Jumperless Aux Battery Bypass

[azwjowner]

True, but the ESS battery is ~200 CCA compared to 800 CCA of the main. So bypassing the N3 fuse might have some implication for those electronics. That's the part I don't know.

No, no. Look at the more detailed diagram, second one: https://www.jlwranglerforums.com/forum/threads/3-6l-ess-battery-diagram.14401/

Look at N2. Observe that N2 connects directly to the main battery positive, no fuse. Look where else N2 connects -- on the fuse array it connects directly into the left side of the N3 fuse. The right side of the N3 fuse connects, through the PCR relay, to aux positive.

So on one side of the N3 fuse you have main battery positive. Right on the other side of the fuse is aux positive. There are no devices involved whatsoever. The only current that passes through that fuse is between the batteries.

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[azwjowner]

I agree with you. I just don't know for sure about any downstream fuse protection. So not retain the factory connections? That is, what's the advantage in taking the risk of connecting the ESS/Aux positive battery cable terminal connector to the main battery positive post?

Just simplicity, remove the aux battery and have the fewest cables laying about. There is zero risk, assuming the diagram is correct.

 

[ecidiego]

All this because Jeep uses shit batteries.

Buy a quality 94R and Aux bat. Keep them charged if your truck sits a lot. You can put a maintainer on the 4/7 pin in the back. System stays reliable. The ESS system is well designed, some bean counter just selected terrible batteries.

 

[THAW]

Just simplicity, remove the aux battery and have the fewest cables laying about. There is zero risk, assuming the diagram is correct.

What makes connecting the ESS/Aux positive cable terminal connector to the main battery simpler than connecting it to N1?

And isn't insulating the connector the most simple solution?

 

[azwjowner]

What makes connecting the ESS/Aux positive cable terminal connector to the main battery simpler than connecting it to N1?

And isn't insulating it the most simple solution?

I don't think you follow. You connect N1 to the main battery positive. When you remove the aux, you have to supply power to N1. You could jumper N1 to N2 (or N3) but the aux battery devices are fed off N1 so you have to do something. Either jumper or just take the cable and reroute.

 

[THAW]

I don't think you follow. You connect N1 to the main battery positive. When you remove the aux, you have to supply power to N1. You could jumper N1 to N2 (or N3) but the aux battery devices are fed off N1 so you have to do something. Either jumper or just take the cable and reroute.

I think you're missing that there's no F42 in the original post. No need for a jumper.

 

[azwjowner]

I think you're missing that there's no F42 in the original post. No need for a jumper.

Right, but I thought we're now talking about entirely removing the aux battery, rather than just bypassing it by pulling F42 and disconnecting one end of its ground cable. If you're just bypassing it, no need to do any more.

JeepinPete, who launched your original reply, said he removed the aux battery entirely and rerouted the positive aux cable as I've described.

 

[THAW]

Right, but I thought we're now talking about entirely removing the aux battery, rather than just bypassing it by pulling F42 and disconnecting one end of its ground cable. If you're just bypassing it, no need to do any more.

JeepinPete, who launched your original reply, said he removed the aux battery entirely and rerouted the positive aux cable as I've described.

Yes, removal of the battery AND removal of F42.

I'm not suggesting the JeepinPete method doesn't work; it clearly does (I've used it in my Jeep). I'm just musing about a different way that preserves the factory function of the N3 fuse. So far, I don't see any advantage in bypassing the N3 fuse.

 

[azwjowner]

Yes, removal of the battery AND removal of F42.

I'm not suggesting the JeepinPete method doesn't work; it clearly does (I've used it in my Jeep). I'm just musing about a different way that preserves the factory function of the N3 fuse. So far, I don't see any advantage in bypassing the N3 fuse.

And I'm saying that reading the diagram, it is apparent that the N3 fuse's sole function is to fuse current between the two batteries and it is electrically impossible for it to serve any other purpose. So once you are no longer recharging the aux battery from the main via N3, there is no purpose to the N3 fuse.

But keeping a 150 amp fuse in doesn't hurt anything, so go for it if you prefer it that way.

 

[AndySpill]

@THAW you asked above if it's possible to safely attach the ESS/Aux battery positive terminal connector to N1 on the PDC.

Agreed?

I asked why wouldn't it be given that this connection, based on the diagram I included, seems to be exactly how things are connected from the factory, at least when the PCR isn't energized, which is 99% of the time.

Agreed, or do you think that some aspect of this connection I describe may change given that the two positive cables normally on the ESS/Aux battery positive terminal have been disconnected from this terminal and placed on N1?

Really, these arent trick questions.

I guess I am trying to ask why you are asking, to my way of thinking here, if it's ok for something to happen that already does happen? Why did you ask that question? I am confused why you would ask that question.

You asked me why I don't seem to understand the concept of quoting and replying when I did just that, so I have no reply that question.

"Yes, Andy, connecting the loose ESS/Aux positive cable terminal connector along the original path is exactly the point! "

No, not mine at least. The point I'm trying to make is that you questioned, again I don't know why, why putting the positive cables originally on the positive post of the ESS/Aux battery, on to N1 was ok to do, when it seems that that's what the factory electrical schematic effectively already does--at least when the PCR isn't energized.

As it regards NOCO chargers you write, "Once again, you've completely missed the point. I want to know how the minimum was derived, I don't think there isn't a practical minimum in that neighborhood."

You're wrong. You see I too want to know how that minimum was derived. More to point, and so you'll know I'm not lying I went to the Noco website https://no.co/genius1 and confirmed my suspicion (bottom half of the page under Genius Charging Times) that charger amperage is more about the time it takes to charge back up batteries, not "some size battery bank takes an X amperage charger."

Here's a thought: if your question is motivated by a desire to know minimums, consider saying that. People can't read your mind.

Wow, and to think my NOCO 2 genius has been doing me fine, albeit for me as just the trickle charger I intended it to be, that tops off the batteries from parasitic loss and entropy since 2019 or so.

 

[Jebiruph]

The N3 fuse protects the system from when the aux battery positive is shorted to ground. This happens when the main battery positive cable (with the aux positive connected to it) is removed from the main battery and allowed to contact a ground point.

Have you ever heard of someone connecting jumper cables reversed and causing damage to system electronics? That's the type of damage the N3 fuse protects against.

If you look at the terminals on an eTorque engine that doesn't have an aux battery, the N3 fuse isn't used and N1 is connected directly to N2 with a metal shunt, no fuse. No aux battery, no N3 fuse.

 

[THAW]

You asked me why I don't seem to understand the concept of quoting and replying when I did just that, so I have no reply that question.

Andy, when I write a post about rethinking the way someone changed an electrical path and offer a suggestion for a way to accomplish the same outcome through the original electrical path, and you ask something to the effect of "isn't the original path already connected"... well, it gives the impression you didn't grasp my meaning.

I suspect you were thrown by the word "safely". My reason for using that word isn't fully self-evident. I won't get into all the details, but suffice it to say since I've not experimented I don't know how well the physical shapes of the factory connectors can mesh or where the cables can be routed.

As it regards NOCO chargers ...

You're wrong. You see I too want to know how that minimum was derived.

If I misread your intentions regarding the charger, I apologize. I admit my reading was based on the recent history of you insisting to me a low amp trickle charger was sufficient for maintaining a lightly driven vehicle.

 

[TheBirdie72]

Noticed we are on page 42…?

:::::Pulls F42 fuse::::

Oh, it worked! This thread is now disconnected!

 

[AndySpill]

Andy, when I write a post about rethinking the way someone changed an electrical path and offer a suggestion for a way to accomplish the same outcome through the original electrical path, and you ask something to the effect of "isn't the original path already connected"... well, it gives the impression you didn't grasp my meaning.

Agreed, and that's because what you meant by safely connect is, (at least I think) 'can the terminals in their existing factory configuration, short of modification, create a solid physical connection, because a poor physical connection, even between contact points meant/okay to be together, can be a safety concern.

Sure, there can be safety issues associated with a bad physical connection between contact points that otherwise when connected well don't prove at odds with vehicle design, but that didn't cross my radar because to my mind a good physical connection is always doable, even if the factory one proves difficult to work with, it's just a matter of spending $ on the right size "cables and lugs." In contrast a great electrical physical connection, perhaps precisely because it is one, can reap all sorts of havoc if electrical contacts are made with it that run contrary to vehicle design.

If I misread your intentions regarding the charger, I apologize. I admit my reading was based on the recent history of you insisting to me a low amp trickle charger was sufficient for maintaining a lightly driven vehicle.

With our meeting of the minds regarding what was meant by the safety of electrical connections, I'm back to being confused. Here's why: A low amp trickle charger is to my mind sufficient for maintaining a lightly driven vehicle. It might even be sufficient, at least a Noco one (according to the webpage I linked prior) for maintaining a half drained battery if the owner/operator has few time constraints for quick use of the vehicle: a depth of discharge far greater I think than that likely to occur from parasitic draw and natural losses of power with time and low mileage.

Please tell me why you think this isn't the case. My 2 amp Noco seems to be fine in keeping my batteries topped off on my low mileage JL.

 

[azwjowner]

If you look at the terminals on an eTorque engine that doesn't have an aux battery, the N3 fuse isn't used and N1 is connected directly to N2 with a metal shunt, no fuse. No aux battery, no N3 fuse.

I may find an eTorque at a junkyard and get one of those shunts then, because I intend to eventually fully remove my aux battery. Seems cleaner than a jumper wire.

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