Solar wiring issue

[BarberArias]

I'm sure solar questions have been beat to a pulp but I just can't find the answer.

I don't want to drill holes through my rv roof and found that I could easily run my solar power lines down my fridge exuaghst vent. Thus gives me great access to everything I need.

Question is, can I just use the power lines coming from my battery to the fuse and breaker box to back feed my solar to charge the batteries? Or do I need to run new lines all the way back to the batteries from my control?

[SkiSmuggs]

BarberArias wrote:

pianotuna wrote:
It is not a good idea to "back feed" (which you are really not doing)

The way my trailer is setup is hard for me to tie into the batteries without drilling holes through the roof. Unless I drop down in the kitchen area which also contains my breaker / fuse panel. I don't plan on back feeding through the panel just tie in to the wires feeding the panel. My under belly of the trailer is sealed since it has the cold weather package so getting wires back up to the front of the trailer has numerous obstacles. I feel like this will be the cleanest way to install. The loss of power shouldn't be a issue, currently we only need to charge the batteries every 3 days with the generator. Hopefully the 2 100w panels can keep up with that even with the loss of power in the lines.

Thoughts?

I had a similar problem with my kitchen at the rear and batteries at the front. I ending up running down the bath room grey tank vent, cut a hole in the side of the vent pipe inside the basement and straight to the battery compartment. I used an electrician snake to pull the cable down from the roof. Then gorilla tape over the new hole in the vent pipe to seal it.

[djgodden]

Do not back feed. I used the black water vent to run my cables from the roof into the basement and then into the battery compartment. Drilled a hole in the side and then sealed around the cables with PVC goop.

[RollandB]

BarberArias wrote:

mike-s wrote:
How are you planning on mounting the panels? Glued to a fiberglass roof?

I'll still screw brackets to the roof with lap sealant all over it.

You might want to check out the videos at www.amsolar.com especially on out they secure the mounting feet in fiberglass roofs. There feet come with 3m tape on them which is all that is used.

[BarberArias]

mike-s wrote:
How are you planning on mounting the panels? Glued to a fiberglass roof?

I'll still screw brackets to the roof with lap sealant all over it.

[mike-s]

Get a controller with remote voltage and temperature sensing, and don't worry about the voltage drop in the wiring - it really isn't that much.

How are you planning on mounting the panels? Glued to a fiberglass roof?

[Boon_Docker]

You can connect the output of the charge controller to the battery feed wires anywhere along the line after the output from the converter. Just be sure to put a disconnect switch between the panels and controller. So you can connect the controller to the batteries first then turn on (connect) the panels second.

The above is the way I installed my 200 watts seven years ago and have never had any complaints.

[pianotuna]

Do a proper energy audit. For my detailed thoughts on solar surf here: https://freecampsites.net/adding-solar/

[BarberArias]

pianotuna wrote:
It is not a good idea to "back feed" (which you are really not doing)

The way my trailer is setup is hard for me to tie into the batteries without drilling holes through the roof. Unless I drop down in the kitchen area which also contains my breaker / fuse panel. I don't plan on back feeding through the panel just tie in to the wires feeding the panel. My under belly of the trailer is sealed since it has the cold weather package so getting wires back up to the front of the trailer has numerous obstacles. I feel like this will be the cleanest way to install. The loss of power shouldn't be a issue, currently we only need to charge the batteries every 3 days with the generator. Hopefully the 2 100w panels can keep up with that even with the loss of power in the lines.

Thoughts?

[pianotuna]

It is not a good idea to "back feed" (which you are really not doing)

Here are some reasons why.

Many controllers state that they will burn out if they are connected to the panels but not connected to the battery bank.

When in storage you would want to disconnect the battery bank from the RV. Wiring directly to the bank allows it to be charged while in storage mode.

Wire from the controller to the battery bank may be larger than what is used from the bank to the distribution box.

The charge controller ought to be as close to the battery bank as possible.

[BarberArias]

Thanks that what I thought / was hoping

[12thgenusa]

Welcome to the forum.

Yes, you can do that. It's not really a backfeed. However, depending on the length of the wire run to the batteries, the size of the wire, and the amount of solar, you could have significant voltage drop. Meaning less than ideal performance.