Wiring Diagram, How'd I do?

[Welshie]

Hello all,

After hours and hours and hours of research and learning I think I'm finally near completion on my wiring diagram!

I'm missing the gauges for a few wires that I'm yet to work out. But I do have a few questions about this element of the build.

I want to use AGM batteries because I am a full time freelancer and during the winter I am going to be traveling between ski resorts and staying in these very cold climb for extended periods. From research I want sealed batteries that I can store inside at minimum risk to my safety, because I don't want: a. batteries venting inside and making me go boom, and b. to have the batteries getting too cold so that they don't work.

When connecting sockets to the inverter do people just put in a plug and then wire that to a socket? I can't seem to see any connections to use otherwise, when I'm looking at pictures of inverters that it.

Finally, we're doing research on charge controllers, battery monitors, battery brands, and inverters. Any suggestions relating specifically to AGM setups with these elements? Specifically the first three.

What're all your thoughts?

[dzl_]

When connecting sockets to the inverter do people just put in a plug and then wire that to a socket? I can't seem to see any connections to use otherwise, when I'm looking at pictures of inverters that it.

Depends on the inverter, low budget inverters, or low power inverters of any budget, often only have three prong receptacles. But most inverters above 2000W from reputable manufacturers are available in models that can be hardwired. This is a HW variant of a 1200W Samlex inverter:

Often its not easy to see the hardwire connections as they are recessed or covered for safety etc.

Have you purchased an inverter yet? If it only has 3 prong receptacles, the most common and simplest solution is just hookup power strips. The other solution I have seen is modify an extension cord to be hardwired. I believe--but am not certain--this is technically not legal/code compliant.

Finally, we're doing research on charge controllers, battery monitors, battery brands, and inverters. Any suggestions relating specifically to AGM setups with these elements? Specifically the first three.

Can't go wrong with Victron for the controller (Victron Smartsolar), battery monitor (Victron BMS-712 or Smartshunt), and inverter (Victron Phoenix or Victron Multiplus) if you have the money. They make top quality products and they work very well together as an 'ecosystem' (together they are more powerful than the sum of their parts). The inverters can be pricey (<$1000 if you need 2000W or higher) but than this is true of all of the top quality inverters from reputable companies.

For more budget friendly but decent alternatives, EPever for the charge controller, Aili for the battery monitor. I don't have a budget inverter recommendation, many people seem to use Aims/Sigineer

[dzl_]

A couple notes on your schematic.

First, you are off to a good start, there are a lot of elements I like in your design (for instance I like that most of your loads are DC native, this is more efficient with a battery based system).

Second, you asked about a fuse or breaker for the inverter, either acceptable, a fuse is in some ways better suited, a breaker is more convenient, either can work. What you definitely want to avoid is a cheap no name high current circuit breaker from amazon etc, best case they nuisance trip well below there rating, worst case they fail in a way that does not protect your system. Quality breakers from reputable brands generally top out at 200A unless you want to pay upwards of $100 dollars. Fuses can go much higher. If you use a fuse, a Class T, MRBF, or ANL fuse is well suited for main battery protection and/or the inverter circuit.

Four rules of thumb to keep in mind when thinking about fuses.

(1) the primary purpose of the fuse is to protect the wire

(2) any time you step down in wire gauge you need to step down in fuse size to protect the smaller gauge wire

(3) a fuse should be sized > 125% of max current of that circuit and < the current carrying capacity of the wire it protects.
(4) a fuse should be as close to the power source (beginning of the circuit) as possible

Third, regarding the shunt
A shunt based battery cannot accurately measure state of charge the way you have it wired. Think of current like the flow of water and think of a shunt as a device that measures how much water is in the water tank based on how many gallons flow in and out of the tank. To measure it accurately, all the water must flow through the measuring device. The same is true of a shunt and the flow of electricity. A shunt has to be positioned so all current flowing into and out of the battery is measured if you want it to accurately measure state of charge

How I would accomplish this by moving all the positive and negative connections you currently have going straight to your battery bank and instead using busbars. Then run single wires between your battery bank and the positive and negative busbar. The shunt would be between the negative busbar and the battery negative. This kills a few birds with one stone, it fixes the shunt measurement issue, allows you to use one main battery catastrophic fuse and optionally one disconnect switch, it is also a best practice not to stack a bunch of connections on the same terminal. Here is an example of what I am describing here (the blue square is the battery, ignore the details, it is a lithium diy battery so the details dont apply to your situation):

[Welshie]

Thank you for the responses I'll take these ideas into good consideration.

Regarding power sources, should I have a switch to alternate between the two -solar and B2B charging- or should I have it all just connected to the bus bar and not worry about such a thing? I've seen a few people with this and I'm wondering what the benefit of doing this is.

[dzl_]

Originally Posted by Welshie

Thank you for the responses I'll take these ideas into good consideration.

Regarding power sources, should I have a switch to alternate between the two -solar and B2B charging- or should I have it all just connected to the bus bar and not worry about such a thing? I've seen a few people with this and I'm wondering what the benefit of doing this is.

You can have multiple charge sources connected in parallel without worry so long as it doesn't exceed your batteries limits (I do not know anything about AGM so I can't advise on this latter point).


One reason people use switches (or breakers) is to isolate the system from one or all charge sources or power sources either for maintenance or for safety.