Odd charging curve

were you topping up, or filling from empty?

 

okay, i was thinking more toward the last 20% when the charger does the battery preserving thing, but that would only be 5 miles or so. it does seem odd.

did it really add 75% in 54 minutes? how long does a full charge take?

 

you could be right about the heat, doesn't the prime have battery cooling when charging?

 

Yes, but you have to be quick to turn it on when you power off. The choice shows up briefly on the MFD when you power down . If you are not fast enough, you have to power on then off again.

 

another toyota oddity. when you shut my wife's hycam off, the trip info displays for one second.

 

This phenomenon is normal, same thing occurs with the 2012-2015 series PIP. The charger stops charging momentarily to check battery status. Kinda hard to check battery status while it's charging. From what I've seen it occurs every fifteen minutes

 

We may be seeing what is called sampling error:

If the ChargePoint samples every 5 minutes, it is entirely possible that the ChargePoint sample occurs when the Prime briefly stops charging to check the level. It is the same phenomena that sometimes shows a wagon wheel turning backwards when the camera take a photo at just the right time or using a strobe to check a timing mark.

In contrast, the Emotorwerks EVSE is not time based but only reports when there is a significant change in the charging current. So this is what happens when "A/C enable" charging occurs as seen by Emotorwerks:

• Initially the car is cycling charging because the battery is too warm and/or using the A/C to try and bring the temperature down.
• Once the temperature low enough, the initial 5 minute, charge and test cycles being.
• Then the Prime switches to a 15 minute interval until approaching end of charge.
• Approaching 100%, the Prime switches to 5 minute samples and eventually a 1 kW rate to top off the battery.

Bob Wilson

 

I took the following charging profile from July 11 and digitized the graph:

	mm:ss	kW
1	00:00	0.00
2	00:02	3.25
3	04:45	3.25
4	04:46	0.00
5	05:00	3.24
6	09:50	3.22
7	10:01	0.00
8	10:18	3.22
9	14:52	3.22
10	14:59	0.00
11	15:15	3.20
12	30:05	3.15
13	30:20	0.00
14	30:28	2.60
15	31:30	1.50
16	33:30	0.80
17	43:00	0.80
18	43:07	0.00

You can really see the dips to 0V occur multiples of 5 or 15 minutes. So if the EVSE is doing time sampling, you can get strange charging curves because the two clocks are so close together.

Bob Wilson

 

I wonder if @Team ChargePoint might want to pass this thread along to their technical staff?

My speculation is the ChargePoint EVSE is sampling every 5 minutes which happens to be the same initial and later at every 15 minutes, a pause in the Prius Prime charging. Our speculation is the Prius Prime battery management system turns off or reduces the charge rate to sample the battery charge. If the ChargePoint EVSE is sampling every 5 minutes, it could get into a situation where it is sampling the pause and not the actual charge put on the car.

Thanks,
Bob Wilson

 

@bwilson4web thank you for tagging us here!
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