System component question

[Ben Marascalco]

I came across this image but there was no way to contact this person. I ordered all my Victron components last week, my design is almost identical to this. I wish I could ask him two questions about this and was hoping someone could suggest an answer here. 
Why did he use a breaker box for both MMPT's between them and the batteries?
Also, why would you have two DC/DC converters? I have one. 
The only thing I can think of is he is running two battery banks. 
Thanks for any help
Benny
|

[TheoW]

Looks like all the wires are going through those breaker boxes so it's hard to tell but circuit breakers at least on the output from the MPPT's is a good idea.

Those DC/DC convertors can be paralleled so he may be doing that to double the available output from a single unit.

[Pete Jaeger]

It's common practice to place breakers (DC breakers!) between both the solar panels and the charge controller and the charge controller and the charge bus, as is shown in this installation. For one, it allows you to disconnect the solar panels from the controller when performing maintenance, etc. It's debatable whether or not a breaker at the controller's inputs actually provides any "protection" but it certainly doesn't hurt (as long as the connections are good so voltage drop is minimized). And again, being able to disconnect the panels can be quite useful. Good luck!

[Ben Marascalco]

Thanks for the responses, can you offer a reason why he would use those big black DC breaker boxes instead of something more compact? I need to keep my components as small as I can. He used the Blue Sea breakers on the DC/DC converters, would those not work for the MPPT breakers?
Thanks!

[TheoW]

I don't know what those breakers are, but the blue sea breakers work fine  for me.

[Pete Jaeger]

You're welcome! Hard to know why he used that size box. Definitely seems like overkill! Maybe that's all he could find or he wanted room for something else in the future. Yes, you could use Blue Sea (or or less expensive Bussman breakers) instead. A lot of people seem to use the Midnight Solar breakers for the solar panels, which is likely what he is using here. Check out AM Solar's website for sample schematics. Just make sure that whatever breaker you choose is capable of handling what can be high voltages produced by your panels, especially when several are placed in series.

[Ben Marascalco]

Thanks for the help gentlemen! I have been told that Blue Sea and Midnite Solar breakers are comparable in quality and dependability, just built for different applications. I like the Blue Sea design, breaker boxes not so much. I will look at AM Solar thanks for the point! Appreciate it fellas! 
I will be back when this is assembled and I have purchased the prismatic system I am building soon.
I hope the sbmso will control all this stuff for me. 
Benny

[Ben Marascalco]

Pete I went to that website and looked but I dont see any schematics that you mentioned there. 
Am I missing something here?
Thanks

[Pete Jaeger]

Hey, Ben. Click on the DIY INSTRUCTIONS LINK. Scroll down and then click on the green "Wiring Drawing Archive" link. That will open up a Google Drive page with a crap-ton of diagrams. Check out 99-VANSIG.pdf and 99-SKOSIG.pdf for some good examples. Victron also has some sample schematics. Have fun!