Battery capacity measurement method

xiaoyu80305 · Jul 22, 2018

I bought an energy meter online, which can be used to 110v ac only. I put it in between 110v outlet and my charging plug. It will display the charging time, total output energy (kwh),...... The most important number is kwh, which could tell you about your battery's capacity, if you start charge close to empty. I tried once for my LEAF, but have not tried to Bolt yet, since it will take very long time to finish. I may try it when I take a trip abroad.

xiaoyu80305 · Jul 22, 2018

I just thought that I can charge the car fully first, then drive it 100 miles in normal flat road condition. Put the meter on and charge it fully again. I would calculate based on the kwh that I put in.

like2bike · Jul 22, 2018

If you have the Kill-A-Watt meter, be careful with it. I remember when someone used it to measure LEAF charging energy, it started having a meltdown. However, I used my Kill-A-Watt meter at 11 amps with the LEAF and it did OK. I also bought a KWH meter that I added to my L2 charger. I will post some details on that, so if anyone WITH THE TECHNICAL ABILITY wants to try adding one.

SparkE · Jul 22, 2018

an energy meter will tell you how much electricity you pull out of the wall, NOT how much you put into the battery, so it isn't very useful to measure battery capacity.

I have heard figures of 83%-90% efficiency when charging the vehicle from a 120V source (EVSE).

xiaoyu80305 · Jul 22, 2018

Spark E,

You are correct. We need to know the charging efficiency from the ac outlet to the battery. There are two parts in between them. The first will be the charging cable, which I think the lost will be minimum. The second will be the AC/DC converter, which should be provided by Chevy Bolt manufacturer. Do someone know this information?

xiaoyu80305 · Jul 22, 2018

I would assume the new Bolt has 60 kwh battery. The owner may figure out the charging efficiency under certain temperature by putting the energy meter inline. Is there anyone did this test by using the factory included charging cable?