HIS system with AC coupled solar and ability to charge truck via DC off grid.

[tearitupsports]

I have bought a HIS system and am about to install it, but am trying to get a couple answers before diving in. I have searched spec sheets, installation manuals, etc. but have no conclusive answers. Just hints that it may work here and there.

Question 1: Can the HIS system (E4-BDI inverter) be used with an AC coupled solar system? The E4-TL-US has this setup shown specifically on the architecture diagrams, but the E4-BDI spec sheet does not. The E4-BDI spec does say AC coupled compatibility though, but it has no specifics. Has anyone gotten this to work? I would love to be able to use solar in off-grid mode.
For reference I should be getting an LG battery to have even when the truck is not plugged in.

Question 2: Can the truck actually be charged in off grid mode using the DC connection? I have seen a couple of random posts indicating someone says it can be done, but nothing specific. It would be nice if excess solar can be used with the truck in an off-grid scenario, as the AC charging would be off as per the system diagram.

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[smandel]

Yes, mine is AC coupled to my Solar and during the daylight when I’ve tested the system the truck battery level increased. I’m looking to get a battery installed for when my truck isn’t plugged in as well.
my power at home is solid from the grid so any interruption has been less than the time to initiate his system. I guess that’s a good thing and the reason I haven’t moved on an extra 5-10 kw battery.

 

[tearitupsports]

Yes, mine is AC coupled to my Solar and during the daylight when I’ve tested the system the truck battery level increased. I’m looking to get a battery installed for when my truck isn’t plugged in as well.
my power at home is solid from the grid so any interruption has been less than the time to initiate his system. I guess that’s a good thing and the reason I haven’t moved on an extra 5-10 kw battery.

Thank you. I assume the solar is back feeding a breaker in your critical loads panel?

 

[smandel]

Correct

 

[Runaway Tractor]

Yes BUT... The amount of hours per day that there would be sufficient 400vdc from the solar system is very limited. Peak voltage is a few hours a day when in full sun. And the majority of users are not even home when that happens since it's mid-day. It requires a whole new hardware and firmware implementation to comply with industry DCFC standards and be safe. So it is a LOT of work, a LOT of hardware/software to implement, and minimal to no actual useful purpose.

You COULD use massive battery storage power walls to capture solar energy while you're away. Then it's DC-DC boost from 48vdc to 400vdc. Still some loss, and still additional hardware and software. So honestly still not work it IMO.

Level 2 AC charging requires nothing special and is universal. So despite some conversation loss during coincidental peak sun hours, IMO sticking with level 2 AC is stilll the best way.

 

[Runaway Tractor]

Sure. But 400vdc residential power systems are far fewer and further between, more complex, and far fewer options on the market. There are significant safety and code compliance implications that do not apply to traditional 48vdc systems. In other words, you'd be paying out the ass for a complex system that likely has little to no ROI on that extra cost even with the small efficiency improvement over a traditional 48v system.

Just to put system size in perspective here in very very rounded terms, you'd need ~0.6 industry standard 400w solar panel per kWh of EV recharging. My 60kWh round trip daily commute would require 36 panels. More the further north you live. A 14kWh battery power wall is about $3600. So that would be about $18k in batteries just for EV charging storage here.

It is usually more economical to just do net metering where your excess solar is sold back to the grid, and that offsets (some or all) of your EV charging grid power in the evening. A smaller battery system, maybe on 14kwh power wall services a home UPS for power outages on a critical load panel if you want that.

 

[Runaway Tractor]

ok

 

[chl]

I have bought a HIS system and am about to install it, but am trying to get a couple answers before diving in. I have searched spec sheets, installation manuals, etc. but have no conclusive answers. Just hints that it may work here and there.

Question 1: Can the HIS system (E4-BDI inverter) be used with an AC coupled solar system? The E4-TL-US has this setup shown specifically on the architecture diagrams, but the E4-BDI spec sheet does not. The E4-BDI spec does say AC coupled compatibility though, but it has no specifics. Has anyone gotten this to work? I would love to be able to use solar in off-grid mode.
For reference I should be getting an LG battery to have even when the truck is not plugged in.

Question 2: Can the truck actually be charged in off grid mode using the DC connection? I have seen a couple of random posts indicating someone says it can be done, but nothing specific. It would be nice if excess solar can be used with the truck in an off-grid scenario, as the AC charging would be off as per the system diagram.

Q1: the HIS can have a solar input, but an inverter takes a DC input from the PVs and produces AC, so solar panels to the HIS BDinverter is provided for (see the Sunrun documents) as a DC input through the J box.

However, you could use the solar AC system as an alternate power source through a transfer switch to the BACKUP BREAKER panel.

In this diagram, the solar cells are shown on the far right top of the diagram.

If another AC source is provided, it could be connected via the BACKUP SUBPANEL and another transfer switch.

The Lightning and the other AC source (e.g., the solar inverter AC output) could be switched with another AC DISCONNECT to input to the AC IN of the DELTA BDI. So if the Lightning is not connected the solar cell inverter AC output would power the BACKUP SUBPANEL.

Or one could switch the solar DC output from the solar cells, from the solar inverter to the BDinverter PV IN.

Best to check with Sunrun/DELTA or the installer about what is the best way to have the solar connected.

But there are definitely multiple ways it could be done.

Q2: It could be done, but I have not heard of anyone doing it. To do it, you have to do all the handshaking that a DC Fast Charger does to negotiate the DC charging with the Lightning. So there needs to be some emulation in the off-grid DC source of a commercial DC fast charger.

Another way would be to have a large-ish battery bank charged by the solar/wind/whatever, and use that to power a DC fast charger. There are some DC chargers for home use available.



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But the FCSP at 80A give you 19.2kW charging power so a L3 at 25kW is not that much better and costs a heck of a lot more!

To get really high power L3 you need a high voltage high current utility source which most people don't have at a residence.

And commercial ones are pricey (tens of thousands).
But there are government subsidies if you want to set up a commercial one and have a place where it can be done - an appropriate utility hook up.

But remember, DC fast charging stresses the HVB so not a good idea to be doing it at home every day if you want your battery to last.

The slowest charging you can live with is the best for battery longevity, if that matters to you.

 

[tearitupsports]

Yes, mine is AC coupled to my Solar and during the daylight when I’ve tested the system the truck battery level increased. I’m looking to get a battery installed for when my truck isn’t plugged in as well.
my power at home is solid from the grid so any interruption has been less than the time to initiate his system. I guess that’s a good thing and the reason I haven’t moved on an extra 5-10 kw battery.

I have a very specific question. In the invert M-professional app, do you have the AC coupled setting turned on or off?

 

[colonel K]

Sure. But 400vdc residential power systems are far fewer and further between, more complex, and far fewer options on the market. There are significant safety and code compliance implications that do not apply to traditional 48vdc systems. In other words, you'd be paying out the ass for a complex system that likely has little to no ROI on that extra cost even with the small efficiency improvement over a traditional 48v system.

Just to put system size in perspective here in very very rounded terms, you'd need ~0.6 industry standard 400w solar panel per kWh of EV recharging. My 60kWh round trip daily commute would require 36 panels. More the further north you live. A 14kWh battery power wall is about $3600. So that would be about $18k in batteries just for EV charging storage here.

It is usually more economical to just do net metering where your excess solar is sold back to the grid, and that offsets (some or all) of your EV charging grid power in the evening. A smaller battery system, maybe on 14kwh power wall services a home UPS for power outages on a critical load panel if you want that.

My utility won't let me tie to the grid. The cheapest approach to off grid solar ev charging would be to stay dc. That would require solar panels, a mppt 48 volt dc charger and 48 volt batteries. I calculate about an 8 year payback for this system, because I am avoiding a hybrid inverter. The problem is that I cannot find an EV charger that uses 48V as input power. Does such a charger exist?

 

[Runaway Tractor]

The problem is that I cannot find an EV charger that uses 48V as input power. Does such a charger exist?

Probably not. Remember a level 2 charger just passes 240vac through to the vehicle. The actual charger is onboard the vehicle. So what you're asking for would be an normal inverter and a level 2 charger in a box. Kinda pointless.

For off-grid solar EV charging, I cannot think of a different setup than what you're already thinking. Enough solar to meet your full daily kWh requirement, and enough battery storage of your choice to hold you full daily requirement. Inverter of your choice providing 240vac to your loads, which includes your EV charger.

You could use a hybrid inverter like the EG4 18k. It can operate in grid following mode that does not push power out to the grid. It will sync with the grid for normal daily operation, and therefore reduce your grid utilization.

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