12vdc wiring under my 22RBHL

[Quadna71]

I’m prepping to install some parts on my 22RBHL, primarily batteries and a charger, and am in the process of identifying all the wires that will be involved in the upgrade. I started off with snapping a lot of photos near the circuit breaker panel, the battery charger, and under the frame where a majority of the 12v wires congregate. I was surprised to see how unprotected all the wiring is considering it is very exposed to the elements…but then again a lot of the wiring in these RVs seem to leave much to be desired.

WildWood 22RBHL (Forest River) by Chris Koran, on Flickr

1 - Black 6awg cable is negative from battery to ground distribution block screwed to the frame.
2 - Red 6awg cable is positive from battery to small 12v distribution block screwed to frame.
3 - Red 6awg cable is positive from 12v distribution block to shut off switch located in pass thru storage compartment.
4 - Black 10awg cable is positive from 12v distribution block to center pin of plug coming from tow vehicle.
5 - Black cable is positive from 12v distribution block to power jack on tongue of frame.
6 - Red 6awg cable is positive from shut off switch in pass thru storage compartment and goes up above the underbelly plastic shroud and into the cabin of the RV.
7 - Red 6awg cable is a jumper that connects one small 12v distribution block to the other small 12v distribution block..
8 - White w/red stripe cable that connects 12v distribution block to (something in the small box of hitch plug wiring…maybe sends signal back to tow vehicle saying connected?)
9 - White cable from ground distribution block screwed to frame to goes to (something in the small box of hitch plug wiring…?)
10 - White w/blue stripe cable that goes from ground distribution block to up above the underbelly plastic shroud and into the cabin of the RV.
11 - White cable that goes from ground distribution block to up above the underbelly plastic shroud and into the cabin of the RV.
12 - White w/red stripe that goes from 12v distribution block to (something in the small box of hitch plug wiring…?)

[CedarCreekWoody]

I don't understand your question. Just connect new battery parallel to current batt, no need to rewire everything.

[U.S.ArmyVeteran]

Originally Posted by Quadna71

4 - Black 10awg cable is positive from 12v distribution block to center pin of plug coming from tow vehicle.
5 - Black cable is positive from 12v distribution block to power jack on tongue of frame.

)

You have to love a wiring convention that uses black wire for positive 12VDC.

On our trailer they used 14 gauge white wire for both positive and negative on the FM radio and amp.

[Quadna71]

Originally Posted by CedarCreekWoody

I don't understand your question. Just connect new battery parallel to current batt, no need to rewire everything.

There is no question. Just thought I’d show the level of quality used in weatherproofing the 12vdc wiring and maybe open up some discussion regarding my accuracy in identifying the wires. Thanks for playing

[Quadna71]

Originally Posted by CedarCreekWoody

I don't understand your question. Just connect new battery parallel to current batt, no need to rewire everything.

So I’m unsure what to do about the shut off switch that located in the pass thru storage compartment. I’m installing a new shut off at the batteries when I relocate them from the tongue to their new location under the bed, but think it would be prudent to keep a second shut off external to the camper. The bedroom is cut off when the slide is retracted, so if I wanted to get to the batteries to disconnect them I have to open the slide. But if I want to kill them without getting into the camper then I can hit the disconnect in the storage compartment. Having more connections isn’t as efficient, but seems like it is worth the hassle. What do you think?

[Quadna71]

Originally Posted by U.S.ArmyVeteran

You have to love a wiring convention that uses black wire for positive 12VDC.

On our trailer they used 14 gauge white wire for both positive and negative on the FM radio and amp.

Yes. I can see having a black wire coming out of the tongue jack since everything else around it is black, but why wouldn’t you have a red wire from the hitch wiring junction box to the little distribution block?

If they would provide schematics then it would be easier to forgive their decisions…but of course they don’t/won’t.

[PopFla]

What type of battery/ies are you putting under the bed? If lead/acid, how are you going to vent the area? And doesn't the trailer already have a charger?

[CedarCreekWoody]

Originally Posted by PopFla

What type of battery/ies are you putting under the bed? If lead/acid, how are you going to vent the area? And doesn't the trailer already have a charger?

PopFla is correct. Be careful what you are doing. Those games are explosive.

[Quadna71]

I appreciate you guys looking out for me. I’m pulling the flooded lead acid off the front and putting two LiFePO4 batteries under the bed. No leaks, no outgassing, no worries. That is also where the second shut off switch, 60 amp fuse, and Victron smartshunt are being mounted. Then I’m removing the original WFCO (brand) charger that is made for FLA batteries and replacing with another version from WFCO that is made for the lithium batteries. Higher voltages that lithium likes, 2 stage instead of 3 stage, and is practically plug and play in the footprint of the original.

But the point of this post is I was looking at where I’d be tying in the new cable that will route back up to under the bed. I was just surprised at the lack of weather sealing to the factory wires not to mention how such a small screw is all that is used to secure that grounding block. Seems easy to work loose a little and then cause intermittent issues as it starts growing corrosion.

And I was also trying to decide if I should keep or lose the shut off switch in the pass thru storage. I might keep it but upgrade the wires from the 6awg to 2awg. That might make up for the added lengths plus all the additional connections.

[Ballistic]

I’m pretty sure those ‘distribution blocks’ are the 12v circuit breakers.

[Quadna71]

Originally Posted by Ballistic

I’m pretty sure those ‘distribution blocks’ are the 12v circuit breakers.

Thanks Ballistic - this is exactly why I post here. Definitely looks like CBs now that you mentioned it. I will keep that in mind for if/when I redo the wiring so that any sealed box I install will have the space to mount a new one inside. Much appreciated!

[Larry-NC]

Originally Posted by U.S.ArmyVeteran

You have to love a wiring convention that uses black wire for positive 12VDC.

On our trailer they used 14 gauge white wire for both positive and negative on the FM radio and amp.

There are two conventions for DC wiring in RVs.

• Red=Positive (+), Black=Negative (-). This is the one we see in cars, trucks, and consumer goods (like the snap-on connector used in smoke detectors, etc.)
• Black=Positive (+), White=Negative(-). This is the one we often see in RVs. The story goes that when they were teaching the assemblers, they wanted to use the same convention for 120 Vac and 12 Vdc, namely Hot=Black, Return=White.

The only place where it could get confusing is where the two are mixed, often at the batteries where the initial cables are Black/White but the jack or slide feeds are Red/Black. This leads to some black wires going to Positive and some to Negative. When you get confused (I have), you trace each black wire back to its pair. If the other wire in the pair is white, that black wire goes to Positive. If the other wire in the pair is red, that black wire goes to Negative.

[5picker]

Originally Posted by Larry-NC

There are two conventions for DC wiring in RVs.
Red=Positive (+), Black=Negative (-). This is the one we see in cars, trucks, and consumer goods (like the snap-on connector used in smoke detectors, etc.) Black=Positive (+), White=Negative(-). This is the one we often see in RVs. The story goes that when they were teaching the assemblers, they wanted to use the same convention for 120 Vac and 12 Vdc, namely Hot=Black, Return=White.

The only place where it could get confusing is where the two are mixed, often at the batteries where the initial cables are Black/White but the jack or slide feeds are Red/Black. This leads to some black wires going to Positive and some to Negative. When you get confused (I have), you trace each black wire back to its pair. If the other wire in the pair is white, that black wire goes to Positive. If the other wire in the pair is red, that black wire goes to Negative.

And to carry that farther...
Many units (my last two) also has 12v DC wiring that is white wire w/white and a colored stripe. In this instance, the white is negative and the white with colored stripe (not always easily seen) is positive.

[Quadna71]

Wrapped up the install this afternoon and now the new system is charging up the batteries. Not sure how long to expect the charging cycle to go but it’s been running for a few hours full blast and still not topped off. The batteries were shut off when I installed them so not sure of their state of charge from the start. I’m going to give it about 30 more minutes and then maybe kill power and check to see what the resting voltage of the batteries are. That should give me an idea of how full they are, right?

[Larry-NC]

Originally Posted by Quadna71

Wrapped up the install this afternoon and now the new system is charging up the batteries. Not sure how long to expect the charging cycle to go but it’s been running for a few hours full blast and still not topped off. The batteries were shut off when I installed them so not sure of their state of charge from the start. I’m going to give it about 30 more minutes and then maybe kill power and check to see what the resting voltage of the batteries are. That should give me an idea of how full they are, right?

When you finish charging batteries, the plates have something called "surface charge" which gives an artificially high voltage reading. You have to let them sit for at least an hour to let the charge dissipate. Alternatively, I believe you can simply draw some current from them to get a more accurate reading. Maybe turn on some lights for a few minutes before turning them back off and taking a reading.

[Quadna71]

Originally Posted by Larry-NC

When you finish charging batteries, the plates have something called "surface charge" which gives an artificially high voltage reading. You have to let them sit for at least an hour to let the charge dissipate. Alternatively, I believe you can simply draw some current from them to get a more accurate reading. Maybe turn on some lights for a few minutes before turning them back off and taking a reading.

I knew this was a think with FLA batteries but didn’t know it was also present with LFP batteries. Thanks for the tip.