Regen braking unavailable while at Standard full charge

[n3ckf]

Something interesting occurred to me the other day and i think this is a "bug" in the car.

My house is at 3300' in the mountains and i often drive downhill from here if i go into town (the main town around here is at 1500').
So i had charged the car to a standard charge when i arrived here, then went into town the next day.

Halfway down the hill i got the "regen braking unavailable" alert.

But i had the charge at "standard". So there's a full 15% of the battery pack "available" to suck up additional charge from braking.

I am used to seeing this when i did an extended charge to drive a long distance (like back to the Bay Area). Howewver i'd never seen it, when at a standard charge level before.

My opinion: this is a bug. It shouldn't disable regen braking when there's capacity available in the battery pack. Especially since in most cases where this happens, you're going to run that charge back out a few miles later (you wont go downhill *forever*). If you did go downhill long enough to fill 15% of the battery pack (thats a big mountain) it could shut off *then*, since it obviously knows how to do so.

Anyone else notice this?

Anyone have a Tesla (which has the same concept of standard and extended i think?) and notice how this works on the Tesla?

 

[doug401]

Yes... I have seen this same behavior. Mine, mostly back in April when new, would give this message when I would leave work after sitting uncharged all day outside. I found it odd because it would happen with 14 bars showing, plenty of room for regen. It may have something to do with outside temperatures cooling the pack because I hadn't seen it all summer until last week, after the car sat outside overnight at 40 degrees and unplugged. It also has always happened in B mode, but I always drive in B mode... so go figure. Either way... it always goes away after a few minutes on the road. I don't think its a bug. I believe the car wants to limit high current regen for some reason.

 

[Kohler Controller]

What was the temperature at the time (and overnight)?
Were you using B or D?

Like Doug401 says, B will allow greater regen levels to occur and lower temperatures will increase the pack's resistance such that at high regen levels the overall voltage shoots up quickly and may reach a preset threshold earlier than normal.

Try programming the climate control to turn on 15 minutes before you leave which might precondition the pack and normalize everything.

 

[n3ckf]

so when this happened it was kind of mid-day (probably 70-75F outside)? The car had finished charging (to standard) about 12 hours earlier though (at night when it was 45-50).

I was using "B" which i mostly do when on mountain roads.