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(Calling All Electricians) Two Charger Setup/ Subpanel/ Power Sharing

So I'm looking for some guidance on a new two wall connector install:

My current setup is an old nema 14-50 plug, powered by a 60amp breaker from my main panel.

My plan is to remove the nema plug, install a 125 amp sub panel (feeding it from the old nema plug), install two 60 amp breakers in the subpanel, and run new lines to the two gen 3 Tesla wall connectors.

With power-sharing (setting the max output to 48amps) between the two is this possible without overloading the subpanel? From my understanding, powersharing should not allow both chargers to run simultaneously, thus I would never overload the subpanel.

I'm not at all familiar with how this works in practice as my last setup was two dedicated 60 amp breakers to two wall connectors.


Thanks for your replies!
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Moderator
Nov 28, 2018
14,659
18,781
Riverside Co. CA
I am certainly no where near being an electrician (not even close), but did read the articles on power sharing a few times. I did so because I have a gen 2 wall connector already, and wanted to do power sharing with it (or buy 2 gen 3s and do power sharing).

The gen 2 and 3 have different setups for power sharing, as you might know. The gen 2 doesnt need a separate breaker for each wall connector, and if I remember the install videos for gen 3 it does want a separate breaker (I think setup like you mention but am not 100%)

In any case, here is the information on power sharing with gen 3s, hopefully it helps you some:


 
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jcanoe

Well-Known Member
Oct 2, 2020
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First, you should never have a NEMA 14-50 receptacle on a circuit with a 60 amp circuit breaker. The 14-50 is rated for a maximum of 50 amps.

Up to 6 Gen3 Wall Connectors can be configured for automatic load balancing. In the home 2 Wall Connectors would be the likely scenario.

Each Gen3 Wall Connector now is required to be on its own circuit breaker, up to a 60 amp breaker. Your sub panel would have it's own circuit breaker.

I.e. if you have a 100 amp service, wire run to the sub panel. 80% of 100 amps is 80 amps and would be the maximum when charging. When both Wall Connectors are in use they would be limited to 40 amps each. When only one Wall Connector was in use then it would be support charging at the full 48 amps. (If the service to the sub panel is 60 amps then when both Wall Connectors are in use they would each be limited to 24 amps (48 amps when only one Wall Connector was in use.))

Another option is to limit the maximum charging amperage of one of the Wall Connectors if you know that the vehicle to be charged is always driven fewer miles. I.e. one Wall Connector could be permanently limited to a maximum of 32 amps while the second Wall Connector could charge at the full 48 amps (for a total of 80 amps.) This would require 100 amp service at the sub panel. You could do this with 60 amp service to the sub panel but one of the Wall Connectors would be limited to charging at a much lower amperage, i.e. 16 amps while the second could charge at 32 amps for a total of 48 amps.

The automatic load balancing feature requires that the Gen3 Wall Connectors are able to connect to the home's Wi-Fi network. If you don't have Wi-Fi in your garage you would have to add a Wi-Fi extender.
 
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First, you should never have a NEMA 14-50 receptacle on a circuit with a 60 amp circuit breaker. The 14-50 is rated for a maximum of 50 amps.

Up to 6 Gen3 Wall Connectosr can be configured for automatic load balancing. In the home 2 Wall Connectors would be the likely scenario.

Each Gen3 Wall Connector now is required to be on its own circuit breaker, up to a 60 amp breaker. Your sub panel would have it's own circuit breaker.

I.e. if you have a 100 amp service, wire run to the sub panel. 80% of 100 amps is 80 amps and would be the maximum when charging. When both Wall Connectors are in use they would be limited to 40 amps each. When only one Wall Connector was in use then it would be support charging at the full 48 amps. (If the service to the sub panel is 60 amps then when both Wall Connectors are in use they would each be limited to 24 amps (48 amps when only one Wall Connector was in use.))

Another option is to limit the maximum charging amperage of one of the Wall Connectors if you know that the vehicle to be charged is always driven fewer miles. I.e. one Wall Connector could be permanently limited to a maximum of 32 amps while the second Wall Connector could charge at the full 48 amps (for a total of 80 amps.) This would require 100 amp service at the sub panel. You could do this with 60 amp service to the sub panel but one of the Wall Connectors would be limited to charging at a much lower amperage, i.e. 16 amps while the second could charge at 32 amps for a total of 48 amps.

The automatic load balancing feature requires that the Gen3 Wall Connectors are able to connect to the home's Wi-Fi network. If you don't have Wi-Fi in your garage you would have to add a Wi-Fi extender.

I learned that the load sharing has a safeguard that if it were to lose wifi it would limit both chargers until they picked the signal back up. Pretty cool technology. Thanks for the detailed reply as it helps break it down better.
 
First, you should never have a NEMA 14-50 receptacle on a circuit with a 60 amp circuit breaker. The 14-50 is rated for a maximum of 50 amps.

Up to 6 Gen3 Wall Connectosr can be configured for automatic load balancing. In the home 2 Wall Connectors would be the likely scenario.

Each Gen3 Wall Connector now is required to be on its own circuit breaker, up to a 60 amp breaker. Your sub panel would have it's own circuit breaker.

I.e. if you have a 100 amp service, wire run to the sub panel. 80% of 100 amps is 80 amps and would be the maximum when charging. When both Wall Connectors are in use they would be limited to 40 amps each. When only one Wall Connector was in use then it would be support charging at the full 48 amps. (If the service to the sub panel is 60 amps then when both Wall Connectors are in use they would each be limited to 24 amps (48 amps when only one Wall Connector was in use.))

Another option is to limit the maximum charging amperage of one of the Wall Connectors if you know that the vehicle to be charged is always driven fewer miles. I.e. one Wall Connector could be permanently limited to a maximum of 32 amps while the second Wall Connector could charge at the full 48 amps (for a total of 80 amps.) This would require 100 amp service at the sub panel. You could do this with 60 amp service to the sub panel but one of the Wall Connectors would be limited to charging at a much lower amperage, i.e. 16 amps while the second could charge at 32 amps for a total of 48 amps.

The automatic load balancing feature requires that the Gen3 Wall Connectors are able to connect to the home's Wi-Fi network. If you don't have Wi-Fi in your garage you would have to add a Wi-Fi extender.
Thanks for sharing!
 

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