Originally Posted by KJR
We are going to look at a 2019 Ventana Le 3717 that doesn’t have the 6g solar prep. We would like to add solar later. How is solar wire led down from the roof with so many slides. I believe the six 6v batteries are located behind the drivers front wheel under the living room slide. Is it a difficult DYI or should if be left to a qualified installer? I would imagine the labor to just run the wire to the battery compartment would be a lot more than the cost of the factory option.
Running wire from the roof is NOT going to be fun. On our floor plan...the wire probably is run down thru the 1/2 bath walls (non slideout) to the basement. The roof wires are located under a metal plate on the roof. The other end was terminated on the bulkhead nearest the battery compartment in the pass thru bay. A network cable is also included...that starts in the control panel location..and terminates along with the 6 AWG wire near the battery compartment. The idea is to keep the run as short as practical.
If you have 6 Interstate Lead Acid batteries...they are usually around 220aH each. Wired together as 12v...that would be a 660aH bank. Interstate recommends C/10 charge rate...in your case 66 amps. I use 14.51 volts as my absorb voltage. At that rate...you are putting 66A x 14.51V = 957.66 watts.
If you wire two 180watt panels in series...they output around 42v when pushing out a bulk charge. 957.66 watts / 42v = 22.8A. So...the assumption that the wire running from the roof to the controller needs to be rated for 100A is not correct.
For your bank...I would go with six 180w solar panels configured in three Strings of two... but check the input requirements for your particular MPPT controller.
I have eight x 232aH 6v Interstate batteries..running eight 180w panels 2s4p...and use the 6 AWG solar prep... Victron SmartSolar MPPT150/100 controller.
I performed all the calculations ...included the recommended factors to the voltage and amperage for my system...and 6awg from panel combiner to controller is what was needed.
I would recommend either doing the computations yourself...or patterning your system off someone that knows how and has performed the calculations.
I have a lengthy thread on my learning experience. I am extremely happy with my final result. Here’s the link...
If you are capable of handling the panels and basic wiring and power tool use...I think you’ll perform a quality installation. I can’t comment in the professional installers. I would get reviews from other coach owners with their systems installed.
Don’t get the factory option...you can do much better, in my opinion.