T-Max Dual Battery Install (2 Viewers)

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KlausVanWinkle

KlausVanWinkle

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T-Max / IBS Dual Battery System Install Guide

It took me a long time to wrap my head around everything needed to install a dual battery system. I tried to compile a step by step how to guide to make it easier for others. Thanks to SanDiegoCruiser for the help and DomSmith for the crimper and cable making lesson.

TOOLS:

SUPPLIES:

The project could be a lot cheaper if you chose a thinner gauge cable because smaller gauge terminals, heat shrink and crimping cutting tools are cheaper too.

You don't necessarily need to use the in-line 200 Amp fuses. The instructions don't call for them. But the national luna kit does include them. The idea is that if the solenoid craps out, or if there is a short in one of the positive cables, the fuse will blow, preventing a fire. The 200amp fuse is sturdy enough to allow for self jumping. The fuses should be placed as close to the batteries as possible.

For the green cable, you can use the in-line fuse holder that comes with the T-max kit, but I chose to use a heavy duty weather proof one instead.

The T-Max kit comes with most of the cable you'd need but it's only 6 gauge black cable. I chose to go with 1/0 gauge to allow the headroom for a future inverter and winch.
 
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This is how I wired my system. It's a little simpler than the diagram that T-Max/IBS recommend.

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This is T-Max's tiny wiring diagram:

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They have the wiring harness's tiny blue, red and black wires running all the way to battery terminals. I only connected the black cable directly to the negative auxiliary battery terminal. Instead of connecting the tiny red cable to the starter battery's positive terminal, I just connected it to the end of the new positive battery cable at the solenoid post. Same idea for the blue and cable.

Okay, lets get started.

First, install the Slee Dual Battery Tray according to the instructions.

I mounted the battery with the negative terminal closer to the firewall.

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The mounting holes for the T-Max Solenoid line up perfectly with the 2 bolts that hold the Slee Tray to the lower wheel well. Unbolt these bolts and place the Solenoid underneath the little tray on the Slee Battery Tray. Then bolt everything back together.

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(this picture was taken after hooking up all the cables and is just to reference the location)

Before creating any new cables, plan how to route the new cabling.

I chose to start with the primary/starting battery. It was kind of dirty so I used battery terminal cleaner before starting.

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Using the uncut spool of red 1/0 cable, route the cable from the main starter batttery's positive terminal (don't actually touch the terminal) to where you plan to mount the 200 Amp In-Line Fuse Holder. Mark the length on the cable with a Sharpie and cut the cable with heavy duty cable cutters. Before moving to the next measurement, labele this piece of cable "Red Main #1."

Proceed to do the same for the "Red Main #2," running from the in-line fuse holder around the firewall to the #1 Post of the Solenoid.

Next, use the black spool of 1/0 cable to run a cable from the main battery's negative post to the negative post of your aux battery. I chose to have mine follow the route of the positive cable. Label as "Main 1."

I decided to create a better ground cable from the main negative terminal to the body of the truck. Measure the distance, cut and label the cable "Main 2."

I decided to create another heavy duty ground from the PS of the truck body to the Aux battery's negative terminal ("Aux 1"). Do do this, I utilized one of the extra bolts from the Slee Battery Tray to secure the ground to the body of the truck near the PS upper fender dual battery tray mounting bolt. Make sure to sand some of the paint off from around the hole you're going to use in order to get a good connection.

Next, use the red spool to measure out cable from the Aux Battery's positive terminal to the mounting location you choose for your other 200 Amp in-line fuse holder. I mounted mine to the side of the Aux battery but will probably change this in the future. Cut and label as "AUX 1."

Next, measure out the cable "Aux 2," from the in-line fuse holder to post #4 of the Solenoid. I routed mine down under the power steering fluid reservoir then looped up to the solenoid.

You should have 3 black cables if you chose to create additional body grounds.
And 4 red cables if you chose to use the 2 in line fuses.
 
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Time to make some cables. This is cable making 101. So if you've done it before, feel free to skip this.

Take each of your cables and measure out how much cable insulation to cut off to accomodate your terminals/lugs (known as terminals from this point forward). I placed the terminal next to the end of the cable and marked where to start stripping the insulation with a sharpie.

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Using a cutting board and utility knife, carefully cut through the insulation, being careful not to cut into the metal. If you have giant wire strippers, that would work better. I rolled the cable while keeping the utility knife in place to get a good cut.

Then, pull off the insulation you cut off and fit the terminal over the cable's end, double checking that you have a good fit. You want the cable to stick as far into the terminal as possible without creating a gap between the insulation and the end of the terminal.

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To keep the terminal on the end of the cable temporarily, use a small piece of electrical tape. This will come in handy later.

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Do this for all your cable ends.

Next, measure out however much heat shrink wrap you want t use for each terminal. I used 1.5 to 2.5 inches depending on how long the cable was. Cut the heat shrink wrap with the scissors and place it on the cable to keep track of it.

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Because the terminals were completely closed on the ends and I was using self adhesive marine grade heat shrink tubing, I opted to just crimp and not solder the terminals on. It's up to you.

Battery cable this thickness isn't super flexible. So don't crimp on the terminals yet. Figure out the orientation of the terminal on the end of each cable before crimping first.

If you have covers for the aux battery terminals, this is as good a time as any to install them on your Red Aux #1 and Black Main #1 cables. Mine were $5 from West Marine. I had to cut them to get them to fit. This is where labeling your cables comes in handy.

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The jump cable that comes with the T-max seems dinky compared to the 1/0 cable used else where. So I opted to use the 6g cable and provided terminals to create a more heavy duty one. I used the self adhesive heat shrink tubing variety pack instead of the non self-adhesive shrink tubing that came with the T-Max.

Similarly, the inline 30amp fuse holder for the T-max wiring harness's green cable is pretty dinky. I a heavy duty, weather-proof 30amp fuse holder instead.

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I soldered/crimped this on to the end of the green cable and covered it with the smaller diameter self-adhesive heat shrink wrap tubing. The end of the green cable is now orange.

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Place a piece of heat shrink tubing on the end of the orange cable. I stuck some dielectric grease in the terminal for weather proofing before crimping. Then, crimp on the smaller sized terminal from the t-max kit. Then, use a heat gun to shrink wrap the connection. Plug the 30amp fuse into the holder and place the spare fuse in your truck.

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Placed a piece of heat shrink tubing on each of the cables in the T-max's wiring harness. Using the 5/16" terminals that came in the T-max kit, crimp them onto the ends of the blue, black and red cables. Then use the heat gun to shrink wrap them.

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At this point my assistant was sleeping on the job (rabbits sleep with their eyes partially open, but their noses stop wiggling).

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All my cables are ready to go back outside to be oriented and crimped.

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Cable making continued:

I didn't get any pictures of this, but...

Next, take your cables outside. Place them in the engine bay the way you plan to route them. Figure out how the terminals will have to be oriented. Unstick the electrical tape, then restick it at the correct orientation.

Place the terminal in your crimper and crimp the terminals on the end of each cable at the correct orientation. The cables should not slip out of the terminals when pulled on. Since I was using a hammer crimper, I had to use the 0, 1 or 2 size slots to get a good crimp. When crimping, try to keep the cable in the terminal as tightly as possible, with no gap between the cable insulation and the end of the terminal.

Next, use the heat gun to heat shrink wrap the terminal/cable connections.

The adhesive is nice and forms a water tight seal on both ends.

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Have a friend inspectyour heat shrinking for quality.

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Installation:

We'll start with routing the T-Max's wiring harness through the firewall. A lot of people mount their battery monitor on the dash. I don't see the point, don't like a lot of extra stuff on the dash and only plan to check it once in awhile. So I mounted mine insid the glove box. Regardless, this seems to be the best firewall pass through point.

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First, unclip the the stock wiring harness to get better access to the firewall pass through we'll be using. Removing the aux battery from the tray while you do this part gives you more room to work.

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Place the battery monitor in the cabin.

Route the the T-max wiring harness through the firewall into the cabin.

To make your life easier, use a tiny flat head screw driver to press down on the little tabs on the end of each wire inside the white connector.

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While pressing down, pull the each cable out of the back of the white connector. Hold onto the white connector.

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I taped the 4 wires together but in retrospect it wasn't necessary.

Pull out the rubber boot with the white dot on it that the factory wire harness runs through.

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Use scissors or a knife to cut a small slit in this rubber boot by the white dot. Slip the 4 wires through this small slit into the cabin.

Inside the cabin in the passenger foot well, unbolt the glove box by removing the two bolts on the hinges at the bottom of the glove box.

Then, unbolt the black plastic cover, 3 bolts IIRC.

Disconnect the light switch cable. Then, unbolt the engine control module, 3 or 4 bolts.

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You should now be able to see the hole in the firewall where you removed the rubber boot. Grab the T-max wiring harness cables and pull them through the fire wall.

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Using the tiny screwdriver, press the metal tab you compressed back out, then look at the wiring on the battery monitor to make sure you put the right color cable in the right slot of the white connector. Hold off on clipping the wiring harness into the Battery monitor until you're done. Reassemble the glove box.

Stick the rubber boot back into the firewall. Cover the hole that you ran the t-max wiring harness through with some di-electric grease or otherwise reweather proof it. Clip the factory wiring harness back into its clip on the firewall.

I'm going to cover these dainty t-max wire harness cables with some braided loom.
 
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Next we're going to hook up all the 1/0g battery cables.

Disconnect the positive cable from main battery to prevent you accidentally starting a fire or electrocuting yourself while routing cables. Remember to never touch a positive and negative terminal at the same time. We're going to attach to the positive battery terminals last.

I covered all my connections with the Di-electric grease.

Connect the Black Main #1 cable to the negative terminal of the Main Starting battery. Route it however you planned to the negative terminal of the Aux battery.

Then, connect the Black Main #2 cable to the Main Starting Battery's negative terminal and to the factory body ground bolt on the DS fender.

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Then, connect the Black Aux #1 cable from the negative Aux battery's negative terminal to the grounding bolt on the passenger fender.

While you're at it, connect the black cable of the T-max wiring harness to the negative terminal of the Aux battery.

Moving on to the red cables:

Insert the 200 Amp fuses into the two inline fuse holders. Then bolt the inline fuse holders between the Red Aux #1 and Red Aux #2 cables. Do the same between Red Main #1 and Red Main #2.

I used a zip tie to keep the fuse holder covers closed. I covered the connections with di-electric grease.

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Route your long Red Main #2 cable. Connect the end of Red Main #2 to the appropriate stud on the T-Max solenoid. While you're at it connect the thin Red cable from the T-max wiring harness and the short jumper cable to the same stud.

Then, connect the other end of the short jumper cable (yellow in my wiring diagram) to the appropriate stud of the solenoid.

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Next, route the Red Aux #2 cable. Then connect its end and the thin blue T-max wiring harness wire to the appropriate stud on the solenoid.

Next connect the end of Red Aux #1 cable to the positive terminal on the Aux Battery.

Then connect the end of the Red Main #1 cable to the positive terminal of the main starting battery while reconnecting the factory positive cable to the main starting battery.

Connect the battery monitor to the t-max wiring harness. If you havent' shocked yourself or started a fire yet, congratulations. When closing the hood, make sure that your hood doesn't touch the either positive battery terminal.

This is how I routed my cabling:

I utilized rubber padded cable clamps attached to the factory bolts that hold the brake lines and wiring harness to the fire wall. I need to go back to homedepot to get some more of these.

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In the future, I'm going to wrap all these expensive new cables in some quality looming and maybe make the Red #1 cables a little longer to give my routing a little extra slack. These short cable can be reused when I install the circuit breaker and fuse box on the Slee Battery Tray shelf.

In the future I'm going to run 1/0 red and black cable to a fuse box in the rear cargo area, running it on top of the frame rail and the into the cabin. the heavy duty cable will be great for a future inverter and solar charging system.

Other changes in the future: replacing the starting battery with a Group 35 Yellow top or Die hard platinum. Only driving the 100 once a week is killing the 3 year old starting battery. At the same time, I will upgrade the battery clamp terminals on the new starting battery to military style.

How it ended up:

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Hi-Res:

http://farm9.staticflickr.com/8003/7624078190_be979cc966_o.jpg
 
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Sweet!

Very well written as electrical is not thing, so I can actually understand it.

Shane
 
great write up ! I need to finish my install and this will help ! I should have my other wiring here this week including another aux plug for the back..
 
Nice work but what did you spend on your system vs purchasing a system with cables ready to go?
 
Gottagetone said:
Nice work but what did you spend on your system vs purchasing a system with cables ready to go?
Click to expand...

$400 not including battery or tools.

It could definitely be done cheaper, I just opted for higher grade or thicker cable every opportunity I had.

But I still have 11 Terminals, and 10-15ft of cable, and a lot of smaller sized heat shrink tubing, and 95%the T-max 6g wire and lugs. So I still have enough supplies leftover to run 1/0 gauge to the rear cargo area and wire up all the fuse boxes, etc.

Pre-made battery cables would probably be cheaper but I don't know how you'd get the custom lengths for the cruiser's engine bay.

Maybe you could repurpose some jumper cables to save money? Amazon.com: Heavy Duty Booster Jump Cable - 6 Gauge X16 Ft: Automotive
 
no-pistons said:
Now only if I could get my little guy off his lazy butt to help me...
Click to expand...

What is that?
 
Custom Battery Cable

KlausVanWinkle said:
Pre-made battery cables would probably be cheaper but I don't know how you'd get the custom lengths for the cruiser's engine bay.
Click to expand...

I have had good luck in the past dealing with these folks for custom cables Genuinedealz . They use marine grade cable and ship relatively quickly.

Found them on fleabay ...
 
Nice write up.
 
^^ what he said!

Wow - with this write up and pics, I might even be able to get this done.

Thanks.
 
4 gauge is perfect for this application. 1/0 gauge is overkill IMO.

KlausVanWinkle said:
Pre-made battery cables would probably be cheaper but I don't know how you'd get the custom lengths for the cruiser's engine bay.
Click to expand...

I've made hundreds of grounding kits back in the day for the Lexus community and still have quite a bit of supplies left.

If anyone is looking for either raw materials - 4 gauge cabling, or custom made terminated lengths of cable, feel free to PM me. I'm sure i can get you something for more than a reasonable price so I can get rid of my stash of spools of cable. I probably have 500ft left in various colors.
IMG_1157.jpg
 
this is a very nice writeup, I'll put it in the FAQ. It's very nice to be able to see what one needs to do, especially with good pics.
 
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