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2012 LR4 Dual Battery Install - Part 2 - Clearing the bay & Securing Battery
Please see my post "2012 LR4 Dual Battery Install - Part 1" for the start of this story.
Now that I had the 2nd battery bay open and my primary components were on hand - 2nd battery and DIY controller kit - I was ready to begin removing items in the 2nd battery bay, which is located on the driver's side of my 2012 LR4 NAS.
This Part 2 of the story includes some important "customizing" you will need to do in order to complete the project - don't skip this part of the story!
I began by removing the plastic shroud covering the ECU. There are bolts on the bottom and on the top. In addition, once the plastic shroud is removed there are other small plastic parts that you will remove from under the ECU that will allow the battery to be secured and stable in the bay.
Here are a few photos showing the plastic shroud coming off and the ECU sliding out of the plastic housing. Note that once the plastic shroud is removed you just slide the ECU off the bracket. Once it is out of the shroud you can kind of push it aside. BEFORE unhooking the ECU I just worked it out of the way so I could dry-fit the battery.
Once I was sure the battery was going to fit I disconnected the negative terminal from the primary battery and then disconnected ECU completely by pulling the wiring harnesses from the base of the unit. I took a bunch of pictures, but as I recall all of the wiring harnesses are unique and only plug in one way. Double check this to keep me honest, but this makes getting things connected back up properly super easy!
Once the ECU is out of the way you can work on removing the horn. Take your time removing the 2 screws that hold the bracket to the base of the bay so you don't lose them or damage the brake lines. Note that the 3rd connector, on back holding the horn itself to the bracket, does not need to be removed right now - that will come later. So just the 2 screws at the base, then kind of wiggle the whole bracket out from under the brake lines. Disconnect the wiring harness and set the horn aside for remounting later.
As noted above, before unhooking the ECU and after the horn was removed I did a dry-fit of the battery. You can see that it is a snug fit in there, but it does fit!
With confirmation that the battery would fit I went to work figuring out how to mount the battery so it wouldn't be bouncing around in the bay, and also how to re-mount the ECU and horn under the brake lines. Remember, just the horn took up the space below the brake lines before, so some careful fitting is needed - but it will work!
I quickly figured out that I did not have, and could not find, a battery bracket that would fit my Optima battery, was the correct shape, or would align with the pre-made bracket screw inserts already built into the base of the battery bay. There may be an expensive LR part available, but I didn't have it, so I went to work taking out the base of the 2nd battery bay so I could craft a way to hold down the battery once it was mounted in the bay. If you can find a source for this bracket - with the right angles and the right size to fit inside the bay please reply to the thread so others can learn how to save these next few steps.
The steps that follow are all focused on getting the battery secured in the bay - If you have an actual bracket you can skip this part!
My goal was to have the whole system enclosed and the top of the battery bay snapped on just as it was before I made my mods, so I set about using parts of several battery mounting kits I bought at O'Reilly, Walmart and NAPA to come up with something that would work. None of these kits matched the dimensions within the bay, try as I might to mix and match them. In the end I determined I would drill holes in the base, use "J" bolts from one of the battery mounting kits I bought, and use a flat piece of steel for the bracket going across the top of the battery. Same idea as a pre-made kit, but would require me to take out the base of the bay and do some drilling. I'm including a bunch of pictures for this section to save you time trying to figure out where to put the mounts, still have clearances for the battery top, etc. My apologies for the funny shape of the picture matrix for this section.
Start by taking off the left edge of the bay. If I recall correctly it is just held in place by snap tabs. This will give you better access to the base and allow you to pull it out after you remove the base screws. There are three easily accessed nuts at the bottom of the bay. Remove them and pull out that roughly triangle shaped piece of plastic. This is the part you will need to drill to make allow the J bolts to fit within the bay and still secure the battery.
As a side note, I bought 4 small magnetized bowls at Harbor Freight for about $3 apiece to help separate the nuts and bolts so each activity had it's own holder and I didn't have to try to remember which parts went with which step.
Once you have the base removed you will drill your holes for the J bolt. See my photos for where to drill the holes to ensure the battery fits and the J bolts reach the right height to secure the battery. Note that on the end that goes closest to the firewall you want to measure down far enough for your hole so that the tip of the short leg of the J doesn't hit the base from underneath. See the larger 3 photos in the middle to see what I am talking about here. Once you drill the hole you will feed the J bolt from underneath. I recommend a bigger piece of duct tape or more electrical tape than I used to hold them in place while you put the base back togther and get the battery situated. They fell out several times for me before I figured out I needed to put some tape on them to keep them from falling down through the holes.
I couldn't find a piece of steel or rectangular aluminum tubing that would fit across the top of the battery what I wanted, so in the end I decided to cut the shorter end from an extra steel framing square I had. I know this is NOT the best solution, but after trying a bunch of different solutions this one ended up being one I could do with materials I had on hand, and which would allow the bay cover to be snapped back into place. The steel in the square was pretty strong, and once cut, shaped and painted it worked perfectly. I've had this in place for almost 2 years now and no issues. If you find a more elegant solution to this problem please reply so others can benefit! You'll see this "custom mod" in one of the next parts of the story.
Here are some pictures of me removing/drilling and fitting my custom "battery containment system" in place. Hopefully you just bought the bracket I have since seen for sale online! ) :
Mounting the ECU
I think the member who originally posted the help guide for this re-mounted the ECU under the brake lines without the cover, but after going through the steps to try to mount it I realized I might be able to trim the plastic shroud enough to actually fit in the space and keep the ECU covered!
Out came the trusty Dremel with an assortment of cutting wheels and bits! See some of those items here if you don't already have a Dremel. HOME DEPOT was my preferred source for these. I had a nice assortment already, but here are some ideas to help make the project easier for you:
With the Dremel out I began cutting off bits of the plastic shroud I knew I wouldn't need. Take it slow, and begin cutting the most obvious pieces from the cover. Be patient. Use my photos below as a guide to what you want the two pieces to look like after you get all the extra parts off. This probably took me 2 hours when I was doing it, but I think you can get it done much faster - maybe 30 minutes - by looking at the photos below to see the final shape of the shroud.
Remember that horn and mount from earlier? We are going to reuse the mount to secure the ECU inside the bay, under the brake lines, right where the horn used to be! See the photos to attach the back plate to the horn mount. If you follow my design the ECU unit will slide all the way down and not hit the screw.
Next, follow my design on the top piece to drill a hole and mount the horn to the shroud top piece. Be sure to use a machine screw going from the inside out so the top piece will slide all the way down over the bottom piece. A little Loctite on the screwn then position the horn at an angle, as shown in the pictures. Finally, slide the top piece of the shroud down over the ECU unit.
DONE! You have a mounted, covered ECU unit and horn ready to be installed under the brake lines in the spot the horn used to occupy! Best of all, the ECU is upright, mounted firmly inside the 2nd battery bay as it was before (but in a new location), and still covered by the two-piece factory cover it was in before!
See Part 3 of this build for mounting the ECU box and connecting the Dual Battery Control Unit. Thanks!
Last edited by MikeGraef; 01-16-2021 at 11:07 AM.
Reason: Photos missing - re-inserted photos inline.
06-16-2020, 12:01 AM
2012 LR4 Dual Battery Install - Part 2 - Clearing the bay & Securing Battery
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