Friday, January 6, 2017

DC Fast Charge data

I sat on the charger for 90 minutes tonight to get a better idea of the various tapers the car undergoes as it is charged. The main takeaway is that the tapers are not gradual, they are hard drops in charging power. The first drop I noticed was around 50% charge, then another around 70%, and then another around 80ish%. I ended up around 85% charged and pulling in around 16 kW at that time. Ambient temperature is around 60F.

There were two times once at 30% and once at 40% where some fans/pumps came on and drew around 5 kW from the charger for a few minutes. Other than that no real abnormalities in the charge.

Overall charge vs time

Charge rate vs SoC

Overall charge from 1-35%

Overall charge from 35%-68%

Overall charge from 68-87%


12 comments:

  1. That is very interesting indeed. It might actually mean that Bolt is able to charge at full power(perhaps 80kW?) up to 50% SOC.
    0-50%-> 80kW
    50-70%->36(?) kW
    70-80%->24 kW
    going from 5 to 80% SOC in ~55minutes. A roadside picnic? More like lunch. Also charging beyond 80% becomes a bit pointless.

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  2. It's important to point out that this charging cycle had to be broken into three sessions, which likely affected the charging power.

    Also this was done at a "50kW" charger capable of 125A. Some "50kW" chargers only provide 100A and would be slower.

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    1. I am charging now in one session and just passed 55% and the same behavior I noticed before, dropping from 45kW to 37kW, is happening. So there is a hard taper starting at that charge level.

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  3. The Bolt has voltmeter and ammeter but chooses not to display the numbers, right?
    --

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  4. Great report, thanks! It would be very interesting to see if charge speed increases on a 70kW+ FC. Any chance you could test this?

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  6. As far as I know there are no chargers over 50kW right now in the USA.

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  7. Thought I read somewhere av few faster FCs existed in the US, but I cant find anything when searching now. Might have to wait for Bakers in June.

    It would be interesting to see a charge speed graph from an FC that doesn’t terminate the session. Im hoping a continous charge will allow 40kW+ way over 50%. Falling below 40kW at 50% is disappointing for at 60kWh battery.

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  8. The result you show is disappointing. Using 125A ABB charger, maximum would be 50 kW (400V). Even if the battery isn't full and only 360 V, that should still be 45 kW. Could it be that the charger was faulty? Can you try it again at different charger? Maybe not sit there for full 90 minutes but maybe spot checks to see how different it is?

    SparkEV shows constant 48kW in many chargers, but there are few that show less, anywhere from 36kW to 47kW. If you have or know someone who has SparkEV, you might ask them to plug-in first to see how the DCFC performs before starting your session.

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    1. I have tried several chargers around my area and nothing will go above 46-47kW and the taper points seem pretty consistent as well. Seems like the best zone to charge in is 0-55%. Anything above that and you start to see much longer charge times.

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    2. If you're getting 46-47 kW, that's ok. Your graph above showed less than 45 kW, so that was the concern.

      But it is concerning that Bolt with 3X bigger battery than SparkEV cannot charge at same power level to 80%, which SparkEV can. With such big battery, I had expected Bolt to keep close to 50 kW way beyond 90%. I hope this is something they can improve upon with service updates.

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