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Gen 3 Charger Power Sharing - who has this working?

davedesa

New Member
Oct 27, 2020
4
2
Boston
I just setup power sharing via subpanel and seems to be working okay. Noticed the following behavior and just wanted to see if others are seeing the same thing. Overall it appears to be working, but not quite the behavior I was expecting.
  • Wifi to home network is only on the master wall connector. The other one shows connected to my network, but doesn't have a local IP or shows up on my client list.
  • When both chargers are connected, even if only one is charging it defaults to 24A. Then it slowly ramps up the amps on the car that is charging. If just one charger is plugged in it will charge at 48A right away.
I'm experiencing the same situation. Not really what I expected. It's not ideal to have to unplug the other car to get the full 48amps. It's not a deal-breaker since I don't need the 48 amps in most cases, but I'm hoping Tesla fixes this.
 

miimura

Well-Known Member
Aug 21, 2013
6,865
6,759
Los Altos, CA
The lowest possible pilot signal for a J1772 compatible EVSE is 6A. I would expect that if a non-charging car is plugged in, that 6A must remain allocated to that plug. In theory, with a 60A breaker setting, the actively charging car should eventually have 42A available, even if it starts out at 24A and ramps up from there as indicated above.
 
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Sophias_dad

Active Member
Supporting Member
Jul 29, 2018
1,903
2,111
Massachusetts
I'm experiencing the same situation. Not really what I expected. It's not ideal to have to unplug the other car to get the full 48amps. It's not a deal-breaker since I don't need the 48 amps in most cases, but I'm hoping Tesla fixes this.
I'm not sure what you mean. "slowly ramps up the amps on the car that is charging" is presumably only tens of seconds or low-minutes. I don't think there's anything to fix.

I mean, lets suppose for a moment the rule is "When a car gets plugged in, it gets full power immediately, and over time we figure out how much the two cars together are using and turn them down appropriately." If you were to plug in two cars at the same time, they'd be drawing double the amount they were supposed to, at least for a time. In truth, since this is a Gen3 thing, you might be okay since they are supposed to have separate circuits at least back to a subpanel. If they are going back to a main panel(rated at 100A or better main breaker), it probably won't trip, since 48 extra amps for the tens of seconds it takes to ramp-down might not be enough to trip it. If they are instead going back to a subpanel specifically installed in the garage for charging, it might have only a 60 amp feed breaker coming to it, and that feed breaker may trip because the charge level isn't curtailed fast enough.

When the other choice is "wait (literally) a minute to get up to full current levels", that's really easy to decide, since a typical charging session is hours long.
 

davedesa

New Member
Oct 27, 2020
4
2
Boston
I'm not sure what you mean. "slowly ramps up the amps on the car that is charging" is presumably only tens of seconds or low-minutes. I don't think there's anything to fix.

I mean, lets suppose for a moment the rule is "When a car gets plugged in, it gets full power immediately, and over time we figure out how much the two cars together are using and turn them down appropriately." If you were to plug in two cars at the same time, they'd be drawing double the amount they were supposed to, at least for a time. In truth, since this is a Gen3 thing, you might be okay since they are supposed to have separate circuits at least back to a subpanel. If they are going back to a main panel(rated at 100A or better main breaker), it probably won't trip, since 48 extra amps for the tens of seconds it takes to ramp-down might not be enough to trip it. If they are instead going back to a subpanel specifically installed in the garage for charging, it might have only a 60 amp feed breaker coming to it, and that feed breaker may trip because the charge level isn't curtailed fast enough.

When the other choice is "wait (literally) a minute to get up to full current levels", that's really easy to decide, since a typical charging session is hours long.
I agreed, a few-minute ramp would be excellent, but it's closer to hours and never reached 48amps. The max I was able to see is 40amps after multiple hours. On the other hand, my Gen 2 setup would take a few seconds.
 

tm1v2

Member
Oct 18, 2021
670
446
USA
I agreed, a few-minute ramp would be excellent, but it's closer to hours and never reached 48amps. The max I was able to see is 40amps after multiple hours. On the other hand, my Gen 2 setup would take a few seconds.
If you can find a way to report this to Tesla, please do! I might deploy a power sharing setup soon, and while this behavior wouldn't be a deal-breaker, would be nice to have a quicker ramp.

I assume the charging protocol lets it ramp a car back down, if another car starts requesting more...
 

Sophias_dad

Active Member
Supporting Member
Jul 29, 2018
1,903
2,111
Massachusetts
I agreed, a few-minute ramp would be excellent, but it's closer to hours and never reached 48amps. The max I was able to see is 40amps after multiple hours. On the other hand, my Gen 2 setup would take a few seconds.
I agree that that sounds like defective charging behavior. I'd definitely report it to Tesla.
 

Maybe22

Member
Jan 28, 2021
236
331
PA
Is there any reason I could not use the gen 3 load sharing capability to share between two vehicles, 1 Tesla and one non-Tesla? Each would have a gen 3 wall charger and I would use an adapter to plug in the non-Tesla Vehicle.

Separately, has Tesla addressed the question re: ramp when two cars are plugged in? If it’s not going to give the full 48 amps to the non-fully charged car, I feel like I’d be better off with a single charger and just charge each night whichever car needed it more. Any updates on that question would be much appreciated. Ty
 

brkaus

Well-Known Member
Jul 8, 2014
8,283
6,838
Austin, TX
Is there any reason I could not use the gen 3 load sharing capability to share between two vehicles, 1 Tesla and one non-Tesla? Each would have a gen 3 wall charger and I would use an adapter to plug in the non-Tesla Vehicle.

Separately, has Tesla addressed the question re: ramp when two cars are plugged in? If it’s not going to give the full 48 amps to the non-fully charged car, I feel like I’d be better off with a single charger and just charge each night whichever car needed it more. Any updates on that question would be much appreciated. Ty

I have the same question when using a Tesla to J1772 adaptor. I assume it would work... I charge our leaf with the WC (gen2) and it works fine as a single charger.

Regarding balancing... I prefer the split the charge evenly approach. Both will be full anyway in the morning (under most circumstances). If there was a special case, I'd just leave one car unplugged that evening. No algorithm is perfect for all situations.
 
I know this is old, but I wanted to revisit this topic again as there are a lot of miss informations about each wall connector supposed to have its own circuit breaker.

Here in the Wall Connector guide it says the following:

Power sharing is ideal for households that need to charge more than one Tesla at the same time, but may not have enough power for multiple electrical circuits. This functionality allows up to four Wall Connectors to share power from one circuit while still allowing your vehicles to receive a sufficient charge.


I have had Power Sharing working with two gen 3 Wall Connectors connected to one 60amp breaker.

Each Wall Connector is setup to its maximum allowable amp (60 amps for 48amps continuous)

When both cars are connected which ever car has the lowest charge requests more energy. Both Wall Connectors never exceed the maximum supply amp (in my case 48 amps between the two).

As soon as one car is fully charge, the other car gets all 48amps assigned.
I am thinking I have to do the same thing as there is not enough space in my main panel. My question is how is the charging? Will both cars be charged completely during the evening?
 

Maybe22

Member
Jan 28, 2021
236
331
PA
These are probably really dumb questions, but 1) the gen 3 wall connectors communicate with each other exclusively by wifi, no hard wired, correct? and 2) I can successfully have 2 appropriately set up and configured Tesla gen 3 wall chargers load share with no local wifi network whatsoever, correct? They just need to communicate with one another via wifi, right?

ty
 
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miimura

Well-Known Member
Aug 21, 2013
6,865
6,759
Los Altos, CA
These are probably really dumb questions, but 1) the gen 3 wall connectors communicate with each other exclusively by wifi, no hard wired, correct? and 2) I can successfully have 2 appropriately set up and configured Tesla gen 3 wall chargers load share with no local wifi network whatsoever, correct? They just need to communicate with one another via wifi, right?

ty
I believe that is all correct.
 

dailo

Member
Jul 22, 2017
807
881
Bay Area
Looks like a few days ago firmware 21.36.5 was pushed to both my Wall Connectors and now both are connected to my network. Not sure how the 2nd one got the update, guess they master one had the ability to update others connected to it. Don’t see any other obvious changes for this firmware release.
 

dailo

Member
Jul 22, 2017
807
881
Bay Area
Looks like a few days ago firmware 21.36.5 was pushed to both my Wall Connectors and now both are connected to my network. Not sure how the 2nd one got the update, guess they master one had the ability to update others connected to it. Don’t see any other obvious changes for this firmware release.
Whoops nevermind, looks like it actually broke my power sharing and that is why both started showing up on my network. Had to factory reset both wall connectors and pair them up again.
 
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