Atkinson controller to Victron MPPT Question

[jgbagley]

I am going to replace my Atkinson solar controller with a Victron MPPT.
I was assuming that this would essentially be a straightforward change, but it looks to me like there is no negative cable wired to the Atkinson coming from the Zamp roof mounted solar panels. Any suggestions as to what I might be missing?
Also, I don't believe I need to wire anything to the "Load" ports of the MPPT, but please correct me if I am wrong about that.

[PB_NB]

When I put Victron Controller in, I just ran 2 wires to the battery side and 2 wires coming in from the solar roof connection. Then added a chassis ground to the negative bus bar to the side of the Victron. Then picked the charge profile for Lithium (in my case).

It was pretty easy to do, I did install fuses on the input and output sides of the controller just in case of surges.

[jgbagley]

That's where I am confused...it doesn't seem like there are 2 wires from the solar panels based on how the factory installed them, it is just the PV positive cable. The factory installed wiring diagram shows the PV negative being wired directly to the battery and not going through the charge controller.

[PB_NB]

Oh you are right, I see that the green wire is missing from your photo. My pre wire has a yellow and green wire. Is there a green wire floating around or already grounded to the chassis or bus bar in the vicinity? It could be that the ground is attached nearby and is coming through the screw holding the unit down.

[Glen Carter]

As I recall when I installed my Victron MPPT the Atkinson solar controller was in the DC box and both the yellow and green solar wires were there. I just pulled the yellow and green out and connected to the MPPT

[PB_NB]

I had a look at the install from Atkinson's website and it looks like the input and output ground are shared.

So somewhere nearby there must be the green wire attached to the ground or the black wire coming out of the controller.

I hope you can find it.

[jeffmc306]

You’ll find the solar ground attached to the ground bar in the DC box. The yellow is connected to the Atkinson controller. It’s the large green wire in the lower left part of the DC box photo.

I swapped my Atkinson in our 2019 Globetrotter for a Victron 100/30 SmartSolar controller and put a disconnect in so I can do maintenance without having to climb on the roof and disconnect the panels.

I had installed a BMV-712 earlier but you can now get a SmartShunt without the display and just use the App.

BTW, my Victron does not have “Load” terminals - just PV and Battery
Good luck with your build!
-Jeff

[jgbagley]

Sorry it took me a few days to respond...was away for the trailer, so couldn't check it until yesterday. You are right, there is a green wire which was just not plugged into the Atkinson solar controller, but instead went directly to the battery. I was able to install get it installed with this info. Thanks a million!