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Regenerative Braking off at 60% and less battery?

Regenerative Braking off at 60% and less battery?

I understand why regenerative braking wouldn't function when the battery is at or near 100%. However, more than a few times in the past month we've had our SR+ M3 tell us that regenerative braking isn't functioning and the battery has been at 60% or less. Eventually it starts to work, but when you get used to driving with regenerative braking it's extremely jarring to not have it functioning, forcing you to adjust the way you drive. Does regenerative braking being off or on have anything to do with the outside temperature? i.e.: does it not work when the vehicle is cold? That's the only variable I can think of that's changed in the past month.

I can't find a mention of this in the forums - though they don't make searching easy - so forgive me if this has been discussed previously.

FISHEV | December 1, 2019

The cold will do it. Same with charging, if too cold, the charging is at a very low rate.

"When it comes to recharging lithium-ion batteries, however, there’s one hard and fast rule: to prevent irreversible damage to the battery, don’t charge them when the temperature falls below freezing (0°C or 32°F) without reducing the charge current. Unless your battery management system (BMS) communicates with your charger, and the charger has the ability to react to the data provided, this can be difficult to do. "

https://relionbattery.com/blog/lithium-battery-cold-weather

Bighorn | December 1, 2019

Regen is reduced below 60F.

M3phan | December 1, 2019

Apologies in advance for being pedantic, but just in case:
Look closely at that “line” under the speedo that shows green regen and black power usage; the “dots” on the left part of the line, in the green regen area show how decreased the regen is. More dots = less regen. Yes cold affects. And yes, as you drive and battery warms, those “dots” decrease/disappear and regen is restored.

lbowroom | December 1, 2019

Don’t worry about the fish scare post, the car knows what’s its doing.

CRAIGJFIFTY3 | December 2, 2019

One time I had reduced power according to the power indicator. It had a few dots on the right end of the line.
Anyone else see this?

FISHEV | December 2, 2019

"Yes cold affects. And yes, as you drive and battery warms, those “dots” decrease/disappear and regen is restored."

it's never really gone. You typically have what looks to be about 40-50% of regen to use. It would only be harder regen via the brakes that is missing. I guess in really cold weather you could have all dots for the regen and then no regen at all but if there's some solid line you have some regen.

spuzzz123 | December 2, 2019

On the right side? Interesting, have never noticed that. Could you feel it noticeably more sluggish?

Bighorn | December 2, 2019

@CRAIG
Routinely in the cold.

hokiegir1 | December 2, 2019

@Craig - I've had that when the battery gets under 30% or when it's been very hot outside (over 100*F).

Bighorn | December 2, 2019

@spuzz
Same as when soc is low. Reduced top end acceleration

andre | December 2, 2019

Note that the operator's manual for the 3 does mention (twice) that the Regenerative Braking "may be limited when the
ambient temperature is either very warm or cool" (among other reasons).

Pg3ibew | December 2, 2019

+1 @M3phan. About the regen dots on the left side

Pg3ibew | December 2, 2019

I have routinely run below 60 percent. I have not had that issue with regen. I do have an issue with the cold and regen.

Silver Ronin | December 3, 2019

Makes a lot of sense, thank you everyone. I have the manual in PDF format and have been meaning to read it all the way through; this is a good reminder I need to do that. ;-)