So we've had the car for over a month, but used a 110 or other chargers until now.
My electrician just installed the 14-50 outlet and the car seems to be charging normally.
The app is showing 28 miles per hour at 230v at 32amp.
So it appears about normal, but not the 'ideal' 30 miles per hour?
We have a pretty long cable run. Maybe a bit over 100 ft from the main panel to the sidewalk charger.
Am I looking at a voltage drop or is this just normal and could be due to the car battery being over 70% at this point?
So while 230v is a little bit low, it is just barely within 5% of nominal which is 240v. 5% low is 229v.
You should expect the utility to fluctuate up and down throughout the day within a range, and then you further have significant fixed losses for your long run to the car.
If you take the ideal 30 miles per hour of charge and subtract 5% then that is about 28 miles per hour.
It would be interesting to check your voltage at the EVSE prior to charging, and then after commencing charging. The same goes for at your main service entrance (electrical panel).
I think that's less than a 5% drop so I wouldn't be concerned about that 1-2 mph that you aren't getting. We have a long cable run as well and have been seeing some voltage drops (and then the amps dropping when charging). We believed it was due to the long run but had Tesla out to investigate yesterday. They found we're getting 247 volts right where the lines connect to the electric meter. If we turn start charging, turn on the oven, etc., we saw it drop to less than 220 volts in the garage. In our situation, it looks like a transformer issue and has nothing to do with the long cable run. Tesla is checking our charging logs and will be providing them to our utility company. Hopefully they'll see that our usage (along with our neighbor's pool pump, etc.) warrant a newer transformer.
That is awesome that Tesla will help you provide logs! Yes, this absolutely sounds like a power company problem. Probably just an undersized transformer, but could also be undersized conductor wires to your meter or loose / poor connections. I am curious what the result will be!
I believe 6 gauge. It was originally run 2.5 years ago for a phev with a 15 amp breaker and regular outlet at the end.
A different electrician just swapped the outlet and breaker today.
Ah yes, at 6 gauge you are going to get some decent loss at that distance with 32 amps flowing over it. I think it is totally fine though.
I also did not mention - might it have been taking some power to heat / cool the battery? What were temps during this test?
So I was just noticing my utility was at 229v last night which shocked me. It normally is maybe + or - 4 volts from 240v.
The power grid is a pretty fascinating thing. Typically they have "Online Tap Changers" on the output side of all the substation utility transformers. Throughout the day as transmission voltages fluctuate (due to loading on the overall grid) the tap changers will operate (change settings) to boost/drop the voltage on the distribution system periodically throughout the day. So if you ever look at a graph of it you will see voltage smoothly (usually) fluctuate up and down, but then it is interrupted by big jumps up and down (well, jumps of like 2-4 volts I think) as the tap changers operate.
I would check your voltage at different times of day to see what you see over time. I doubt you need to worry too much!
