Author Topic: MNDC-GFP50-300  (Read 180 times)

WillEert

  • Full Member
  • ***
  • Posts: 156
MNDC-GFP50-300
« on: July 24, 2018, 11:42:23 PM »
I am installing a HotSpot ACDC12C mini split heat pump. This unit is not connected to AC nor does it have batteries or any form of charge controller. Basically it operates on a PV direct system. Neat.

http://www.hotspotenergy.com/solar-air-conditioner/

I intend to connect 6 345W STC panels in series to run it. The Voc will be 278.4V. I want to install ground fault protection using the Midnite MNDC-GFP50-300. The wiring diagram for the GFP shows the negative wire from the GFP connecting to the battery negative after the charge controller. But no batteries or charge controller....
So I am thinking - could I put the GFP in a MNPV6 and connect the negative from the panels to the negative bus and then the negative from the GFP to the same bus? Maybe I could put the surge protection in the same combiner box. From the MNPV6 I would go to my disconnect and then the minisplit.

Any feedback welcome.

Will
(1) 24 ET 185 mono, Classic 150,8x Surrette 6CS25p, 3x Magnum 4448, homecooked diversion system;
(2) 15 Heliene 330 mono, Classic 150; (3) 2 X 6 Hansol 345 mono, 2 stand alone Hotspot ACDC12C Mini-split heat pumps.

ClassicCrazy

  • Hero Member
  • *****
  • Posts: 1898
Re: MNDC-GFP50-300
« Reply #1 on: July 25, 2018, 12:02:41 AM »
Will
I don't know the answer to your GFI question but thanks for passing along the info on that heat pump. No batteries - neat !
Let us know how it works when you get it hooked up . I haven't read all the info on it yet but will take a closer look.

Larry
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie

WillEert

  • Full Member
  • ***
  • Posts: 156
Re: MNDC-GFP50-300
« Reply #2 on: July 25, 2018, 11:00:37 AM »
Hi Larry,

This mini-split answers many needs for us. With the heat we have had this summer, although our house is earth sheltered, we anticipate the need for additional cooling in the future. Additional heat in the winter will reduce our wood use / carbon emissions. I have a shop I only heat with wood so putting a unit there as well will reduce my wood use in that building. My PV system is getting more complicated and it was starting to hurt my head thinking about how I was going to add capacity in order to run a heat pump. Now I don't have to modify what is working to add capacity for a heat pump.

I am learning about GFCIs. There are definitely two schools of thought about if they are needed and if they create more problems. I would like to learn about how to install a GFCI in a system with no batteries and charge controller.

Also when looking at arc fault protection you can find some very scary pictures. Seems like there is really nothing one can do for arc faults in certain locations except use good careful installation practices.

Will
(1) 24 ET 185 mono, Classic 150,8x Surrette 6CS25p, 3x Magnum 4448, homecooked diversion system;
(2) 15 Heliene 330 mono, Classic 150; (3) 2 X 6 Hansol 345 mono, 2 stand alone Hotspot ACDC12C Mini-split heat pumps.

ClassicCrazy

  • Hero Member
  • *****
  • Posts: 1898
Re: MNDC-GFP50-300
« Reply #3 on: July 25, 2018, 11:28:30 AM »
Aren't both of those protections mainly for working around live circuits ? So if you do all the hookups with the solar deenergized are they really needed ?  I guess there are always accidents that can happen - like me testing a GFI because I touched an open exposed 120v AC terminal on a SSR relay -  it was experiemental setup and I know I was the only one around so no worries - ha ha - but I put a thermostat next to it and bumped the hot SSR connection. The GFI worked and cut out  but still got a nice shock out of it. Needless to say I have since made a cover for the SSR so it won't happen again !

Larry
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie

WillEert

  • Full Member
  • ***
  • Posts: 156
Re: MNDC-GFP50-300
« Reply #4 on: July 25, 2018, 01:49:47 PM »
I found this installation manual under the MNDC-GFP80 heading. On the first page there is a picture of what I want to - Install the GFP in a combiner box before the disconnect. Yay. I don't know the rights or wrongs of GFP installation but I do try to comply with code.  My minisplit cost has just gone up a bit but maybe I will be safer.

http://www.midnitesolar.com/pdfs/DC-GFP.pdf

Will
(1) 24 ET 185 mono, Classic 150,8x Surrette 6CS25p, 3x Magnum 4448, homecooked diversion system;
(2) 15 Heliene 330 mono, Classic 150; (3) 2 X 6 Hansol 345 mono, 2 stand alone Hotspot ACDC12C Mini-split heat pumps.