Rethinking the battery tray

As part of my Boostwerks Comp Mount installation I have been trying to decide just where I wanted to mount the winch controls. I found an easy answer, mounting on the AC bracket ( http://www.naxja.org/forum/showthread.php?t=1136273 ), but my own life experiences have taught me that the easy answers always come back to bite me when it is least convenient. Better to pay the price up front and get it over with. So I kept looking.


Having to replace my alternator a few months ago I was reminded of just how much extra space there is underneath the battery. Perhaps this isn’t quite so obvious with the factory battery tray, but running a Dirtbound tray it becomes evident. I got to doing some thinking about what could be done with that space. Unfortunately, the Dirtbound tray is not quite high enough to clear the winch relays, but it is really close, like ¼”close. That got me wondering if I could create the space I needed underneath the battery.


First question, how much clearance is there above the battery? I swiped a lump of Play Dough from The Varmints and ran a squish check. I have easily 1 ½” of clearance above the negative terminal, and even more above the positive:


So next was the question of what will it take to make a custom battery tray? I sent an email to Dirtbound to inquire about getting a tray without a bracket or perhaps a tray in un-welded pieces. No response. I take that as a “No”.

Okay, fine. I have another Dirtbound tray which I bought for “The Parts Jeep” (because XJs accumulate). Lets cut up a perfectly good battery tray.

I did at least stop and think things through a bit. Before I started cutting I first made a fixture to locate the tray relative to the mounting bracket, but to still allow height adjustment:








Then I finally got some time to tear into this task in earnest. I pulled out the existing tray and played around with options for locating the relays. I was expecting that I would have to replace some of Warn’s copper straps in order to position things so they would all fit, but I found a spot where they all fit as already configured (Yes, I know, that picture shows them too close to that one stud. The clearance exists with proper positioning.).






A new baseplate was cut out of 10GA sheet metal (after first making a cardboard template):






Here is how the plate will look with relays (See? There is clearance.):






And then with the battery tray in rough position:






Comparison of the new baseplate to the Dirtbound baseplate:






Outside view with roughed in supports:







And another perspective:






Hopefully I will get time on Monday to weld this together. The plan is for the tray to be held to the baseplate and supports with four ¼-20 machine screws so that I can access all the connections. This location should make for nice, short runs to the winch. Additionally, I think I will have some extra room for mounting lighting relays underneath the battery as well. My headlight relays I intend to keep on the fender where I can easily access them if there is an issue, but auxiliary lighting is generally not so crucial, so burying those under the batter is probably not going to be a decision I will regret. Maybe.

Just because I'm paranoid I'd find a rubber sheet to place between the winch relays and your tray. About a thousand amps ( depending on your battery) to the bottom of the trey and melt a hole in the battery would make for a fun thing to explain to people why your jeep isn't drivable. Or god forbid you hit something hard enough to push the front end in and do it


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My SOP on winches, since I have yet to come up with a compact fuse that will handle 500 amps, is to leave the positive battery cable disconnected. A race Jeep would be different story, but for my own use, if I need to use the winch I probably have time to connect a cable lug too.

Have you seen about car audio fuses?
I'll try to post a pic.


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I have not seen those. It looks like ANL is the key search term there. They make them up to 750 amps.

The size is the challenge though. Anything with that kind of amperage wants some space around it. Here is one sample for dimensions:

Size
•3.38” long, 09.5” wide, 1.62” tall

Click to expand...

(Source: http://www.cooperindustries.com/con.../product-datasheets-a/Bus_Ele_DS_2024_ANL.pdf )

I am going to hope the decimal is in the wrong place for the width, but that still takes up a good bit of space.

I may order one just to get a hands on sense of the form factor, but I have my doubts that it will fit gracefully in a serviceable location.

I used one of those when I redid all my battery cables. While they are kind of big, they fit pretty much anywhere. Mine is mounted to the inner fender.

I got some more time into this little project today. First step was welding some 1” x 1/8” angle iron to my supports because I don’t have a press brake. I then clamped my supports to the bottom of the battery tray, drilled through them and countersunk the holes while keeping things clamped together. I needed the countersink to go partway into the support brackets because the battery tray is not quite thick enough to accept the entire head of the 1/4"-20 screws. There is just a bit of a relief needed into the support brackets in order to keep everything flush.






And everything still fits nicely in the jig.






Then there is the fit in the Jeep. I had to a little bit of extra clearancing underneath the one support bracket in order to clear the inner fender. I expected this. There was no good way to template that one bracket, so I just eyeballed it and planned to scribe and grind afterwards. It worked out fine.






And here is how it fits with the relays. Adequate clearance for the three factory mounting studs.






My biggest fear with the increase in height was that I would end up with too much interference with the upper radiator hose. I had wrapped a couple of zip ties around the radiator hose because the battery was chafing its way into the hose with the old tray. Now I was going up even higher, and there was the risk I would make things even worse. To mitigate this I fudged the tray as far back on the base of the jig as I could get away with (actually, to be more precise, I fudged the new base as far forward as I could on the jig—same net result). I knew that by going higher I had a little more room to work with on the arc of the inner fender. It worked out beautifully. I now actually have more clearance to the radiator hose than I had before.






After those fit checks I had one more detail to refine: I had to change the contour of the socket clearance notch in this one bracket (consequence of having fudged the relationship between the base and the bracket/tray. I could work with it as it was before, but the socket was fighting the bracket. It should be fine now. I will find out for sure when I get to the next phase of fit checks.


New profile on bracket:







At any rate, I think this is a winning proposition. All the larger details are working out perfectly. I just have minor details to work through now, and I don’t think any of them have the potential to deep six this.

I am going to have order one of those ANL fuse holders. I think I might be able to fit it under the tray, on in the inner fender, in that triangle of space that will be left between the new base, the inner fender and the tray itself. If it fits I will run it.