kWh meter for charging

[GizmoEV]

After metering my charging use for my Gizmo EV using a Kill-a-Watt meter on a 120V outlet I wanted to measure how much my KIA uses when charging at home. I ordered and installed the basic meter from http://www.ekmmetering.com for 240V single phase. Other than having to rewire my charging outlet it is very simple to install. If I had purchased one of the meters with remote sensing I could have avoided the rewiring part. These meters are accurate enough for billing purposes so should be good for our uses.

 

[tractioninc]

Great idea. When charging at 120v, how did the 'actual' power consumed compare with the 'available' power added to your Soul EV's battery pack?

 

[GizmoEV]

I don't know exactly but one time, before I received my 20A EVSE, I arrived home with 4 miles/4% remaining. It took over 28 hours to charge on 120V and IIRC it took a little over 33kWh to charge. If we assume that there was 25.9kWh needed by the pack that gives a charge efficiency of about 78%. Given the cooling/heating and monitoring loads this sounds reasonable to me. The extra 7.1+kWh over 28 hours means the parasitic load is around 250W for the given conditions I was charging in. I would assume that in hot weather or cold weather that the parasitic load would be higher.

This morning I charged from 80% to 100% in 1.5 hours on 240V 20A (18.5A measured at start). That should mean the pack needed 5.4kWh but 7.89kWh was measured at the wall. 68% efficient, which might be reasonable given the slowdown as the battery reaches 100%. 2.49kWh over 1.4 hours averages to 1778W which sounds quite high. No climate control was programmed so I'm not sure what is going on. My wife will be back with little range left so I'll do a 100% charge and see what it takes in the morning.

Too bad KIA doesn't display charge rate in the instrument cluster.

 

[GizmoEV]

This morning I charged from 80% to 100% in 1.5 hours on 240V 20A (18.5A measured at start). That should mean the pack needed 5.4kWh but 7.89kWh was measured at the wall. 68% efficient, which might be reasonable given the slowdown as the battery reaches 100%. 2.49kWh over 1.4 hours averages to 1778W which sounds quite high. No climate control was programmed so I'm not sure what is going on.

What is going on is that my Wife drove about 5 miles and came home and charged back to 100% before going on her longer trip! That is where some of that 2.49kWh went. She came home with 18% battery left and it is now charging to 100%. I'll report back on the results. I told her to let me read the meter before she charges again.

 

[GizmoEV]

Here are the results of a charge from 18% to 100% so about 22.14kWh. Using my 20A 240V EVSE it took 24.45kWh at the wall over 5h 32min (5.53h). The extra 2.31kWh means about 418W in overhead and losses.

 

[tractioninc]

An average of 90% efficiency during the charge isn't bad. Thanks for the update!