EVSE adapters

[Rocky_H]

Lower voltage should not be a problem. The mobile connector handles 120v just fine. I'm not sure since I haven't used it yet, but I don't see why it would be dangerous to put less than the rated power through the 14-30 adapter.

This works totally fine and has been used by Tesla owners for many years

I don't understand the wiring of the adapter you bought to say one way or another but your reasoning is not inspiring confidence. '120v' is is one hot wire referenced to neutral. '240v' is two hot wires, each 120v to a common neutral, 180 degrees out phase with each other. The Tesla EVSE is flexible in part because the adapter signals the EVSE what to expect. In your config, the EVSE is expecting two hot, out of phase, inputs while the TT-30 receptacle is providing something different.

It's absolutely fine. Your statement about signaling "what to expect" is overstating it a little. The adapters are built with a chip in them to specify what current level to use. They do not signal any information about what voltage to expect.

Yes, these TT-30 pigtail adapter plugs are doing some crosswiring that flips between what we know should be 120V or 240V, but the Tesla mobile charge cable doesn't care a single bit. It just looks at the two pins that are the incoming voltage, and it will detect and use whatever is there, in a very broad range.

But you are correct about what is physically being done in there. A TT-30 has a Hot and a Neutral for its voltage connection. In these kinds of adapters to 14-30 or 14-50, it is taking the Hot and Neutral, but applying it on the Hot1 and Hot2 that the 14-30 outlet would normally have. That would not work right for normal appliances, but the Tesla charging system uses either voltage level at any time, so it has no issue with it.

 

[SageBrush]

The adapters are built with a chip in them to specify what current level to use. They do not signal any information about what voltage to expect.

Does the adapter signal which pins will be energized ?

 

[freeAgent]

I don't understand the wiring of the adapter you bought to say one way or another but your reasoning is not inspiring confidence. '120v' is is one hot wire referenced to neutral. '240v' is two hot wires, each 120v to a common neutral, 180 degrees out phase with each other. The Tesla EVSE is flexible in part because the adapter signals the EVSE what to expect. In your config, the EVSE is expecting two hot, out of phase, inputs while the TT-30 receptacle is providing something different.

These work, though I went with a 14-30 adapter because I am hoping it would default to 24 amps rather than relying on me remembering to down-rate the car before plugging in. Mine is wired for Tesla charging already, unlike the one in this video which had to be modified:

 

[Rocky_H]

Does the adapter signal which pins will be energized ?

It doesn't have to. That's why this works. The Tesla system of the switchable adapters that go into the charging box are already doing this kind of pin remapping behind the scenes. It only has the two input pins that are the voltage that go into the box. (For example, with a 14-50 or 14-30, it does not pass through all of those pins. The neutral prong of the plug isn't useful, so it's just a dummy piece of metal that's disconnected.) So even when you're using Tesla's own official adapters, they are already putting either Hot/neutral or Hot1/Hot2 on the same two pins that the box is looking at, depending on where the voltage difference is supposed to be for that outlet type. So doing this one step farther out, in a 3rd party pigtail adapter thing, is still transparent to that process.

 

[SageBrush]

It doesn't have to. That's why this works. The Tesla system of the switchable adapters that go into the charging box are already doing this kind of pin remapping behind the scenes. It only has the two input pins that are the voltage that go into the box. (For example, with a 14-50 or 14-30, it does not pass through all of those pins. The neutral prong of the plug isn't useful, so it's just a dummy piece of metal that's disconnected.) So even when you're using Tesla's own official adapters, they are already putting either Hot/neutral or Hot1/Hot2 on the same two pins that the box is looking at, depending on where the voltage difference is supposed to be for that outlet type. So doing this one step farther out, in a 3rd party pigtail adapter thing, is still transparent to that process.

I'll have to take your word for it since I don't understand the underlying re-mapping. My reasoning leaves me unsure though. I'll try to explain:

A 14-30 adapter expects a receptacle to energize specifc pins. It then maps these inputs to give a correct output to the EVSE.
In the case of a TT-30 attached to the 14-30 Tesla adapter, the inputs to the 14-30 are somewhere between wrong and unexpected unless the TT-30 adapter has itself remapped its inputs to match the input that the 14-30 expects.

Sorry if the above is hogwash.

 

[Rocky_H]

A 14-30 adapter expects a receptacle to energize specifc pins.

Wait. An adapter? What kind of adapter? And these things aren't sentient, so what do you mean about them "expecting" something. There are just physical connections.

It then maps these inputs to give a correct output to the EVSE.
In the case of a TT-30 attached to the 14-30 Tesla adapter, the inputs to the 14-30 are somewhere between wrong and unexpected unless the TT-30 adapter has itself remapped its inputs to match the input that the 14-30 expects.

Maybe I can explain this in a few examples. But the one fundamental principle underlying all of this is that there are ONLY TWO input voltage pins that the Tesla charging cable is looking at, before even thinking about any kind of Tesla plug that gets connected or other pigtail that might get plugged into. Only two voltage pins. And they do not have any kind of "expectation" of whether that is 120V or 240V.

So for 14-30 outlets: Sure, those outlets can be dual voltage, getting either 240V or 120V, depending on whether you are probing between Hot1, Hot2, or Neutral. But for the Tesla charging, there wouldn't be any need to use the lower voltage, so it just connects to the Hot1/Hot2 directly into the two input voltage pins of the cable.

For TT-30, it has the Hot and Neutral as the only voltage you can use. So obviously those two lines get connected onto the cable's two input voltage pins.

If you're trying this thing of two chained adapters, to do a TT-30 to 14-30, the two voltage lines are just getting passed through two stages. The TT-30 outlet on the post has Hot and Neutral. If those get adapted to a 14-30 plug, they just put those wires onto the "Hot1" and "Hot2" pins of the 14-30, because that's where the Tesla 14-30 plug is looking for voltage. The actual value of how high or low that voltage is never matters.

Sorry if the above is hogwash.

I wouldn't say hogwash. In most electrical appliance kinds of things, you do need to be aware and get things right that you are giving the correct voltage level to what the device is built for. But for some things, like this, the voltage amount is fine either way, so that's not the issue. It's just a matter of putting the wires into the right places. Laptop power cords and some other electronics things are like this too. Their power bricks are made to detect 120V or 240V and use either one too, so they can be used easily in other countries by changing the little pigtail cord that plugs into the brick.

 

[SageBrush]

^^ Thanks for the reply -- I am a bit further along in understanding

 

[wws]

^^ Thanks for the reply -- I am a bit further along in understanding

Basically the on-board charger in Teslas support voltages from 100V (e.g., Japan) to 277V (found in some three-phase environments). The Mobile Charge cord doesn't really care about voltage. The plug-in adapters for the UMC only set amperage for the plug it supports. Per the J-1772 protocol, a EVSE, the UMC in this case, tells the car the max amperage. In the case of TT-30 and 14-30, max amperage is 24A. It is then up to the on-board charger to determine if the voltage is within spec or not. (E.g., most non-Teslas do not support 277V.)

 

[SageBrush]

Thanks for the explanations. If I am following correctly, the daisy chaining is electrically equivalent to to wiring a 14-30 receptacle with a single hot 120v wire to hot1 and a neutral wire to hot2. The 14-30 plug then passes current along its hot1 pin to the OBC.

Is the OBC two components ? I'm imagining each component responsible for one phase of current.

If you're trying this thing of two chained adapters, to do a TT-30 to 14-30, the two voltage lines are just getting passed through two stages. The TT-30 outlet on the post has Hot and Neutral.

Basically the on-board charger in Teslas support voltages from 100V (e.g., Japan) to 277V (found in some three-phase environments). The Mobile Charge cord doesn't really care about voltage.

 

[wws]

Thanks for the explanations. If I am following correctly, the daisy chaining is electrically equivalent to to wiring a 14-30 receptacle with a single hot 120v wire to hot1 and a neutral wire to hot2. The 14-30 plug then passes current along its hot1 pin to the OBC.

Is the OBC two components ? I'm imagining each component responsible for one phase of current.

In North America and other countries where single phase AC power is input into the on-board charger, the charger sees a single sine wave - regardless of voltage. The charger basically transforms the voltage to what is needed to charge the battery and rectifies it to DC.

European and other cars with Type 2 connections support three-phase AC. So there are two additional input wires. Since there are three sine waves, the charger has three input sections whose DC outputs are then wired in parallel.

 

[SageBrush]

In North America and other countries where single phase AC power is input into the on-board charger

But isn't 240v in N. America two 120V inputs 180 degrees out of phase with each other ?

 

[wws]

But isn't 240v in N. America two 120V inputs 180 degrees out of phase with each other ?

Split-phase electric power - Wikipedia

en.wikipedia.org

 

[SageBrush]

Split-phase electric power - Wikipedia

en.wikipedia.org

Superb article. Too bad I don't understand it. I particularly was impressed by this line

Since the two phasors do not define a unique direction of rotation for a revolving magnetic field, a split single-phase is not a two-phase system.

Sigh

 

[Rocky_H]

Thanks for the explanations. If I am following correctly, the daisy chaining is electrically equivalent to to wiring a 14-30 receptacle with a single hot 120v wire to hot1 and a neutral wire to hot2.

Yes, that is exactly right. You just have to take the two wires that have the voltage difference and put them in the appropriate places the charge cable is looking for them.

The 14-30 plug then passes current along its hot1 pin to the OBC.

Close, except you don't get to send that in on just one wire. The word "circuit" sounds like "circle" for good reason. It has to be a full loop, so you do have to connect two sides of this into the UMC to complete the circuit. That's why you hear the phrase "voltage difference" frequently. You have to measure between two points to see any of that electrical force. So when the UMC has the official Tesla 14-30 plug attached, it is looking at the Hot1 and Hot2 prongs for a voltage difference, so whatever voltage difference you have would need to be applied on those two pins.

 

[wws]

Superb article. Too bad I don't understand it. I particularly was impressed by this line

Sigh

Clearly you didn't suffer through undergrad EE classes...

 

[SageBrush]

Clearly you didn't suffer through undergrad EE classes...

Thankfully no. I'd hate to think I had and was still so clueless.
But I do remember sitting in class with my fist out and thumb up. Flux this, flux that. It's all a blur.

For this stuff though, I really should buy a science kit and play with safe levels of electricity. I bet some hands on experience goes a long way.

 

[kayak1]

The Amazon listing changed, so the product you're looking at there is not what I have. What I got is a TT-30 to 14-30 adapter. I already have the Tesla 14-30 adapter. I just wanted to be able to plug into TT-30.

If your looking for 120v TT-30 adapter I would recommend the following:

TT-30 Adapter for Tesla Model S/X/3/Y Gen 2 – EVSE Adapters

Charge your Tesla vehicle at RV parks and campgrounds with 30 amp service, using our TT-30 Gen 2 Tesla adapter. Made exclusively by EVSE Adapters, this adapter automatically sets the correct charging rate at 24A and features advanced thermal protection.

www.evseadapters.com

 

[Mrbrock]

A little off topic but I have a 10-30 adapter for the UMC that I had plugged into an EV only 10-30 outlet with ground swapped for the L shaped neutral pin. Can I do the same thing with the TT-30? Use a 10-30R to a TT-30P so the L shaped pin on the 10-30 plug will see ground from the TT-30? It should run at 24A, 120V correct?

 

[wws]

A little off topic but I have a 10-30 adapter for the UMC that I had plugged into an EV only 10-30 outlet with ground swapped for the L shaped neutral pin. Can I do the same thing with the TT-30? Use a 10-30R to a TT-30P so the L shaped pin on the 10-30 plug will see ground from the TT-30? It should run at 24A, 120V correct?

No. TT-30 blade dimensions, angles, and spacing are different.

 

[Rocky_H]

A little off topic but I have a 10-30 adapter for the UMC that I had plugged into an EV only 10-30 outlet with ground swapped for the L shaped neutral pin. Can I do the same thing with the TT-30? Use a 10-30R to a TT-30P so the L shaped pin on the 10-30 plug will see ground from the TT-30? It should run at 24A, 120V correct?

Yes, that will work fine. The UMC is basically looking for just these three connections: two pins that have a voltage difference, so however you can map a 120V or 240V connection to them is fine. And then the other is something it can test as a ground. In the Tesla 10-30 plug, they are fudging that and just testing the neutral as if it were the ground.

No. TT-30 blade dimensions, angles, and spacing are different.

You didn't seem to follow what he was asking about. Here's the key part:

Use a 10-30R to a TT-30P

He's talking about just a third party kind of cable converting pigtail that has a TT-30 plug on one end and then remaps the wires to a 10-30 receptacle so the Tesla adapter can plug into that. So yeah, of course they don't fit directly; that's what this little adapter cable would be for.

@Mrbrock That would be something you would probably have to make for yourself, because you probably won't find off-the-shelf adapter pigtails that would remap 240V onto 120V pins. So I was answering the question of "Would this work?" but really I don't think you should bother. Just buy the TT-30 adapter from EVSEAdapters.

TT-30 Adapter for Tesla Model S/X/3/Y Gen 2 – EVSE Adapters

Charge your Tesla vehicle at RV parks and campgrounds with 30 amp service, using our TT-30 Gen 2 Tesla adapter. Made exclusively by EVSE Adapters, this adapter automatically sets the correct charging rate at 24A and features advanced thermal protection.

www.evseadapters.com