DC - DC Charger Project

[Jlawles2]

Yoda Keith, I would not drill it on the battery. If something goes wrong in the drilling (bit hits battery, or other random thing) you are potentially opening up a whole lot of other things that can go wrong. I would only disconnect the one terminal to do the drilling. It's much easier to deal with one thing that you can control. One lead will still retain everything in the truck. Also use a stepped drill not a twist drill as it does a better job in thinner metals with less chance of grabbing the metal.

Let me ask, have you considered following the battery leads to see if there is a junction point? If the junction point is a bolted connection, simply tap in there. WHY? B/C the battery cables are designed to deliver over 400 amps to the starter when cranking the truck. Once the truck is started, amperage through the system drops by that amount. This will keep you from having to alter select items in the truck. You may even be able to tap into the stock wiring just before the MEGA fuse (don't own or have access to one of the newer fords).

Just my thought on how / where to tap into the wiring. Use the information as you please.

[Yoda]

Hi Keith,

With reference to your question in post #173 . . . I have the same wheel well liner, so can't see any more than what is in your picture.

You have correctly identified the engine compartment end of the pass through harness. (red arrow on your picture to confirm for others) This is ridiculously short to connect to (what was Ford thinking ). I could not get any of my wire connector crimping tools to this short harness, so had to revert to (rather crudely) soldered connections covered with double layers of heat shrink. This harness has three reasonable gauge (16 or 18) wires and one very small one. I extended the connections to the three, but am only using one for my dash cam at the current time.

To find the inside end of this harness will likely take more disassembly than just opening the fuse panel door as shown in the owner's manual. In the other picture, the kick panel is pulled and the end of the pass through harness has green tape added by my dealer for identification.

BUT . . . for your DC-DC project, you do not have to come through the firewall. The wiring from the upfitter switches to the relay box is already in place. All you have to do is go from the relay box harness (a little more accessible once the box is released from its tabs) to your relay. All underhood.

Rob

Thanks Rob on where the other end of the pass through wires are. All I had done was open the kick panned access door, so it good to know the whole panel can be loosened.

ncitro Hogdrv Thanks for the tip on the cross over

Jim your picture of the battery in post 177 now has me thinking. I distinctly remember the cable connections being bigger on the passenger side, then the drivers side. Also the alternator power is delivered there too. I think I need to investigate further. For my 60A charger I may need to do the connections on the passenger side as the cross over wire is considerable smaller than what I an using. I believe I have enough cable as I ordered a bit extra. Maybe that is why there is no post on the drivers side as that is the aux battery, not the primary.

Thanks folks

Keith

[Hogdrv]

Yoda
Keith, I just don’t have the conejos to drill anything on my new truck! I used this setup to attach the positive wire with a fuse and in the bed I used one of the drain holes by the tailgate. I also use my Anderson connection not only for the dc-dc but for my viair compressor and in the future to run a water pump to transfer water from a 60gallon bag to the 5th wheel.



Jim

[Yoda]

Yoda Keith, I would not drill it on the battery. If something goes wrong in the drilling (bit hits battery, or other random thing) you are potentially opening up a whole lot of other things that can go wrong. I would only disconnect the one terminal to do the drilling. It's much easier to deal with one thing that you can control. One lead will still retain everything in the truck. Also use a stepped drill not a twist drill as it does a better job in thinner metals with less chance of grabbing the metal.

Let me ask, have you considered following the battery leads to see if there is a junction point? If the junction point is a bolted connection, simply tap in there. WHY? B/C the battery cables are designed to deliver over 400 amps to the starter when cranking the truck. Once the truck is started, amperage through the system drops by that amount. This will keep you from having to alter select items in the truck. You may even be able to tap into the stock wiring just before the MEGA fuse (don't own or have access to one of the newer fords).

Just my thought on how / where to tap into the wiring. Use the information as you please.

Joseph
Very timely as I am going to take a hard look at the passenger side battery area again today and take a few more pictures. I believe you are correct on there being a primary junction box. Its front and center with lager battery cables running to it. I just need to figure out how the cover comes off. It may be where the aux battery cable comes across and ties in.

I am going to go slow on this and test fit everything before changing anything - including any drilling. Thanks for the tip on the step bit. I have a set somewhere.

Keith

[Yoda]

Yoda
Keith, I just don’t have the conejos to drill anything on my new truck! I used this setup to attach the positive wire with a fuse and in the bed I used one of the drain holes by the tailgate. I also use my Anderson connection not only for the dc-dc but for my viair compressor and in the future to run a water pump to transfer water from a 60gallon bag to the 5th wheel.



Jim

I have that same fuse based on your recommendation before and if I end up on the passenger side I wont need to drill and tap anything. I did get the bulkhead fitting for the bed, but may do as you did for the initial set up. I too am planning on using that connection for my air compressor.
Thanks again

[ncitro]

Yoda FYI I recess mounted my bed connector next to my seven way connector. I got it here:

https://www.etsy.com/listing/7780785...anderson-sb120

[ncitro]

Yoda Here's some photos, I like the way it finished out.

[WondersAwait]

I just don’t have the conejos to drill anything on my new truck!

I just finished drilling/cutting out an opening for a flush mount like Neils pictures above, and oh my this is the truth; I had such a difficult time mentally making a cut into the bed of my new truck. I took it slow though and very happy with how it's turning out.

[Yoda]

Yoda FYI I recess mounted my bed connector next to my seven way connector. I got it here:

https://www.etsy.com/listing/7780785...anderson-sb120

Thanks Neil
That's the one I got. and I plan to install in the same place. Folks were great to work with - quick email response. Shipping took forever. I think it came by boat and then got hangup in customs.

[ncitro]

Thanks Neil
That's the one I got. and I plan to install in the same place. Folks were great to work with - quick email response. Shipping took forever. I think it came by boat and then got hangup in customs.

That's right I couldn't remember if we talked about it. Mine took forever too.

[Yoda]

Ok here we go. First Caution! when crawling under the truck watch your head.

I know think I have this figured out.

First is what I will call the positive combiner box.
This box is on the passenger side right next to the battery. The second battery cable on the left comes from the drivers side from what I can figure. While I got the cover loos it cant be removed without disconnecting the cable from the battery. It also appears the power feed from the alternators comes into the bottom of the box too.
Te left smaller purple wire runs over to the alternators. I have two on the truck. I am not sure where the center red wire goes - possibly to the starter. At the bottom left you can see the cable from the passenger side battery and hidden behind left the cable from driver side battery.

As you can see the alternator power appear to be the cable labeled AE.

[Yoda]

Now lets trace the drivers side battery cable path.

The positive and negative enter a loom and are directed downward in a plastic housing.


Down towards the engine the positive wire goes left behind the drivers side alternator and crosses over as best as I can tell. This appear to be #2 battery cable and is the sam size as what I fond on the passenger side battery.

[Cate&Rob]

Maybe that is why there is no post on the drivers side as that is the aux battery, not the primary.

Hi Keith,

You may be on to something with this theory . . . there has to be a reason (other than saving 2 cents) that Ford would not put an aux attachment post on the driver's side battery. Tagging howson Howard on this since I know that he came off the passenger side battery and brought the cables down that side of the truck.

Rob

[Hogdrv]

I brought the cables down the driver’s side because of the exhaust and I had a place to mount the solenoid, passenger side too busy no room for it.

Jim

[Yoda]

howson ncitro Cate&Rob Hogdrv WondersAwait Jlawles2 did I forget anyone?

So after looking at this and finding the bracket to mount the solenoid has easy access I am still going to add a power stud to the drivers side positive battery terminal and run power from there. Ford cables appear to be #2 so the feed across in the stock wiring to the second battery should not be an issue. Whats nice is the main cable loom with Fords wiring runs down the drivers side so plenty of good places to tie up the #2 bundle of feed lines to the bed.

So advice please - am I looking at this correctly? Drivers side will be much cleaner and I will only need to run one small wire across the back from the up fitter switch box.

Thoughts?

Thanks Keith