Drop in amps after a couple hours.

[daybreakca]

First, read this: Voltage Ratings: 110/115/120, 220/230/240 or 440/460/480

so minimum of 116v at the pole/transformer, whatever feeding your condo. Are you seeing more voltage drop than you should? Well yes, but it’s certainly possible.

then you have these situations:

Con Edison Reduces Voltage System-Wide | Consolidated Edison, Inc.

To help keep electric power flowing reliably during a record-breaking heat wave, Con Edison reduced electric voltage today by five percent system-wide. In addition, it urged its 3 million customers to work with the company by curtailing unnecessary use of energy-intensive equipment, including

conedison.gcs-web.com

CVR Is Here to Stay

Conservation voltage reduction enables utilities to achieve significant energy and peak demand reduction at little cost and without customer impact.

www.tdworld.com

As to why you’re seeing fall-off over time, I got nothing to add.

Thank you.

It's seriously time to check all the wiring for that circuit. Not only the outlet in question, but any outlets that the circuit may be daisy-chained through. Turn off the breaker and use an outlet tester to identify all of the outlets on the circuit. Verify that none of the connections show signs of overheating. Check that none of the connections is back-stabbed, especially not daisy-chained through an outlet by back-stabbing. Finally, check the connections at the panel are tight and correct.

Also make sure nothing else is being run off that circuit, like your hair dryer or garage door opener.

It may turn out to be something else pulling the voltage down, but this is the first step.

unfortunately the outlet is in a community garage. It is going to be hard to tell how many circuits is on the line. There might be someone using the same line. My issue is why the drop after an hour.also I usually charge at night so less likely that someone in using an outlet in the garage at that time as I am the only person so far with an EV.

 

[davewill]

unfortunately the outlet is in a community garage. It is going to be hard to tell how many circuits is on the line. There might be someone using the same line. My issue is why the drop after an hour.also I usually charge at night so less likely that someone in using an outlet in the garage at that time as I am the only person so far with an EV.

A parking garage? You should have told us that from the beginning. It would totally explain the low voltage if it were a really long wire run back to the panel. It would also mean that that circuit could go somewhere else in the garage and be used for anything.

My advice to you in this case would be to try using the standard 5-15 adapter...assuming you even have permission to use this circuit.

 

[ucmndd]

My issue is why the drop after an hour.

Your issue is you’re trying to completely max out a non-dedicated circuit in a semi-public place without any knowledge of said circuit or what else is drawing from it.

The car is doing its best to save you from your bad decisions.

 

[mongo]

A parking garage? You should have told us that from the beginning. It would totally explain the low voltage if it were a really long wire run back to the panel. It would also mean that that circuit could go somewhere else in the garage and be used for anything.

My advice to you in this case would be to try using the standard 5-15 adapter...assuming you even have permission to use this circuit.

What would using the 5-15 accomplish in terms of charging performance (as opposed to infrastructure*)? It would start at 12A instead of falling back to 12A.
Could also set car to a 12A charge limit for that location.

*If it drops to 8A from 12A, then that indicates a worse issue.

 

[dafish]

day:

ugh. Yea, hearing you don’t know more about the circuit isn’t too good. I’ll skip the harsh words the electrician deserves for dropping in a 5-20r. I wish I could claim we don’t see stupid *sugar* by some “electricians”, but it seems like half the time we do.

Rocky’s call on post #5 is almost certainly it. I believe I’ve decoded the why of the voltage situation adequately, but as Dave has also stated you’re probably taking considerable v loss to the wire length.

While I don’t suspect others are using that circuit, else you’d be popping that breaker, you have no business running that at 16a. I’m really amazed you were allowed to change that receptacle. It’s gonna cost somebody’s ass one day. I’m sorry my brother, but this is a no-fly zone. You need to be go back to the 15a tail, charge at 12a, and be crossing your fingers nothing else happens In that garage.

 

[Rocky_H]

Ah, yes, the public parking garage explains a lot. Very long wiring run would explain much of this, where there already would be a lot of voltage drop, and that extra resistance contributes even more, where the more current you try to draw from the outlet, the farther it will sag the voltage, which will trip this safety detection in the car.

Switching to the 5-15 plug is a decent suggestion, or you could try turning it down a bit from 16A to start. With the situation I described before, where people's cars would drop from 40A down to 30A, they could frequently get by with it by setting the current somewhere in the middle, like 34A. It wouldn't pull the voltage down as hard and would stay running and was still more than 30.

 

[davewill]

What would using the 5-15 accomplish in terms of charging performance (as opposed to infrastructure*)? It would start at 12A instead of falling back to 12A.
Could also set car to a 12A charge limit for that location.

*If it drops to 8A from 12A, then that indicates a worse issue.

Because overdrawing the circuit so badly the car has to drop the amperage is dangerous thing. Now that we think we know why it is falling back the only thing to do is to run it at a lower amperage. While you COULD dial the car back, we all know that the car may forget that setting and start at 16a again when he least expects it.

And yes, if it were to drop to 8a when he starts at 12a, then we would know that he shouldn't try to use it at all.

He's also likely to already have the 5-15 adapter, so it's an easy thing to do.

 

[mongo]

Because overdrawing the circuit so badly the car has to drop the amperage is dangerous thing. Now that we think we know why it is falling back the only thing to do is to run it at a lower amperage. While you COULD dial the car back, we all know that the car may forget that setting and start at 16a again when he least expects it.

And yes, if it were to drop to 8a when he starts at 12a, then we would know that he shouldn't try to use it at all.

He's also likely to already have the 5-15 adapter, so it's an easy thing to do.

Which is infrastructure.
Even then, a long 12 gauge run at 16 amps is not inherently unsafe when feeding a current limited load. If it were a motor or other fixed power type load, that would be different.
So it's quite possibe that it is not overdrawing the circuit.