Any considerations when charging two vehicles at home?

[Npa201]

Hi all,

Will be picking up my R1S in a few days. Currently also own a BMW IX that I charge in my garage with a Tesla Wall Connector with an adaptor. The Tesla charger is connected with a 60 amp breaker for 48 amp charging and we installed a sub panel in the garage for future proofing if we install a 2nd charger. Now that this day is coming, what do I need to consider here? I’m assuming my whole house is on a 200amp panel, so when charging both vehicles at night am I potentially using up half the capacity of the home? If I have the laundry running, dryer, a dishwasher, and an oven…am I at risk of tripping the whole thing (in addition to two fridges, two beverage fridges, two freezers)? I ordered a Rivian charger but wonder if a Tesla Universal Wall Connector has any features where they can smartly speak to each other and not overload the system? Do I need to change a setting on the Rivian or IX to only charger at 32 amp instead of 48 amp (I’m assuming there is a menu to do so? ). Any thoughts would be much appreciated. I could be overthinking this and am in over my skis here but just want to know the situation before calling the electrician before a second hookup.

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[R.I.P.]

Hi all,

Will be picking up my R1S in a few days. Currently also own a BMW IX that I charge in my garage with a Tesla Wall Connector with an adaptor. The Tesla charger is connected with a 60 amp breaker for 48 amp charging and we installed a sub panel in the garage for future proofing if we install a 2nd charger. Now that this day is coming, what do I need to consider here? I’m assuming my whole house is on a 200amp panel, so when charging both vehicles at night am I potentially using up half the capacity of the home? If I have the laundry running, dryer, a dishwasher, and an oven…am I at risk of tripping the whole thing (in addition to two fridges, two beverage fridges, two freezers)? I ordered a Rivian charger but wonder if a Tesla Universal Wall Connector has any features where they can smartly speak to each other and not overload the system? Do I need to change a setting on the Rivian or IX to only charger at 32 amp instead of 48 amp (I’m assuming there is a menu to do so? ). Any thoughts would be much appreciated. I could be overthinking this and am in over my skis here but just want to know the situation before calling the electrician before a second hookup.

Send the Rivian L2 unit back. It is not a great EVSE (the Tesla unit is much better) and will not load-share with your existing unit the way a 2nd Tesla setup will.

 

[mikehmb]

The Rivian EVSE can be de-rated through DIP switches inside the main panel.

Biggest concern would be overdraw from whatever circuit you pulled the 2nd panel from.

Like RIP said, you may be best served by getting another Tesla charger and load-sharing across them.

 

[Npa201]

So when I call the electrician, the load sharing is off the same 60amp circuit when connecting 2nd tesla charger or a separate line from subpanel with its own breaker? Thanks so much for the help.

 

[R.I.P.]

So when I call the electrician, the load sharing is off the same 60amp circuit when connecting 2nd tesla charger or a separate line from subpanel with its own breaker? Thanks so much for the help.

If you are using load sharing, it is off the same circuit.

 

[NY_Rob]

Go to the Tesla Store, from there you can DL the instructions for installation including power-sharing for their Wall Connectors.

 

[dixosw]

So when I call the electrician, the load sharing is off the same 60amp circuit when connecting 2nd tesla charger or a separate line from subpanel with its own breaker? Thanks so much for the help.

I read the instructions and spoke to an installer. Recommended setup is to put the 2nd Tesla HPWC on it's own 60-amp breaker and then let the Tesla software load-balance between the two chargers. Supposedly, they will not draw more than 60-amp (well, 48 I guess) whether it's from a single charger or spread across the two.
Both Tesla connectors/chargers have to be the same gen - so you can't mix an HPWC gen 1 or 2 with a newer gen 3 or the new Tesla Universal Wall Connector. But a regular Tesla gen 3 and a universal is fine together. At least that is what I believe and what I was told, but not 100% certain. In the end I'm still using a single regular gen 3 for our Tesla and Rivian (with Lectron adapter).

 

[SparkyR1t]

I read the instructions and spoke to an installer. Recommended setup is to put the 2nd Tesla HPWC on it's own 60-amp breaker and then let the Tesla software load-balance between the two chargers. Supposedly, they will not draw more than 60-amp (well, 48 I guess) whether it's from a single charger or spread across the two.
Both Tesla connectors/chargers have to be the same gen - so you can't mix an HPWC gen 1 or 2 with a newer gen 3 or the new Tesla Universal Wall Connector. But a regular Tesla gen 3 and a universal is fine together. At least that is what I believe and what I was told, but not 100% certain. In the end I'm still using a single regular gen 3 for our Tesla and Rivian (with Lectron adapter).

This is the way to install. Tesla Power sharing when properly set up will limit total current draw using multiple wall connectors of the newer generation. Assuming you charge two or more vehicles at e same time. Plus Tesla vehicle charging support is excellent. Had an issue recently with one of my wall connectors and while communicating with a tech over the phone I took a few measurements with my Flukes, sent an photo of the instruments screens, and a replacement wall connector was overnighted to me. Nice working with techs that understand utility power and its quirks. .

 

[azbill]

I have two chargers with a 200A panel and have never had a main breaker shut down. I also have two heat pumps. I charge at night and the heat pumps are running a lot during the hot summer months in Phoenix. My chargers are running 48A and 40A.

 

[Grabs10]

What generation is your existing Wall Connector? I believe/think only Gen 3’s load share but may be wrong.

Ditch the Rivian wall connector and get another Tesla.

Do a load calc on your service and if you aren capable have an electrician do it.

Do run each wall connector on their own 60 amp circuit and own breakers. Don’t run them on the same circuit

Set a “lead” wall connector up in the system with the peak ability that your load calc says you have available. It talks with your other wall connector and you set the limits it for your whole system of EV charging.

long story short I have about 76 amps available in capacity in my 200 amp panel so each of my wall connectors will pull 38 amps when both are going…. When one charge is complete the other will automatically jump up to 48 amps.

if you run multiple wall connectors off the same 60 amp circuit, legally you can pull only 48 amps according to code, you can simultaneously only pull 48 amps in total spread across multiple wall connectors. So if you don’t have load sharing connectors that communicate with each other you better set the max charge rate on each connector to 24 amps. Cause 2 wall connectors running at 24 amps each will be the max you can pull off a 60 amp circuit.

 

[Rainman]

Are you sure you need two EVSEs or do you just want two? We have an R1T and a Taycan and never have issues with sharing a single EVSE.

 

[HaveBlue]

Lots of good advice here. I'd recomend always limiting at the charger wherever possible as cars sometimes forget and reset to 48a. If you have lots of spare amperage and they are on 60a breakers each, then no load sharing needed. If a load calc says you have less than 120a available, then load sharing or charger limiting is appropriate. If so the Tesla universal unit with j1772 built in might be a way to load share to your other Tesla connector.

My poor old 100a panel can't muster 40a delivery on a 50a breaker without getting seriously hot. I'm relegated to the low 30s and that's in the winter so no air conditioning running.

 

[Jccoryell]

Hi all,

Will be picking up my R1S in a few days. Currently also own a BMW IX that I charge in my garage with a Tesla Wall Connector with an adaptor. The Tesla charger is connected with a 60 amp breaker for 48 amp charging and we installed a sub panel in the garage for future proofing if we install a 2nd charger. Now that this day is coming, what do I need to consider here? I’m assuming my whole house is on a 200amp panel, so when charging both vehicles at night am I potentially using up half the capacity of the home? If I have the laundry running, dryer, a dishwasher, and an oven…am I at risk of tripping the whole thing (in addition to two fridges, two beverage fridges, two freezers)? I ordered a Rivian charger but wonder if a Tesla Universal Wall Connector has any features where they can smartly speak to each other and not overload the system? Do I need to change a setting on the Rivian or IX to only charger at 32 amp instead of 48 amp (I’m assuming there is a menu to do so? ). Any thoughts would be much appreciated. I could be overthinking this and am in over my skis here but just want to know the situation before calling the electrician before a second hookup.

When I was waiting for my Rivian (I already have a Bolt EUV) I set up a 2nd L2 charger with a load sharing arrangement. Guess what? I have never used it. Not once. I charge the Rivian 1 night and the Bolt on another. There was never a day where both vehicles used their entire battery or anything close. I wasted a ton of money on boxes and wiring needlessly.

 

[logan]

When I was waiting for my Rivian (I already have a Bolt EUV) I set up a 2nd L2 charger with a load sharing arrangement. Guess what? I have never used it. Not once. I charge the Rivian 1 night and the Bolt on another. There was never a day where both vehicles used their entire battery or anything close. I wasted a ton of money on boxes and wiring needlessly.

This may be the case but as another data point. My partner and I both have EVs and we have a clippercreek/enphase dual charger (built-in load splitting.) I'd say it is about 50/50 of when we both charge at the same time. Both have a commute or weekend activity the next day. Easier to hook up both and let them start charging after peak hours even if at a slower rate before our commute the next day than to coordinate or charge during peak hours then switch. Also although I know where her backup card is I don't have my phone set up on her m3p so that'd be another hassle to disconnecting to switch.

Anyway, fwiw, easier to just hook them both up as applicable and let the charger figure out whether they get a full rate or half rate. No coordination, thought, or planning. Both of us sleeping either way.

 

[LL75]

I have two separate chargers one for r1s and one for tesla model 3 LR on a 200 amp panel. We have this for almost a year now and never have anything tripped. Both cars start their charging at 9 pm. We use Emporia chargers from Amazon at 48 amp max

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