Jan 10 14 7:08 PM

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Here is how I built my own dual battery kit, all measurement provided are approximate, make your own measurement for everything. This will be 2 parts, the tray and the wiring.

Part 1 – The Battery Tray


36" 1/8" x 1" aluminum strip
36" 1/8" x 1" aluminum L strip
Battery Tray ~ 10.5" x 7.25" - Amazon Attwood Battery Tray, 24 series

Battery Strap - 38" - Amazon JR Products 17384 38" Battery Strap
1 - 1/4" x 4" Bolt
1 - 1/4" x 3" Bolt
2 - 1/4" x 1.5" Bolt
9 - 1/4" Stainless Steel washers
5 - 3/8" Stainless Steel washers
13 - 3/8" Zinc washers
4 - 1/4" x 1-1/4" Neoprene washers
4 - 1/4" lock nut
4 - 1/4” OD X 1/4” ID X 1” long Nylon spacer

Home Depot - $~20
Amazon - $~13
Total for Tray ~$33

I cut the side off the tray that the plastic battery retainer bar would use, no room for these with the Cold Air Intake, I doubt the plastic would holdup off road.

Drilled a ¼” hole in each side of tray.

I made an aluminum frame to support the tray and disperse the weight. I also made the right side higher to help shift the battery weight back toward the fender and less on the “stilt”. Top strip ~10.5”, the 1 strip on the left and 2 on the right are ~7.25”. I drilled holes through them to match the tray.

I cut a ~ 7.25” of the L strip to fit inside the tray. This will keep the battery snug, prevent left to right shifting. I drill holes to match to existing on ones.

I used 4 of the 3/8” zinc washers under each end of the L strip, it made it flush.

Some of the referenced parts.

All relative to how you drill the holes in the battery tray and the fender.

Example of the order used for the stilts and supports (a few extra parts used later). The general order was going top to bottom. Bolt, ¼” washer, tray and or aluminum, nylon spacers (some cut in half), ¼” washer, 3/8” washer, ~1.5” strip of aluminum to help disperse weight on fender, neoprene washer to cushion. Under side of fender, ¼” washer and ¼” lock nut.
On the front right, used 3, 3/8” Stainless washers under the tray, then the aluminum. (raised the tray height)
On the front left, used an extra zinc 3/8” washer under the top ¼” washer (reduced the amount of bolt on the underside of the fender)
On the rear left, used 4 extra zinc 3/8” washer under the top ¼” washer (reduced the amount of bolt on the underside of the fender)

Bolts in underside of fender (extra washers from above remove the excess sticking down)

Tray mounted

Battery mounted and tied with the battery strap, no movement, totally solid.

Part 2 – The Wiring


20Amp mini fuses - Littelfuse MIN20BP MINI 297 – Amazon $3.14
Fuse Holder - Littelfuse FHM2BP MINI In-Line Fuseholder – Amazon $5.39
ANL Fuse holder - Raptor RGFHW-ANL Rose Gold Fuse Holder ANL 1/0 In and Out – Amazon $11.35
ANL 250amp Fuse - DB Link ANL250 250 Amp ANL Fuse – Amazon $4.99 Amazon Total $38.13

4 pack Screw on 1g ring terminals - Lightning Battery Cable Compression Fittings – jcwhitney $25.99
S&H $6.99
JCWhitney Total $32.98

Battery Cable Cutter - CHANNELLOCK 911 – Summit Racing $19.95
Battery Cables & terminals - Summit Racing SUM-G1208 – Summit Racing $79.95
Solenoid - Painless Wiring 40112 – Summit Racing $91.95
Heat Shrink - Taylor Cable 41056 – Summit Racing $6.99
S&H $11.95
Summit Total $210.79

Grand Total No Switch $~302 (including battery tray) I’m sure it can be done for even less.

Switch DPDT - VJDJD66B-00000-000 – OTRATTW $9.00
Switch Lense - VVASC2J-100 – OTRATTW $3.


Ratchet set
Deep sockets for ratchet
Heat Gun – for shrink tube
15mm wrench - for twisting the ring terminals
Vice – Used for holding wire when threading the ring terminals
Allen wrench - for fuse holder
Wire Cutter
Wire Stripper
Wire Crimper

8mm x20mm Stainless bolt
2 - 6mm x 20mm bolt,
4- 3/8 washers and one
2 - 6mm lock nut
6mm x 45mm Stainless bolt
16 gauge wire

A pic of the parts

I started with the placement of the Solenoid. On top of the driver side fender was perfect, the existing holes were an added bonus.

I used one 6mm x 20mm bolt, 2- 3/8 washers and one 6mm lock nut on each side. Put the ground wire with the ring terminal on it through one of the bolts.

Bolts from underneath the fender

I cut the negative cable to ~28”. Slide one of the heat shrink tubes onto the wire, strip the end so it will fit into one of the ring terminals.

Thread on the ring terminal

Slide up the heat shrink tube and use a heat gun for a nice fit

Make sure to have the battery terminal and the ring terminal parallel.

Pull down the flap under the passenger side wheel, there is a threaded unused hold in the frame, clean it out with a pipe cleaner and some liquid wrench. This bolt shows the location, it is a 8mmx 20mm stainless.

The cable mounted to the frame

Looking down from above, the cable is far from the exhaust and engine.

The battery terminal covers don’t fit over the crimp, I sliced the bottom and zip tied it on the negative terminal of the aux battery.

Install the supplied wire clamps onto the metal posts, use 6mm locking nuts to hold them on, there are six posts.

The next cable is the positive, disconnect the negative cable on the aux battery. I cut the positive cable, from the tip of the terminal to ~11.5”

Put the 250A fuse into the fuse holder, strip the end of the positive cable and place it into the fuse holder. Make sure the fuse holder is perpendicular to the battery terminal.

I test fit the fuse holder into where it is going.

The cable is going to hold up the fuse holder with easy, but it could vibrate against the body, I cut strips of Velcro and placed them on the feet. I didn’t attach the adhesive until I was done.

Strip the end of the spool of positive battery cable and connect it to the other end of the fuse holder, place everything where it is going to make the next measurement, run the cable along the body to the solenoid and make the next cut, make sure to account for the length of the ring terminal. This piece was ~ 58”. Slide a shrink tube over the and end screw on another ring terminal.

Here is the entire cable run from the battery to the solenoid.

Now measure a piece of cable to go from the other terminal on the solenoid to the main battery positive terminal. I cut a piece ~ 19”

Slide a heat shrink tube on each end then screw on a ring terminal to each end, the terminal should be parallel. Attach both ends. Notice I bought a large bolt for the battery terminal, I couldn’t fit everything on the stock one, I use a 6mm x45mm stainless.

I cut the cover for the positive terminal of the aux battery as I did for the negative and zip tied it on.

The small terminal on the solenoid activates the solenoid, attach a wire, 16 gauge with a ring terminal and run it through the firewall and into the cab. The white wire in the pic.

Attach a ring terminal to a wire, 16 gauge to the large terminal on the solenoid that the wire from the aux battery attaches to. This wire will provide power to the switch for “jump mode” and active the solenoid. The red wire in the pic.

Attach a fuse holder to the wire, place a 20A fuse and then run it into the cabin.

Pic of the firewall

Pic of the firewall from inside the driver side foot well, under the dash.

Reconnect the negative cable on the aux battery

The wiring for the switch will be a follows. I used a switch from OTRATTW.

-The white wire was attached to the “power out” or “out to relay”
-The red wire was attached to one of the “power in” for the switch, depends on which position (up or down) you want the “emergency mode” or “jump mode”.
-Another wire is attached to an add a circuit mini to a fused slot in the fuse panel that is active when the ignition is on, this was attached to the other power in for “Normal mode”, both batteries are connected for use and charging.
-The middle of the switch, neutral, no connection is the “off mode”, the aux battery is not connected. You should leave the system like this, so you can’t possibly drain both batteries. Use normal now and then to keep a good charge on the aux battery.


Fuse Panel for switch wiring