09-12-2017, 11:54 AM | #1 |
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question re brake regeneration
I'm not the most techie person so I wonder if someone can give me a simple explanation about the following, or explain how I'm looking at this wrong:
In heavy traffic, our i3 brakes supposedly "regenerate" the battery. That's how I understood it. But after driving my i3 in Los Angeles traffic for about three months, it seems what happens is the range is extended by brake regeneration, but the actual battery charge is not increased. M-F, in my drive home from downtown LA in heavy traffic for the first 10 miles or so, my range barely decreases or even creeps up a little, but the battery level still seems to be drained. So I'm getting more range from by charge, but not actually charging the battery... In other words, if our brakes truly "recharged" the battery, after several miles of driving in heavy traffic and employing brake regeneration, wouldn't the battery level indicator either stay at the same level or possibly even move to the right? I've never seen it do that. It always continues to drop lower. No mistake, I love my i3. But I guess I've misunderstood the concept of brake regeneration... |
09-12-2017, 12:07 PM | #2 | ||
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If you lift off the accelerator but don't touch the brakes, all you get is electric engine's reg charging drag. Quote:
You just need to find a nice downhill slope where the reg braking gets to recharge the battery for longer than you discharge it by pressing on the accelerator. This is hard to observe over flat landscape stop'n'go driving, as every fractional battery recharge from reg braking gets offset by battery drain from subsequent acceleration. Every time I go up a major mountain in NE, my consumption drops to ~3.x miles per kWh. After I crest, i3 goes into reg mode, and I recharge the battery upto +2.5% of the total charge (on the longest descents). Net net, my consumption is at 4.8 miles /kWh after 6K miles of driving. HTH, a
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09-12-2017, 04:31 PM | #3 |
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I live on a hill, so driving to work (or rather coasting) I can get 2% charge - so end up with more charge than when I started from home. Unfortuntaely I lose a lot more going up the hill back home.
Afadeev, do you know if the amount of regen charging increases depending on driving mode, ie more charging in eco mode?
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09-14-2017, 10:37 AM | #4 | |
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The kinetic energy potential of the car is not effected by the driving mode, nor should the engine's efficiency in converting the kinetic energy to electricity. The only remaining variable is the current draw from sitting in the car (while the battery is being recharged coasting downhill), and there Eco+ will consume less than Comfort mode. So the net amount of charge added to the battery may be marginally higher in Eco+, but due entirely to lower parasitic loss from HVAC and other creature comfort systems. HTH, a
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09-14-2017, 10:45 AM | #5 |
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This is a question I've been pondering as well.. I do know that the different Drive Modes have a different Throttle Curve (especially between Normal and EcoPro, cant quite feel a difference between EcoPro and Pro+) Scaled Throttle, I think, is what they call it..
That being said, there could be a potential of a greater Regen Rat (EcoPro vs Normal) And if I'm not mistaken, I also believe the Throttle Curve alters itself in the EcoPro modes when you are traveling on incline (uphill vs downhill) Last edited by baldyloxx; 09-14-2017 at 10:55 AM.. |
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09-14-2017, 10:50 AM | #6 |
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One thing is for sure, on my commute to work from my door is mostly down hill.. By time I get to the Freeway, I still have 97-98% SOC from a full charge, after 11mi of undulating road travel..
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