Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Load Shed Module?

MN-MS100D

Member
Dec 10, 2018
150
119
Minnesota
He's saying that the whole house generator cannot give you the power you need to charge your car during a power outage, so he wants a relay to dump (kill) the HPWC on a power outage so you don't overload the generator. A pneumatic delay relay might be the ticket so you can ride through momentary outages.

You don't have a non-generator panel?
 

jcanoe

Active Member
Oct 2, 2020
4,382
4,565
Maryland
Some plug-in vehicles actually state that you should not use a generator to charge the vehicle. I am unaware of any such restrictions for the Tesla Model Y. What if you just raise your right hand and promise never to charge your EV while your generator is running? The two biggest electrical loads would be the HVAC compressor and the plug-in or electric vehicle charging circuit. AC compressors, electric water heaters, electric dryers and electric ovens cycle on and off to maintain a specific temperature. The EV charger just runs and runs.

Suppose you did need to charge the Tesla vehicle using the generator as the power source. You could lower (but not raise) the maximum charging amperage for the charging session from the Tesla charging screen from the maximum (in this case 48A all the way down to 5A.)
 

MN-MS100D

Member
Dec 10, 2018
150
119
Minnesota
Maybe a shunt trip breaker on your EVSE circuit, if you can find one. Might be only available for commercial panelboards.

If you can find one, wire 120 or 240 volt wiring directly from the generator to the shunt trip actuator circuit, so anytime the generator is running, it immediately trips the breaker (requiring a manual reset of the handle). No need for pneumatic delay if the generator has a delay already built in before it starts. Usually a few seconds.
 
Last edited:

Gellie

Member
May 27, 2021
132
67
NJ
Some plug-in vehicles actually state that you should not use a generator to charge the vehicle. I am unaware of any such restrictions for the Tesla Model Y. What if you just raise your right hand and promise never to charge your EV while your generator is running? The two biggest electrical loads would be the HVAC compressor and the plug-in or electric vehicle charging circuit. AC compressors, electric water heaters, electric dryers and electric ovens cycle on and off to maintain a specific temperature. The EV charger just runs and runs.

Suppose you did need to charge the Tesla vehicle using the generator as the power source. You could lower (but not raise) the maximum charging amperage for the charging session from the Tesla charging screen from the maximum (in this case 48A all the way down to 5A.)
Yes. While I have desires to charge via generator, I’m concerned if the generator kick on at night while I’m charging and can’t disconnect the charger in time.
 

jcanoe

Active Member
Oct 2, 2020
4,382
4,565
Maryland
Yes. While I have desires to charge via generator, I’m concerned if the generator kick on at night while I’m charging and can’t disconnect the charger in time.
You could lower the maximum amperage while the vehicle is charging (you can do this anytime.) I think you can even lower the maximum charging amperage from the Tesla phone app.

If the generator is running during the middle of the night chances are the AC isn't running at that time.

If charging the Tesla overloads the generator, then the generator is protected by a circuit breaker.
 

Rocky_H

Well-Known Member
Feb 19, 2015
7,310
9,006
Boise, ID
You could lower the maximum amperage while the vehicle is charging (you can do this anytime.) I think you can even lower the maximum charging amperage from the Tesla phone app.
Interestingly, that part of the charging setup is not made available in the app. You can start and stop, and you can set the state of charge limit, but they don't let you change the amps on the phone app. That has to be done on the car's screen. I don't really know why.
 
  • Informative
  • Like
Reactions: Gellie and jcanoe

jcanoe

Active Member
Oct 2, 2020
4,382
4,565
Maryland
The electrician said the Tesla can handle the “surge” of power when the generator kick on and off,and when the natural power comes back on?
I have a Generac standby power system. When the power goes out the generator starts, stabilizes power and will restore power to my home in ~30 seconds. When the mains power is restored (after waiting ~2 minutes) the power system will attempt to transfer power back to the grid. There should be no power surge from the generator or when switching back to the grid.

I will ask my electrician about the load shed module. He did not state that I needed one when he installed the 50A charging circuit. This was 4 years after he upgraded my electrical service to 200A, replace my 50+ year old fuse panel and installed the 14kVA Generac standby power system. There is a 60A breaker on the outside of the generator.
 
  • Like
Reactions: Gellie

Sophias_dad

Active Member
Supporting Member
Jul 29, 2018
1,903
2,111
Massachusetts
A few things to note... The 'surge' isn't a problem. If the Tesla/HPWC notices a loss of power for even a second or two, it'll treat it as a power outage and then start charging after a random 0-3 minute delay. That delay is so the electric company doesn't see a giant slug of EV's all trying to start charging at the same moment(whether that is the moment the power turns on or exactly N seconds later). Additionally, it'll be ramping up as a usual charge connection and, if the generator bogs down and voltage starts dropping as a result, the Tesla will probably abort the charging session on its own. Its easy to test this, preferably not during a bout of bad weather.

Notably, switching back to utility power might be more interesting, depending on how long the switch takes. I presume its almost immediate(subsecond), and the tesla might not even notice.
 
Last edited:
  • Like
Reactions: alexcue and Gellie
Just had a Tesla Wall charger installed. My electrician said that I need a Load Shed Module installed because I have a whole house generator? Is this true? What should the cost be if needed. Thanks
It depends on the KW of your generator anything under 20KW will not cut it. Basically if you are charging at 48Amps at 240Volts, which is basically 11 kwh at peak charging. In my case it was a Generac SMM module I believe the model was 7006. My electrician charged me $285 for it
 
  • Like
Reactions: Gellie
It depends on the KW of your generator anything under 20KW will not cut it. Basically if you are charging at 48Amps at 240Volts, which is basically 11 kwh at peak charging. In my case it was a Generac SMM module I believe the model was 7006. My electrician charged me $285 for it
The 7000 is rated for 50 Amps and the 7006 for 100A . I have two of the 7000's on my AC units and I just picked up a 7006 for the Tesla wall charger. I have only seen my Power usage spike or maintain over 20KW a few times (testing lots of load) so I don't think my 36KW generator will ever need to shead .
You paid a good price on that unit with install , I picked one up on ebay today and have the electriction coming monday to give an estimate for install of a 60A line , the load shead and the wall charger
 
I presently have a Tesla charger on a 60 Amp circuit installed directly. I have a 200 amp panel and do have some capacity. My electric company is paying for behind the meter installation and only gives discounted electric rates on ChargePoint chargers. I am thinking of installing a second non-Tesla charger and want suggestions i.e.

1. Run a new circuit and have the second charger on that dedicated circuit
2. Can I have junction box and run the two chargers one at a time
3. Convert the Tesla charger to NEMA outlet and use a non-Tesla charger

Any suggestions are welcome
 
My electrician wants $825 just for the tesla wall charger. He wants to add an additional 4 shields. 1 for each of my AC units and one for the pool. If I did all 5 he charge 625 each. Why is this so expensive?
I have my electriction coming tommorow morning to give me a quote .

That 100A load shed is about $260 so if he is running a new line and providing the 100A 7006 then he's charging you about $500 for the install which isn't bad.

The Pool and ac units will use the 50 A 7000 and those boxes run $140 each. This box can be installed at the device or panel. They just disconnect one end and wire it to the box and then from the box they run a few feet of new cable . are you shure he isn't charing 625 for all 4 boxes ?

I would get another couple quotes
 
My electrician wants $825 just for the tesla wall charger. He wants to add an additional 4 shields. 1 for each of my AC units and one for the pool. If I did all 5 he charge 625 each. Why is this so expensive?


My Electriction wants $950 to install the Tesla wall charger and the 7006 ( which I purchased) ( a 40-50' run of 6 Gauge ) and through a concrete wall. I am mounting it outside between my 1 & 2 car garage doors.

So that $825 is looking pretty good to me :)

I was told most of the cost is Wire and then you have the labor and breaker . He didn't believe I needed the 7006 because of the Gen sizing but I figure I'll install it just as an extra protection for the generator .
 

Gellie

Member
May 27, 2021
132
67
NJ
My Electriction wants $950 to install the Tesla wall charger and the 7006 ( which I purchased) ( a 40-50' run of 6 Gauge ) and through a concrete wall. I am mounting it outside between my 1 & 2 car garage doors.

So that $825 is looking pretty good to me :)

I was told most of the cost is Wire and then you have the labor and breaker . He didn't believe I needed the 7006 because of the Gen sizing but I figure I'll install it just as an extra protection for the generator .
$825 Just. For the Load shield.
 
$825 Just. For the Load shield.
So this is just to add a load shed to an existing wall charger?
That guy is charing you about $550 labor for the 7006 and $480 labor for the 7000's . The picture below shows the 50A sheds connected directly to the subpanel. For AC units they are usually installed directly on the Air handlers . Get another couple quotes I would never pay that.


mqdefault.jpg

generator-jpg.22903
 
Last edited:
  • Like
Reactions: Gellie

patmurphey

Member
Aug 26, 2020
198
270
New Jersey
If you install the Tesla wall charger on a 60 amp circuit and charge at the allowable 48 amps, you are using almost 60% of that generators max capacity or 72% of the allowable 80% continuous load. If Kohler's load shed modules are 50 amps (like my Generac's) the a 50 amp connection is called for and the numbers are a bit better. You can set a Tesla's charging rate to a lower number and increase it if needed temporarily. YES, you need load shedding and if you want to charge on the generator the big A/Cs should be on load shedding. Your electrician can guide you on load calculations. It's a one tome deal, don't complain about the cost of a professional's service, but get a second bid if you want to be sure. A permit is a necessity, especially if you ever sell your house.

A standby generator is a good thing, but EV charging is a big continuous load.
 

Products we're discussing on TMC...

About Us

Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.

Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


SUPPORT TMC
Top