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01-22-2021, 10:14 AM
(This post was last modified: 01-22-2021, 10:15 AM by danbrotherston.)
(01-22-2021, 09:34 AM)tomh009 Wrote: (01-22-2021, 09:08 AM)Coke6pk Wrote: My comment was do non-hybrid EV's "recharge themselves" to supplement the plug in, not replacing it... I realize perpetual motion isn't a thing.
My thoughts were more of a plug in and charge for 1/2 hr as opposed to a 3 hr charge if the battery wasn't drained over the course of a trip because it was regenerated by braking, wheel turning etc.
Regenerative braking is how non-plugins charge. And, yes, plug-ins and BEVs do the same, it's just less significant given the much larger batteries.
Charging from normal wheel motion would be counterproductive as it would increase the energy required for keeping the car in motion.
I think it's actually more significant, yes, it is a smaller fraction of the total battery storage capacity in the vehicle, but it is more total energy that can be recovered both because the battery is larger and because the electric motors are considerably more powerful, so can generate more braking force.
Most BEVs do regenerate power from the wheels when the driver releases the accelerator. For some reason this mode has been popular, I think because manufacturers believe (with data or not, I'm not sure) that this encourages drivers to make better use of regeneration, because hard braking will obviously make use of the brakes, and many drivers do not drive particuarly....smoothly. This is also not without precedent as it mirrors the engine braking effect you can make use of with a manual transmission.
I personally don't like this mode, but I am also generally aware of how to brake gradually, and I plan my stops well in advance, as a result, this mode requires me to feather the throttle to coast the vehicle, which is significantly more complicated than just releasing the gas.
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(01-22-2021, 10:14 AM)danbrotherston Wrote: I think it's actually more significant, yes, it is a smaller fraction of the total battery storage capacity in the vehicle, but it is more total energy that can be recovered both because the battery is larger and because the electric motors are considerably more powerful, so can generate more braking force.
Most BEVs do regenerate power from the wheels when the driver releases the accelerator. For some reason this mode has been popular, I think because manufacturers believe (with data or not, I'm not sure) that this encourages drivers to make better use of regeneration, because hard braking will obviously make use of the brakes, and many drivers do not drive particuarly....smoothly. This is also not without precedent as it mirrors the engine braking effect you can make use of with a manual transmission.
I personally don't like this mode, but I am also generally aware of how to brake gradually, and I plan my stops well in advance, as a result, this mode requires me to feather the throttle to coast the vehicle, which is significantly more complicated than just releasing the gas.
Yes, I meant more significant as a percentage of battery capacity.
My recently-sold car (no, not EV) was still on original brake discs after 9+ years, courtesy of gradual slowing down, frequently with no brakes needed. It's really not hard to do once you get used to it, you just need to anticipate the need to slow down some more.
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(01-22-2021, 01:33 PM)tomh009 Wrote: My recently-sold car (no, not EV) was still on original brake discs after 9+ years, courtesy of gradual slowing down, frequently with no brakes needed. It's really not hard to do once you get used to it, you just need to anticipate the need to slow down some more.
On my PHEV (plug-in hybrid electric) there is a actually a display mode which shows the energy flows: when braking lightly one can see the energy going from the wheels back into the battery. My only suggestion would be that when the friction brakes engage (sufficiently heavy braking, or braking at extremely low speeds) this should be displayed somehow too; perhaps a red halo around the wheels to indicate that energy is being lost as heat.
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(01-22-2021, 01:33 PM)tomh009 Wrote: (01-22-2021, 10:14 AM)danbrotherston Wrote: I think it's actually more significant, yes, it is a smaller fraction of the total battery storage capacity in the vehicle, but it is more total energy that can be recovered both because the battery is larger and because the electric motors are considerably more powerful, so can generate more braking force.
Most BEVs do regenerate power from the wheels when the driver releases the accelerator. For some reason this mode has been popular, I think because manufacturers believe (with data or not, I'm not sure) that this encourages drivers to make better use of regeneration, because hard braking will obviously make use of the brakes, and many drivers do not drive particuarly....smoothly. This is also not without precedent as it mirrors the engine braking effect you can make use of with a manual transmission.
I personally don't like this mode, but I am also generally aware of how to brake gradually, and I plan my stops well in advance, as a result, this mode requires me to feather the throttle to coast the vehicle, which is significantly more complicated than just releasing the gas.
Yes, I meant more significant as a percentage of battery capacity.
My recently-sold car (no, not EV) was still on original brake discs after 9+ years, courtesy of gradual slowing down, frequently with no brakes needed. It's really not hard to do once you get used to it, you just need to anticipate the need to slow down some more.
Indeed, it's especially frustrating as drivers often speed towards their stop point, then brake hard...well...that stop point is often a crosswalk...as a pedestrian, I'm not going to be comfortable watching a car speed towards me, only to brake at the last second.
But it's ironic that the decision also costs the drivers money.
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(01-22-2021, 03:00 PM)danbrotherston Wrote: (01-22-2021, 01:33 PM)tomh009 Wrote: Yes, I meant more significant as a percentage of battery capacity.
My recently-sold car (no, not EV) was still on original brake discs after 9+ years, courtesy of gradual slowing down, frequently with no brakes needed. It's really not hard to do once you get used to it, you just need to anticipate the need to slow down some more.
Indeed, it's especially frustrating as drivers often speed towards their stop point, then brake hard...well...that stop point is often a crosswalk...as a pedestrian, I'm not going to be comfortable watching a car speed towards me, only to brake at the last second.
But it's ironic that the decision also costs the drivers money.
Yeah, just lifting off will typically shut off the fuel injectors and drop the fuel consumption to zero.
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(01-22-2021, 03:00 PM)danbrotherston Wrote: But it's ironic that the decision also costs the drivers money.
Given how few drivers ever accurately total up their cost per ride when they start ranting about how their car is cheaper than the bus, are you really surprised by them not knowing or understanding how their driving habits makes thing more expensive that it need be?
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(01-26-2021, 01:45 PM)Bytor Wrote: (01-22-2021, 03:00 PM)danbrotherston Wrote: But it's ironic that the decision also costs the drivers money.
Given how few drivers ever accurately total up their cost per ride when they start ranting about how their car is cheaper than the bus, are you really surprised by them not knowing or understanding how their driving habits makes thing more expensive that it need be?
Surprised, no, I just thought it was ironic.
As an aside, I'd be curious to know if there is any correlation between these forms of bad driving, and believing oneself to be a good driver. I suspect there is a strong correlation, but I am mostly judging based on highly outspoken outliers. "I'm a good driver, that's how I know I need to speed and drive aggressively....for safety of course". I could be wrong, there are problems with drivers who are too timid or just plain disinterested as well.
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(01-19-2021, 07:19 PM)danbrotherston Wrote: If tomorrow, everything we ever built was electric, it would still take 10-15 years to convert the existing fleet. More likely everything going electric means a 30-50 year timeframe.
This is more than enough time to transition.
Exactly. Where were all the drill rigs, refineries, pipelines, and gas stations in 1900? Now contrast that to 1950...
...K
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