Optimal speeds for recapturing energy during descend and lowering consumption on ascend

[rrolsbe]

Point taken, this would work best on fairly straight rolling hills roads. What I described should be a selectable option by the driver just like the blended brake option on Teslas. I have owned under powered gas vehicles which basically required what I described but they did not have regen capabilities (not enough power to maintain speed uphill thus requiring additional speed gain going downhill).. With an under powered gas vehicle doing what I described could increase gas mileage but would mostly be done to help maintain the uphill speed.

 

[QtownTaxiGreg]

when the traction batteries are very cold

This is a concern for me. I climb ski mountains in the freezing cold.

The motors will be working reasonably hard and the climate control working to keep me and passengers warm as well. Will that amount of draining of the battery serve to keep the battery warm enough for regen on the way back down? Guess horsepower engaged equivalent to a constant 85mph so maybe 50%?

There is a supercharger at the bottom of one hill. I could conceivably tell it fibs to get it warmer while still going up. It's about 20 minutes from the top. Then cancel the charge on the turnaround but a nice warm battery to regen on all the way down.

Productive use of power or no?

What would be really great is if we could tell the BMS what we are up to and leave it over to it to manage. Drop pin for the turnaround point and note expected ambient temp up there. It's definitely clever enough to take the change in elevation and the current ambient temp and work something out.

 

[ewoodrick]

This is a concern for me. I climb ski mountains in the freezing cold.

The motors will be working reasonably hard and the climate control working to keep me and passengers warm as well. Will that amount of draining of the battery serve to keep the battery warm enough for regen on the way back down? Guess horsepower engaged equivalent to a constant 85mph so maybe 50%?

There is a supercharger at the bottom of one hill. I could conceivably tell it fibs to get it warmer while still going up. It's about 20 minutes from the top. Then cancel the charge on the turnaround but a nice warm battery to regen on all the way down.

Productive use of power or no?

What would be really great is if we could tell the BMS what we are up to and leave it over to it to manage. Drop pin for the turnaround point and note expected ambient temp up there. It's definitely clever enough to take the change in elevation and the current ambient temp and work something out.

The problem with "back home" is that I'm assuming that the vehicle has sat at the slope and cold soaks for hours. Something has to warm the battery first.

If there is any way that you cold plug into at least a 120V plug during the day and set a departure time that may help.

 

[QtownTaxiGreg]

The problem with "back home" is that I'm assuming that the vehicle has sat at the slope and cold soaks for hours. Something has to warm the battery first.

If there is any way that you cold plug into at least a 120V plug during the day and set a departure time that may help.

It's a taxi. No ski for me. Very occasionally there could be a late one up and a booking for an early one down that makes it worthwhile to wait for an hour. Nearly always it's turn and burn.

f you re read it now it should make a lot more sense what I am up to.

 

[ewoodrick]

It's a taxi. No ski for me. Very occasionally there could be a late one up and a booking for an early one down that makes it worthwhile to wait for an hour. Nearly always it's turn and burn.

f you re read it now it should make a lot more sense what I am up to.

The you really shouldn't have any issue, just make sure that you include the Supercharger in any trips where you think that you are going to need it. The car will make sure that the battery is in good shape.
When I go on day trips, I often route to my destination and then back to home. I add both waypoints in the correct order to my route. It will add a Supercharger if needed. I often decide I want another Supercharger, so I explicitly add it to the route.

If the car is hot, more specifically the battery, then except when the battery charge is very high, you should be getting full regen.

I think that the part that you may be missing is that the car keeps the battery at optimal temperatures whenever possible. Best Supercharging is a tighter temperature range, AFAIK.

 

[QtownTaxiGreg]

I think that the part that you may be missing is that the car keeps the battery at optimal temperatures whenever possible.

Indeed. Thanks! So nothing to worry about unless I do get a pitstop at the top.

Best schedule a departure if there is another job on later. That would bring it back up to temp for some range penalty, but "free money" for getting a 2fer up and down.

Otherwise turn and burn in the old parlance. Turn and charge no worries. Cheers.

A related question. Parked in my garage for charging overnight in winter how much of a shock to the system will it get venturing out into -7°C at very low power usage? Probably use more heating the cabin than driving along for the first few miles and then get shortly parked up.

 

[N..8]

At -7C when you first start up in the morning I would bet almost 3 times the usage for 15 mins or so and Regen will be very limited if any at all. This is why in cold climates plugging it in and pre condition is so important, you're still going to use the same amount of electricity but it will be from the plug and not your Range that takes the hit.

 

[QtownTaxiGreg]

At -7C when you first start up in the morning I would bet almost 3 times the usage for 15 mins or so and Regen will be very limited if any at all. This is why in cold climates plugging it in and pre condition is so important, you're still going to use the same amount of electricity but it will be from the plug and not your Range that takes the hit.

It seems like you are saying a -7 car will take 15 minutes of driving to warm up?

Without any preheating the car will start out at +8°C or thereabouts by my internal chill meter. It is well above freezing in the garage. Good enough if I delay charging so as to be finishing at departure?

 

[ewoodrick]

Indeed. Thanks! So nothing to worry about unless I do get a pitstop at the top.

Best schedule a departure if there is another job on later. That would bring it back up to temp for some range penalty, but "free money" for getting a 2fer up and down.

Otherwise turn and burn in the old parlance. Turn and charge no worries. Cheers.

A related question. Parked in my garage for charging overnight in winter how much of a shock to the system will it get venturing out into -7°C at very low power usage? Probably use more heating the cabin than driving along for the first few miles and then get shortly parked up.

It will be about 25C less impact than if the car was parked outside.

Yes, a little heating will be needed, but if you have schedule departure, then everything should be nice and toasty using home power and not the battery. That's what a lot of the Canadians suggest.

 

[QtownTaxiGreg]

25C

?? Did you mean 15C s in -7 vs 8 inside perhaps?

Or maybe -7 and car set to 18deg Canadian comfy = 25deg headstart for the car A/C.

 

[ewoodrick]

?? Did you mean 15C s in -7 vs 8 inside perhaps?

Or maybe -7 and car set to 18deg Canadian comfy = 25deg headstart for the car A/C.

From 15C in the garage to -7C outside