diy solar

diy solar

How do I connect additional charge controller to Flex Power One?

Skye Crofter

New Member
Joined
Aug 18, 2021
Messages
1
Greetings from the Isle of Skye in the Highlands of Scotland! New member here. I am trying to install our new off grid system. Panels are up and wired.

I was persuaded by my supplier to buy an Outback Flex Power One as we are beginners and he believed that a "plug and play" system would be better for us to avoid any wiring mistakes. This cost us a fair bit more than buying the components separately. As we are in a low light area for most of the year, we bought panels that would give us a large surface area, therefore an extra Outback FM80 was required to send two strings combined to the CC integrated in the FP1 and an additional FM80 for the other two strings. Now, the official word from Outback is that I need to purchase a dual GFDI unit and exchange it for the existing single GFDI unit in the FP1 and also buy another external shunt, then rewire the DC enclosure in the FP1 to accommodate the additional CC (they explained that my professional installer will be able to assist with this, but of course as we live very remotely and cannot afford a professional, we are the ones installing the kit). They admit that it is very tight in the DC enclosure and not easy. I am wondering why my supplier had not though of this, as we are novices!

So, other UK off grid self installers told me to simply wire the second 2 strings combined via a second 80A pv disconnect (which I have and could fairly easily fit in the DC enclosure) and then connect the batt pos and neg to the battery busbars. Now, the way the FP1 is wired it looks like the connections would be made to the Inverter/Battery disconnect and Shunt A. I guess my main question is this: do the shunts simply give you readable numbers (which are surely also available on each of the FM80s) or does the system require this information to optimize charging, etc? There is a Flexnet DC with Mate3 attached, via Hub10.

What are my options? Bypass the GFDI and shunts for the additional FM80? Connect to shunt A or B but not the GFDI? Pay out more money and rewire the FP1 as Outback are suggesting?

I will be very grateful for any insight you clever people can give me, including options I haven't though of!
Photos/wiring diagrams available if you need them.

Many thanks
Gareth and Sarah
 
I don't know jack about your specific components. With many systems, you can wire a solar charge controller independent of everything else. Wire the solar charge controller to your common bus bar and you're set.

The shunt exists to track power into and out of the battery bank so that you know the overall state of charge of the battery bank. Adding a solar charge controller should not impact the shunt.

Solar charge controller -> common bus bars -> shunt -> battery
 
Hmmm I would think you would have to run the new fm 80 thru a shunt so that you have the in put information in the mate .
 
Back
Top