Battery tender for JL 3.6 (with ESS)

Jebiruph

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Yeah, you posted right before my question.

Have you seen the wiring diagram?

https://www.jlwranglerforums.com/forum/threads/3-6l-ess-battery-diagram.14401/

If this is correct, it doesn’t appear your method will charge the aux unless the N1 and N2 are connected on the PCM.

N2 and N3 are connected to main battery, but then it’s up to the power control rely to be closed in order to charge the aux. Maybe this is the case.

Pic is from the thread. Not mine.

B1759E99-80D8-42D0-8D32-9BDC6A5771ED.png
I need to add a note to this diagram that when everything is working correctly, the batteries appear to be connected in parallel, except when auto stopped. Trickle charging and jump starting should work from the main battery.





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Jeepsterfreak

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I need to add a note to this diagram that when everything is working correctly, the batteries appear to be connected in parallel, except when auto stopped. Trickle charging and jump starting should work from the main battery.
Good to know. I was thinking this could be verified with a volt meter by comparing voltage with and without the battery tender connected to the main battery leads. You can take reading from N1 and neg post on main battery with and without tender connected. If you see voltage increase at N1 when the charger is connected to main battery then you know it’s charging the aux battery as well.
 

Jebiruph

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Good to know. I was thinking this could be verified with a volt meter by comparing voltage with and without the battery tender connected to the main battery leads. You can take reading from N1 and neg post on main battery with and without tender connected. If you see voltage increase at N1 when the charger is connected to main battery then you know it’s charging the aux battery as well.
Every time I've checked battery voltages, running or not, they are always exactly the same.
 

Jeepsterfreak

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Every time I've checked battery voltages, running or not, they are always exactly the same.
So I guess that verifies they are wired in parallel.

Which brings up another question. The Jeep can warn you when the ESS battery is too low to function and reports the ESS is not ready. See it in many posts. Do you think the Jeep isolates the aux battery from the main battery through the power control relay intermittently to take voltage readings of the aux battery to measure its condition?
 

viper88

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Uuuhhh just start the thing a few times a week..keeps the engine and fluids flowing instead of sitting there. My limited experience with tenders is it cooks the battery in one way or another.
I plan on daily driving the JL when I get it. I don't drive my other cars all the time so they are always on a smart charger. There are different battery maintainers and smart chargers. Not all are created equal. Better smart battery chargers will not cook a battery. Better ones actually will condition your battery also while trickle charging when you are not using your battery for extended times. There are others but I have never had a problem with CTEK.

https://smartercharger.com/
 
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viper88

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Starting a vehicle that is in storage a few times a week for 10-20mins at a time is very good for the vehicle and highly suggested to do so. It's practically common sense.

You say, "Actually, quite the opposite". So, your saying it's not good to start and just leave the car sitting for months without running at all?? That's ridiculous.

If I misunderstood you forgive me..never made it past 4 grade and the highest number I can count to is potato
There are a couple of different schools of thoughts on this. Cars stored in very cold climates and cars stored in heated garages can make a difference in how you want to store a car. Just make sure your engine reaches operating temps long enough to burn off moisture or condensation in the oil if you do start it.
 

Rhinebeck01

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@viper88

My guess is YOU have a decent understanding of the why's to using a decent battery charger.
---------------

This thread started off with a guy asking about a battery tender for his JL. A battery tender such as you use.

For sure if you are going to store a vehicle for a few weeks because you are going to be out of town, etc., it makes real sense to place the vehicle on a decent trickle charger/battery tender. If you do not, there is a good chance that parasitic, 12v use will leave the battery depleted and when you go to start the vehicle you will be chitt out of luck.

Also, say you have a guy/gal/old person, vehicle collector, etc. that uses his/her vehicle once every few days or every other day to drive to the grocery store and back or to a relatives house.. They turn off and restart the vehicle a few times during their excursion. They only end up driving say 5-10 miles or so. WELL, in this scenario, the vehicle's alternator does not have enough time to replenish all the power they used with the 4 or 5 restarts... So, they come home with a depleted battery. Now, two days later they do a similar trip and the battery depletes more.... after a few weeks of doing this the battery has become very depleted and on a cold morning or whatever the vehicle's battery does not have enough oomph to start the vehicle... TO PREVENT this end result, it would be best for the old guy/old gal, etc. to have been hooking the vehicle to a battery tender
when they got home. There are quick disconnects that can be used so it is easy even for grandma to do this...

So, just a couple of reasons why a decent battery tender can save the day lets say.

I might mention.... lets say you go away and have your Dad go out every day or 3 and start the vehicle and let it run for 15 mins.. Not good!
In this scenario battery would be depleted in a couple of weeks time and you would have promoted lots of condensation in the engine. So, best bet is to place a battery tender on the vehicle and just leave it be.... not start it for the week, or 6 weeks you are away.

.
 

viper88

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My new wrangler will be garaged for a couple months this winter (long story), and I was planning to get a battery tender to protect/maintain the battery.

Does the extra battery with the ESS system complicate this or require a certain type?

Any recommendations on tenders?
There are a lot of brands but I highly recommend a CTEK smart battery charger.
 

viper88

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Another note on batteries. Never let a battery run down if at all possible. Letting your battery run down is not good for the long term health of the battery. You might be able to charge or jump a dead battery so it starts your car but it is very possible there was damage done to the battery. New car dealers are notorious for killing brand new car batteries. A lot of brand new cars have compromised batteries because cars sit in inventory so long without charging. Some car companies actually have a check list for new car batteries where dealers have to log and show dates and battery condition while in their inventory.

A better smart charger can help recondition a battery that was run down and recharged.
 

viper88

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@viper88

My guess is YOU have a decent understanding of the why's to using a decent battery charger.
---------------

This thread started off with a guy asking about a battery tender for his JL. A battery tender such as you use.

For sure if you are going to store a vehicle for a few weeks because you are going to be out of town, etc., it makes real sense to place the vehicle on a decent trickle charger/battery tender. If you do not, there is a good chance that parasitic, 12v use will leave the battery depleted and when you go to start the vehicle you will be chitt out of luck.

Also, say you have a guy/gal/old person, vehicle collector, etc. that uses his/her vehicle once every few days or every other day to drive to the grocery store and back or to a relatives house.. They turn off and restart the vehicle a few times during their excursion. They only end up driving say 5-10 miles or so. WELL, in this scenario, the vehicle's alternator does not have enough time to replenish all the power they used with the 4 or 5 restarts... So, they come home with a depleted battery. Now, two days later they do a similar trip and the battery depletes more.... after a few weeks of doing this the battery has become very depleted and on a cold morning or whatever the vehicle's battery does not have enough oomph to start the vehicle... TO PREVENT this end result, it would be best for the old guy/old gal, etc. to have been hooking the vehicle to a battery tender
when they got home. There are quick disconnects that can be used so it is easy even for grandma to do this...

So, just a couple of reasons why a decent battery tender can save the day lets say.

I might mention.... lets say you go away and have your Dad go out every day or 3 and start the vehicle and let it run for 15 mins.. Not good!
In this scenario battery would be depleted in a couple of weeks time and you would have promoted lots of condensation in the engine. So, best bet is to place a battery tender on the vehicle and just leave it be.... not start it for the week, or 6 weeks you are away.

.
I like maintaining my car batteries with a smart charger that also has repair/desulphination mode.
 

jeremyjeep

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Any recommendations on a solar trickle charger? And should it have a regulator to keep it from over charging? It would be great if it could also charge a cell phone while camping.
 

Jebiruph

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So I guess that verifies they are wired in parallel.

Which brings up another question. The Jeep can warn you when the ESS battery is too low to function and reports the ESS is not ready. See it in many posts. Do you think the Jeep isolates the aux battery from the main battery through the power control relay intermittently to take voltage readings of the aux battery to measure its condition?
Good point, how exactly does it monitor one battery that is in parallel with another? I don't expect that they are doing it by intermittently isolating the aux battery. I wonder if they can derive the status of the aux battery from battery sensor on the negative terminal of the main battery. If I know the the status of the batteries as a pair and the status of one of the batteries through the sensor, can I calculate the status of the other battery? I'm also a little suspicious that connecting the negative terminal of the aux battery to the negative terminal of the main battery (where the sensor is) might have something to do with monitoring the aux battery. And it could be that we are missing some critical information that would clear it all up.
 

Fatboy97

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A lot of good info here. When I use to work at a motorcycle dealership we use to have all the batteries on a shelf hooked up to a battery tender, no new motorcycle on the floor had a battery in it. When I was looking at a New JK, it was sitting on the dealer lot for so long they couldn’t even jump the battery to start the Jeep.
 

WranglerAz

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The posts here are very good, I will add for my situation with batteries, I bought the Digital 1200 12V Performance Battery Charger and Maintainer when it was on a really great price (using Honey on Amazon). I have found this works great and I no longer get ESS EVIC messages.
 

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