So this is a repost form this thread plus a little more info. Didn't want to hijack that thread.

Installed @sarek battery tray last weekend. Decided to do it so the winch has a little more power readily available and can run a few more accessories without the low battery warning light coming on while camping. This is technically the third battery in the vehicle. My second battery is in the back under the floor and runs my fridge, external lights, starlink, and a few other accessories. It is a LiFePo4 type battery.
This third battery is specifically for the the winch and making sure the main battery doesn't completely drain during a weekend camping trip with all the doors opening and closing.
I actually bought the battery tray about 9 months ago. Just before I received it I had a minor fender bender that damaged the passenger aux radiator. So I had to wait to get that fixed. After that was fixed I noticed they changed the connection point on the aux radiator and installed a whole new coolant pipe. This new coolant pipe along with @Saltek Motorsports aux relocation kit now interfered with where the battery tray would sit. I was going to need to cut the coolant pipe and reroute it. Not something I was thrilled about doing but not that big of deal. The only problem is I had a coolant leak somewhere and needed to get that fixed under warranty before I messed around with modifying the cooling system. Didn't need them claiming my mods caused the coolant leak. Got that fixed, turns out it was the electronic thermostat body that was leaking. So with all those things taken care of I started the install

The tray was a little bit of a struggle to get in. I believe this tray was designed around a 90 p300 with standard headlights. The coolant pipe to the aux radiator needed to be modified. The tray itself needed to be notched to fit correctly as the aux radiator was in the way. That is because I installed saltek aux radiator relocation kit, so shouldn't be a problem for most. The relocation makes the top of the radiator interfere with the tray. The final problem was I think the tray might have been designed around the standard LED headlights, I have the premium headlights, which appear to be longer. So that caused the battery to push closer to the wheel well, but that wouldn't work because of some structural ribs being in the way. The solution was to raise the battery about 3/4 of an inch. I made some brackets out of aluminum.

As for wiring. Both the vehicle battery and this battery are wired in parallel. I go from the auxiliary take off point on the passenger side (450amp fuse) to this new battery. This puts both batteries in parallel. Then I go to a 500amp relay and then to the winch. The relay is wired to a switch just to the right of the steering wheel. This switch can only be live (even if in the on position) when the vehicle engine is running. I did this because I didn't want power live to the winch all the time.


Installed battery tray with mods to lift the battery up about a half inch. You can see the ribs on the wheel well just on either side of the aluminum bracket I made. Also you can how much the light comes over the top of the plate. Also not as easy to see the plat is touching the plastic bracket that holds the aux radiator. It is also touching the the coolant pipe. I put a piece of self adhesive rubber between the pipe and plate.

Here is my 500amp relay. Left side goes to the winch. Right side is coming from the second battery. On the for left above the red area is the power take off point with my 450A fuse.

Installed battery all wired up. I also fused the second battery.

 

Awesome write up! Thanks for the insights & second post.

 

Wow. Great write up. We have seen the new updated coolant hose on some newer p400s we have been installing these on. Unfortunately that does now interfere with the battery and tray. Gotta love production changes 😀. We are currently looking at modifying the design in hopes of avoiding the coolant pipe modification which we now do add some hose for in the current kits. I will have a video soon on the installation on a defender with the updated coolant pipe. It is a pretty simple mod to replace the pipe with hose. But it does add messing with the cooling system. The tray and battery is a bit tight against the headlanp (with or without the led headlamps. The tray is a bit of a wrestling job to get in place and the lower nut and bolt are a challenge to tighten. Very nice setup with the battery and isolator for the winch. Great info on the Saltek relocation interfering with the tray. I have not installed one with this mod. It looks like making the tray an inch taller might be a good way to make it compatible with this Saltek kit. I will reach out to Sal and see if we can work together on this.

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I agree that lower nut is a royal pain. Probably spent most of my time figuring out how to tighten it. I didn't have anything small enough to get on that nut. As for the tray location, I would say an inch higher and and inch closer to the wheel well would be about perfect.

 

We will look at those adjustments in the model. Thank younfor the feedback