Finally! Dynamic Power Management for wall connector

[Olle]

I just discovered that Tesla has launched Dynamic Power Management, AKA upgrade avoidance, for the Wall Connector. Something I have been wanting for years. Really Awesome.
Here is the link. Not offered together with the Wall Connector Group Power Management yet.
As you can see in the article, you also need the approved power meter for $250, probably much cheaper than service upgrade.

 

[ItsNotAboutTheMoney]

For the above link the relevant section is:

https://www.tesla.com/support/charging/wall-connector/power-management#dynamic-power

Also a _huge_ deal for people who _cannot_ upgrade their service or who are significantly power limited by normal calculations.

And, with the universal connector available and North America switching to NACS this is an even bigger deal. It simplifies the questions for buyers enormously.

And there's more! If anybody pays demand charges, this should be able to be used to limit demand, not just stay with the panel's limits. That could be great for installation at some businesses, especially if they can develop it further to have a system for larger group installations.

 

[miimura]

This is awesome. I have a 50A 240V circuit dedicated to a J1772 EVSE today. I want to upgrade to a heat pump water heater, most of which require a 30A 240V circuit. The main panel is far away, so pulling a new circuit is not practical. The EVSE circuit was installed during construction and passes right by the desired water heater location. I was looking for a solution that would allow me to share the circuit between the water heater and the EVSE. I believe this solution would allow me to put a small sub-panel on the 50A dedicated circuit with the feeder monitored by the Neurio meter. Both the Wall Connector and the Water Heater could have their normal 50A and 30A breakers in the sub-panel and the Wall Connector should be modulated to never overload the 50A feeder.

I believe Emporia also released this feature recently, but I haven't looked into the details.

 

[MP3Mike]

It really is too bad that they don't allow it to work with multiple Wall Connectors:

Can Dynamic Power Management work across multiple Wall Connectors at the same time?
No. Dynamic Power Management is only available for single Wall Connector installations and cannot be utilized across multiple Wall Connectors.

That would be something that could help with installs at smaller condos, etc.

 

[wwu123]

This is awesome. I have a 50A 240V circuit dedicated to a J1772 EVSE today. I want to upgrade to a heat pump water heater, most of which require a 30A 240V circuit. The main panel is far away, so pulling a new circuit is not practical. The EVSE circuit was installed during construction and passes right by the desired water heater location. I was looking for a solution that would allow me to share the circuit between the water heater and the EVSE. I believe this solution would allow me to put a small sub-panel on the 50A dedicated circuit with the feeder monitored by the Neurio meter. Both the Wall Connector and the Water Heater could have their normal 50A and 30A breakers in the sub-panel and the Wall Connector should be modulated to never overload the 50A feeder.

I believe Emporia also released this feature recently, but I haven't looked into the details.

So basically this thing is monitoring the total current through a CT, and will dynamically adjust the Wall Connector amperage to keep the total of all loads below the setting?

I have a similar desire to repurpose a 30A circuit currently used by a 7.2kw instant hot water booster (EcoBoost). It's halfway between our tankless gas water heater and our master bathroom taps, so it heats the standing cold water in the hot water pipes for 15 seconds, until the hot water from the tankless reaches it. It cuts the amount of wait time for the master bath shower from 30 to 15 seconds, along with half the wasted water going down the drain.

But it's running at full 240V 30A for those 15 seconds a few times a day, a waste of precious 30A circuit. How quickly and dynamically do we think this feature adjusts power, can it respond within a few seconds to a 15 second burst of 30A? I know if the EcoBoost and the Tesla wall connector were both running at max (30A + 24A), it wouldn't trip the circuit breaker immediately at only 2X breaker rating for 15 seconds. But I'd rather be safe about it; would be worth upgrading my Gen 1 Wall Connector, if I can reclaim that 30A circuit for another use.

 

[miimura]

So basically this thing is monitoring the total current through a CT, and will dynamically adjust the Wall Connector amperage to keep the total of all loads below the setting?

Yes, that is my understanding of this feature.

 

[Zorg]

The Neurio is no longer sold. Any other load management device is available?

 

[miimura]

The Neurio is no longer sold. Any other load management device is available?

Through which sales channel are you basing this statement on? Tesla may have their own supply channel for these Neurio devices even if the manufacturer stopped selling them at retail. This is an important piece of the Tesla Energy ecosystem, so I am pretty sure Tesla can still get them.

 

[MP3Mike]

The Neurio is no longer sold. Any other load management device is available?

Huh? This is a specific version for gen 3 wall connectors and is available from Amazon.

Amazon.com

 

[MP3Mike]

It does appear that Amazon has sold out the stock from the primary store that was selling them for $250, and a third-party is now selling them. But given the product just started shipping I'm sure they will come back in stock. (And they may still be available at the normal prices from other sources, like through Tesla installers.)

 

[Olle]

How quickly and dynamically do we think this feature adjusts power, can it respond within a few seconds to a 15 second burst of 30A?

The short answer is: probably faster than it needs to, otherwise nobody would buy it.

Longer answer. Most power bursts in a home will be immediate, or worse. Some AC units e.g. will momentarily draw more than their rating on startup. Your case is milder than that, if the heater just draws 30 A linearly.

In order for the WallCharger Dynamic Power Management (DPM) Algorithm to work, one would assume that it is calibrated to at least beat the tripping curve of a typical breaker. Since the DPM knows the rated current and is able to measure actual current, it also knows multiples of rated current drawn.

tripping curve for Schneider (includes Square D)

As you can see in this curve, if you are charging max (on the 50A circuit x 80% ) which is 40A + running the water heater at 30A = 80 A = 1.6 x 50A.
In the curve here you'll see that it takes >30 seconds for a breaker to trip at 1.6 x rated current. Your breaker would therefore likely not trip during the 15 seconds of water heating even if DPM was not responding.

 

[ItsNotAboutTheMoney]

The Neurio is no longer sold. Any other load management device is available?

Neurio was bought by Generac in 2019. They switched to Generac branding.

I think it's essentially the same as this device:
Go to amazon. Search: B0874G7T8H
It certainly looks very similar.

But for Tesla's purposes I assume they're getting it and want to sell it without the Generac branding.

What the!?

If you click on "Vist the Neurio Technology Store" it takes you to a Tesla Amazon store and says the price is $448.00!
I suppose they must have had a positive reaction to the release.
But at that price, hell no.

 

[MP3Mike]

I think it's essentially the same as this device:
Go to amazon. Search: B0874G7T8H
It certainly looks very similar.

People report that that is the same as the Neurio W1 device. While the one that Tesla says you can use is the Neurio W2 device. They look the same, but who knows what differences there are. (It may be that the W2 is just a version with custom firmware to be able to talk to the Tesla Wall Connector over RS-485.

 

[ItsNotAboutTheMoney]

People report that that is the same as the Neurio W1 device. While the one that Tesla says you can use is the Neurio W2 device. They look the same, but who knows what differences there are. (It may be that the W2 is just a version with custom firmware to be able to talk to the Tesla Wall Connector over RS-485.

Well, the W2 seems to have a red light.

 

[Olle]

The short answer is: probably faster than it needs to, otherwise nobody would buy it.

Longer answer. Most power bursts in a home will be immediate, or worse. Some AC units e.g. will momentarily draw more than their rating on startup. Your case is milder than that, if the heater just draws 30 A linearly.

In order for the WallCharger Dynamic Power Management (DPM) Algorithm to work, one would assume that it is calibrated to at least beat the tripping curve of a typical breaker. Since the DPM knows the rated current and is able to measure actual current, it also knows multiples of rated current drawn.
View attachment 1015537
tripping curve for Schneider (includes Square D)

As you can see in this curve, if you are charging max (on the 50A circuit x 80% ) which is 40A + running the water heater at 30A = 80 A = 1.6 x 50A.
In the curve here you'll see that it takes >30 seconds for a breaker to trip at 1.6 x rated current. Your breaker would therefore likely not trip during the 15 seconds of water heating even if DPM was not responding.

My apologies, I re-read your post now and see that you are running a 30 A breaker, so 1.8 x rated. Same principles apply.

 

[ashish mittal]

Is 1938241-99-a the same as 1938241-00-a. The latter is what tesla recommends, but I can only find the former online

 

[mongo]

It really is too bad that they don't allow it to work with multiple Wall Connectors:



That would be something that could help with installs at smaller condos, etc.

Yet...
Unless WiFi lag is too slow to support peak shaving.
Worst case is secondary WC passing full current.
Meter -> wire -> primary WC -> WiFi -> secondary WC -> vehicle -> charger
Or... WiFi -> vehicle -> charge if everything is Tesla

Still, might be able to multi-point the 485 link or make a hub module.

 

[Visvism]

Is 1938241-99-a the same as 1938241-00-a. The latter is what tesla recommends, but I can only find the former online

I've been able to find the brand new packaged unit (1938241-00-a) via Tesla's Online Store and Amazon. From what I have determined, the reworked / refurbished version of the Tesla W2 (Neurio) product only is p/n 1112484-99-A (without the RS-485 data connect cable).

The data connect cable only is listed under p/n 1133339-00-A.

So I'm guessing the 1938241-99-a that you mentioned is likely the reworked / refurbished Tesla W2 AND the data connect cable in one package. It should be listed at a lower price if that is the case. I just purchased the refurbished unit and data cable for $100 shipped from eBay.

 

[jcbottorff]

I have one of the 1938241-00-A devices from Amazon. Actually I have two, one for tinkering and one that will get installed. A little glitch has come up. The CTs don't fit around the input bus bars on my year old SquareD SC3042M200PF meter panel. I'm assuming CTs will not work correctly unless the split side fully closes. I'm pondering if PG&E would let the CTs be connected around the service entrance wires upstream from the meter, in the utility sealed section of the panel. I think it's likely they don't exceed the 0.75" limit, and the meter panel is customer owned, but assume the wires are utility owned and maintained. I'm not sure who to contact at PG&E support for a question like this. I'm super happy to see Tesla Wall Charger support dynamic load management, and perhaps they will read this and for future customers use CTs with a larger hole. The CTs for my Enphase solar fit just fine, I think they have a 1" square hole.

The device talks RS-485 modbus RTU at 115200,8,1. I unfortunately don't know what the modbus register map is but am putting together some stuff to make good traces of the communication to the Universal Wall Connector. I looked at it on a scope and the Wall connector polls every second and the Neurio responds. The serial decode said the RTU request was read 10 holding registers at address 0x88 and the sensor responds back with 20 bytes of payload, which I don't know the meaning of yet. There may also be some startup handshaking, like asking what model of load controller it is. When I get good tracing working I'll try to vary the power parameters and see how the returned data changes. I see if the Wall Connector looses connectivity to the modbus sensor it retards back to 6A charging. I don't yet know what it does when the current limit is reached.

I don't have things installed yet, and am currently collecting parts and verifying everything fits and works. I haven't decided for sure if I will do the actual install or get an electrical contractor. My brain says DIY, my not so young back says hire an electrical contractor. Either way, I do want to be sure all the parts will work out. I'm guessing a contractor would not have figured out the CT doesn't fit until installation was started, so discovering this beforehand was fortunate. I don't know of a different load manager for a Tesla Wall Connector.

In an ideal world, what I probably want is a little gadget that talks ZigBee to my PG&E electric meter (I have a Rainforest Automation Eagle that does this now for years) and constantly reports power consumption to some local energy manager. Ideally, the Wall Charger could pull the power limit over WiFi. A little less ideal, a little box, like maybe a modbus to wifi gateway ($38 on Amazon) could bridge communication to the local energy manager, and respond to the modbus requests from the Wall Connector, avoiding the need for another CT sensor. My meter panel already has CT coils to my Enphase solar controller, so it's a bit silly to need a second set of CTs for the EV charger. The first CT's are silly because my meter already talks ZigBee reporting instantaneous power consumption (well delayed a second or two). I'm probably just going have a straight install of the Wall Connector and load manager, but figure while it's not yet connected I should record what it does for some future home automation company or DIY. Tesla could just make this really simple and perhaps could even make load management of the mobile connector plugged into a NEMA 14-50 outlet.

 

[miimura]

PG&E is not going to like anything in the meter side of your panel. I have a friend who has a center fed 200A panel and he did the same thing you are suggesting- putting CTs on the service lines before the meter. They made him remove it before they would set his meter. He had installed an Energy monitoring system in his newly upgraded panel and he was using the space below the meter to house the monitoring box. They made him remove everything from that space before the meter.