On Monday, July 26, 2021 at 5:01:00 PM UTC-4, Jasen Betts wrote:
> On 2021-07-26, Rick C <gnuarm.del...@gmail.com> wrote: 
> > On Sunday, July 25, 2021 at 9:25:48 PM UTC-4, bitrex wrote: 
> 
> >> If one drives the same route day in and day out for a long time the net 
> >> impact of terrain tends to average out. But the range estimates are only 
> >> estimates based on a moving average, if you spend more time going up big 
> >> hills than down them for a while the range estimate will start to change 
> >> to reflect that. 
> >> 
> >> Maybe CD or the owner he's talking about didn't realize the car can only 
> >> derive the estimate from the data it has at a given time, it can't 
> >> predict the fuckin' future. 
> > 
> > The impact of terrain on EVs is approximately zero, but not actually 
> >since it requires more current to ascend a hill and power is related 
> >to the current squared.
> False. It's a battery, not a resistor. 

Much of the losses are not in the battery, but in the motor and other electronics which have resistive losses.  The battery is around 90% efficient I believe.  The number that has been tossed around the Tesla forums is 80% typical for regenerative braking round trip.  However, this is sensitive to the rate of charging and discharging due to the resistive losses so can be higher when the power levels are higher.  In the Tesla the rate is limited to approximately 100 kW.  

Regeneration is used in other situations than hill climbs.  Simply slowing for traffic or signals also uses regenerative braking with rather low losses.  Gentile hills also require little regenerative power and so lower losses approaching 90% efficiency. 

-- 

Rick C.

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On Monday, July 26, 2021 at 4:40:57 PM UTC-4, ke...@kjwdesigns.com wrote:
> On Monday, 26 July 2021 at 04:32:43 UTC-7, gnuarm.del...@gmail.com wrote: 
> ..
> > > The next dominant factor is tire rolling resistance for which the energy consumed is fairly independent of road speed (and wind speed of course). 
> > This all depends on the individual car. Many EVs are designed to minimize the wind resistance with a much lower drag coefficient than other vehicles so it is not as important until higher speeds.
> ... 
> Actually the Cd of EV's as a group are only slightly better than conventional vehicles that are designed with fuel economy in mind. 

That does not conflict with what I posted.  

-- 

Rick C.

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On 7/26/2021 4:29 PM, ke...@kjwdesigns.com wrote:
> On Monday, 26 July 2021 at 03:00:30 UTC-7, John Doe wrote:
>> Wrong.
>>
>> There are losses involved with recouping energy from going downhill.
> 
> The majority of the energy does not need to be recouped by regenerative braking so the losses do not apply.
> 
> Imagine  a conventional vehicle going up a hill.
> 
> It will require that the engine provide more power that it would to drive on the flat. However, on the downhill
> section the engine does not have to operate at such a high power output so the overall fuel consumption for the entire
> trip will average out to be close to what would it would be on a flat journey.
>   
>> And if you don't have regenerative braking, the losses are HUGE.
> 
> Every mainstream EV and hybrid does have regeneration, it's virtually free. In fact it's difficult to avoid it.
> 
> kw
> ...
> 

The best mileage I ever got in my Volt running on gas as a straight 
hybrid was in the rolling hills of eastern CT, 53 mpg over about a 50 
mile stretch between Putnam and Hartford. Apply just enough power to top 
the hill, engine shuts down near the top and coast/regenerate down, then 
again over to the next, etc.

On the mostly flat 50 miles between Boston and Providence about 42 mpg 
is the best I can do when I make that trip on gas.

> The troll doesn't even know how to format a USENET post...

As ironically stated by the John Doe <always.look@message.header> troll
in message-id <sdhn7c$pkp$4@dont-email.me>.
As ironically stated by the John Doe <always.look@message.header> troll
in message-id <sdhn7c$pkp$4@dont-email.me> who has posted yet another
incorectly formatted USENET posting.

On Monday, 26 July 2021 at 14:01:00 UTC-7, Jasen Betts wrote:
...
> > The impact of terrain on EVs is approximately zero, but not actually 
> >since it requires more current to ascend a hill and power is related 
> >to the current squared.
> False. It's a battery, not a resistor. 
...

The power losses being referred to are the internal resistance of the battery, motor and motor controller. They  increase with current into the motor.

kWh

It avoids my argument by pointing out a speech recognition error.

It doesn't pay me enough to correct such trivial errors...

-- 
"ke...@kjwdesigns.com" <keith@kjwdesigns.com> wrote:

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> 
> On Monday, 26 July 2021 at 13:49:08 UTC-7, John Doe wrote:
>> "ke...@kjwdesigns.com" <ke...@kjwdesigns.com> wrote: 
> ...
>> 
>> Think harder. The problem is in fact BREAKING. What you are saying might
>  
>> be mostly true if much of that downhill energy wasn't a complete waste 
>> (without regenerative braking) by slowing yourself down. You must expend
>  
>> energy SLOWING yourself when going downhill. The amount of slowing depend
> s 
>> on the hill and the speed limit (and other factors like safety, especiall
> y 
>> when talking about lesser forms of transportation).
> 
> It's you that needs to think harder.
> 
> Yes, the energy that must be stored will incur the round trip inefficiency that you calculate. However depending upon the nature of the hill a large proportion of the energy does not require that.
> 
> There are some very long hills in California (Highway 80 to/from Truckee or the south end of Highway 395) where even a conventional car can go for many miles with braking (notice the spelling!) or the application of throttle and still keep a reasonable speed. For those instances there is zero loss of energy due to regeneration inefficiency.
> 
> kw
> 
>

On Monday, 26 July 2021 at 13:49:08 UTC-7, John Doe wrote:
> "ke...@kjwdesigns.com" <ke...@kjwdesigns.com> wrote: 
...
> 
> Think harder. The problem is in fact BREAKING. What you are saying might 
> be mostly true if much of that downhill energy wasn't a complete waste 
> (without regenerative braking) by slowing yourself down. You must expend 
> energy SLOWING yourself when going downhill. The amount of slowing depends 
> on the hill and the speed limit (and other factors like safety, especially 
> when talking about lesser forms of transportation).

It's you that needs to think harder.

Yes, the energy that must be stored will incur the round trip inefficiency that you calculate. However depending upon the nature of the hill a large proportion of the energy does not require that.

There are some very long hills in California (Highway 80 to/from Truckee or the south end of Highway 395) where even a conventional car can go for many miles with braking (notice the spelling!) or the application of throttle and still keep a reasonable speed. For those instances there is zero loss of energy due to regeneration inefficiency.

kw