Fast DC Charger Effect

Discussion in 'Prime Main Forum (2017-Current)' started by bwilson4web, Aug 28, 2017.

  1. bwilson4web

    bwilson4web BMW i3 and Model 3

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    The 40kW, fast DC charger went down Thursday and it changed my preference between the BMW i3-REx and Prius Prime:
    • 6.4kWh - Prius Prime battery ~= 10 minutes for full charge (if it had a fast charger option)
    • 18kWh - BMW i3-REx, 18/40 ~= 27 minutes for full charge
    With the fast DC charger, I can confidently drive the BMW i3-REx to low SOC so when I returned to town, a short stop by the fast DC charger and then home again. But with the charger down, there was no advantage of the BMW i3-REx over the Prius Prime. Which car to drive becomes a 'toss up'. Let me share two scenarios:
    1. Prius Prime, ~25 mi EV range - this is a three stop car. It is roughly 10 miles from home to the usual haunts; a second 5 mile jaunt, and; 10 miles home.
    2. BMW i3-REx, ~72 mi EV range - this is a dozen stop car: 10 miles from home; ten, 5 mile jaunts, and; 10 miles home. Alternatively, Decatur is ~30 miles away and has an excellent southern-style, breakfast cafe ... drive over and back. Then a quick stop at the fast DC charger and drive home.
    Understand both cars have gasoline power for longer ranges. My eclipse trip in the BMW i3-REx was just over 300 miles, three tanks. My delivery trip of a Gen-1 battery pack was about 400 miles. Either car can fully backup the other and individually they completely cover our transportation requirements.

    A working, fast DC charger biases towards the BMW i3-REx. It is on long range trips that the Prius Prime is preferred.

    Bob Wilson
     
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  2. heiwa

    heiwa Active Member

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    Am I incorrect to think that charging with a fast DC degrade the traction battery faster than with a level 1 or 2 ?

    Posted via the PriusChat mobile app.
     
  3. bwilson4web

    bwilson4web BMW i3 and Model 3

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    I think that is over broad since there are several LiON chemistries and the battery control module can be programmed to minimize the risk. The key is to properly taper the charge as it approaches full SOC and/or leave enough headroom.

    Bob Wilson
     
  4. Lee Jay

    Lee Jay Senior Member

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    You are correct, usually, but it depends heavily on the specific battery design used. Some batteries can handle a 10C charge (I have some). Some are degraded by a 2C charge. The Leaf manual tells owners to avoid DC fast charging when unnecessary because of battery degradation. That's a roughly 2C charge.
     
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