How to connect power for amps. inverters and other high current loads

[Don Ridley]

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

Important notes:

1. 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.

2. 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. 

3. 

4. 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.

[103west43rd]

Don, Terrific posting!

[Beta Don]

I agree  -  Great post and very well documented, as always

This will help many of us do a more professional job of adding high current accessories in our TC's.  I've been wanting to install a 500 watt inverter so we can recharge our two Segways and wasn't really eager to take the car apart to find what would fit and where . . . . and what size wire I needed to use

Thanks Don!

Don

[Don Ridley]

I forget to add that I wrapped the cable with Tesa wire loom tape. This stuff is strong and helps pull the cable under and through things. 

Tesa's Most Advanced High Heat Harness Tape 51036 Mercedes, BMW, Audi, VW https://www.amazon.com/dp/B01I2MLN2Q/ref=cm_sw_r_cp_apa_zWL5yb4JATNJH

I found it cheaper on eBay.

[Beta Don]

Don,

Is there a 'quick and easy' way to get a 4 gauge wire from the BJB to the back of the van?  I would like to install an inverter in the opening panel at the rear on the drivers side.  I'm thinking a 750 watt inverter, though I would likely never draw more than 300 to 400 watts from it.  A 4 gauge wire with a 60 amp fuse for the positive should be all I'd need  -  I can ground the negative lead of the inverter to the chassis near the inverter

Don

[Don Ridley]

Routing #4 cable to the back in your wagon will take 3-4 hours but it is not too difficult.

1 remove the rear side panel. Start at the jack storage opening. Take your time on each clip.The "pillars" on top snap onto the main panel.... Carefully disconnect these. This process takes patience and some strong fingers.

2 Remove the bottom threshold on the side door.

3 Fish/pull the cable through the rear passenger foot well under the carpet.

You could run the cable in flex, plastic conduit on top of the carpet. Look at the light blue plastic conduit at Home Depot.

http://m.homedepot.com/p/Carlon-1-in-x-25-ft-ENT-Coil-Blue-12008-025/202688856

[Beta Don]

Thanks!  -  Man, that's some expensive conduit.  I bought a 25' coil of super flexible red #4 Stereo power cable on eBay for $15 with free shipping.  Don't you hate it when the plastic tube to protect your expensive cable costs more than the cable itself? 

Don

[Beta Don]

Quote

Is there a 'quick and easy' way to get a 4 gauge wire from the BJB to the back of the van?

Yes, as it turns out, there is!    -  And it doesn't take 3 or 4 hours

I managed to do it without removing anything.  I pulled up the lower portion of the rubber door seal around the drivers side sliding door and looking in the crack, I could see the light above the jack storage compartment  -  I found a straight shot back to the jack compartment without removing any of the panels.  It looked like there would be enough room to tuck the #4 cable under the bottom plastic threshold below the door without removing it, so I gave it a try

I poked my cable back into the jack compartment and began working my way forward, tucking the cable under the plastic threshold and replacing the rubber door jamb seal as I went.  I removed the lower part of the door jamb seal from the drivers door and pushed a fish wire between the drivers door and the sliding door, taped my #4 to the fish wire and pulled the cable around the door post into the threshold of the drivers door  -  Buttoned up the door seal on the rear door

Repeated this same procedure, tucking the cable under the threshold of the drivers door and replacing the seal.  Found an easy exit for the cable just above the hood release lever and pulled the cable out there.  It's just above the kick panel, right behind the OBD jack under the dash.  So, I got a #4 power wire from the drivers kick panel area to the rear jack compartment in the back in about 20 minutes.  The cable is tucked in tight everywhere, so there should be no rattles

It truly was 'quick and simple!'  -  Now all that remains is getting it through the firewall and into the engine compartment where I will hook it to my 80 amp fuse.  I found the fuse and in-line fuse holder on eBay for $7

Don

Edited April 11, 2017 by Beta Don

[Don Ridley]

Nice! 

[Beta Don]

A small note for clarifaction   -  Don's last photo (of the firewall knockout) is taken from inside the car, looking up and to the left of the brake pedal and not from under the hood like the other photos.  If you drill your hole in the plastic knockout in the lower left corner (looking under the dash facing forward) the cable will be routed alongside the battery box when you put it back in.  I cut an 'X' hole in the padding removed from the inside and routed the cable through it so that sound insulation could be put back over the knockout

I armored my cable under the hood with 3/8ths protective wire wrap, Item # 66987 from Harbor Freight, $2.99  -  It's a perfect fit for a single #4 cable.  I tied the cable doown with cable ties so it can't move and rub against anything

A note for the not so capable DIY'ers  -  When your Gen 2 battery dies, buy the new battery from someone who offers 'Free Installation' . . . . if you watch them install it, you'll surely thank me after 

Don

[dbv]

When you ran that cable to the back for power, did you run a ground return with it?  I've seen problems with vehicles that have rear heat/cooling where corrosion was caused apparently by residual current in the fluids. 

I hear you on the battery installation. A friend has a car where you have to remove a frame member to get the battery out.  That car always draws blood for any service.

 

I don't anticipate going that far, I'm still trying to find the right place for the control heads, but it's likely my radios will live under the front seats.  I always run power and ground though, and I fuse both. I set the fuses appropriate to the load, and the wire well beyond, so that there's no possibility of fire if something goes wrong.

 

[Don Ridley]

dbv,

The chassis is a proper ground, especially in a newer vehicle. A separate ground wire only increases the voltage drop. You also don't want to fuse the negative or ground leg. The + fuse at the battery protects all the wiring and it could be a problem if the ground leg opens while the + is hot. In high voltage applications this would be dangerous. Here it may only cause you to touch 12V.

[Beta Don]

Yes, on the TC the negative battery cable is only about 6 inches long.  It runs from the battery to the nearest point on the chassis and bonds there.  There is no negative cable from the battery to the engine block, or from the battery to any other high load application.  Every negative in the car is a short cable direct to the unibody chassis . . . . and there are literally hundreds of them  -  Negative connections take up several pages in the car's book of wiring diagrams

I've already scoped out the place near the jack where I'll bond the negative for my inverter

Don

[Beta Don]

Since I already had the battery out, and since it's already 3+ years old, and since it's so doggone difficult to get at . . . . and since I'm hooking up a high current load which will need to run off the battery when I stop for gas or to eat lunch, it only made sense to replace it with something better.  Ford has chosen to use 'Ford sized' batteries in all their newer vehicles which I suspect was done to try and enhance battery sales at the dealerships.  Our battery is a 'BXT-96R' which doesn't seem to exist anywhere but from Ford  -  Granted, you can buy a few 'equivalent' size replacements elsewhere

Anyway, I wanted a higher capacity battery and I wanted an AGM, so after a good bit of research I settled on a Duracell Group 48 (H6) AGM from Sam's Club  -  $159.99.  It has a 20 amp hour rate of 70 (3.5 amp draw for 20 hours) and much better specs than the OEM battery and it's made in the USA.  3 year free replacement  and a 5 year pro-rated warranty

• Battery Electrolyte Composition: Glass Mat
• Battery End Type: Top Post
• BCI Group Size:48
• CA at 32 degrees F:875
• CCA at 0 degrees F:760
• Polarity: Right Positive
• Reserve Capacity:120

The BXT-96R has only 500 cold cranking amps

It's *almost* a drop in replacement for our OEM battery.  It's about 1/2 inch taller, but fits in the battery box OK and you can even use the OEM hold down clamp if you remove the rear battery box spacer so the battery can slide back just a little to center the battery on the hold down studs.  Then the clamp fits OK if you raise (or remove) the lifting handles that come on the battery  -  They fold back down after the clamp is installed, so you don't have to remove them

If you intend to run high current accessories for even a short time with the engine not running, an upgrade to a better battery is probably a smart move . . . . especially if your current battery is 3 or 4 years old

Don

 

[Don Ridley]

Replacing the battery in the 1.6L TC is worse: the dealer has to reset the battery monitor. This function controls power so you can't run the battery dead...Or so they claim. Maybe someone knows a way to reset this without having Ford hardware and software.

[Dandytc]

The video posted by rectalogic (forum member) yesterday on another thread, shows the mechanic using a battery tender to avoid losing data and memories.

 

[Beta Don]

A couple observations after completing this.  Don mentioned that "You will have to cut some cable ties holding the cable on the front of the BJB."  I cut them too, but I think if I was going to do it again, I would just pry those three ties out and not cut them.  They are special cable ties which mount in a hole and I'll have to source some replacements for them  -  Likely from Ford.  I can't imagine that when a Ford dealer replaces a battery (you would need to remove them for that too) that they're cutting and replacing these . . . . maybe they are, but if you just pull them out of the hole, you can just put them back when you're finished

I needed a big #4 wire for my inverter install in the rear of the van  -  The cable is more than 15 feet long.  If I was installing amps or radios, especially if they're in the front of the van, I would use a smaller wire.  Certainly a #6 would suffice, but probably a #8 would be large enough to support 30 or 40 amps if the wire was only 6 or 8 feet long.  Getting a #4 wire in the BJB isn't a simple thing and it would be oh so much easier if it was a #6 or a #8

Don 

Edited April 15, 2017 by Beta Don

[Don Ridley]

Sorry, I forgot I ordered some special cable ties.

https://www.amazon.com/gp/product/B01M07A8CN/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

https://www.amazon.com/gp/product/B011LYJXXS/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1

The ones with the cable tie attached come from China so delivery takes a while. The other ones are Amazon Prime and should work.

 

[DonShockley]

7 hours ago, Beta Don said:

.....  They are special cable ties which mount in a hole and I'll have to source some replacements for them  -  Likely from Ford.  .....

Don 

If these look like what you mean, and the post size is about right, I can hook you up with a couple free. I have leftovers from when I did my project. But I did have to find the right size existing holes in the bodywork to use. IIRC I got them on eBay because I'm not seeing them in my Amazon history.

 

[Beta Don]

Thanks for the offer.  Those are a bit different from the OEM Ford ones because the tie strap can be replaced on those whereas the Ford ones cannot  -  Once you cut them, they're junk

I'll look around on eBay and see if I can find me a package of them to have on hand  -  Gotta be cheaper than buying them from Ford!!

Don 

[Fort Mohave Grocery Del]

This is exactly why I joined this forum! What an excellent post and for exactly what I am wanting to do. I have 2 apartment-size freezers mounted just behind the seats, with a 5000 Watt Inverter bolted to the top secure-plate that holds everything together so it all doesn't kill me in a crash. I have to get at least a #6 charge wire from the engine compartment to the auxiliary battery that will provide the 12v's to the inverter. I had my fabricator make a steel battery box that will hold a group 31 battery, and he welded it all to the frame that secures the freezers. He did just an awesome job. If anyone is interested in pictures, I can take some and post them, if anything, just to show another option of what can be done with these vans.

 

I went by the Ford store where I bought my van to ask about the safest place to go through the firewall, and no one wanted to help me at all. I did a duckduckgo search this morning, and viola, here I am reading what I needed to know.

 

Because the freezers have thermostats, they won't be running at the same times, nor all of the time, so the 5000 Watt inverter is overkill. I have a 3000 Watt running a 5000btu A/C unit in my 1976 F250 just fine. I bought the 5000 only because it is an Aims, and was a few dollars more than the 3000. I'm somewhat of a independent-power junkie.

[Fifty150]

A lot of Transit Connect delivery vans in my area use a rooftop mounted refrigeration unit. 

 

 

 

[Dacflyer]

On my van I am wanting to install some led strobe lights, I was having a horrible time to find an access point, until I read this thread.

On my 2013 TC XLT the access hole under the dash is covered with just a piece of tape, Hmmm.

But when I peeled it back to investigate it, i see 2 oval holes, no rubber plugs.

Would anyone happen to know what the ford part number would be for these plugs ?

 

And also..under the hood, I'd have never have found that access hole, it's practically behind the fuse box. I spent almost 45 min under the van looking for an access, Almost got stuck getting all jammed up in there trying to find a spot.

seems they are making it to where it is almost impossible to put anything thru the firewall..

 

Also with my 2013, what so called Generation is mine ?   I see a lot about gen 1,2,3 etc.

Thanks..

 

 

[G B L]

9 hours ago, Dacflyer said:

Also with my 2013, what so called Generation is mine ?   I see a lot about gen 1,2,3 etc.

Thanks

Yours is a Gen 1. Welcome to the club

Edited October 13, 2019 by G B L

[ten25]

Hey Don, I noticed you mentioned the alternator produces 88 amps at 1800 rpm. Is that referring to the alternator RPM or engine RPM & is that the alternator RPM when you are idling the engine? 

 

PS: Thanks for the informative post.

Edited July 18, 2022 by ten25