[RE-wrenches] Two MPPT Charge Controllers, One PV Circuit

[Jay]

Hi Mick,

Outback and midnite have a common negative design. So what you describe works fine. 
You can connect the PV neg to the main neg buss and then connect to the CC, works fine. Ie only 1 negative connect to the controller.  

For the Schneider 60-150 controller it doesn’t as it measures on the negative side. So wouldn't work in that configuration 

I’m with dave on the 80-600.
I can’t see it as a danger but not sure how the two controllers handle it. 
Would be interesting to see the output!

You’re all good

Jay





> On Nov 7, 2019, at 2:43 PM, Mick Abraham <mick at abrahamsolar.com> wrote:
> 
> 
> Greetings, Wrenchies~
> 
> Matt Sherald's subject today resembles a client inquiry that is on my radar this week--perfect timing!
> 
> Dave Angelini & All~ What if only the PV array negatives are in parallel but the PV positives are divided across more than one charge controller? 
> My client is on the Outback platform instead of Schneider, the battery negative is grounded & by extension the PV negatives are also grounded. 
> Client has no DC GFI since it's an older installation & he would add three Flexmax 80 controllers; we'll put appropriate DC breakers on each PV+
> & Battery+ controller wire. Client's Mate 1 is old school so the revved up Flexmax 100 (with no built in display) is not of much interest in this case.
> 
> The reason the client needs to share PV negative across the controllers is it's a retrofit situation with some wires in place & no simple
> way to add more.  No inspectors are involved & I see no technical problem. Your thoughts?
> 
> The Wrench List is the Bomb!
> 
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> www.abrahamsolar.com
> 
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