Battery Capacity

Discussion in 'Clarity' started by Timothy, Jul 9, 2018.

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  1. Timothy

    Timothy Active Member

    We almost never let the EV estimate get to zero so I generally don't have this info. But it did this weekend. Charging at a public ChargePoint station this morning from 0 EV, I took 14.44 kWh. I am curious what others have seen in this scenario.
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  3. Viking79

    Viking79 Well-Known Member

    Yes, mine always takes around 14 to 14.4 kWh. Some tech documents someone found show it has 27.3 Ah (20 Ah usable) cells, wired in 84s2p with 311 V battery for a total of 12.44 kWh usable (useful if you want to know your driving mi/kWh or something).
    VTSAX likes this.
  4. ace base

    ace base Member

    The max I have seen once from my charge point use is 15.22 kWh, the car showed 2 bars for battery and 0 EV miles.
    Second highest I have seen is 14.86kWh

    I think this also has to do with any cooling that happens concurrently while charging.
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  5. Wayne Wilson

    Wayne Wilson Member

    The most I have ever charged is 16.36KWH with the HondaLink App showing 9% of the battery charge left and the car showing 0 miles left. Now here is the complication, that was with the supplied 120V charger. If the charging process was 100% efficient (which it can't be) that would mean the battery had a 100% charge of 16.36/.91 = 17.98KWH which we know is impossible since Honda says it has a 17KWH battery. So, no surprise, charging has some efficiency level, but we don't know what it is, so we really don't know how many KWH made it into the battery. I have since switched to a 240V charger (which charges at 3.3KW/H compared with the 1.25KW/H of the 120V) and comparing charge consumption with similar HondaLink battery percentages shows that the 240V charger is more efficient, which is not unexpected. That means in the same situation, my 240V charger would most likely have used 14.8KWH. Furthermore, we don't really know whether the HondaLink is measuring from the 17KWH battery rating or some lower "usable" KWH rating, but the consensus is that it must be measuring from some "usable" rating. Same thing goes for the EV range indicator, when it reaches 0 miles, the battery is not dead and the HondaLink app will read some percentage left.

    What get's confusing for someone reading about Lithium batteries is that almost all the data on how to maximize their life and what voltages to charge them to and discharge them to, is based on actual measurements at the battery. The indicators we have to go by, miles left to drive in the car's display, battery percentage left from the HondaLLink App and actual KWH hours used in a charge from our charging meters are all somewhat removed from actual flows at the battery. We have to assume that the Honda engineered Battery Management System is designed to make some good decisions about battery state of charge management with regards to trading off battery life with car performance.
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  6. Wayne Wilson

    Wayne Wilson Member

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  8. Wayne Wilson

    Wayne Wilson Member

    Tonight I charged at 240v 14.5A from 0 miles EV range and what initially showed as 0% battery in HondaLink but 2 bars in car readout. HondaLink updated as soon as charge started and showed 10%. At any rate a full charge consumed 14.4 KWH. That’s a little less than I estimated up above.

    With this data we can play a what if game. What if the charging efficiency was 95%? That would mean that 13.7KWH went into the battery. Since the battery is rated at 17 KWH that would mean 3.3 KWH was being held in reserve or about 19%. 2 bars and 10% are the same so let’s say 0 miles of range and ICE turn on is at 10% of 13.7 which is roughly 1.4 which is 8% of 17. So we see the Honda battery management maintaining the battery between 8% and 81% of it’s rated capacity. I have seen other estimates on this forum of 10% to 80%.

    This shows us that Honda is already taking care of the battery according to guidelines established in battery engineering and we do not need to do anything ourselves, like only charging to 80% on the gauges or HondaLink app, or never letting the EV range drop to zero.
  9. bpratt

    bpratt Active Member

    I totally agree.

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