Inaccurate energy consumption calcs on trip computer???

[spencerledlow]

I wonder if the charging efficiency goes down as the car approaches 100% charge. I'll try to limit it to 80% and see if that makes a difference. Any opinions on charging to 100% on battery life?

 

[notfred]

Better for battery life to only charge to 80%.

 

[ksoul2084]

Yes, I believe the closer the battery-pack gets to "full" the higher the resistance, thus, more power lost to heat.

 

[ksoul2084]

In theory it should trip after 3 hours. In practice it almost certainly will not.

The breaker is measuring the current, it can't tell how hot any of the rest of the parts of the circuit is getting, If you have a brand new good quality socket with good contacts and good connections to it, you'll probably be OK. But any poor contacts any where on that circuit and it can cause a fire.

Okay, I will run some tests and check the wiring and plug.

Thanks for the heads-up.

Yesterday, while the car was charging in my unheated garage I took some temperature readings using an IR temp. gun. It started charging with 45% left in the battery, so was probably at 65% state of charge or so when I took the readings:

Ambient temp. in the garage = 3c.
120v Adapter Cord between wall socket and charger = 30c
Wall socket near plug = 31c
Breaker in electrical pane in basement = 34c
Wire leaving breaker in basement = 34c

These seem completely safe to me and far from being hot enough to melt anything. Thoughts?

 

[notfred]

I checked while charging mine on a 240V 30A EVSE. After 1 hour my breaker is a similar temperature (there is a thermal element to breakers so this is expected), but everything else is at ambient to maybe 1C higher.

Right now you don't have anything that is hot enough to cause a fire, but you are running outside of specs and one slight imperfection away from a house fire that your insurance will not pay for as it is not CSA certified. That cord is 27C above ambient. It could get close to its limits in the summer and high ambient temperatures - with all the other corners that they have cut I'd be surprised if they used high temp cable. A couple of unplug/plug cycles on that socket could increase the resistance slightly and a dramatic increase in temps. I wouldn't risk it, but it's up to you.

 

[IanL]

As another data point:

While I was fitting my 240V 30A EVSE, I wanted to test the setup before I had wired it back to the breaker board (is that what it's called in the US? - here it's the consumer unit). The EVSE is switchable to 32, 16, 13 and 8A, so I supplied the setup via an extension cord from a domestic socket (designed for 13A), started at 8A and worked up to 16A. I don't have an IR thermometer (must get one!), but feeling the two plugs in my temporary supply chain, they were unpleasantly hot at 13A, let alone 16. Neither were new, but they looked in good shape, as did the sockets.

I think that reinforces Notfred's point.

 

[Gordo]

It's the wiring in your walls you need to be most concerned about. But even at 12amps some outlets don't do well under continuous load, if they aren't quite up to spec...

But on topic, I've had my meter at 3.1 or so for months when it suddenly started jumping around randomly. I reset it and it started again, then seemed to calm down and now it's around 3.3.

 

[archiesrevardel]

TITLE 24 CALIFORNIA

 

[spencerledlow]

I have a 2016 Kia Soul EV+. I like to reset the "energy consumption" computer daily on the instrument cluster. However, it seems like it is really inaccurate. I have it set to "manual reset".

As far as I know, the car has a 27kWh battery. Today, I started at 100%. I reset the energy consumption computer. I drove 92.69 miles, charging midway with an EVGo DC Fastcharging station for just 6.83kWh. I finished my drive at the end of the day with 17% remaining. By my calculations:

(100% - 17%) X 27kWh = 22.41kWh

22.41kWh + 6.83kWh (from EVGo) = 29.24 kWh consumed TOTAL

92.69 miles / 29.24kWh = 3.17 miles/kWh

For some reason my energy consumption computer reported 3.8 miles/kWh. Why is there such a discrepancy? Am I missing something?

I have a 2016 that I bought used in 2018 for $13k. It got a replacement battery soon afterward and then we got the battery recall last year and got a new battery then. All seems well now. I think the range is a little better now at about 88 miles on an 80% charge. All the time I've had my car I have kept track of the KWH used with a meter I bought in 2018. It has consistently given me a 3.1 miles per KWH +/- 0.1. The car on the otherhand tells me that I'm getting about 4.5 miles per KWH. I wonder why there is such a difference. Does anyone know how efficient charging at 110 volts is. If both numbers are correct then I'm losing a lot in the charging process.

 

[IanL]

The car's consumption figure represents only the energy expended when driving. The energy expended when charging is heat losses in the wiring between the meter and the car, the heating in the car's ac/dc conversion and the voltage increase to match the battery voltage, plus the heating in the battery while charging. These losses are not trivial.

@ DrivingForce - the percentage energy displayed by the car is the percentage of the actual capacity of the battery at the time of use. Unless the battery is quite new, this value will be less than the 27kWh nominal capacity. If you want to use the data, you need to know what the current State of Health (SOH) of the battery is. eg. with an SOH of 80%, the capacity of the battery is 80/100*27 kWh = 21.6 kWh.