Basic understanding of HIS (Home Integration System) functionality

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?

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.

NealG said:

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

Click to expand...

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.

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.

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

djwildstar said:

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.

Click to expand...

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.

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.

NealG said:

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.

Click to expand...

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.

It looks to me like the BID is getting grid power to keep the dark start battery charged from the main service panel "feeder breaker" that feeds AC to the "backup sub-panel" through the MID as I boxed in red in the circuit diagram:



Not shown is a block diagram of the BID insides where there must be a AC-DC converter to keep the 12v dark start battery topped off.

The Block Diagram below confirms the BID gets grid power when the grid is up.

Does this mean that only the home owner's vehicle can use the HIS to power the home? I am curious if any F150L can pull up to this HIS, plug in, and power the home during a power outage? For example, if this HIS was installed on a community center, or homeless shelter, could any F150L pull up and help power the building? I am curious if the HIS is specific to a certain truck (somehow paired where other F150Ls would not work).

rraustad said:

Does this mean that only the home owner's vehicle can use the HIS to power the home? I am curious if any F150L can pull up to this HIS, plug in, and power the home during a power outage? For example, if this HIS was installed on a community center, or homeless shelter, could any F150L pull up and help power the building? I am curious if the HIS is specific to a certain truck (somehow paired where other F150Ls would not work).

Click to expand...

It’s a great question. I will try it in a few weeks hopefully.

rraustad said:

I am curious if the HIS is specific to a certain truck (somehow paired where other F150Ls would not work).

Click to expand...

Yes, your truck must be BT-paired to the FCSP to provide backup power. AFAIK the reason being that the FCSP lets the truck know through BT that there is no grid power and it's OK to initiate backup power transfer. In past forum discussions, the poor BT connectivity between truck and FCSP has been cited by forum members as a reason for the failure of backup power transfer, with advice to park the truck with the right rear passenger seat as close to the FCSP as possible to facilitate the BT communication needed to enable power transfer. The truck's BT module is behind the right rear passenger seat, whereas the FCSP is typically positioned on the left side of the truck, as that's where the charging port is located ( ). Poor BT communication = failed power transfer.

OK, so let's assume that a blue tooth pairing is required. Couldn't any F150 pull up , pair with the system, and just get started?, is the initial pairing a show stopper?

What I don’t understand (and I mean that I don’t understand, not that I’m smarter than the engineers) is why when you have a battery in the system you don’t simply let the truck be one of the additional charge sources for it. You need no communication for a system like this other than the internal relays of the charger (multi-input chargers exist in the marine world).

What is the advantage of this complexity? On my boat I essentially have an inverter/charger that can be powered by the dock mains, generator, or an engine alternator. You can disconnect from the dock and not even know, and more complicated systems can even help boost the power when shore power voltage is low. There is no Bluetooth or anything particularly complicated or ”dark start” batteries. This has all been worked out since AC was put on boats - why is it so complicated on land?

rraustad said:

Couldn't any F150 pull up , pair with the system, and just get started?, is the initial pairing a show stopper?

Click to expand...

Ford probably didn't think they'd sell enough Lightnings and HIS units for starters to worry about such things, i.e., what is the likelihood that you're going to round up enough Lightnings to round-robin swap into the provision of backup power - the owners might be more worried about using their vehicles to power in their own homes in an area outage, etc. I should also imagine some security considerations in everyone widely pairing up with the same device. Before you can do the BT pairing, the truck(or user in FP) has to be able to join the same Wi-Fi network the FCSP is on (the pairing is initiated in FordPass thru a Wi-FI connection to the FCSP), so there's sharing of secure information there, too. Basically, the FCSP and HIS unit are designed to be on a private network and not publically accessible, so Ford would have to rethink the way the truck/FCSP connections work to make it more user-friendly, and there probably isn't enough call for the Lightning to provide backup power in a communal way to make it worth worrying about.

Newton said:

What is the advantage of this complexity? On my boat I essentially have an inverter/charger that can be powered by the dock mains, generator, or an engine alternator. You can disconnect from the dock and not even know, and more complicated systems can even help boost the power when shore power voltage is low.

Click to expand...

The truck has to know there is no grid power and that the critical loads panel is disconnected from the grid before backup transfer is initiated. Similarly, when grid power is restored, the truck has to stop providing power. This can all happen fully automatically without any human intervention. There is the ability to set a reserve battery limit so that power transfer to a house stops when the HVB is drained to that point, allowing the truck to still be driven somewhere, say, to a neighboring area to recharge if the outage is very local. What's going on with the truck and home power can be monitored in the truck and now via a Ford website, Energy App (ford.com) (doesn't seem to be working well in either Edge, Chrome, or Firefox right now; after logging in, the web page goes blank as soon as it loads). So, all this "stuff" requires complex monitoring and is not like manually switching power sources at your dock. Your dock system probably doesn't have to continuously monitor the state of grid power and disconnect or reconnect your boat to grid power according to grid power status. The Lightning setup also waits a minute or two at least before initiating backup power transfer to avoid flicking power transfer on/off/on/off, etc., with a flickering unstable grid. I haven't been able to use the Ford "Energy (web) app" yet but formerly, you could control backup transfer in FordPass from anywhere you had a Wi-Fi connection and monitor how the system was handling the outage remotely, i.e., your truck could be home to backup the house while you're vacationing somewhere else.