diy solar

diy solar

Completely confused with my solar system!!

The BMV needs set up for charging via solar,
You need to change the following , the default settings are OK for the rest.

Battery capacity, your actual capacity, 400
Charged voltage
, the charge voltage your chargers are set to, minus 0.1 volt, example charge voltage 14.2, BMV setting 14.1
Puekert Exponent
1.05
Charge efficiency factor 99%


The shunt is connected as follows, nothing else is connected to the battery negative terminals (except in the case of other batteries negatives when connected in parallel). If the system has a negative buss bar, this connects to the shunt load output and every other system negative to the buss bar.
BMV shunt connections.jpg
Mike
 
Ok, so I'm finally settled at my work location for the winter and not in travel mode. I also have a day off here so I can resume trying to resolve my wiring issue.
Now I've made sure that both the Mppt and BMV settings have been set as mentioned above and in conjunction with Battleborn's instruction page.
Considering the wiring suggestions given previously, I think I've got some rewiring to do. But still have questions about this to be sure. So here goes:
I've submitted a drawing of my current set-up for better reference although it looks a bit like spaghetti (sorry bout that!)

1. It sounds like I should do away with the second shunt (the one that only has the inverter ground on it. Should or can this ground be attached to the negative bus? Or should I just route it directly to the trailer frame?

2. The BMV shunt should only have the negative battery lead on the "bat" side and a lead from "load" side to the negative bus bar. So it sounds like the lead that I have going off the BMV shunt to ground should be eliminated? And so does the negative bus bar then need to have a grounded lead? Or is it all just completing the circuit through the negative connection at the battery?

3. I currently have my positive from the Mppt going through a breaker and then directly to the positive battery lead. I am intending to add a cut-off switch in this connection, but would it be safe to say that I could run that lead from the Mppt through the breaker/cut-off and to the positive bus bar with the wire I already have running to the positive post on the battery and sharing the connection with the Mppt?

I hope these are making sense or that I'm making sense. I'm still just not exactly sure how the current flows through some of this so the busbars are for sure a mystery. I am wondering if it matters where things are connected or in what order on the bus bar, ya know? That's why I separated the Mppt connection and the inverter connection so that they weren't on the same bar because I wasn't sure if that was a catastrophic idea or not!!
Anyway, hopefully you guys can help me sort this out and learn this in the process. I appreciate all of your responses.

16359646477022377733982408924338.jpg
 
Your drawing of the wires for the BMV712 is incorrect.
The battery side of the shunt should go to the batteries. The only thing attached to the negative side of the batteries is the BMV712 shunt.
The load side of the shunt - send that to the negative buss bar and then ALL other items attach to the negative buss bar (including the ground).
 
Thanks for your reply!
Ok, so in my drawing the top of the shunt is the battery side and it is, as you suggested, connected to the negative post on the battery bank. The load side is connected to the lowest post on the negative bus bar. The only other Connection on the BMV shunt is the ground wire, so I can remove that.
Then the ground that you're referring to is that the the inverter ground or adding a ground to the negative bus to replace the ground I have currently coming off of the BMV, or both?
 
On your drawing you show the ground to the frame on the battery side of the shunt - that is incorrect. The ground to frame must be either on the load side of the shunt or on the negative buss bar (your choice).

If you just drew the negative to frame ground in the wrong spot - opps. But if you wired it to the wrong- that will cause incorrect readings on the BMV712- because not all the loads are being counted.
 
OK, so I've checked my connections to the 712 and my ground wire IS on the load side of the shunt. Perhaps it looks like it's on the wrong side because I mounted the shunt with the battery connection furthest from the battery (or on top) but, ultimately I am considering moving that frame ground lead off of the shunt and over to the negative bus bar so that my system ground will now come off of the busbar rather than the shunt. I am also going to get rid of that 2nd shunt on the far right of the photograph that has the inverter case ground on it and just pin that wire to the chasis underneath the inverter.
Will this plan help my wiring to be correct and provide more accurate readings?
 
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