TEG

As many have heard, Martin Eberhard designed and built himself a mobile charging kit that is more flexible than what the "factory" currently offers. When others saw what he had created they decided they would like to make something similar.
Bill Arnett provided some pictures that Doug posted here:




EVcomponents has announced that they plan to sell them, hopefully starting next month.

From what I know, the production rate isn't yet known, and parts supplies for the kit still need to get worked out, so there could end up being a wait list or delays depending on what happens.

I got a chance to look at the manual for the kit, and thought it might be helpful to pass along some observations of what the kit can and cannot do.

The EVcomponents link currently includes this:
So, basically you have a choice of stubby adapter cables that go from the socket you have found to the "logic box" which then feeds a 20 foot long cable to the Roadster connector. The "logic box" will "know" what source cable you have inserted, and in turn will tell the Roadster what "default" charge rate to pull. In some cases you may need to adjust the charge rate manually from the VDS if the circuit breaker feeding the circuit is too low for the default charge rate.

See also:
NEMA 14-50: How much current can you pull?
Campground Charging
Charging the Roadster
Road trips

Note, I have no idea if Tesla has any kind of 'stance' with regards to warranty impact from using this kit.

TEG

Going through the different socket/cable options, here are some notes:

1. NEMA 5-15 120V 15A



This is the "Standard" USA household outlet. It will draw 120V@12A just like a Tesla MC120 would.

TEG

2. NEMA 10-30 208V-240V 30A



This would plug into a common home dryer socket. The kit would tell the Roadster to take 240V@24A.

Note, don't mix this up with a campground TT-30 120V trailer socket. The kit's NEMA 10-30 plug has one L shaped pin, and the socket must have a L shaped hole in the same position. Don't try to force the plug into a socket with a round hole there. This plug is NOT meant to be used at a campground or boat dock.

TEG

3. Nema 14-30 208v-240v 30a



This would be to plug into household dryer outlets in newer homes that have a grounding pin. The kit would tell the Roadster to try 240V@24A

TEG

4. Nema 10-50 208v-240v 50a



This is typically used for home ovens and electric stoves. It would be unusual to find one in a public place, but should you find one, the Roadster will be told that it can try to draw 240V@40A

TEG

5. NEMA 14-50 208V-240V 50A



This one is used in a bunch of different places. The Tesla MC240 uses this, but takes a conservative approach of only using up to 30amps. The Roadster Foundry kits tells the Roadster that it should be OK to draw 240V@40A but this isn't always appropriate. Some home stoves, dryers or other large electric appliances may use this, but only offer a 40amp breaker (32amp max allowed draw), some RV/campground adapter cables may provide this socket but offer far less current capability. Some adapter kits used to convert a public EV charger (e.g.: Avcon) to NEMA14-50 may also have lower current capability and charging at 24amps may be most appropriate there. Even if the breaker doesn't trip, some installations may have wiring that is not rated for 40amp current load, so it is really best to research the true capability of each NEMA 14-50 socket you find to know the max current capability. (Just because it turns on doesn't mean it is OK - it could cause something to overheat if you pull more current than the wiring was designed to handle).

Related topic: NEMA 14-50: How much current can you pull?

TEG

Suggestions for future improvements:

• A different version of the NEMA 5-15 cable that tells the Roadster that 120V@16A is OK. This would be for cases where you know the socket has a 20A breaker, and nothing else is plugged into the circuit.
• A campground TT-30 cable that tells the kit to let the Roadster know that it could use 120V@24A
• A different version of the NEMA 14-50 plug that tells the Roadster 240V@24A (instead of @40A) to be used when connecting to the EAA Avcon adapter box. (Modifying the EAA box to have a 14-30 could also suffice).

Note, the logic box has a small limit to how many different cable types it can be trained to detect. Adding more types might mean a redesign, or sacrificing one of the existing cable types to make room for something different.

vfx

I'm still trying to get up to speed here so apologies in advance.

What about measuring? Either carry an Ampmeter meter that can measure the available current and be able to program it into the box (or of course the car) or build the meter into the box or car so it automatically determines the maximum safe draw and applies that amount.

Is it one of those things where you have to have a load to test it and if you drive up to a charger and test it with different loads then you might blow the breaker? Then that breaker is in a panel somewhere that no one at the mall has access too?

The other problem seems to be that with hall effect clamp meter you would have to get open access to the cables to measure the current flow.

Still though, it seems like someone would have figured this out by now.

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The world loves to be deceived.

TEG

Yes, that is a real concern. So, if possible, understand what wiring, breakers and over-current protection lives behind the socket you are about to use. If you can't find that out then it is probably best to draw a conservative amount (which is usually 240V@24A). I would think it best to leave the "learning by probing" to some team of experts (e.g., the EAA folks) who then will (hopefully) label things as needed. The EAA Avcon box should probably have a label next to the NEMA 14-50 saying "not for more than 30 amps".

I wish those RV adapter cables had clear warning labels on them.
Like the "cheater" and "dogbone" adapters should say something like "not intended for use with 240V devices" as they are meant to provide two paths of 120V service at < 30amps each.

Those in the know think so much of this stuff is obvious, but for the non-electrician out there, seeing a NEMA14-50 socket with "50 amps" stamped right on it can be misleading.
Just because the plug fits in the socket doesn't guarantee it is going to work.

vfx

Measuring current

__________________
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.
.
.
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The world loves to be deceived.