What does this tell you?

I was on a 6.6 kw public charger all day.
(Sunday at an office park with 12 charge stations and I saw only 2 other cars all day, so I didn’t prevent a soul from charging today by being parked there all day.)

It was a 50 to 55 degree day. Unknown if any battery conditioning took place. I suspect not.

I started exceptionally low, at 5%. The lowest this car has even been since birth. (I usually don’t let it get below 15-20% but wife used it the past couple days and also used a lot of heater time.)

So that means I had room for 95%.
.95 x 60 kWh = 57 kWh

This is what I was charged for:


59.374 kWh from the wall socket to add presumably 57 kWh to the battery is 96% efficiency on a 6.6 kw charge station. I was a little shocked at that.

Notice after the car told me “charge complete” and reset my “usage since last full charge” to zeros, so I know it was really full, the car was drawing 0.21 kw from shore power just sitting there. Maybe that was from the dome lights in the car. I think I had my door open at the time.

Even if the car had more than 5% (lets say 5.999% and the system is poor at rounding and counts everything less than 6 as 5%..... that is still 56.4 kWh input into the battery for a cost of 59.374.

Pretty. Darn. Impressive.

It says I have 203 miles of range and I’m getting 3.4 mi / kWh using some heat (in 50 degree weather).

That's almost too good to be true. Do we really know that this car has 60.0kWh available to use, and that indicating 5% remaining means you have 3kWh left? I feel like there is some rounding error in there. I would expect it to be in the range of 85-90% efficient. Then again, I don't know, and maybe Chevy really nailed the charging circuitry.

If your 5%-full figure was taken from the bars on the driver display, you actually have somewhere between 2.5% and 7.5% - it's not precise, just an approximation with a 5%-wide range.

The EPA says a full charge takes about 68 kWh from a completely empty battery and I think owners have experienced similar numbers. So, it seems like you should have seen more energy used to charge, in theory. Here are some reasons that might explain the difference:

* you actually had a bit more than 5%. How did you get that number?

* it wasn’t super cold outside at 50F but how much had you driven before charging that day? It’s possible that the pack temperature was lower than 50F if the car was left outside all night in colder temperatures. Colder batteries cannot accept or discharge as much energy as warmer batteries.

* the builtin electric metering in the charging station could be a little inaccurate and overly conservative to avoid overbilling accusations if it were configured to be used for per-kwh fees.

That sucker was on EMPTY! How much $ did it cost you?

The 20 bars on your dash gauge work exactly like this.

1 bar = 0.1 to 5%
2 bars = 5.1 to 10%
3 bars = 10.1 to 15%
4 bars = 15.1 to 20%
5 bars = 20.1 to 25%

10 bars = 45.1 to 50%
15 bars = 70.1 to 75%
16 bars = 75.1 to 80%
17 bars = 80.1 to 85%
18 bars = 85.1 to 90%
19 bars = 90.1 to 95%
20 bars = 95.1 to 100%

I use the myChevy app to get 1% increments all the time. The myChevy app and the bars on the dash jive perfectly. I don’t get decimal readings. I used the .1 in the chart for “greater than 95%” etc.

In the 800 miles we've had the Bolt I get a charging efficiency of 93-94%. That's kWh at the wall meter (digital) and kWh in the car.

BTW. When I first charged the car I saw 7 kW draw on my indoor power monitor. However, since then it's been drawing 6.6 or thereabouts as there are other loads in the house. It's not a critical difference, but I've already noted some other odd electrical/electronic behavior.

Most (if not all) public L2 charge stations from ChargePoint say 6.6 kW.

Recently, I found one that gives my car 7.2 kW every time. (Even though it is advertised as 6.6 kW.)

32A x 208V = 6,600 watts (approx.)
30A x 240V = 7,200 watts.

If they are splitting 3-phase you’ll get 208 volts.

Tells me that is one happy charging station. Friendly too!

gpsman said:

Most (if not all) public L2 charge stations from ChargePoint say 6.6 kW.

Recently, I found one that gives my car 7.2 kW every time. (Even though it is advertised as 6.6 kW.)

32A x 208V = 6,600 watts (approx.)
30A x 240V = 7,200 watts.

If they are splitting 3-phase you’ll get 208 volts.

Click to expand...

That's what I've observed as well. The FREE all-damn-day plugs at Lowe's are all putting out 6.5 kw or so, and the ChargePoint units in front of the State Building throw down at 7.2. I haven't had to share a unit with anyone yet, so I don't know if the power gets halved or not.

Just got my ChargePoint Home EVSE up and running here at work. It's getting 208 volts because we're a manufacturing building using three-phase. I considered getting the JuiceBox EVSE because it ran 40A, but I didn't think the Bolt would be able to take advantage of it. In the end, 6.6kw is fast enough to top me off in about 2.5 hours anyway, so I'm more than happy.