Wiring through floor questions

[sbgrimm]

I'm replacing a broken solar charge controller with a new one that has a battery temperature wire. And I'm putting in a battery monitor. Both require wires through the floor to the battery. I was hoping to run the new, small gauge wires right through the existing holes that the large cables run to the ground and the separator, but that doesn't look feasible.

Before drilling new hole(s) in the floor I searched the forum but didn't find much. I want to do it right, but I don't know if a simple rubber grommet is enough since I have to drill through the plywood floor and the metal underbody. The 3 existing holes have some sort of grommet that is screwed into the floor. Also, what kind of sealant is best to caulk the opening from below? These are pretty small gauge wires, does each need its own hole?

Below are pictures of what I currently have, from both sides.

Any tips on doing the job right?

Thanks in advance, Brad

[JWA]

The biggest concern with drilling or cutting through factory-original sheet metal is thoroughly sealing the bare metal edges against the elements. Because you will have penetrated the various processes used to keep rust at bay its necessary to restore that as best you can.

The more extreme or best practice way would be drilling/cutting as needed then applying something like POR-15 over the exposed area(s). If that's not possible any good grade of bare metal primer would work well too.

My preferred method involves using something like these: http://www.ebay.com/itm/Scosche-WPG0...item3aa57b47c1. Very effective by themselves, can be further sealed with silicone adhesive etc for a bit of over kill if desired.

The photos show a decent way to do this too---just remember to protect any bare metal edges created.

[86Scotty]

Originally Posted by sbgrimm

Both require wires through the floor to the battery. I was hoping to run the new, small gauge wires right through the existing holes that the large cables run to the ground and the separator, but that doesn't look feasible.

Why not feasible? I know it may be difficult, but hopefully it is feasible. I would recommend using the original holes taking advantage of the big plastic grommets SMB uses. They are the best grommets I've ever seen for thick floors. I would use a coat hanger to get through one and run your wires through it, adding your own wire loom on either side to protect the wire if you feel that's necessary.

Good luck!

[Scalf77]

Yes, I believe it is feasible, I have at least two temperature sensors and battery monitor wires and solar sense wires riding with the larger cables. It was not easy but doable.

-greg

[E350]

For a different take on the topic, my biggest concern with holes in the floor are not the holes, I've cut a few, but exhaust intrusion into the vehicle, especially when snow builds up a dam around the van over night while parked. This is what I did, install the appropriate size Non-Metallic Male Terminal Adapter* with electrical ring or female adapter on the bottom. And then after the wires are placed appropriately, "pot" (i.e., fill) the connector with silicone.





* Electrical male adapters are straight non-interference threads, not conical interference threads like Plumbing male adapters.

** I have not thickened my floor with plywood. If you have, these will not be long enough to work n the thickened areas.

*** For holes that I have drilled which I am not using, I have just placed the appropriate pcv nonthreaded plug in the male adapter to seal the hole.

[BrianW]

You can't squeeze a few small wires in those existing wire looms that you have pictured? They look to be pretty good size. I'd try that before putting a new hole or two in my floor...

[sbgrimm]

OK, I'll see if I can fish the wires through the existing openings. First I'll have to remove the seat, I'm tired of it hitting me on the head while working there!

Thanks to everyone for your advice, we newbies appreciate the accumulated wisdom of the forum!

Brad

[sbgrimm]

Thanks to everyone who encouraged me to fish the wires through the existing holes. I did it today using a coat hanger and it worked fine. A few days ago I cleaned the underside area with a pressure washer. A little water came up through the floor, but at least it's clean. Now that the wires are fished I'll have to seal it back up. You can see in the picture the existing sealant is black and was applied messily. It's also very rubbery. I'm not too impressed by SMB having run the battery wire thru the floor inside the cable protector, it looks harder to seal and more prone to water intrusion that way.

Next I have to drop the battery and attach the solar controller and battery monitor wires. I'll rent a floor jack this weekend. It doesn't look easy.

So today's questions:
What is that sealant? Butyl rubber? Is that what I should use again, or get something else?

Regarding dropping the battery, SMB manual says to first remove a cable clamp. I'm guessing it's the one in my second picture below. Any tips on dropping/re-installing the battery?

[boywonder]

If the sealant is still gooey it's probably butyl. If it's pliable but not gooey (won't get on your fingers) then it's probably silicone RTV sealant......Hard to tell from the pics.....

[sbgrimm]

Boywonder: It's pliable, rubbery, but not gooey. So sounds like the silicone sealant. Do you have any strong opinions about which keeps the water out best? This is a very wet location, just in front of the rear passenger tire. (At least it's a wet location if you live in Seattle!)