Engineering Question

J

Jim In Tucson

Well-Known Member
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This is Minime and me getting a free DC fast charge at the office building of our local electric utility, Tucson Electric Power (TEP). If you look closely you will see there are actually 2 of the Enel fast chargers. I’m plugged into #2. The chargers were installed almost a year ago now, but mysteriously #1 has never worked.

A TEP engineer saw me plugged in and came over to chat. I of course asked why has only one of these chargers ever worked. He said the Enel engineers have not been able to definitively ascertain, but they think that the close proximity to the 480V overhead live-wire that powers the streetcar might be the problem. They think that perhaps the overhead trolley line is generating sufficient RF interference that it is causing station #1 to simply not work.

My question, does this seem feasible? Viable solutions?


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It's certainly possible. I'm sure there are some pretty intense electric and magnetic fields coming off of that streetcar lines. You would have thought they folks installing the charger would have considered that possibility. Begs the question, why does the other charger work?
 
They can easily test it around midnight when street cars are sleeping in their home and the power is shut off.
 
Jim In Tucson said:
My question, does this seem feasible? Viable solutions?
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It shouldn't effect the power delivery, but it is realistically possible the overhead lines are creating RF interference to the computer circuitry inside the EVSE. Which should be solvable with proper shielding. Although if that were the case what about the cars themselves, they would experience the same level of interference.

But I kind of question the premise, because if the interference was that bad you'd think #2 would at least act flakey, since they're so near to each other. Even taking into consideration the inverse square law, if the interference is strong enough to disrupt the first one I can't imagine a couple of feet would be enough to eliminate it for the second.
 
That DC fast charger unit is a Tritium Veefil RT50. There are a multitude of reasons why charger #1 won't work, but the fact that #2 seems to operate without issues suggests that RF interference is unlikely. Normally it's a CHAdeMO + CCS unit so it could be as simple as #1 CCS hardware but software set to CHAdeMO (factory reset?).

CCS uses the PLC protocol for communication and CHAdeMO uses CANbus.
 
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That explanation seems unlikely. It seems like it would be a very poor design to have a high power EV charger be poorly shielded when it will almost always be installed and operating near significant sources of EMI.
 
Yes, these are both CHAdeMO and CCS combo units. CCS on the far side and CHA on the near side.

I might go downtown at midnight sometime to see if that makes a difference. However, even if it does the unit probably needs a reboot or something.

This directly affects me as my opportunity for fast charging would double if both of these units were working.

It sounds like a lot of finger pointing as TEP says it’s not their charger and not their problem, and Enel says they were not responsible for site selection.

It’s most frustrating for me when I encounter a Leaf or Bolt charging on #2, and #1 is available, but simply not working.


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Okay so the CHAdeMO #1 plug isn't working, and I thought it was a double CCS unit. Wiring the CHAdeMO controller is certainly more difficult than CCS and it would be fairly easy to mix up the communication wires. As for native CHAdeMO (non-adapter) in USA, I'd say only the Nissan Leaf would use it.
 
Each of the two charging units is a dual CHAdeMO/CCS, but only one or the other. It can’t charge a Leaf and a Mini simultaneously. One cable or the other is energized, but not both.

I do know that charger #2 works for both, but charger #1 will not work for either.


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If the reason for the unit not working is the high voltage electrical/magnetic interference from the transit line, I would think it might be a good idea to avoid the area if one had a cardiac pacemaker.


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There shouldn’t be any interference from the overhead lines of a tram. It’s not “high voltage,” it’s 750 V. The bare power lines that crisscross 25 feet above backyards all over this continent are 750 to 30,000 V and much higher current than a single overhead line for a tram. The charging station doesn’t work because nobody fixed it.
 
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Agreed. I’m also convinced the problem is the charging unit and not the power supplied or the site location near the trolley.

These Enel units are very cheesy looking and feeling, at least externally. The outer shell is thin plastic and very flimsy. The dashboard is a pictograph type with no clear directions. These have got to be the lowest quality and probably the least expensive charging units that TEP could find.

Now a third Enel charger has been installed a few blocks away at the train depot. It requires payment, which is fine by me. But, I’ve only been able to get it to work once and that was by going through some website and entering my CR CD info manually. I couldn’t figure out how to get the card reader on this charger to work.

As I’ve said numerous times, the charger manufacturers and charging networks need to focus on being as simple to use as gas pumps. So far, only Tesla appears to understand this.


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