Benchmark Designs Dual Battery Tray Writeup
05-16-2009, 06:47 PM
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Benchmark Designs Dual Battery Tray Writeup
Background
I have been planning a dual battery setup for a while now. Given that so much of the JK's operation depends on electronics of one form or another, it seems like the battery system is a single point of failure that I don't want to have to deal with when I'm by myself in the bush 50 miles from civilization. Add to that an increasing number of electronic accessories (lights, compressor, winch, and most recently my sweet new ARB Freezer/Fridge), and I figured it was time to bite the bullet.
The hardest part of this upgrade so far has been coming to terms with the price tag for the whole operation -- close to a grand once you factor in batteries, tray, wiring, a proper charger/isolator system. But now that I've done it (well, most of it, charger/isolator coming soon) I'm glad that I did.
Unboxing and First Impressions
I PM'ed John from Benchmark Designs on Monday, and my tray showed up on Wednesday -- super quick ship, no hassles whatsoever. The tray was very well packaged for shipping, and John emailed me a PDF with excellent instructions with lots of pictures in the meantime.
Because the instructions are so good, this is going to be less of a step-by-step writeup, and instead just some real-world impressions and a couple of suggestions.
Since I managed to completely over-expose the pics of the tray in the box, I will substitute a gratuitous pic of my ARB fridge, which I love. Contact David at Alpha Expedition, he will hook you up:
OEM Battery Tray Removal
When I first got John's instructions, I was a little shocked that recommended equipment included "jack stands" and that there were no fewer than 38 steps involved. This made a little more sense once I got in there are discovered that the OEM tray is a giant thermoplastic monstrosity, which includes not only the visible portion that you can see by popping the hood, but also extends under the TIPM (fuse box) and all the way forward to support the factory air box:
Here is a pic of the entire thing that you will be replacing:
The instructions are quite detailed regarding removal of the old box, but I did find that there were a couple of little "christmas tree" style cable management posts that I needed to pop out that were not explicitly called out in the instructions. I actually managed to snap a corner off the OEM tray trying to remove one of these. Since you don't reuse any of them, I suggest clipping them instead of trying to pry them out.
Main Battery Tray Installation
The main portion of Benchmark tray re-uses the three firewall mounting studs from the OEM tray and one of the inner fender mounting locations. It also includes a clever support brace that bolts to the inside of the shock tower. While this is a nice design, it does complicate the installation somewhat. The instructions state that you may need to remove the shock to access the bolt hole location (I'm borrowing this pic from the instructions):
However, even though I have some aftermarket shocks that mount with the main cylinder up (unlike that photo), I jacked up the other side of my rig with a hi-lift which moved the shock body away from the inner tower just enough that I could get a small 10mm wrench on it and do the final torque down. I suspect this might also work with a stock setup, so it seems worth a shot to avoid having to drop the axle and remove the shock.
Once I tightened down all the mounting bolts, it was clear that the tray with its new support brace was extremely stout. This is good, considering how much Group 34 AGM batteries actually weigh
Air Box Support Installation
The Benchmark airbox support is a separate piece that bolted up with no fuss. You re-use the factory grommets to locate the air box. It felt slightly more shakey than the factory box once it was in place, but nothing to cause any real concern:
Here's a pic from a different angle showing the new tray and airbox support ready to accept the batteries:
Battery Installation and Cable Routing
I opted for a pair of Die Hard Platinum AGM batteries. These are re-branded Odyssey Group 34 PC1500DT batteries, the only difference is that you buy them at Sears, and they cost $60-70 less per battery. They are still shockingly expensive (har har) at $189 each, but they are generally preferred over Optimas.
One thing that struck me as being a little awkward was the fitment of the factory evap purge valve. There are hard plastic lines that feed it, and I had to kind of torque them out of the way. There is also no provision for a mounting post for this valve (like on the factory box) so I zip tied it to the TIPM mounting bracket like so:
Due to the factory cable lengths, I decided to use the inboard battery as my primary (starting) battery. After snipping a zip tie and re-configuring some of the leads, both terminals bolted right up:
Note that I have not connected any accessories (visible to the left of the outboard battery in the pic above) until I sort out my isolator/charger situation (stay tuned).
Clean Up (Grounding Strap!)
The instructions mention that you should relocate or replace the factory hood grounding strap so it doesn't short across the positive terminal of the new inboard battery. I decided to insulate the existing one using some woven wire loom like the kind you can get from Painless wiring (I picked up mine locally at Fry's):
Here's a pic of the newly-insulated grounding strap re-fitted (yay mud!):
Conclusion
In a nutshell, I was a little bit surprised that fitting a new battery tray would be so involved, but once I saw the OEM setup, it was clear. It's obvious that Benchmark took the time to get the details of this kit correct, and so far I'm very happy with it. It's actually rare that something bolts right up to a rig with no modifications necessary, but this was the case with the benchmark kit. I'll check back in and update this writeup when I complete the install with the charger/isolator, but for now I thought folks might be interested in what I have so far.
I have been planning a dual battery setup for a while now. Given that so much of the JK's operation depends on electronics of one form or another, it seems like the battery system is a single point of failure that I don't want to have to deal with when I'm by myself in the bush 50 miles from civilization. Add to that an increasing number of electronic accessories (lights, compressor, winch, and most recently my sweet new ARB Freezer/Fridge), and I figured it was time to bite the bullet.
The hardest part of this upgrade so far has been coming to terms with the price tag for the whole operation -- close to a grand once you factor in batteries, tray, wiring, a proper charger/isolator system. But now that I've done it (well, most of it, charger/isolator coming soon) I'm glad that I did.
Unboxing and First Impressions
I PM'ed John from Benchmark Designs on Monday, and my tray showed up on Wednesday -- super quick ship, no hassles whatsoever. The tray was very well packaged for shipping, and John emailed me a PDF with excellent instructions with lots of pictures in the meantime.
Because the instructions are so good, this is going to be less of a step-by-step writeup, and instead just some real-world impressions and a couple of suggestions.
Since I managed to completely over-expose the pics of the tray in the box, I will substitute a gratuitous pic of my ARB fridge, which I love. Contact David at Alpha Expedition, he will hook you up:
OEM Battery Tray Removal
When I first got John's instructions, I was a little shocked that recommended equipment included "jack stands" and that there were no fewer than 38 steps involved. This made a little more sense once I got in there are discovered that the OEM tray is a giant thermoplastic monstrosity, which includes not only the visible portion that you can see by popping the hood, but also extends under the TIPM (fuse box) and all the way forward to support the factory air box:
Here is a pic of the entire thing that you will be replacing:
The instructions are quite detailed regarding removal of the old box, but I did find that there were a couple of little "christmas tree" style cable management posts that I needed to pop out that were not explicitly called out in the instructions. I actually managed to snap a corner off the OEM tray trying to remove one of these. Since you don't reuse any of them, I suggest clipping them instead of trying to pry them out.
Main Battery Tray Installation
The main portion of Benchmark tray re-uses the three firewall mounting studs from the OEM tray and one of the inner fender mounting locations. It also includes a clever support brace that bolts to the inside of the shock tower. While this is a nice design, it does complicate the installation somewhat. The instructions state that you may need to remove the shock to access the bolt hole location (I'm borrowing this pic from the instructions):
However, even though I have some aftermarket shocks that mount with the main cylinder up (unlike that photo), I jacked up the other side of my rig with a hi-lift which moved the shock body away from the inner tower just enough that I could get a small 10mm wrench on it and do the final torque down. I suspect this might also work with a stock setup, so it seems worth a shot to avoid having to drop the axle and remove the shock.
Once I tightened down all the mounting bolts, it was clear that the tray with its new support brace was extremely stout. This is good, considering how much Group 34 AGM batteries actually weigh
Air Box Support Installation
The Benchmark airbox support is a separate piece that bolted up with no fuss. You re-use the factory grommets to locate the air box. It felt slightly more shakey than the factory box once it was in place, but nothing to cause any real concern:
Here's a pic from a different angle showing the new tray and airbox support ready to accept the batteries:
Battery Installation and Cable Routing
I opted for a pair of Die Hard Platinum AGM batteries. These are re-branded Odyssey Group 34 PC1500DT batteries, the only difference is that you buy them at Sears, and they cost $60-70 less per battery. They are still shockingly expensive (har har) at $189 each, but they are generally preferred over Optimas.
One thing that struck me as being a little awkward was the fitment of the factory evap purge valve. There are hard plastic lines that feed it, and I had to kind of torque them out of the way. There is also no provision for a mounting post for this valve (like on the factory box) so I zip tied it to the TIPM mounting bracket like so:
Due to the factory cable lengths, I decided to use the inboard battery as my primary (starting) battery. After snipping a zip tie and re-configuring some of the leads, both terminals bolted right up:
Note that I have not connected any accessories (visible to the left of the outboard battery in the pic above) until I sort out my isolator/charger situation (stay tuned).
Clean Up (Grounding Strap!)
The instructions mention that you should relocate or replace the factory hood grounding strap so it doesn't short across the positive terminal of the new inboard battery. I decided to insulate the existing one using some woven wire loom like the kind you can get from Painless wiring (I picked up mine locally at Fry's):
Here's a pic of the newly-insulated grounding strap re-fitted (yay mud!):
Conclusion
In a nutshell, I was a little bit surprised that fitting a new battery tray would be so involved, but once I saw the OEM setup, it was clear. It's obvious that Benchmark took the time to get the details of this kit correct, and so far I'm very happy with it. It's actually rare that something bolts right up to a rig with no modifications necessary, but this was the case with the benchmark kit. I'll check back in and update this writeup when I complete the install with the charger/isolator, but for now I thought folks might be interested in what I have so far.
Last edited by mmccurdy; 05-16-2009 at 06:54 PM.
05-17-2009, 05:40 PM
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Great job on the write-up and install, I'm just behind you on my installation of the bracket and was considering the same batteries as well.
I'm digging the ARB freezer as well, schweet.
I'm digging the ARB freezer as well, schweet.
05-19-2009, 05:23 AM
#7
Nice to see a manufacturer go to the trouble and get something RIGHT for a change. Although expensive...but worth every penny, this is on my list too. .....and you might have to remove a shock. Oh, I think I am just gonna die over that.....NOT. 
Nice write up.
Nice write up.
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05-19-2009, 08:42 AM
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JK Super Freak
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05-19-2009, 08:53 AM
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