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I just bought a second EV that uses a J1772-type connector, which I need to park outside (in the driveway). I also have a Tesla (NACS connector) that I park in the garage, where I have a Tesla Wall Connector on a 60A circuit.

Since the Tesla Wall Connector won't reach the new car, I'd like to install a second EVSE outside for the second EV, but I don't want to add another 50-60A to my main panel's load calculation*. Because the second car has a J1772 connector, I don't want to install another Tesla Wall Connector since I'd have to use an expensive adapter that costs almost as much as the EVSE itself.

I'm aware that some EVSEs can share a power allocation so they don't pull more than a certain amount of current (combined) at the same time, but I'm not sure if this is supported cross-vendor, or if there's a way to do it using some external device. What's a good way to do this across a Tesla Wall Connector (3rd gen) and another good J1772 EVSE?

* I'm aware that I can just add a second dedicated small circuit, e.g. 20A @ 240V, for the outside charger. If there are no other alternatives I might do that. But if there are, I'd rather charge faster / not have to charge every night, especially since I'm already dedicating 60A of my panel capacity for charging.

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  • You’ll never have a CCS home charger - that’s only for high-power DC charging. CCS cars do AC charging with a connector called J1772, which can be adapted from the Tesla connector with a fairly inexpensive adapter.
    – nobody
    Nov 23, 2023 at 21:50
  • @nobody looks like I got the wrong terminology, thanks for the correction
    – peter
    Nov 23, 2023 at 22:18
  • @peter J1772 needs a catchier name. I've been recommending "Fetch" for awhile... but with the industry switching to NACS, it appears that is not going to happen. Nov 24, 2023 at 7:13

2 Answers 2

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Why not get a Tesla Universal Wall Connector. $595 compared to $475 for the regular Tesla Wall Connector, so an upcharge of $120, which is quite a bit less than the gadget from Amazon.

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  • Thanks! I just ran into that immediately after posting this question, and was digging into the details. I think I'll do that.
    – peter
    Nov 23, 2023 at 19:17
  • Do you by any chance know if that Universal Wall Connector is different from their J1772 wall connector?
    – peter
    Nov 23, 2023 at 19:18
  • My understanding is that it has j1772 and nacs. Like a residential magic dock. Which is a good investment as most new evs will have nacs in 2025. Future proof. Nov 23, 2023 at 19:43
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    yeah I figured that part about the Universal connector, but was wondering if that was a different product from the J1772 (or if it was another name for it). But I think they're two different products. I ended up buying the Universal at the end.
    – peter
    Nov 23, 2023 at 22:20
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    @peter they discontinued the J1772 Wall Connector when they announced the Universal. Nov 24, 2023 at 7:10
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Negative Ghost Rider. Differing brands of EVSE ("charger") cannot intermix using Power Sharing.

The reason is that every manufacturer does it differently. Tesla's gen 2 Wall Connectors used hardwired RS422. Gen 3 Wall Connectors use a proprietary radio scheme. Wallbox uses a cat 5E to carry a CANbus-like signal. CrippleCreek used a clunky, proprietary 3-bit system to indicate charge level (which on the upside was fairly hackable).

However, since you're already in the gen-3 Tesla ecosystem, you might as well scrounge up NOS of the obsolete J1772 Wall Connector or the brand new Universal Wall Connector which replaces it. Both of these will interact properly with the modern gen-3 Tesla Wall Connector.

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  • Is there an external tool that could be in the path of both EVSEs and "break" when the total exceeds a certain amount (e.g. 60A)? I realized I got an expensive EVSE for free with my car purchase so I cancelled the Tesla wall connector, but now I'm back to the load calc issue.
    – peter
    Dec 1, 2023 at 2:43
  • @peter yeah there are two versions of that, the caveman version that does it by brute force in an ugly way, and the sophisticated version that asks nicely and can adjust dynamically. The second one is cheaper, because brute force is expensive. Here diy.stackexchange.com/q/277803... I would recommend the Wallbox Pulsar Plus if a cable is easier, or the Emporia Load Management bundle if WiFi everywhere is easier. Dec 2, 2023 at 22:14

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