2018 400 battery wire routing

cafyrman

Hi all,
I searched around, but didn't find a good answer to a simple question.

Where does the battery wiring get routed to the power distribution center (PDC) from the 40 amp breaker?

I'm diving into some electrical mods that include replacing the 2x6 volt batteries with a big LiFePO4 battery.  So I'd like to run new battery wiring at the same time.

The current (no pun intended) wiring goes from the battery > battery switch > breaker to ???  Under the floor, under the battery, and back to the power distribution center under the closet?  And then from the power distribution center forward to the 7 pin junction block?  That's the best I can tell from feel and sort of a picture shoving my cell phone in the hole.  Picture attached.  Blue circle is where I think the wiring goes under the floor.

Anyone tried to put in bigger wiring to accommodate an upgraded PDC?  If that's the routing, it seems to add a lot of wire, though I get the reason for the switch to be accessible from the exterior.  Is there room to upsize from the 8 gauge to 6 or 4?

Thanks!

Horigan

There is a sub-floor under the bed that is above the main floor. The space between is less than an inch I believe.  The wires run between the floor and sub-floor. The small gap on front of the bed for the Alde register air source is an access to the space. 

I’ve wondered myself how to upgrade the battery wiring. One thought would be to use the original wires to pull the new ones through. I’m sure others will chime in that have done this wire mod. 

pthomas745

Try this thread.  A discussion of wiring and the "false floor".

https://tab-rv.vanillacommunity.com/discussion/14776/three-batteries-in-a-2019-tab400

MuttonChops

cafyrman said:
. . .  current (no pun intended) wiring goes from the battery > battery switch > breaker to ???

Ignoring the extra complication of the False Floor (discussed in early comment links)

Typical 12VDC Power Routing from Battery to Trailer Systems:

cafyrman

pthomas745 said:

Try this thread.  A discussion of wiring and the "false floor".

https://tab-rv.vanillacommunity.com/discussion/14776/three-batteries-in-a-2019-tab400

Awesome. Your Google-Fu is always better than mine on these.

My setup looks a lot like Jeffro or Denny's.  Neither is an exact match, but probably close enough.

As to the diagram above, I'm not sure that makes total sense, but I'll have to dig in to see, I guess.

I found 10 gauge from the junction box to the PDC, but not the line from the battery.  I'm not sure I buy that they ran 8 gauge all the way to the front of the trailer and then all the way back to the PDC, which is in the rear in mine.  Not seeing any 8 gauge in the front compartment with the CoolCat and haven't had time to pull the PDC or junction box apart.

MuttonChops

cafyrman said:
As to the diagram above
. . . I'm not sure that makes total sense, but I'll have to dig in to see . . .

Please let us know what 12VDC Wire Routing from the Battery you find.

Denny16

The battery wires, along with the hot and cold water pipes are routed under the false floor of the rear storage compartment, which is 1:5” above the trailer Azdel composite floor.  There is are two 2x2 strips under the battery location, to take the batter6 weight and distribute it to the trailer floor.  Here is the photo I posted in the discussion referenced above:

Battery cables I believe go under the floor against the front divider on top the plastic angle bracket shown in the photo by the red arrow, or they are just laying flat under the false floor.

The cables gon along the front, under the floor, and through a hole into the Alde compartment, then forward under the closet to the WaCo power converter.  The 7-pin cable comes from the front, under the shower pan, back (aft) to the power buss bars on the outside wall under the closet floor, where it connects to the WaCo power converter.

I believe the battery cables are secured along the way, and doubt you could use the old wires to pull new larger cables.  One approach, is to remove the old batteries, and unscrew the false floor (you will need to remove the rear bunk bedding and plywood panels under the bunk first) to gain access to the wiring from the breaker to where it goes through the bulkhead to the compartment under the closet floor.  

Good news, this is not too bad of a job, and is how I plan to replace the battery cables and AC wires (also running through here to the galley) with larger marine grade cables.  The battery and AC wires I believe, are cabled together with zip ties, which prevents them from just being pulled out.
 Cheers 

cafyrman

MuttonChops said:

cafyrman said:
As to the diagram above
. . . I'm not sure that makes total sense, but I'll have to dig in to see . . .

Please let us know what 12VDC Wire Routing from the Battery you find.

Everything I'm seeing now says that Denny is correct.  I've verified all of that except what it looks like under the sub-floor and whether there's a positive side buss bar or just a negative one.  I can't really tell what's behind the PDC yet, but maybe Denny was referring to inside the PDC itself.

Picture is of the Alde compartment from the perspective of the outside.  Bed is towards the top and closet/PDC to the left.  Second picture is of the back of the PDC showing the negative buss bar.  Which I guess will probably get upgraded as part of this.  Don't mind the dust. I've just figure out that there are openings in the bottom of those compartments that allow playa dust in.

So... if I upgrade to a Progressive Dynamics PD4655V and 4 gauge battery wiring, what size breaker do I need on the main battery connection?  I've already split it off by feeding a Blue Sea buss bar, with one line feeding my 1000 watt inverter (2000 peak) and the other feeding the PDC.  The PDC needs less amperage than the inverter.

Denny16

I would stay with 40 amps, as the TaB has a 40 amp 12VDC wiring scheme, and the breaker should trip before any wires burn.  That said, AWG#4 wire is rated for 95 amps, so you could use a 60 MP breaker on the No 4 cable to battery connection.   This depends on the max load you anticipate drawing from the battery to the Converter.  The Inverter has its own fuse connection to the battery, to cover its higher load.  

I found this photo showing the wire routing u dear the storage area floor: 

The battery cables to converter have been moved (upper right corner) to a new battery location (top), but you can see the other DC and AC wire runs, the battery cables originally followed the other DC wire runs.

Cheers 

Denny16

@cafyrman, a quick tip, the dust you see in the Alde compartment, may be coming from under the closet, where the water lines go to and from the water tank.  There is a large hole in the floor the water filler snd pump hose go through.  This hole goes all the way through the floor to allow access to the top,of the water tank, which is 1-2 inches below the bottom of the trailer floor.  You can plug this with some foam and a cover sheet, but this needs to be something you can easily remove, if the water tank needs servicing.
 Cheers 

cafyrman

Denny16 said:

I would stay with 40 amps, as the TaB has a 40 amp 12VDC wiring scheme, and the breaker should trip before any wires burn.  That said, AWG#4 wire is rated for 95 amps, so you could use a 60 MP breaker on the No 4 cable to battery connection.   This depends on the max load you anticipate drawing from the battery to the Converter.  The Inverter has its own fuse connection to the battery, to cover its higher load.  

I was thinking more about the higher charging ability of a lithium and PD4655V.  But yes, I think 60 amps will cover it.

My inverter was an add on by me, and that's exactly how I wired it.  I added a bigger battery cable to a Blue Sea busbar and then fed the original battery wiring and inverter from there.  Inverter is on a 125 amp breaker and I still have the original 40 amp on the battery wiring.

cafyrman

Denny16 said:

@cafyrman, a quick tip, the dust you see in the Alde compartment, may be coming from under the closet, where the water lines go to and from the water tank.  There is a large hole in the floor the water filler snd pump hose go through.  This hole goes all the way through the floor to allow access to the top,of the water tank, which is 1-2 inches below the bottom of the trailer floor.  You can plug this with some foam and a cover sheet, but this needs to be something you can easily remove, if the water tank needs servicing.
 Cheers 

Yes, I'd agree 100% given the amount of dust in that compartment.  I'll probably seal it with duct tape or something removeable.  Plus I really don't have a decent pass through for the solar wiring so dust gets in through the Alde compartment door when the solar is connected.  But that's another project and another thread.

Denny16

I used the black dense packaging foam to seal the hole,in the floor around the water tank lines, worked great.  I am going to add a plastic panel on top to keep it in place.  

Cheers