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Regen Dots

Mrklaw

Member
Mar 5, 2020
433
229
Berkshire
Really what’s the point of wasting juice pre-heating to get more regen. I just don’t get it. The logic seems to be if I use 2kwh preheating my driving efficiency will improve and save me 1kwh on my journey. I get the warm car in the cold bit of pre-heating course, just not the obsession with preheating to get rid of the dots.

to a degree, if you’re plugged in when doing it so you aren’t using the battery, it can be a range min-max kind of thing. You’re spending more overall but less from the car and it’ll give a little extra range
 

VanillaAir_UK

Well-Known Member
Jun 17, 2019
8,247
5,772
Surrey, UK
to a degree, if you’re plugged in when doing it so you aren’t using the battery, it can be a range min-max kind of thing. You’re spending more overall but less from the car and it’ll give a little extra range

If you pre heat whilst plugged in, you are potentially using power with a much higher carbon footprint (warmup morning commute often coincides with ramping up power generation) and at a higher electricity tarrif rate.
 
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Tigermad

Member
Mar 1, 2021
237
44
UK
If you pre heat whilst plugged in, you are potentially using power with a much higher carbon footprint (warmup morning commute often coincides with ramping up power generation) and at a higher electricity tarrif rate.
Im going to preheat when plugged in but no power being used. Don’t fancy paying normal octopus go rates at 6AM. I wonder how much percentage of battery is used in a 15 minute preheat.
 

Avendit

Member
Apr 18, 2019
845
555
EDI
Really what’s the point of wasting juice pre-heating to get more regen. I just don’t get it. The logic seems to be if I use 2kwh preheating my driving efficiency will improve and save me 1kwh on my journey. I get the warm car in the cold bit of pre-heating course, just not the obsession with preheating to get rid of the dots.
I think its not just for regen - that is just the most user facing aspect.

If its icon-on-the-battery cold then the car is going to use quite a few KWh of power to bring the battery and cabin up to heat. It doesn't really matter where you get that heat from, but if you are doing a long trip, it can eat into your range, which is already suffering a bit in the cold. Also, if its really cold you can use lose a fair chunk of forward power too. Not enough in the UK generally to cause a -real- problem, but it might be in the US. Better to top off from the plug if you can basically, but not essential.
 
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CD_WE

Member
Jan 13, 2021
50
41
Ireland
It's been reported several times on this forum and elsewhere ... Google it, I didn't make it up honestly! Could your car be one of the last that have the options? Or did they bring it back again with a software update? Or maybe Fremont cars lost the options?
Weird, I definitely have the options. Maybe one of the last like you say
 

Kenners

Member
Sep 29, 2019
206
178
London
I think its not just for regen - that is just the most user facing aspect.

If its icon-on-the-battery cold then the car is going to use quite a few KWh of power to bring the battery and cabin up to heat. It doesn't really matter where you get that heat from, but if you are doing a long trip, it can eat into your range, which is already suffering a bit in the cold. Also, if its really cold you can use lose a fair chunk of forward power too. Not enough in the UK generally to cause a -real- problem, but it might be in the US. Better to top off from the plug if you can basically, but not essential.
I understand the logic when doing a long trip, although 99% of the time battery is not an issue as I either have to stop at a supercharger at some point anyway or the journey is within the range anyway. Most people don’t drive that far 99% of the time, which was sort of parting the point.
 

Tigermad

Member
Mar 1, 2021
237
44
UK
Had my car a week now. Because it’s cold and I finish charging hours before I leave, I don’t really have any regen. So it’s to be expected since I only travel about 11 miles to work and 11 miles back. It will be nice when I can go on longer runs to try the regen out properly. I definitely think the heat pump removes some heat from the battery like the reviews and tests have proved.
 

Adopado

Active Member
Aug 19, 2019
4,177
3,142
Scotland
Had my car a week now. Because it’s cold and I finish charging hours before I leave, I don’t really have any regen. So it’s to be expected since I only travel about 11 miles to work and 11 miles back. It will be nice when I can go on longer runs to try the regen out properly. I definitely think the heat pump removes some heat from the battery like the reviews and tests have proved.
Yes, but even the non heat pump wouldn’t offer much regen in cold weather with that pattern of use unless you precondition... but that’s probably a waste of electrons ...
 
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RedSky1

New Member
May 26, 2021
2
0
Tasmania
Very interesting

Been looking around some forums to see if the MIC LFP SR+ Model 3 has more Regen available at or near 100% than the USA NMC SR+ model under the same battery/ambient temperature conditions.

A post in an Australian forum suggested they still had reasonable amount of Regen while at 100% charge in their LFP model and where that person is located it's about 8 min - 15 max degree Celsius daily temps this time of year.

Technically LFP cells can take some overvoltage abuse without degradation where NMC cannot like might happen under regen conditions at or near 100% SOC so I do wonder if Tesla has made allowance for this in software and loosened the cut-off a bit.

As they recommend the LFP battery be charged to 100% often i'm sure Tesla would be doing everything they can get away with to still keep some regen at that point.

The LFP charging profile also suggests it allows more kW while charging than NMC models when above 90% SOC, so it just might be the battery is able to accept more current in the last ten percent of SOC and thus also more Regen but doesn't actually push past the LFP cell full voltage (3.6v)

In all cases NMC or LFP batteries just can't accept heavy charge when really cold at any state of charge level without potential degradation hence regen limited at all states of charge in like 0 degree weather when the battery is also cold.
 

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