Adding an audio amplifier, power inverter or other high current loads requires connecting heavy gauge cable directly to the battery. The Gen 2 TC’s battery is tucked under the front cowling and is enclosed in a covered box so making this connection difficult. Plus, having a big cable bolted to the battery with a big in-line fuse looks amateurish.
There is a professional, safe and easy alternative. The front wall of the battery box holds the high current battery junction box (BJB). This is where all the power is distributed to other fuse blocks and modules in the TC. Remove the air filter housing. The BJB is attached to the front panel of the battery box. This panel lifts up and out to access the battery. Disconnect the (+) terminal and carefully pry open the BJB cover (5 tabs). You will have to cut some cable ties holding the cable on the front of the BJB.
Here is the front of the BJB (air filter housing has been removed)
This is the inside of the BJB. I have already added a cable on the bottom post of the unused slot on the right.
The BJB has 10 circuits from 40A to 150A. The last slot on the right is used for glow plug power (60 amp) for a diesel motor. This slot will be available in all TCs in the United States. Connect your new power cable to the bottom terminal of this or any other open slot. Install the proper size MIDI style Littlefuse brand fuse. Attach with 5mm nylon locking insert nuts. I used #4 AWG cable and this fit with some trimming of the plastic housing. The #4 lug had to be shaved to fit the narrow slot. #4 AWG was overkill in my application.
Remove the battery and battery box. Run the cable into the cab using the plastic square knock-out located on the firewall on the left (driver’s) side behind a perforated cutout in the padding/insulation. You can see the knock out under the master cylinder. I routed the cable under the center console. The console is easy to access by removing 4 screws. You do not need to remove any dash panels if you use an electrical fish tape or other stiff wire to pull the new cable under the short section of carpet and padding between the dash and console. The fish tape will poke out under the carpet near the accelerator pedal. Route the cable to your load.
Plastic knock-out on the driver side firewall
Use the proper size and type of cable. I bought power cable designed for automotive audio amps. This is much different from cable used in homes and buildings (THHN for example). Automotive cable has many more strands of wire and is much more flexible…and expensive. Many of the cheaper offerings will be copper clad aluminum and the gauge may not be true. Use pure copper if you can afford it. My cable was sold by Kicker.
What size cable? Note that the OEM cables in the BJB are #8 or #10 AWG but they are fused at 50 to 80A. This amperage does not comply with the NEC and does not need to. Do a Google search and you will find that you can safely use # 8 cable for automotive, 12 volt loads of 70 or 80A depending on the length of the run. The #4 AWG cable I used can handle well over 150A.
If you are going to run large loads continuously, like power tools or large air compressors, you need to use an external generator. The TC is not a power plant and you should only connect large loads that are on intermittently, like a coffee maker or espresso machine. The standard alternator outputs 88 amps at 1800 rpm (150 amp max), so running the engine may not be enough power for large loads.