Discussion: Powerwall 3 [Speculation / Discussion etc]

[BGbreeder]

Let me flip the question. How could a direct DC link (pack, contactor, port) not support bidirectional current flow?

Protective diodes for a start, current monitors, firmware code with limits...

I'm not saying that it can't; but that doesn't mean that it can either. Hence the question.

There are vehicles that can do this, but all the ones that I am aware of were all designed for it.

 

[cali8484]

Let me flip the question. How could a direct DC link (pack, contactor, port) not support bidirectional current flow?

Direct DC bus link does not mean direct connection to the battery. There is a least a BMS and potentially another DC-DC converter in front of the actual battery. So, depending on the actual HW, SW of these components and system conditions, bidirectional charging may or may not be possible.

 

[mongo]

Direct DC bus link does not mean direct connection to the battery. There is a least a BMS and potentially another DC-DC converter in front of the actual battery. So, depending on the actual HW, SW of these components and system conditions, bidirectional charging may or may not be possible.

Protective diodes for a start, current monitors, firmware code with limits...

There are no diodes. The flow is Supercharger -> charger bypass contactor -> pack contactor -> pack. That's it, direct connection.
The BMS monitors charge and discharge already.
Yes, the BMS/ vehicle would need to allow discharging, but @wk057 already figured out how to do it on (I think) stock software.

 

[cali8484]

There are no diodes. The flow is Supercharger -> charger bypass contactor -> pack contactor -> pack. That's it, direct connection.
The BMS monitors charge and discharge already.
Yes, the BMS/ vehicle would need to allow discharging, but @wk057 already figured out how to do it on (I think) stock software.

There is also charging port interface controls/protocols. Assuming the preliminary CCS bidirectional charging standard, the direction is set during the handshaking phase and if what you say is true then stock software already supports it? Seems doubtful bu I would love to see someone show a demo of it working and prove me wrong. Because if that is true then the available bidirectional DC chargers (e.g. dcBel) would already support Tesla EV's.

 

[metalblaze]

My Tesla advisor just called to inform that the Town building department has approved our plans. Of course, I asked him about PW3 -- he replied that he is unaware of any PW3 installations in and around the NYC area. Apparently, the Tesla Energy people were a bit "shocked" to learn about official confirmation of PW3 from Mr. Musk in Twitter. Per our advisor, mass installation of PW3 will probably won't happen until Spring 2024.

 

[mongo]

There is also charging port interface controls/protocols. Assuming the preliminary CCS bidirectional charging standard, the direction is set during the handshaking phase and if what you say is true then stock software already supports it? Seems doubtful bu I would love to see someone show a demo of it working and prove me wrong. Because if that is true then the available bidirectional DC chargers (e.g. dcBel) would already support Tesla EV's.

Stock Tesla software likely doesn't have bidirectionally built in, but they could add it.

 

[apacheguy]

Anyone order Powerwall direct recently in SoCal? I’d be curious to know the PW version and whether anyone has requested PW3.

 

[kpanda17]

PW owners with VPP, can you pickup cheapest TOU electric and sell back to the utility during the day?

 

[andy92782]

Update: We're in a holding pattern. It's looking like Tesla won't return to finish the installation until next week.

 

[Mark Stibbard]

Tesla just updated their website… looks like you can’t install a PW3 alongside a PW2: https://www.tesla.com/support/energy/powerwall/learn/what-expect-powerwall-3#california

 

[Jeremy3292]

Rebate extended til 3/31/24 also

 

[Jeremy3292]

I wonder what this means exactly:

• Scalable
  System expansion available anytime
  40.5 kWh max addition per unit

Wording is kind of confusion. So only 3 PW3’s can be stacked together? 13.5 kWh x 3 = 40.5 kWh

 

[mongo]

I wonder what this means exactly:

• Scalable
  System expansion available anytime
  40.5 kWh max addition per unit

Wording is kind of confusion. So only 3 PW3’s can be stacked together? 13.5 kWh x 3 = 40.5 kWh

One Gateway can only support 4 PW? 4x48Amp = 192A

 

[metalblaze]

Rebate extended til 3/31/24 also

Hmm…where is this information? Tesla website says install must happen by 10/31/23.

What is now explicitly added is that only PW2 & PW+ will qualify for the rebate.

 

[Jeremy3292]

Hmm…where is this information? Tesla website says install must happen by 10/31/23.

What is now explicitly added is that only PW2 & PW+ will qualify for the rebate.

View attachment 973445

I guess they didn’t update the fine print wording yet but it’s shown clearly when you try to order:

 

[Jeremy3292]

One Gateway can only support 4 PW? 4x48Amp = 192A

So you’re saying it’s no different? They’re just calling it out now?

 

[apacheguy]

What size is the solar inverter in the PW3? It seems to depend on the PV voltage? My PV array operates at 240 V so does that mean the max I’ll get is 240 x 13 = 3.1 kW? That would be disappointing.

 

[mongo]

So you’re saying it’s no different? They’re just calling it out now?

Maybe? Although, you could put 10 PW2s in one system so it could be something different. Battery charge/ discharge limit on older units was 5kW or 20A, these may have much higher discharge.

 

[mongo]

What size is the solar inverter in the PW3? It seems to depend on the PV voltage? My PV array operates at 240 V so does that mean the max I’ll get is 240 x 13 = 3.1 kW? That would be disappointing.

The PW+ allowed paralleling MPPTs to increase current. It had 4 inputs of 13A which could be jumpered to make two inputs of 26A (or 13,13, and 26). The PW3 (PW++) likely has the same setup.

 

[Nevyn72]

Tesla just updated their website… looks like you can’t install a PW3 alongside a PW2: https://www.tesla.com/support/energy/powerwall/learn/what-expect-powerwall-3#california

From that link it appears the Powerwall 3 is only available with the included PV inverter, so if you already have solar or need to use microinverters you have to use a Powerwall 2 or 2+.

I wonder if this means they are going to keep manufacturing the PW2 in parallel to PW3 production or will a PV inveterless version of the PW3 be coming in future?