Load-sharing home setup

[Gshenderson]

If your electrician is OK connecting a NEMA 14-50 to a 60 amp breaker, you need to find another electrician! In addition to other things he told you which don’t make much sense.

I agree with others that installing load sharing hardwired EVSE’s is likely your best solution.

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[astonius]

I’d take two circuits but that’s just me. With #6 you can’t technically pull more than 50a anyways so why not have two chargers set to to 35-40a? Might avoid a situation where you have to argue about who has less charge and needs the plug more.

I basically want a solution that can be flexible for future home owners but for our use as the current home owner will manage the delivery intelligently between both vehicles without having to think about it/overloading the house. Seems like two circuits are overkill in the context of our total capability and would be a waste without an upgrade to higher service. It'll also save me a little bit on breakers and wiring to run a single circuit, which is money I can put into a proper load-sharing setup.

 

[astonius]

If your electrician is OK connecting a NEMA 14-50 to a 60 amp breaker, you need to find another electrician! In addition to other things he told you which don’t make much sense.

I agree with others that installing load sharing hardwired EVSE’s is likely your best solution.

We were talking about a lot of different stuff, so it's possible he got it confused when I brought up hardwiring vs NEMA. I think if we landed definitively on NEMA he would have realized we would need to downgrade to a 50A breaker. We were discussing running the 6 gauge wire either way for the option to upgrade both ends to 60A if desired.

 

[Tanuki68]

Here’s how we solved this problem for our vacation home. We have two teslas and a R1S reservation. Highly likely we will have two EVs needing to be charged at the same time. At our main home we have tesla wall connectors. This solved our problem of load sharing the same Nema 14-50. https://www.getneocharge.com/

 

[astonius]

Here’s how we solved this problem for our vacation home. We have two teslas and a R1S reservation. Highly likely we will have two EVs needing to be charged at the same time. At our main home we have tesla wall connectors. This solved our problem of load sharing the same Nema 14-50. https://www.getneocharge.com/

This is cool, but I personally don't want to use the mobile chargers at home. Great idea for a vacation home though!

 

[Gshenderson]

This sounded great, but then I remembered the sub-panel feeds into a 90A breaker in the main panel, so if both cars tried to pull at peak we'd be exceeding the load limit on the sub-panel. I asked him about this, and he said yes, we could potentially cause issues if we're using the oven, the dryer, and charging both cars at the same time.

Your question and his response are not related. If your concern is pulling more into your sub-panel than the 90a breaker can support, then your other appliances running on the main panel have nothing to do with that. Bottom line is that both how much you try to pull at any given time thru your main panel (including the sub-panel) and the sub-panel itself are concerns. They are just different concerns. But with 200a service to your main panel, that would be less of a concern to me than running two EVSE’s simultaneously off a 90a sub-panel.

 

[astonius]

Your question and his response are not related. If your concern is pulling more into your sub-panel than the 90a breaker can support, then your other appliances running on the main panel have nothing to do with that. Bottom line is that both how much you try to pull at any given time thru your main panel (including the sub-panel) and the sub-panel itself are concerns. They are just different concerns. But with 200a service to your main panel, that would be less of a concern to me than running two EVSE’s simultaneously off a 90a sub-panel.

The 90A sub-panel is where the appliances are. The main panel is 200A with three circuits: a 50A for A/C, 60A for heat, and a 90A for the sub-panel. That sub-panel is running everything else in the house, including the dryer and oven. That 90A sub-panel is the same panel we're tapping into for the 2 EV setup.

 

[Gshenderson]

We were talking about a lot of different stuff, so it's possible he got it confused when I brought up hardwiring vs NEMA. I think if we landed definitively on NEMA he would have realized we would need to downgrade to a 50A breaker. We were discussing running the 6 gauge wire either way for the option to upgrade both ends to 60A if desired.

Running the wire is usually the costly part of an EVSE setup. Running anything other than 6-3 wire is crazy IMO. It provides much more flexibility going forward and doesn’t cost that much more. Additionally, running that wire into std junction boxes also allows you flexibility to connect to and install a plug-in outlet (ie. NEMA 14-50), hardwire an EVSE for more power, or simply cap the wires and cover the box. I think “wired for EV” would provide as much to resale value of your home as having a complete EVSE would. I can relate to that since I’m currently in the process of figuring out how to run my wire! Connecting the charger is child’s play compare to that.

 

[Gshenderson]

The 90A sub-panel is where the appliances are. The main panel is 200A with three circuits: a 50A for A/C, 60A for heat, and a 90A for the sub-panel. That sub-panel is running everything else in the house, including the dryer and oven. That 90A sub-panel is the same panel we're tapping into for the 2 EV setup.

Oh. Sorry, I misread that.

 

[crashmtb]

@astonius https://store.clippercreek.com/index.php?route=product/search&search=HCS-D

Or

https://grizzl-e.com/product/usa/duo/grizzl-e-duo/


one plug!

 

[astonius]

Connecting the charger is child’s play compare to that.

I assume this means I could install and remove the wall connectors myself, no need to call the electrician for that after the circuit is setup?

 

[astonius]

@astonius https://store.clippercreek.com/index.php?route=product/search&search=HCS-D

Or

https://grizzl-e.com/product/usa/duo/grizzl-e-duo/


one plug!

Clipper Creek is so pricey! Someone else mentioned the Gizzl-E as well, but I think considering the cost I'd rather just go hardwired.

 

[SANZC02]

There is an easier way to charge two cars at once with one NEMA 14-50 connection. The first option is to buy a Grizzl-E duo charger that connects to one NEMA 14-50 plug and can auto switch to charge one vehicle and then the other. Or it can charge both at once (half capacity to each). It costs $900 on Amazon. This would work better if you didn’t have a Tesla since you will need to use the J1772 adapter for your Tesla so you will lose some functionality with charging your Tesla. Since I have a Model 3, I wanted to find a way to keep using my Tesla charger and not lose that functionality so I found a NEMA splitter called the NeoCharger. It cost about $500 on Amazon and it allows you to split one NEMA 14-50 plug so you can connect two NEMA 14-50 chargers and it can auto switch between the two to ensure only one vehicle charges at once. So now I can plug in my Tesla charger on one plug and the Rivian Charger on the other and it will auto switch between the two at night as both are plugged in. Then I won’t lose the functionality of any vehicle charger. And I only need one NEMA plug. The only limit is that both of these options cap at 40 amps so if you wanted to charge faster, that won’t work for these options. It’s enough for me, though. The Model 3 is capped at 32 amps of charging and 40 amps of charging the Rivian will lead to 20 miles per hour, which is plenty for me.

Curious what you lose with the J1772 to Tesla adapter. I’m using that for my Model S and see no limitations.

 

[Rousie13]

Curious what you lose with the J1772 to Tesla adapter. I’m using that for my Model S and see no limitations.

Absolutely nothing. I ran that setup for over a year with a ChargePoint Home Flex.

 

[Cavalryscout18]

Curious what you lose with the J1772 to Tesla adapter. I’m using that for my Model S and see no limitations.

When you double click the Tesla charger it unlocks the car and unlocks the charger. Truthfully I haven’t used too many non-Tesla chargers so I always fumble with trying to unlock the charger to be on my way. You would need to unlock the car manually, which is a minor inconvenience but it just adds to the process. Also, I’m sure it’s not an issue now but I trust Tesla chargers more than third-party chargers. Since the battery is the most expensive part of the car, I tend to get a little paranoid about using some of those other chargers on my Tesla. They seem to be getting better but a few years back, there were not many I would trust.

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