question

adrianp105 avatar image
adrianp105 asked

One Bus Bar set for Multiple Arrays and Controllers?

Hi all, I've designed my system to have three (3) PV arrays (one east facing, one west, and one south - all 18v max @ 100w) - the eccentricities of the area required this odd combination to achieve the desired output. I have three SmartSolar MPPT 75/15s that I intend to connect to a Cerbo GX with VE.Direct cables. It is my understanding that I need the Cerbo with arrays facing different orientations and drastically different performance throughout the day. All of my loads will be 12v DC, so I will not be using an inverter. I had initially planned on doing a separate busbar out of the load side of each controller, then connecting a group of loads to each of those busbars. But I have seen a few schematics where multiple arrays have one positive and one negative bus bar for the entire system. I want to take advantage of the controller load output to regulate the load for sensitive electronics. Is there anything wrong with doing separate busbars for the load out on each controller or am I missing an important feature/benefit to combining the busbars. Thanks in advance.

MPPT Controllerscerbo gxVE.Directbusbar
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

3 Answers
Mike Dorsett avatar image
Mike Dorsett answered ·

Separate load outputs are fine, you can even set different voltage limits for each of the controllers load switches. I don't see the need for a Cerbo in such a simple system, unless you are also using managed lithium batteries. Careful setting of the MPPT voltages will be needed, as well as attention to volt drop on the battery cables to the MPPT's.

5 comments
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Leslieanne avatar image
Leslieanne answered ·

Hi,

If you were to add a BMV or a Smartshunt to your system (well worth it anyway so you know what your battery is doing), then voltage drop and coordination of controllers is no problem at all. Simply set up a ve network over Bluetooth (BMV or Smartshunt first, then add the mppts to that network), set the same charge parameters on each controller and that's it. It's very simple, no need for a GX device.

Cheers, Leslie

3 comments
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

kevgermany avatar image
kevgermany answered ·

An observation. You say max panel voltage is 18. You need to be higher than this for the MPPTs to start charging ( more than actual battery voltage+5). Hopefully your panels will be wired in a series/parallel setup.

2 comments
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.