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diy solar

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Jul 8, 2021
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Getting ready to do a final install of my solar components. Finally have the interior finished enough that I can install my Victron components.

Already installed:
  • BlueSea systems 12v fuse panel powering three separate LED light circuits on dimmers, three Hike Crew powered ceiling vent fans, a 12 v wall fan, among other components, all running from the fuse panel directly from one Battle Born BB10012 (I have another BB10012 to install with the full system below)
  • 12x Rich Solar 100 watt solar panels run 4S3P. One 10 amp inline fuse on each of the four series circuits before they come together via one of those three to one Y style connectors. (These have been installed for about a month but just not connected to any circuits and not powering anything. Fingers crossed this hasn't damaged the panels.)
  • AC residential 120 style fuse panel with 15 and 20 amp fuses for various appliances such as air conditioner
  • Dometic CFX75 fridge/freezer with both AC and DC options for power
What needs to be installed:
  • Victron Multiplus 24watt/3000va/70amp charger/inverter
  • Victron Smart MPPT 100|50 charge controller
  • 24v to 12v (40 amp) converter
Supplies on hand to install these components:
  • 30amp circuit breakers
  • 9 inches 4/0 Red+Black with 3/8 in lug
  • 2x 12 inches Red+Black 5/16 lug
  • 10ft 4 AWG Red+Black
  • All necessary crimpers, wire lugs, and anything I need from a local home depot or electrical specialty store
I'm fairly comfortable doing the work but I'm not very comfortable reading wiring diagrams. My goal is to add several more BB100012's in the coming months to significantly increase my capacity so I can run AC more comfortably more often. I love the cutting edge fun stuff and don't mind spending money to overkill a system so I'd like to buy the cool screen and other smart components to make the Victron components more easy to understand/monitor but for now I'm starting with these few components listed above. I was planning to run a Camco 30 amp service line directly into the Multiplus by cutting off the female end and wiring it into the AC in. AC out goes to my 120v AC Panel, straightforward enough although I'm not sure what awg of wire I'll need. The batteries and multiplus will all be within a couple feet of each other but the AC and DC Panels are about 10 feet away. I'm familiar with how to turn two 12 volt batteries into a 24 volt battery but how do you create a bank of 24v batteries out of 12s? I assume it's similar to how I wired my panels 4s3p? Does the Solar Charge Controller connect to the Multiplus or just go directly to the batteries?

I would GREATLY appreciate anyone willing to help me by drawing up a schematic or sharing any links/videos that are relevant.

Thank you all who are willing to help us noobies! It's greatly appreciated!
 
12x Rich Solar 100 watt solar panels run 4S3P
Victron Smart MPPT 100|50 charge controller
Hmmmm.... the Rich solar 100W 12V panels have a Voc of 22.3V . 4 in series gives you 89.2V @ 25C.
That only gives you a 12% voltage margin for cold temperatures. With Voc Temp coefficient of -.28, it works out to -18.2C (-1F) before you are in danger of damaging the charge controller. Are you sure the system will never see that temp? (Even when it is sitting at your house not being used?) You may want to consider a 3S4P configuration.

EDIT: Added the following:
This resource explains how to adjust Voc for temp.
 
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I will cover one thing for you....AC breakers are rated for AC only, do not be tempted to use them for DC...AC goes on and off 120 times per second, plenty of low current flows times to extinguish an arc...DC does not go on and off so an AC breaker does not have a chance of extinguishing a DC arc. Use components that are rated for the intended purpose. AC breakers used on a high voltage DC line from the solar panels will arc and weld in the on position and have been known to burst into flame when exposed to the mean DC arc. DC breakers are way more expensive. Fuses on high voltage DC need to be “Touch safe” as DC will kill you at a much lower voltage than AC will.... over 48 volts DC is deadly....it can and will kill the unwary where as 120 volt AC likely will not kill but will leave an impression that you will not soon forget.
 
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Edit: Corrected the SCC model.

The strange disconnect circuit leading to the inverter is a disconnect with a built in pre-charge resistor. It is described here:
 
BTW: You may also want to review this:
 
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