[Arob]

You gain nothing by going NACS now on everything, other than slight simplicity in the future. There is no difference in charging speed/efficiency with or without adapters.

The one plus by adopting NACS now is the adapter for your J1772 port will be useful in travels, hotels more often seem to have Tesla L2 chargers than J1772.

I already had a J1772 plug L2 charger, but got a Tesla Mobile Connector for travels since some of my destinations (family members) have 50A outlets, but no chargers. I have used my Tesla to J1772 adapter many times, including with my mobile connector, so it has been an invaluable investment.

I suspect many EVSE makers will soon be offering NACS cables to swap on existing J1772 equipped EVSEs. Grizzl-e already offers the choice on a few models, and likely will offer a replacement cable at some time in the future. But honestly, the adapters aren't too bulky for AC charging.

 

[Arob]

Thanks, that’s helpful. My neighbor has a Tesla wall charger and I already bought the Lectron adapter so I can use his charger until mine is installed. So if there’s no difference in charging speed then I will probably go with an NCAS charger myself and use that adapter all the time.

Not to be a stickler, but we are talking about the North American Charging Standard (NACS). While most will understand, the EV world is full of technical terms and acronyms and new users will tend to get confused. So, it is important to use correct terms.

Tesla makes great chargers, and reasonably priced too. If you anticipate ever getting a second EV, you can get by sharing a circuit by using their load balancing features in the software settings. So, Tesla Wall Connectors can be a great option. https://shop.tesla.com/category/charging#charging.at-home

 

[Arob]

To be even more technical: J3400 is the name of the industry standard whereas NACS is what Tesla renamed their plug when they finally started to share the plug and actually allow other brands to use the SuperCharger network.

Notable improvements that J3400 added to the standard include 1000v compatibility and “bi-directional charging” aka power sharing. There are slight differences in the physical shape but SAE has started the two standards remain compatible. Some manufacturers have also said they are still planning to use NACS instead of J3400 plugs.

reference link: SAE International Explains SAE J3400 Changes Compared to Tesla's NACS

Tesla had previously tested 1000V/1000A (ie MW charging) on the NACS plug before SAE dug into it. And the plug has virtually no role with bi-directional, in fact Tesla in their NACS release noted it was compatible with bi-directional. They are actually offering bi-directional on Cybertruck using the plug in the original NACS spec.

I suspect what SAE is claiming is the thermal sensor piece, which may be an improvement for safety reasons, but not necessarily for peak charging speeds. Keep in mind, Tesla pushes peak charging speeds, but only for short durations. So the SAE refinement may have more to do with sustained high speed charging rates that models like eGMP can achieve.

ISO15118-20 covers bi-directional charging on both AC and DC configurations (J1772/Type2, and CCS1/CCS2). Tesla was silent on bi-directional in the NACS announcement, other than claiming nothing should prevent it. So, SAE likely just made it a formal thing.

I don't mean to belittle the work SAE did. It is clearly important, but really it seems with the exception of the heat sensors to be a formalized acceptance of the plug using CCS communication standards that are already in place.

BTW, ISO15118-20 also technically allows for Plug & Charge using certificate exchanges for both AC and DC charging. But, AC charging is so saturated with equipment that wasn't designed for advanced communications that the AC part is pretty much ignored by EVSE makers and EV OEMs. Given Tesla has adopted more advanced optional communications on AC chargers (on their Gen 3 Wall Connectors), it could end up being Tesla leading the way to ISO15118 P&C on AC charging...wouldn't that be ironic!

Kind of similar to how J1772/Type2 standards included DC charging on the same pins as AC charging before CCS1/CCS2 were adopted. It was limited power which led to the CCS option for additional pins to carry higher currents. Ironically, Tesla was the only OEM to adopt the AC/DC charging on the Type 2 (Mennekes) plug in EU prior to adopting CCS2 when Model 3 arrived on the scene.

Bottom line, we will all eventually benefit from the single standard with all OEMs and EVSE makers on the same page. The only negative I see in it all is the number of companies needing to make changes makes the whole transition seem like a mine field. Had Tesla agreed to adopt CCS, it would have been one company charging its cars and chargers to the standard everyone else was using.

I know some will argue NACS/J3400 is a better solution, but I think the only benefits are accessibility related, the plug is clearly easier to handle. As for reliability, I am quite certain Tesla could have made CCS chargers with equal reliability to their legacy chargers, in fact they did so in the rest of the world where they use CCS2. The reason CCS lost the plug wars had more to do with poor implementation and maintenance by CCS charging network operators, primarily EA who is only in the game by court order.

 

[Arob]

So I just purchased a 2025 IONIQ 5 with the NACS charging port. I am about to purchase a level 2 charger but after reading the IONIQ ELECTRONIC reference guide I am confused. On page 14 it states: "AC charging Level 2 is using connector SAE J1772. To use it, an adapter is needed for this vehicle".

It seems odd that that a NCAS charger would not work directly. Can anyone clarify this? Thanks.

Look at the port on the car, don't count on manuals being correct.

The shape of the Tesla (J3400/NACS) is different enough to make it absolutely clear.

 

[Arob]

Well it is clearly the NACS port but I thought there might be some proprietary Tesla protocol in the communication. I am all new to the EV world so please excuse my confusion. I would feel more assured if someone with the 2025 model would weigh in.

NACS (tecnically J3400) is nothing more than CCS signaling over a Tesla shaped plug. More details here: Tesla Charging Network FAQ Thread

 

[Arob]

I suspect some Hyundai/Kia EV owners are going to be disappointed when they discover the Supercharger they've been hoping to get access to isn't accessible because it is an older V2 site.

It seems mixed sites (V2/V3), which are fairly common, are not being made widely available. Maybe they look at what the need is in the area, but I have seen reports of folks going to mixed sites that were enabled for other brands and being unable to charge. When pressed, they admit they had no clue V2 weren't compatible, nor how to tell the difference between them. That kind of confusion certainly doesn't help make for a smooth transition.

My guess is, the majority of eGMP model owners will soon be changing their opinion from great elation to ho hum "ok to have as a last resort" when they discover how V3 chargers will be slower than 150kW chargers at other networks. Folks here are going to be more informed than many but forums reach only about 10-20% of owners.

 

[Arob]

Historically, every charging port, including Tesla's, has had its own associated communications protocol. Tesla, however, has implemented support for other charging-port protocols in its cars, thus ensuring compatibility -- Tesla EVs have supported the protocols used by J1772 for years, and added support for the protocols used on CCS about 4.5 years ago. This enables cheap adapters to work with Teslas, and now those same adapters can be used in non-Tesla NACS EVs.

Similarly for their charging equipment; Tesla has added support for the industry-standard protocols (at least, those used by J1772 and CCS; CHAdeMO is not supported by Tesla Superchargers, AFAIK, although Tesla's proprietary protocol is supposedly related to the CHAdeMO protocol) to its charging equipment. The various Tesla Level 1 and 2 EVSEs, in particular, support both Tesla's proprietary AC charging protocols and those associated with J1772. In most cases this works well when a non-Tesla tries to use it; the Tesla Wall Connector or Mobile Connector will first try Tesla's protocol, and when that times out, it'll try the J1772 protocol and charging starts. This can result in a delay between plugging in and charging starting, but this isn't usually a big deal. Sometimes, though, the car will time out or otherwise become confused by the Tesla EVSE's attempt to use a non-J1772 protocol. I've seen reports of problems with all sorts of vehicles, including Hyundais. The last I heard, the incompatibilities with Hyundais were fixed via software update(s) to the EVs and/or Tesla EVSEs quite a few months ago, maybe over a year; however, I've also seen reports of incompatibilities cropping up again with the 2025 Ioniq 5, so this old problem is new again.

In the case of recent versions of the Wall Connector (including the Universal Wall Connector), this problem, if you encounter it, can be overcome by reconfiguring the Tesla EVSE, via its app, to work in "compatibility mode." I'm pretty sure that this just turns off the attempt to use Tesla's proprietary communications protocol, so it starts using the J1772 protocol from the start. Tesla's Mobile Connector, though, can't be reconfigured in this way. I've seen conflicting reports about whether the Mobile Connector has problems with the 2025 Ioniq 5, and in fact, I've seen one report from somebody who had no problems testing a car with it during a test drive, but then the EVSE failed to charge the car that the person ultimately bought. I don't know the cause of that discrepancy, but it highlights the unpredictability of this latest issue.

If you're buying a 2025 Ioniq 5 and you don't already have an EVSE at home, then there are quite a few from various brands that have NACS plugs now. I've got an Emporia unit with NACS that works fine with my 2025 Ioniq 5, for instance. Hyundai offers a free ChargePoint Home Flex (which is available with a NACS plug) as a purchase perk (or you can get a $400 ChargePoint credit). Lectron also offers one, and I'm sure there are others. If you want to buy Tesla's Wall Connector or Universal Wall Connector, that should work, too, but be aware that you might need to set it to compatibility mode. AFAIK, all the third-party NACS EVSEs do not "speak" Tesla's proprietary protocol; to the car, they look like a J1772 EVSE.

Note that some utilities offer discounts, either on the purchase of an EVSE or on your utility rates if you enroll in a "demand response" program, in which the utility can tell your EVSE to delay charging when demand is particularly high -- typically in the late afternoon and early evening on very hot summer days. These programs typically work with only some EVSEs, though, so you should check with your utility if you want to take advantage of such a program. Mine, for instance, supports four EVSEs, only two of which (Emporia and ChargePoint) are available with NACS plugs.

There was a recent thread about a 2025 I5 being unable to use the Mobile Connector, and I speculated timing may be the problem. Apparently, it is a hit or (mostly) miss proposition with a few owners reporting at least some success using the mobile connector. Your comments seem to reinforce my thinking on why it might fail, though I thought Tesla was using J1772 signaling by the book all this time for AC charging. But come to think of it, I believe 1st Gen mobile connectors were incompatible with J1772 cars, so you may be right about that point. I suspect it is a minor variation though, different frequencies or timing but the same general principle of using Pulse Wave Modulation signaling for AC charging.

The current generation Wall Connector defaults to All EVs (compatibility mode), and while provisioning allows Tesla only, or Specific Tesla only (adding up to 8 or 10 VINS), these don't seem to be a problem due to their default being accepted by most users. Further, Hotels (a common place for Wall Connectors due to Tesla giving them to Hotels to proliferate the network) presumably don't want to exclude any guests, it would be bad for business. Further, few Destination chargers are configured for Tesla billing, partly because Tesla won't configure billing if fewer than 6 Wall Connectors are installed, and partly because Hotels probably see no reason to upgrade, or exclude guests.

I have been using the mobile connector on my '23 I6 successfully for the last 8 months without a hiccup. My brother uses a mobile connector with his EV6 as well, without hiccups, and used it on my old Bolt before getting the Kia. He gave the Tesla mobile connector to his son when he gave him my old Bolt, and it is still used exclusively for daily home charging.

I don't get the sense charging initiates any slower than J1772 EVSEs (I used a Grizzl-e for the first 6 months), but there are a series of signals requiring responses for charging to proceed. But these are generally tight response times the EV and EVSE expects. So, ultimately, both EVs and EVSEs need to understand the sequences and respond accordingly. That older models negotiate it properly suggests they know how, but probably overlooked testing with the mobile connector.

I doubt Tesla would try updating the mobile connectors, that is a difficult task that might require factory refreshing the software, quite an expensive undertaking. But I suspect Hyundai (and Kia) will want to look at this as it is a common solution for travel, and quite a bargain I might add since Tesla stopped including these with new car sales a few years ago. And I suspect they would like to hear from 2025 I5 owners about the incompatibility and do something quickly before their new models become widely adopted. My guess is, OEMs will be sourcing charging interface modules from a common supplier for NACS equipped models, and that company would surely like to know about any incompatibilities.

Thanks for sharing your insights. I wrote a lengthy article about Tesla charging and adapters a while ago for the Bolt forum and modified it slightly for this forum. I would love any insight you may have, though much of my knowledge is based on conversations with a friend who was responsible for the Firmware/software on the original Model 3. Albeit, these conversations are generally over several bottles of fine wine, so some details may have been missed. I should probably update these with some of this additional insight.

 

[Arob]

I don't know the technical details, but at the very least, Tesla has significantly extended those protocols. The reason I say this is something else you mentioned:

The J1772 protocols are very rudimentary, and they certainly don't pass VINs back and forth. Tesla does, at least when using a Tesla EV on a Tesla Wall Connector.

I'm pretty sure that the current generation of Wall Connector used to default to "any Tesla"; however, it's entirely plausible that Tesla has changed the default in their settings between the introduction of the current-generation hardware and now. This might be especially likely on the Universal Wall Connector, since it's explicitly intended to be used by non-Teslas. I haven't been testing samples every month or anything, though, so this is largely speculative.

This is the current Gen 3 Wall connector manual, I don't know if it changed, but currently the default is All Vehicles.

Yes, J1772 is very simple, +-12V PWM 1kHz square wave signals intended only to negotiate current. ISO15118 (CCS) and Tesla proprietary are possible on AC charging, both are an option for things like V2G, VIN authentication, even billing. But few actually implement the optional higher level communications. Tesla does offer the Only Tesla and Authorized Tesla Only modes which use higher level protocols. I believe Tesla borrowed from DIN Spec 70121 which CCS is built upon and includes provisions for high level communications, including VIN or MAC address to identify the vehicle.

I doubt Tesla reinvented anything, probably just adopted what was already available and modified it enough for exclusivity.

Here is a good summary of J1772/CCS signaling from Wikipedia:

Unlike the connector and inlet, which depend on the geographical location, the charging communication is the same around the globe. Generally two types of communication can be differentiated.

• Basic signaling (BS) is done using a pulse-width modulation (PWM) signal which is transferred over the control pilot (CP) contact according to IEC 61851-1. This communication is used for safety-related functions, indicating for example if the connector is plugged in, before contacts are made live (or energized) and if both charging station and electric vehicle are ready for charging. AC charging is possible using the PWM signal only. In this case the charging station uses the duty cycle of the PWM to inform the onboard charger of the maximum available current at the charging station (A pulse width of 5% indicates that HLC shall be used).
• High-level communication (HLC) is done by modulating a high-frequency signal over the CP contact (also known as Power Line Communication or PLC) to transfer more complex information, which may be used e.g. for DC charging or for other services such as "plug and charge" or load balancing. High-level communication is based on the standard DIN SPEC 70121 and the ISO/IEC 15118-series.

Tesla used a couple methods to make their DC chargers proprietary, one being different communications methods, involving different frequencies, and backed by a restrictive billing system which didn't allow non-Teslas to register until recently. The different frequencies, like AM/FM radio, would make J1772 EVs incapable of communicating with the EVSE. But CARB mandated J1772 protocols well before Tesla developed their proprietary charging, so they complied. But I don't think CARB prohibited other methods, so Tesla went their own way to build their proprietary network. When Model S arrived in 2012, J1772 was the most common public charging, along with CHAdeMO, so they made the cars to be capable of using the existing charge points in addition to their own. CCS was still being developed, and early specs were out before Tesla adopted their method, but the first CCS public chargers and cars didn't arrive until about the time the Model S went to market.

When Tesla implements the digital methods, they simply use a different frequency for signals which make them garbled to the other end, but they can switch frequencies when there is no response in order to negotiate with CCS equipped cars.

I don't think, or expect Tesla to release their proprietary protocols, there really isn't any reason to do so. Further, in time, they may even abandon proprietary protocols as older cars and chargers age out of the system. There are a lot of useful functions available in CCS signaling, V2X and ISO15118 certificate based Plug & Charge billing among them. So using the standard communications in a truly open network environment actually makes things simpler for all. Most of the older Teslas can buy a retrofit kit to make them CCS compliant.

Back to the mobile connector issue. If Tesla uses proprietary, then J1772 compliant methods (we know they do because simple "dumb" adapters work on J1772 equipped cars), and I5 can use J1772 with a dumb adapter, the only logical explanation is Hyundai's charging interface is timing out before the J1772 signaling sequence is completed.

Here is a good look at J1772 signaling and standard: https://en.wikipedia.org/wiki/SAE_J1772
And CCS: https://en.wikipedia.org/wiki/Combined_Charging_System

Not much publicly available stuff about Tesla standards, but then why bother if billing systems are exclusionary, and CCS and J1772 signaling are supported.