trickle charger when at rest would last longer than one without a trickle charger?

 

[sf5211]

A friend of mine showed me pictures of a contractors van that had burned because of a defective power tool battery. Since then I leave them removed from the tools and only recharge them when on job sites. I had pics but didn’t save them. If you want to see let me know and I will text him.
With that being said I’d be uncomfortable leaving a charger on a battery in my garage for a month. Sorry to be so “negative”.

 

[word302]

A friend of mine showed me pictures of a contractors van that had burned because of a defective power tool battery. Since then I leave them removed from the tools and only recharge them when on job sites. I had pics but didn’t save them. If you want to see let me know and I will text him.
With that being said I’d be uncomfortable leaving a charger on a battery in my garage for a month. Sorry to be so “negative”.

The battery that caused that fire was likely lithium ion. If you've never seen a video of thermal runaway on one of those batteries look it up. There's a reason they ask you if you have any of them in your luggage before they will check it into the cargo hold off an airplane. Scary stuff. That being said leaving a charger on a lead acid battery (at least one that is designed to be left on long term) is a fairly safe practice.

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