Beginners Solar Charging Install

[jbailey]

Due to the expected amount of dry camping we will be doing this year, I have decided to install solar on the trailer. After initial sticker shock and much head scratching I have decided to only do the 1st leg of solar and tackle the inverter, transfer witch etc... later. SO this thread is going to be about the solar charging install I am going to on my 303 RLS. I want the system to be expandable as we add an inverter down the road to be able to handle, heat, TV, coffee pot etc.. At this point I am only done with a materials list, but thought I would solicit opinions on it and get any advice you feel is appropriate. I am fairly basic on electrical, but more or less pretty handy, which means, there will be much swearing and rework over the coming weeks. Thanks for input & help ahead of time, I would love to know if anyone thinks I am missing key components or overlooked anything in the system.

2 @ 165 Watt Solar Panels - Everbright Solar
2 @ Self Leveling Panel Mounts - AM Solar
20' 10AWG Solar Cable - CIE Solar
5 Pack MC4 Connectors - Renology
Combiner box - AM Solar
Sticky Zip Ties - AM Solar
2 Pack Dicor Sealant - Dicor
6 @ 6AWG Copper Lugs - Ancor
50' Feet of Red & Black 6AWG welding wire - WindyNation
2 @ 50 Amp Circut Breakers - IZTOSS
Victron Blue Solar 12V 100/50 MPPT Charge Controller
Blue Sea Systems Battery Switch
Victron BMV 702 Battery Monitor

I am working on a system diagram and will be posting here "shortly".

Ben

[TucsonJim]

It looks like you're going with some nice quality parts. 20' of solar cable seems awfully small, but of course that depends on your run length. I think I used about 50' on my 297RSTS. You might also want to purchase the proper crimping tool for the MC4 connectors. It makes the job so much easier. I don't see a fuse or fuse holder which you'll need to add on the plus side of the feed between the solar panels and the MPPT controller. I assume that since you're using an MPPT controller, you'll run the panels in series and not parallel. What is the purpose of the combiner box if you'll just have one positive and one negative lead to the controller?

Jim

[jbailey]

Jim,
Thanks for your input, my thoughts:
I was planning on running them in series, but was thinking to run the 10AWG into the combiner box would then run 6 AWG cable down to the MPPT, can I get away with 10AWG all the way from the Panels on the roof down to the MPPT?
I think getting the Crimper makes sense.
I had two 50 Amp circuit breakers above, I see now I need fuses and not a manual circuit breaker. All I need is one for between the panels and the MPPT and one for between the MPPT and the battery, correct?

[TucsonJim]

You certainly can run the cables the way you were planning, but yes, you can run the 10AWG solar wires directly to the controller (with a fuse on the positive line).
And you will only need the two fuses that you mention above.

Jim

[Harleycharley22]

If there is a solar ready plug on the side of the trailer, would you need all this stuff? Can't you just plug it in there?

[carnolddsm]

If there is a solar ready plug on the side of the trailer, would you need all this stuff? Can't you just plug it in there?

The Furrion Solar part is for use with Furrion's 95 watt portable solar panel. These panels aren't much more than a trickle charger. The OP would need 3 - 4 of the Furrion panels to equal his system.

[jbailey]

If there is a solar ready plug on the side of the trailer, would you need all this stuff? Can't you just plug it in there?

Harley (I hope),
The plug already in the trailer is just what Colan indicated, its a direct plug for a Furion panel that only has so much capacity. I am trying to plan/install a system that has a high enough capacity to charge the batteries at a high enough rate I can use an inverter to run A/C powered devices in the trailer. Unfortunately this typically means multiple solar panels on the roof, I was planning to start with two 165 watt, giving me up to 330 Watts in ideal conditions (doesnt happen often).

[jbailey]

You certainly can run the cables the way you were planning, but yes, you can run the 10AWG solar wires directly to the controller (with a fuse on the positive line).
And you will only need the two fuses that you mention above.

Jim

Jim,
You are going to have to help me out a little bit, when I look at the Current Flow vs. Circuit length chart that Rob provided way back in the day it shows that for a run of 25 - 40ft that I would need 6AWG cable to carry 20 Amps from the panels down to the battery. Is that not right?

[Paul & Deb]

Ben, my 10 AWG cable run from the panels to the controller is probably 30 ft and I show 19.99 amps at the controller.

[TucsonJim]

Ben - On my panels, the optimum operating current is 5.62Amps and the short circuit current is 5.92A. Yours are probably in the 7-8 amp range. The benefit of using an MPPT controller is that you will be increasing the voltage, but not the current which allows for more efficient usage of the conductors. In my case, I'm obtaining about 63 volts at 5.6amps at when maximum charging is needed. The MPPT controller will reduce the voltage and increase the current to the battery array. That is why I'm using 10AWG wire between the solar panels and the controller and 6AWG from the controller to the batteries. By the way, I can't quite see the details in the chart you've attached, but I think I found the same info on line. There is not need to utilize the 3% critical loss portion of the chart. With that controller, you can easily live with a loss of greater than 3% and still efficiently charge your batteries.

Jim