diy solar

diy solar

Filling in the missing parts

WarpedJester

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Joined
Jul 10, 2020
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Hey all!

So i am getting down to the final bit of planning for my first solar system and i am hoping to get some feedback on the last few parts i need. (full details below followed by a quick ref at the end)

To start with, lets recap what im adding solar too and what parts i have already decided on.

Me, my rig, and my lifestyle:
I am living full time in a 2014 Forest River 3170DS (31 foot) class C motor home. As i noted in my other post, For the most part i am 24/7 "urban camping" so i do not have access to shore services. Additionally, i live on the California coast so even in the summer, we get lingering morning fog some times which may impact my solar a little. i do also have a Onan 4000 genny which is my only means of charging or running AC power at the moment and i tend to run it for 1 to 2 hours a day to keep up with power needs.

My plan:
So after much though, calculation, help, and learning, i have decided that i am going to start out with 4 100Ah battleborn batteries, 8 100w HQST Mono panels, MPPT charge controller and I will be wiring everything up as a 24v system.

Here is the part when i would like some input and help. I think i want to go with Victron for the guts of the system. I am a bit a of a tech nerd so would like to have the Victron color control panel or touch control panel, part because of the visual management and part because i believe it can also show/manage other peripheral elements like tanks monitoring and what not. The issue is that there are a lot of Victron parts and a i am not sure which ones would be the right fit.

As much as i dont want to go over board on this, i really kinda wanna go a little over kill and enjoy this project as it is going to be my "life blood". So As far as MPPT, unless i am missing something, i just need to find the right one that can handle the power coming in and maybe have some forward planning for more solar down the road if wanted/needed. But this is where i hit another snag. when looking into inverters i see that there are combo inverter/chargers and i am wondering it they are the way to go?

*sigh, sorry if this is a bit rambly. Again, this is my first time diving into this world and while i am doing a lot of reading up, it does make my head spin at times. I have sent a email to Victron asking some questions and looking to get feedback from them on how to build out a system that fits my needs but i love this community so i wanted to post here and get your feedback as well.

Quick Ref:
Panels: HQST 100w mono x8
Batteries: Battleborn 100Ah x4
Inverter: Victron MultiPlus 24/3000/70-50 120V VE.Bus Inverter Charger
Solar controller: Victron Smart Solar MPPT 100/50
DC to DC converter: Converter Regulator DC/DC DC 24V to DC 12V
Victron color control or touch control system?
Other things?

-Jester
 
Recommend a $40 Smart Battery Sense.

This will interface with your charge controller via bluetooth and provide direct voltage sensing and battery temperature. I just added one, and I'm very pleased with it. This also enables you to specify a low temperature charge cut-off to protect your LFP batteries from charging in extreme cold.

The color control GX is very nice. I have one, but I have yet to fully deploy it. I bought it based on a friends setup, and it is sweet.

Based on your description, you've sized your system by "gut." However, nothing jumps out as nutty, and it appears you started with something well defined:


...or got pretty close to it on your own.

Another thing to consider is do you want all of your panels mounted, or do you want some of them as a deployable rack? Parking in the shade with your panels setup out in the sun may prove to provide the most comfort.

Something very important about roof mount RV panels is the various things on the roof can partially shade panels a significant portion of the day. Essentially, a panel performs only as good as the cell receiving the least light, and that impacts all panels in series with the shaded panel. This may be a bit of an overstatement, but the bottom line is that shading on your panels will really hurt your ability to harvest solar energy - another argument for having half of them on the ground... 50' away with you in the shade.... :)

If you move around a lot, a deployable array may be a pain, but if you stay put for several days at a time, it's probably just a minor nuisance.

depending on your location and weather, an 800W array can harvest about 4000Wh of energy, which is a little shy of your total battery capacity. It's probably worth doing an energy audit and see where things fall. Don't forget to include the Multiplus 20W "zero load power" (20*24 = 480Wh - over 10% of your total) and the drain of using your off-grid system to float your coach 12V if you retain it.
 
Your Victron SmartSolar MPPT already gives you battery monitoring via a very slick free Bluetooth app. Not sure about temp monitoring since my batteries live inside with me.

I would suggest you go directly to 300 plus watt panels to start with. Your limited real estate on the roof will give you more opportunities to grow the system this way.

Take a look at SanTanSolar.com for panel options. Would be an easy road trip to PHX for you ?
 
Your Victron SmartSolar MPPT already gives you battery monitoring via a very slick free Bluetooth app. Not sure about temp monitoring since my batteries live inside with me.

I would suggest you go directly to 300 plus watt panels to start with. Your limited real estate on the roof will give you more opportunities to grow the system this way.

Take a look at SanTanSolar.com for panel options. Would be an easy road trip to PHX for you ?

Yes, it does, but the voltage isn't accurate. It's current influenced, and there is no temperature monitoring. The $40 smart sense integrates with the SCC and reports V and temp in the app.
 
Not sure about Victron voltage inaccuracies but they do offer a temp sensor for around $20.
 
They are inaccurate. All of them are. There's a resistance internally in the SCC, the cables and the battery itself. It's usually not much, the remote sensor attached to the battery terminals provides a direct measurement of the batteries voltage with very little error.
 
Mine is a few inches from the battery and plenty accurate for my application. YMMV
 
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