Dual Batteries Under the Hood

[Dzimm]

Does anyone run dual batteries under the hood and how did you accomplish it? I have a spare XJ battery box but I just can't seem to find a way to fit it in place of the air box (I know it will need modified). The AW4 lines are in the way at the rad and the ECU plugs also interfere. Even if I move them it seems as though I'd have to bend/cut into the wheel well to have it sit low enough to clear the hood. I've seen some pictures of a battery here but they don't seem to have issues with fitment that I can tell. I do have the horseshoe intake manifold which leaves a little more room to play with but I am running an auxiliary fuse box next to the brake booster so that takes up some space as well. I'll post some pictures soon.

[Jeepman]

There are Dual battery kits you can buy that will fit directly in place of the air box...

 

Bleepin Jeep has a YouTube video as well

[Dzimm]

There are Dual battery kits you can buy that will fit directly in place of the air box...

 

Bleepin Jeep has a YouTube video as well

The bleepinjeep video is how I realized you could use a factory battery box with some modification but I just don't understand how Matt got it to fit so well. Do you have a link to a battery box kit? All the things I'm seeing are ones that set both batteries side-by-side.

[CMMagnussen]

http://www.dirtboundoffroad.com/jeep-cherokee-xj/accessories/battery-trays.html

[johnj92131]

If I remember correctly, the factory offered a dual battery option on diesel Cherokees offered overseas.  Perhaps a google search will locate more information?

 

http://forums.off-road.com/jeep-mid-sized/171099-dual-batteries-xj.html

 

The above post has a dead link to the old MADXJ site talking about using a diesel dual battery.

 

Anyone know if their is a mirror of the old MADXJ site?  It had a bunch of good DIY tech articles.

 

And a bit more useful information here:

 

http://www.colorado4x4.org/vbb/showthread.php?31150-Dual-Battery-Setup-in-Cherokee-XJ

 

Perhaps a battery tray from Ebay.UK?

 

Google search for the old MADXJ site found this 2012 discussion:

 

http://www.naxja.org/forum/showthread.php?t=1079288

 

Following the link provided there leads to the old tech articles and here is the one about the dual battery setup:

 

Relocating or Adding a Battery
To the Left Side in the Engine Compartment of 4.0L XJs/MJs

by Andreas Ritterbusch
Posted: June 3, 2002
Last Revision:

 

This article is for those who either need to relocate the battery for an on-board air (i.e. York style) conversion, as well as for those who plan to install a dual-battery setup (for heavy winching action or high-powered amateur radio use, etc.)

  The XJ's/MJ's engine compartment is already well used the way Jeep engineered it. However, several modifications require more room. Some magic needs to be done to achieve this.
This article assumes that that the air cleaner/intake box has already been replaced with a cone filter (such as K&N). The space freed up by removing the air box can now be used for a relocated battery. Either a second battery can be installed here, or the main battery can be relocated to the left (driver's side), using a late-model diesel XJ battery tray (perhaps an early-model Diesel tray might fit too). Those trays are for the Diesel XJs sold in overseas markets, such as the EU and AUS, etc. More on the Diesel trays can be found below in the "The Parts" section.
The relocation procedure shown here was performed on a 4.0L non-HO XJ (i.e. '87 - '90) and possibly may vary slightly on newer 4.0L XJs.
This article does not discuss any battery relocation options on earlier V6 engines, any 2.5L engines, or any of the Diesel engines.
Also, this article does not discuss any of the wiring that is required for a dual-battery setup. This will be covered in a separate article.

The Parts:

The XJ Diesel battery tray from overseas Cherokees make life simpler. A custom try could be fabricated, but in this case, the dealer option was just too tempting to resist. It will need minor modifications (grinding away what's marked in white in this image), but will otherwise "bolt right in". Not even a single hole needs to be drilled.
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[ Page 008-32]          [ Page 008-33]

 

Part number:

Description:

Year:

5517 4970 TRAY, Battery (Diesel engine) 2000 55014 375AB* BOLT, J, M8x1.25x192 2000

* Optional, not used in this write-up

For all other part numbers and a drawing, click the 2000 XJ parts book scans (issued July 1999).

Depending on what year XJ this is done, a new, slightly smaller, battery is needed. A '97 XJ battery will fit perfectly (BCI Group Size Classification 58). Using bigger batteries could result in damage to nearby parts and/or battery as well as may increase the risk of the pos./neg. posts coming into contact with the hood, effectively causing a short which in turn may cause an electrical fire!

Some type of battery cable is needed --a fairly big one, that is. I used 2AWG welding cable. It is flexible, heat resistant, and cheap. To avoid confusion with a ground cable (black) I wrapped some red wire loom around it. This adds extra protection and also stands out.
For the battery-to-engine ground I used the same cable without the wire loom. Don't forget to get the correct crimp-on ends, as well as some battery-post clamps.
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Another fairly sizeable wire is needed for the accessories main lead. I bought a reasonably priced 6AWG jumper cable. This appeared to be the best option at the moment without having to either mail order this or drive a long distance to obtain it. I used a short piece of the black cable for the battery-to-body grounding.
Again, don't forget the crimp-ons in the correct size.
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Perhaps the most challenging part of this project might be the battery hold-down. I ended up welding up my own, since I was not able to find a commercial version that looked strong enough to withstand anything more than a gravel road.
I used some angle iron welded together with a little square bar across. The problem is that the battery is off-center, and therefore the original hold-down is not suitable (depending on battery used).
I also used some round bar and threaded rod for the hold-down. It might be easier to just order them from the dealer as well.
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The Tools:

There are no special tools required, unless a custom battery hold-down bracket is fabricated which may involve some welding.

The Procedure:

I began with the above mentioned Diesel XJ battery tray.

After some initial test fittings, it became clear that a little grinding is necessary. The lower radiator hose interferes for once. Therefore, the lower mount (marked with the white "X") must be removed. A notch must be cut for the power steering hose.

Same image as above (90 degrees rotated).
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After the battery tray has been modified for a perfect fit.
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A view of the installed tray. No drilling required, all bolt holes are already in place and line up perfectly.
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Installed. Notice the notch for the power steering hose.
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Detail view of the power steering hose.
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Detail view from underneath the vehicle looking up at the fender. Perfect fit.
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Time to test fit the battery! This may get tight... Also, the alert observer may already have noticed that the aux. cooling fan is unplugged. More on this below.
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Ah, here's a gap. The battery needs to be pushed all the way over to the fender to properly clear the power steering reservoir. The battery is shorter (but same width) as the Diesel XJ battery. This causes the hold-down to be offset. More on this below in the hold-down section.
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Another view of the battery in its new location. Notice the original hold-down bracket which does not line up with the hold down bolt holes on the bottom of the Diesel tray. Again, the shorter battery is off-center in this tray.
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OK, well the battery fits, but a hold-down must be found that will work with the off-set. As mentioned earlier, I didn't find a satisfactory solution and started building my own bracket. Initially, I didn't want to comment much on this bracket project and did not take many pictures. Since there are many (better?) ways to build this, I will limit the description to the principal idea behind this: Angle iron.
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This is a side view of the finished hold-down bracket made from 1/8" thick 1"x5/8" angle iron. Instead of the official Jeep J-bold (see parts listing above), I used a threaded rod instead. Here hidden in a little brass tube (for looks only! --Can't show cheap threaded stock on a quality web page, right?)
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Detail view of the installed bracket.
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Detail view of the installed bracket. Here the the angle iron can be seen. Two pieces (per side) make the bracket and one square bar across. One piece (towards the battery) is with the long side down and short side over the battery. Welded to this is the same type of angle iron, but the other way. The short end is welded to the long end of the previous piece and the long end points away from the battery. A hole is drilled for the threaded rod (here hidden inside the brass tube). The spacing was perfect this way.
The top weld beads were ground flush. The weld on the side can be seen in this image, although I smoothed it down too a bit.
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View of the bracket after welding and grinding.
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View of the bracket after welding and grinding.
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View of the bracket after welding and grinding.
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Detail view of the installed bracket.
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The hardware used.
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The finished hold-down bracket.
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Before the final install of the battery, one last detail needed to be taken care of: The aux. fan wire got in the way and needed to be extended.
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I added about 8" or so. This allowed me to reroute the wire out of the way.
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The last step was to prepare the wiring. Here the jumper cables are disassembled. This 6AWG wire was used to run from the new battery to the main accessories distribution panel in the engine compartment.
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Almost done. The new battery cables are quickly prepared since all they need is to add the crimp-on ends on one end and clamped to the battery post clamps on the other. Shown here the main accessories lead.
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All done.
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Notice the bracket from the battery hold-down to nose clip. This was done last, but turned out to be a critical step to provide the necessary strength to hold the battery tightly in place. This can also be seen in some of the above detail views.
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The battery is now installed on the driver's side. The bright red wires coming over the fire wall are the newly routed battery cables.
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Another view of the finished installation.
[Large image] This is a fairly straight forward modification and all went as planned. The hold-down bracket was the only additional job that needed some type of problem solving skills. Nothing major either if a welder is available. A fun little project, which is just one part of another project, such as an on-board air or dual-battery conversion. ©Copyright 2002 Andreas Ritterbusch
All Rights reserved.
Photos: Andreas Ritterbusch

[DirtyComanche]

I'd put it where the coolant reservoir is on a Renix instead.

 

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This is a single battery setup, but you get the point...  It's void space, might as well fill it, and it's on the correct side for shorter cables.

[Dzimm]

I'd put it where the coolant reservoir is on a Renix instead.

 

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This is a single battery setup, but you get the point... It's void space, might as well fill it, and it's on the correct side for shorter cables.

This is a good idea but I plan on having A/C and it has cruise so along with the overflow bottle and fuse box there really isn't space there.

[Dzimm]

http://www.dirtboundoffroad.com/jeep-cherokee-xj/accessories/battery-trays.html

I forgot these existed. I'll have to try and find pictures of this installed. It's more than I want to spend but is an option.

 

Sent from my HTC6525LVW using Tapatalk

[DirtyComanche]

 

I'd put it where the coolant reservoir is on a Renix instead.

 

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This is a single battery setup, but you get the point... It's void space, might as well fill it, and it's on the correct side for shorter cables.

This is a good idea but I plan on having A/C and it has cruise so along with the overflow bottle and fuse box there really isn't space there.

 

 

I understand.  I don't have A/C.  None of my wiring is anywhere near where the factory put it (plus that's a Renix), and my overflow bottle is actually where the factory should have put it (on the driver's side).  I doubt you could get my tray to work with A/C though, to say it is tight is an understatement.

[Knucklehead97]

I'd put it where the coolant reservoir is on a Renix instead.

 

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This is a single battery setup, but you get the point... It's void space, might as well fill it, and it's on the correct side for shorter cables.

I never would have thought about putting a battery there but that is a fantastic idea and very well done.

[Dzimm]

John thanks for the info. I had no idea there were diesels overseas with dual batteries. I'll definitely read up on those. As far as that install, that is exactly what I want to do but what I've noticed with most installs is that the radiator cap is either on the other side or a sealed system. Here is a picture of what I'm working with.

As you can see the rad fill is right in the way as well as the ecu. You can't see it but the Trans lines are in the way as well, and in the upper right is the Aux fuse box mount so there will be many more wires in this area. To make things more complicated, I will be doing a cowl intake that I will run around the brake booster and into the drivers side cowl (I run this way on my xj and it's fine, no water) so it needs to be as far forward as possible.

This is the only orientation I can come up with that it will maybe work but idk if there is enough space between the pinch seam on the inner fender and the hood. I could potentially get a battery with side terminals but I'd prefer to have top mount posts.

 

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[Dzimm]

 

 

 

I'd put it where the coolant reservoir is on a Renix instead.

 

Image Not Found

 

Image Not Found

 

This is a single battery setup, but you get the point... It's void space, might as well fill it, and it's on the correct side for shorter cables.

This is a good idea but I plan on having A/C and it has cruise so along with the overflow bottle and fuse box there really isn't space there.

I understand. I don't have A/C. None of my wiring is anywhere near where the factory put it (plus that's a Renix), and my overflow bottle is actually where the factory should have put it (on the driver's side). I doubt you could get my tray to work with A/C though, to say it is tight is an understatement.

It does look like a tight spot and I'm surprised it clears the hood, but it is a good use of the space since you have it. If I end up ditching A/C I may consider making use of this space.

[DigitalBman]

On 3/29/2017 at 1:42 PM, Dzimm said:

Does anyone run dual batteries under the hood and how did you accomplish it? I have a spare XJ battery box but I just can't seem to find a way to fit it in place of the air box (I know it will need modified). The AW4 lines are in the way at the rad and the ECU plugs also interfere. Even if I move them it seems as though I'd have to bend/cut into the wheel well to have it sit low enough to clear the hood. I've seen some pictures of a battery here but they don't seem to have issues with fitment that I can tell. I do have the horseshoe intake manifold which leaves a little more room to play with but I am running an auxiliary fuse box next to the brake booster so that takes up some space as well. I'll post some pictures soon.

Hey Dzimm, 

I don't know if you ever figured this out or not, just thought id chime in with what i did. 

 

On my dual battery setup I routed a cowl are intake with inline filter. This opened the space up very similar to what you have. Then i went to the JY and got another battery tray, I had no idea about BleepinJeeps video at the time, but after throwing it in there i ground off the one spot on the bottom of the tray, the little round protrusion sticking out the bottom. 

 

 

This allowed me to fit an auxillary fuse box, actuator for my fron tlocker, battery isolator, and second battery. 

 

 

 

 

As you can see, the batteries are pretty dang symmetrical. Every time I pop my hood now I get compliments. 

 

My start battery runs my front winch and putco headlight harness (for now).

My second battery powers:

the auxiliary fuse box with my front / rear lockers and my front LED lights. 

It will power my rear winch and rear LED lights as well as on board air, plus who knows what else. 

 

The Battery isolator is powered off of my second battery, that way if my start battery dies, I can still have switched power to the battery isolator, this allows me to literally jump start myself with the push of a button if my start battery is dead. 

 

 

If you have found a solution already, great! If not i hope this helps or helps anyone else that finds this thread. Some more details can be found in my build thread or I can answer any questions. 

[Dzimm]

1 hour ago, DigitalBman said:

Hey Dzimm, 

I don't know if you ever figured this out or not, just thought id chime in with what i did. 

Thanks man this is exactly what I needed! I had an extra tray but ended up needing it in the 95 XJ I bought.  I was worried it wouldn't fit with the radiator cap and computer on the fender.  All the pictures and videos I had seen before showed either no rad cap or no computer there.  Even Dirtbound's bracket says it requires moving the computer.   I read through your thread a few times but for some reason missed this part of it.  

 

I like the way you have it set up to jump start yourself but I have some questions about it, how exactly is the solenoid wired and how does it work with the switch?  Also what happens if the second battery is dead, does that mean it can't charge since the solenoid won't have power? 

 

I have been busy with other things but this will now be on the top of the "to do" list.  Dual Blue tops, here I come! 

[DigitalBman]

So basically, in order for the battery to automatically charge it needs to be wired into an accessory 12v ignition source. 

 

That way when the truck is being driven both batteries stay charged. 

 

The switch gives you the option to control the isolator I'd the start battery is dead. 

 

There are other options other than what I have layed out for you. 

 

There are also automatic duel volt sensing isolator that does everything automatically. I just wanted the option to control it when I wanted. 

 

Feel free to ask any questions and I'll do my best to answer! 

[Dzimm]

6 hours ago, DigitalBman said:

This makes perfect sense.  I really like the idea of secondary control with the switch.  I will definitely do something similar.  Thanks! 

[Dzimm]

I finally got around to making this happen.  Thanks to the help from you guys, especially DigitalBman since we have basically the same setup.  It took some work since I seem to have tighter quarters to work with but I made it work.  I found that just marking and cutting was the easiest route.  It sits a little higher than I wanted but I can't get it any lower without major modification.   The battery tray mounting holes had to be moved as well and I've got about 1/2" of room between everything around the battery.  Once I get the replacement battery for the cracked one, I'll get it wired and mounted down properly. 

 

 

 

[DigitalBman]

I finally got around to making this happen.  Thanks to the help from you guys, especially DigitalBman since we have basically the same setup.  It took some work since I seem to have tighter quarters to work with but I made it work.  I found that just marking and cutting was the easiest route.  It sits a little higher than I wanted but I can't get it any lower without major modification.   The battery mounting holes had to be moved as well.  Once I get the replacement battery for the cracked one, I'll get it wired and mounted down properly. 

Nice!!! Got some pictures man??

[Dzimm]

Nice!!! Got some pictures man??

Yes I just added them above.

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[DigitalBman]

Yes I just added them above.

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Wow! That's really odd that it sits up so high... I wonder what's different...

[Dzimm]

Wow! That's really odd that it sits up so high... I wonder what's different...

Looking at your pictures I notice your PCM is flat against the fender (I'm guessing you didn't use the small black standoff bracket on the rear bolts?) as well as it sitting at least a few inches away from the hood spring where I mounted mine further forward. Also I think that your rad is narrower than mine, my rad filler is as far outtward as it possibly can go and yours looks to be further inward.

This all forces me to put my tray further back where the inner fender well is taller, thus setting the whole thing higher. You can see in the pictures that if I push the tray further forward, it would go under the PCM plugs and rad filler neck. That would allow the battery to sit lower but also make it rest against the filler and PCM plugs, which is no bueno.

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