Jumperless Aux Battery Bypass

[ScotM]

14 AWG/30 Amp is far too small when the PCR and its wiring are removed. N1 powers the entire PDC (fuse box), so it should have a connection that can support at least a couple hundred Amps. [side bar: 14 AWG should probably be fused at 20A.]

The best option (if you can get one) is an N1 to N2 shunt from an eTorque/4xe.



N1 is the direct connection to the PDC (fuse box). The other High Current Fuse posts (N2-N8) are all connected to each other.

With the Aux (ESS) battery ground cable disconnected, N1 (PDC/fuse box) is powered by the CR[an]K (main) battery through its positive cable to N2 to N3 to the AUX (ESS) battery positive cable (if the PCR opens, the connection is broken, thus the reason for removing the PCR fuse, F42).

Removing the PCR and AUX (ESS) battery cables breaks the connection between N1 (PDC/fuse box) and any power source.

I can't seem to find that shunt, but I did see this. Using a 4 AWG battery cable between N1 and N3. I'd really like your Opinion on that?

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[THAW]

I can't seem to find that shunt, but I did see this. Using a 4 AWG battery cable between N1 and N3. I'd really like your Opinion on that?

That works. Quite well, actually. It uses the 150A N3 fuse.

I'd bump the cable up to at least 2 gauge (last year, I got a 6-inch, 2-gauge cable with heat shrink-ed copper lugs for about $8 on Amazon).

 

[ScotM]

That works. Quite well, actually. It uses the 150A N3 fuse.

I'd bump the cable up to at least 2 gauge (last year, I got a 6-inch, 2-gauge cable with heat shrink-ed copper lugs for about $8 on Amazon).

Awsome, I will do that. Really appreciate your advice!!

 

[Jebiruph]

But wouldn't the voltage drop during cranking with both batteries in place be less than with just the one, assuming both are fully charged at 12.6 volts?

In theory yes with healthy batteries, but that doesn't mean that the voltage drop of a single healthy battery is crossing the threshold to be harmful. I think it's the partially discharged batteries that cause the constant system reboots (flashing dash lights) that have the potential to cause the most harm. Many believe that running a single battery is the best way to maintain battery health and avoid the low voltage partially discharged situations.

 

[ScotM]

Awsome, I will do that. Really appreciate your advice!!

Ended up with an 8" 2/0 that will handle up to 300 amps, so if i end up using N2, that will work. I figured more amps on the wire would make sure I don't burn down the Jeep before the fuse blows. But at this point, i';m going to give the empty N3 a go. Thanks Again

 

[azwjowner]

Ended up with an 8" 2/0 that will handle up to 300 amps, so if i end up using N2, that will work. I figured more amps on the wire would make sure I don't burn down the Jeep before the fuse blows. But at this point, i';m going to give the empty N3 a go. Thanks Again

I haven't installed it yet, but when I remove my aux battery I'm using one of these: https://www.amazon.com/gp/product/B09TFLR661/ref=ppx_od_dt_b_asin_title_s00?ie=UTF8&th=1

Seems to fit OK, although I'll have to put a slight bend in it to account for the different height of the two studs. I can then directly connect N1 and N2, just like the Jeeps without ESS come from the factory.

 

[ScotM]

I haven't installed it yet, but when I remove my aux battery I'm using one of these: https://www.amazon.com/gp/product/B09TFLR661/ref=ppx_od_dt_b_asin_title_s00?ie=UTF8&th=1

Seems to fit OK, although I'll have to put a slight bend in it to account for the different height of the two studs. I can then directly connect N1 and N2, just like the Jeeps without ESS come from the factory.

Will that handle the voltage and amps? That was my concern when looking at those jumpers.

 

[azwjowner]

Will that handle the voltage and amps? That was my concern when looking at those jumpers.

It's been a very long time since I looked at this, but I recall numerous people making 40 amp jumpers from N1 to N2 without problems, and if I remember correctly, N1 and N2 are always connected except during startup, momentarily, and I don't think any of the JL electronics/various devices draw more than 30 amps, much less hundreds, during startup.

 

[ScotM]

It's been a very long time since I looked at this, but I recall numerous people making 40 amp jumpers from N1 to N2 without problems, and if I remember correctly, N1 and N2 are always connected except during startup, momentarily, and I don't think any of the JL electronics/various devices draw more than 30 amps, much less hundreds, during startup.

Yeah the jumper wire I saw used was 30 amps. When sizing my wire , I went with the high capacity fuse array size, the N3 that I’m going to use, because it will be empty has a 150 amp rating. The N1 just says B+ for battery positive, so I don’t know what that rating is. I still may do a N1 to N 2, at any rate my 2/0 wire shouldn’t get hot or cause a fire.

 

[Jammer]

Because he’s full of crap.

Look at how many people on here that have bypassed the aux battery without issue. That should tell you all you need to know.

Can you tell me what is the purpose of the auxiliary battery then? It's not just to run auxiliary stuff like lights and your radio we've been running auxiliary lights and amps and stuff like that on trucks for a long time including Jeeps. Doesn't auxiliary battery help charge the big battery what's the purpose of the little battery then I explain cuz I'm asking I guess I don't know enough about it ? I mean if we don't need it why would they put it there not just to make money office because the ones that doesn't come with it has the different motor

 

[azwjowner]

Can you tell me what is the purpose of the auxiliary battery then? It's not just to run auxiliary stuff like lights and your radio we've been running auxiliary lights and amps and stuff like that on trucks for a long time including Jeeps. Doesn't auxiliary battery help charge the big battery what's the purpose of the little battery then I explain cuz I'm asking I guess I don't know enough about it ? I mean if we don't need it why would they put it there not just to make money office because the ones that doesn't come with it has the different motor

The sole purpose of the auxiliary battery is to power the electronics and other accessories in the Jeep while the engine is off during an auto start stop event. This is done to prevent the main battery from depleting. If you disable the auto start stop, then you don’t need the aux battery.

 

[Jammer]

I'm thinking about putting a Sub-Zero refrigerator and freezer in my Jeep and some other stuff when we go camping. if I do I'm going to do the dual battery setup most people do that it's just so damn expensive with labor and I couldn't even think about trying it. it's about a 4 to 5 hour job I was told to do the dual battery setup. Cuz everybody I know that goes camping that you see on the internet that goes over landing with the Jeep or the gladiator and have the freezers the refrigerators and run all kind of equipment are doing the dual battery setup that's the perfect setup I think but I'm not very electronically minded so there's no way I would try it I'm sure some people on here could do it but there's no way I would try it I think I was quoted $1,000 parts and labor. Yes that's expensive just extra battery it's going to cost you about 300 bucks then you've got the electronics the parts that's going to cost you anybody out here done that I know the thread doesn't talk about that but has anybody on here done a dual battery setup

 

[Ratbert]

I'm thinking about putting a Sub-Zero refrigerator and freezer in my Jeep and some other stuff when we go camping. if I do I'm going to do the dual battery setup most people do that it's just so damn expensive with labor and I couldn't even think about trying it. it's about a 4 to 5 hour job I was told to do the dual battery setup. Cuz everybody I know that goes camping that you see on the internet that goes over landing with the Jeep or the gladiator and have the freezers the refrigerators and run all kind of equipment are doing the dual battery setup that's the perfect setup I think but I'm not very electronically minded so there's no way I would try it I'm sure some people on here could do it but there's no way I would try it I think I was quoted $1,000 parts and labor. Yes that's expensive just extra battery it's going to cost you about 300 bucks then you've got the electronics the parts that's going to cost you anybody out here done that I know the thread doesn't talk about that but has anybody on here done a dual battery setup

@Tredsdert was apparently going down a similar path and expressed some similar concerns to one of our sponsors in regards to how much those kits cost. In summary: it's not a great idea to cut corners when building a dual battery system. The start of the relevant conversation: https://www.jlwranglerforums.com/fo...ions-from-genesis-offroad.125338/post-2989237

 

[Mguy]

So, a thread titled "Jumperless Aux Battery Bypass" is now focused upon installing a jumper. Aside from the irony, this retro discussion has me confused. Installing a fat cable or conductive strap to prevent damage to N1 electronics or fire from a voltage drop or high amperage during a start?

Sorry, I don't see how paralleling N1 loads with the starter load requires a connection that that meets the specifications necessary for the starter load. The overall system voltage drop is caused by the start so beefing up the N1 connection won't stabilize or increase that circuit's voltage, and the N1 loads will not draw more amps just because the start circuit is drawing more.

Finally, I'm unaware of reports, from anywhere, that electronics have been damaged by a momentary voltage drop, such as that which occurs during a vehicle start. We have reports on this forum of an abnormal noise occurring in some JL sound systems during ESS starts, but even those reports don't include mention of damage.

 

[THAW]

So, a thread titled "Jumperless Aux Battery Bypass" is now focused upon installing a jumper. .

Perhaps you deserve some blame?

or take out all the aux battery cabling and install a power connection to the N1 bus. The eTorque method for power, a solid strap from N2 to N1, is great. Without a strap (not too difficult to make if you can find some thin copper), use a fat cable jumper, which could also go N1 to the main battery positive clamp.

3) For owners more electrically inclined there are other options, including connecting N1 to N2 after removal of stock aux battery cabling.

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