Basic understanding of HIS (Home Integration System) functionality

[NealG]

I am working on Innovating with the Ford Home Integration system. I have included a rudimentary diagram showing the parts of the system and how power flows through the system in both modes - charging the F150 (Grid On) and discharging to home AC load (Grid Off). My diagram is a work in progress. it is based on the wiring diagrams in the Ford Home Integration System Installation and Wiring document.

My diagram: https://www.f150lightningforum.com/forum/attachments/f2-pdf.71941/

I have one question that is not obvious to me from that diagram. By what mechanism is the Dark Start battery charged?

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[djwildstar]

NealG,

Looking good! With respect to your diagram:

• What you label as "Grid" is the main service panel and associated equipment.
  • At minimum, this should show the meter, main breaker, and breakers for the FCSP (EVSE) and non-critical loads.
  • An Acrel current meter is used to sense current on the main feeder lines via current transducers (CT) installed on those lines. The sense lines from the CTs to the Acrel Meter are not RS485 -- these are analog sense lines between the meter and its current transducers.
• The connections to the transfer switch (WHB/MID or Whole Home Backup / Microgrid Interconnect Device in SunRun's documentation) don't seem correct. Specifically:
  • There is no connection from the dark-start battery to the WHB/MID.
    • As far as I can tell, the WHB/MID doesn't need power to switch from grid power to backup power -- this happens automatically when grid power fails.
    • I'm guessing that the WHB/MID does need grid power ON as well as confirmation from the BDI (inverter) that either backup power is OFF or that solar production is synchronized with the grid before it reconnects the load to grid power.
  • There is an RS485 connection from the WHB/MID to the BDI (inverter), which would supply this confirmation signal.
• The connections to the inverter (BDI or Bi-Directional Inverter in SunRun's documentation) also don't seem complete.
  • There are RS485 connections:
    • From the BDI to the WHB/MID
    • From the BDI to the FCSP (Ford Charge Station Pro or EVSE)
  • There is a 12V connection from the BDI to the FCSP.
    • This supplies the FCSP with power from the dark-start battery so that the FCSP and BDI can communicate with the truck and bring backup power online.
    • It appears that the BDI manages the dark-start battery, potentially including supplying charging current to the battery when needed.
  • In SunRun solar setups, the solar array and optional stand-alone backup battery also connect to the BDI.

 

[v2h8484]

I have one question that is not obvious to me from that diagram. By what mechanism is the Dark Start battery charged?

Most likely there is a small charger that charges the 12V dark start battery whenever DC power from the truck is enabled. It's similar to how the 12V battery gets charged in cars and generators with electric start.

 

[Jim Lewis]

Check out the Sunrun Field Website if you haven't already. It has extensive details on the FCSP and the HIS unit:
https://sites.google.com/sunrun.com/sop/sops/ev-chargers/ford-ev-charger

The site seems to work better with Chrome and a Google account login than trying to do the same with MS Edge and the same Google account.

 

[Wattsgas]

There is also a communication line from the charger to the inverter.

 

[NealG]

NealG,

Looking good! With respect to your diagram:

• What you label as "Grid" is the main service panel and associated equipment.
  • At minimum, this should show the meter, main breaker, and breakers for the FCSP (EVSE) and non-critical loads.
  • An Acrel current meter is used to sense current on the main feeder lines via current transducers (CT) installed on those lines. The sense lines from the CTs to the Acrel Meter are not RS485 -- these are analog sense lines between the meter and its current transducers.
• The connections to the transfer switch (WHB/MID or Whole Home Backup / Microgrid Interconnect Device in SunRun's documentation) don't seem correct. Specifically:
  • There is no connectionfrom the dark-start battery to the WHB/MID.
    • As far as I can tell, the WHB/MID doesn't need power to switch from grid power to backup power -- this happens automatically when grid power fails.
    • I'm guessing that the WHB/MID does need grid power ON as well as confirmation from the BDI (inverter) that either backup power is OFF or that solar production is synchronized with the grid before it reconnects the load to grid power.
  • There is an RS485 connection from the WHB/MID to the BDI (inverter), which would supply this confirmation signal.
• The connections to the inverter (BDI or Bi-Directional Inverter in SunRun's documentation) also don't seem complete.
  • There are RS485 connections:
    • From the BDI to the WHB/MID
    • From the BDI to the FCSP (Ford Charge Station Pro or EVSE)
  • There is a 12V connection from the BDI to the FCSP.
    • This supplies the FCSP with power from the dark-start battery so that the FCSP and BDI can communicate with the truck and bring backup power online.
    • It appears that the BDI manages the dark-start battery, potentially including supplying charging current to the battery when needed.
  • In SunRun solar setups, the solar array and optional stand-alone backup battery also connect to the BDI.

Thanks for your input, I am going to revise the diagram and repost it here when I figure more things out. Thanks to the other posters for their input.

 

[NealG]

I have also gotten useful information from Sunrun field support. They say the DS Battery is charged during Grid On time from the BDI. which leads me to wonder where the BDI is getting that energy from. It's not clear to me from the diagram.

 

[djwildstar]

I have also gotten useful information from Sunrun field support. They say the DS Battery is charged during Grid On time from the BDI. which leads me to wonder where the BDI is getting that energy from. It's not clear to me from the diagram.

It looks like the BDI gets power from the backup subpanel when grid power is on. In particular: The RSD AC Disconnect labels the side of the disconnect switch that connects to the backup subpanel as "Line" and the side that connects to the BDI as "Load". Similarly, the AC terminals of the BDI are labelled AC IN in the SunRun system wiring diagram.

This suggests that during normal operation the BDI's AC IN terminals are in fact inputs, and the BDI uses that power to run itself, and charge the dark start battery. When grid power is out, the bidirectional inverter reverses this, and outputs power on the AC IN terminals.

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