Wiring Solar closer to 12v fuse panel vs. directly to batts?

[SkullAndSquirre]

Hi guys, I need some expert opinions. I'm installing 2 100w solar panels this weekend. The air vent I would like to use to drop the solar panel wires terminates just above the 12v fuse panel. ..It seems like I could just splice into the wires coming off the batteries there rather than run an additional 20 feet directly to the battery terminals.

..or am I missing something?

There must be a pic of the wiring setup I am thinking about trying, I just don't know which terms to use to search for them.

Thanks for your help?

[SkullAndSquirre]

Thanks for the replies team!!

I installed the kit over the weekend.







Wire Route:

Solar Panel>
Sealed Junction box on roof>
Hole through junction box into bedroom cabinet>
Bedroom Cabinet into Family Room Cabinet>
Family Room Cabinet into water pump cabinet surround>
Renogy controller on water pump cabinet exterior>
Back into water pump cabinet large fuse>
Battery battery bay>
15 amp fuse>
Battery..

Total run, appx. 9-10 feet.

Avoided Problems:

-Roof is thinner at the angle joint between the bedroom and main room, try not to mount too close to the joint.
-Mount on the front of the RV, backing in (for us) usually means shade on the back end of the trailer.
-Acorns dropping from the trees, now worried about them hitting the panels, moved trailer.
-Didn't need more wire than the kit included, but one wrong cut and it would have been another trip.
-Decided to run straight down from panels through cabinet to batts, saving time, wire and frustration.

Unanticipated:

-No fuse in kit, head to store.
-Battery cable kit too big ga. for controller, head to store.
-Added spacers under controller to help heat dispersion, head to store.
-Hard to get to screws, needed flex drive shaft for drill, head to store.

Potential problems:

-Roof needs maintenance soon.
-Cheapo controller, is it working correctly? Bought voltage meter, don't know how to use it.. lol.
-Battery bay is tight, need to move it.
-Renogy controller is in a nook, watching to see if it warms up.

[westend]

Yeah, the flex conduit makes a good housing for under-deck wiring. The stuff is very durable and fittings are available everywhere. I housed my brake and taillight wiring in flex, couldn't be happier. I have a split bank battery system and pulled 1/0 from one bank to the distribution panel. I used 1 1/2" ABS for that.

[doughere]

I brought my panel wire down from the roof in flexible conduit (blue flexible conduit available at HD and Lows). Drilled hole in roof next to vent line, installed waterproof box on roof, sealed to roof with Dicor. Ran conduit in wall cavity next to vent line to basement (I have a small 5er), in basement to next to converter which is next to battery.

FWIW I have run wire under trailer from front to back in same conduit; does nice invisible job.

Doug

[MrWizard]

I ran my wires down behind the fridge
Under the fridge and thru the bottom of the closets and cabinets

Everything run through the ceiling goes IN before the ceiling / roof is covered, anything that goes very far has to go thru the roof supports

One or two people have "fished" wire thru a/c ducting , but that might have been HDMI cable for the TV
Might be an option for you

[time2roll]

Post some pictures of the relevant area inside and the roof.

[SkullAndSquirre]

I went through all the installs. None are quite exactly my situation, but they are all informative. Wow some of them are not my style, I really want the wiring to be invisible. I am hoping I might be able to fish the wires through the tv antenna cable route. I have yet to see an install that tried it. Off to look for a tv antenna mount diagram because the cable seems to be stapled or something.

[Ron3rd]

Handy Bob gives some good basic info, but much of his info is dated.

[EsoxLucius]

PFitt wrote:
Go to Handy Bob's solar blog everything you need to now in one spot!!
https://handybobsolar.wordpress.com/

Not really.

[doughere]

You should mount the solar controller as close to the battery as possible. Wire from the panels to controller would probably need to be #10 minimum (assuming that its 20 feet from entrance to RV to batteries, and guessing 20 feet up pipe and to panels). For a 2 ft run from controller to battery #10 is OK.

Doug

[SkullAndSquirre]

Nice! I knew I was in the right spot.

I bought the Renogy 200w kit with the cheaper PMW controller. I saw a video where a guy went from Panel > Controller > to just behind the DC panel because his run to batts was too long. here https://youtu.be/oqfIjfF5eGQ?t=8m38s

I read the comments and there were a few too many that said it was a bad install for my taste. I think I came up with an alternative option which will allow me to put the controller close to the batts, but would include mounting it on the door of the battery compartment (would like your feedback on the idea of mounting it on the door).

Thanks again.

[MrWizard]

It's a 20 ft run to the batteries ..
Okay that means the converter wiring has a 20 ft or more run to the batteries

What size is the wire?
Is it bigger than what you bought?
Is it 6 gauge our is it 10 gauge ?
What size did you buy for this run?

Once the wire leaves the controller, it's at charging voltage, the longer the wire the more voltage drop, the smaller the wire the more voltage drop
In 99% of the time, there is loses that could have been avoided,
10 gauge wire is rated for 30 amps at 120v
But at 14v charging it will have too much voltage drop, and the batteries will rarely reach full charge..they will if the camper is not used for several weeks, but they won't when the camper is being used
Voltage drop means slower charging

[westend]

I used bus bars to connect the solar controller, the converter, and the inverter to my batteries. Here's a picture of my DIY bus bar:



There are also commercial products that will do this type of connection/distribution.

You want to make sure that the wire size that leads from your batteries to your solar controller is large enough so that you are not losing too much voltage. The calculation for wire size revolves around amount of power and distance. Personally, I don't use any wire gauge smaller than 4 AWG to connect batteries. I paid good money for my solar system. There's no reason to throw away the power harvested by using too small of a wire. The alternative to spending $30 on wire upgrade is to lose harvested power continually, forever.

Voltage drop calculator

[PFitt]

Go to Handy Bob's solar blog everything you need to now in one spot!!
https://handybobsolar.wordpress.com/

[fitznj]

As stated, you need a controller; I wired mine directly to the batteries.

In my instance, I can isolate the batteries from the TT (using the cut-off switch) and still have the solar panels charging the batteries (or keeping them topped up during storage).

Gerry