Page 4 of 6

Re: Max regen - at what point do mechanical brakes engage?

Posted: Mon Aug 05, 2013 1:44 pm
by TomT
Considering how often I see less than a full compliment of regen circles these days, I'd question that... That MAY be true on a new pack but does not appear to be on a degraded one...
EVDRIVER wrote:The regen is presently not pack restricted. All of this can be regulated in real time.

Re: Max regen - at what point do mechanical brakes engage?

Posted: Mon Aug 05, 2013 1:49 pm
by DaveinOlyWA
TomT wrote:Considering how often I see less than a full compliment of regen circles, I'd question that... THAT may be true on a new pack but does not appear to be on a degraded one...
EVDRIVER wrote:The regen is presently not pack restricted. All of this can be regulated in real time.

regen is pack restricted FREQUENTLY and can be due to cold, hot, SOC, speed, etc...

RPMs are part of the equation but not all of it.

Re: Max regen - at what point do mechanical brakes engage?

Posted: Mon Aug 05, 2013 10:38 pm
by DaveEV
TomT wrote:
EVDRIVER wrote:The regen is presently not pack restricted. All of this can be regulated in real time.
Considering how often I see less than a full compliment of regen circles, I'd question that... THAT may be true on a new pack but does not appear to be on a degraded one...
Since taking my car in for the latest updates at the beginning of July, I now often see only 4 regen bubbles and regen limited to 20-25 kW despite battery temps 75F+ until SOC gets below 70-75%. Never used to see that before unless it was in the winter when I presume battery temps were in the 60-65F range.

The car is much more reluctant to max out regen at 30 kW+ until the SOC is much lower and it's more difficult to keep the mi/kWh gauge pegged at 8.0 mi/kWh the first couple miles of my commute unless I am much more careful driving those first couple miles.

Not sure if this was a result of the LBC update or the "low speed grabby brakes" update as I had both done at the same time. I kind of regret having the latter done at this point in time...

Re: Max regen - at what point do mechanical brakes engage?

Posted: Tue Aug 06, 2013 12:33 am
by cwerdna
DaveinOlyWA wrote: i think Nissan was using this fact when boasting a big range and also the reason why it did not show up in Tony's Range tests
Interesting hypothesis. That would make sense since the EPA tests dictate being at a particular speed at a particular time. I don't think they dictate when to apply the brakes. And, since Tony's range test was a constant speed, there was likely very little regen.
dgpcolorado wrote:Seems strange to be making suggestions to someone who has been "here" so long but here goes:

Use regen only when slowing is needed. Coasting is usually more efficient so max regen is to be avoided unless significant slowing is required.
Heh. Well, there are certain things that I paid little/no attention to as I didn't have the car yet. The same goes for Gen 3 HSI related stuff (http://techno-fandom.org/~hobbit/cars/HSI/" onclick="window.open(this.href);return false;). Gen 2 Prius has no such indicator and has a different engine than Gen 3, besides a significantly redesigned transaxle and very different circuitry inside the inverter box. So, I pay little attention to how best to drive a Gen 3 Prius and use its HSI since I don't have one.

Yes, I agree that it's best to not change your speed much at all, in either direction. The principles are the same when driving a Prius.
DaveinOlyWA wrote: But you had a Z before so guessing it would be easy for you to get used to going from N to D to B, etc... ;)
It was an automatic. :oops: I can only drive stick very poorly. :oops: On the flip side, my Z's transmission had 0 problems, unlike the folks who went thru several manual transmissions.
DaveinOlyWA wrote: congrats on finally getting one! any details (or link) to share?
Sorry, not many details. I posted about getting it at http://www.mynissanleaf.com/viewtopic.p ... 98#p313898" onclick="window.open(this.href);return false;.

Work and other things have been keeping me busy.

Re: Max regen - at what point do mechanical brakes engage?

Posted: Tue Aug 06, 2013 5:24 am
by Klayfish
Starting to get a better grip on this, thanks for the replies. I used the energy screen this morning to try to monitor what I was doing. I typically try to maintain constant speed anyway, even when I was driving my ICE cars. Doing that always let me beat the mpg ratings for the car, and always above what most others report...for instance I can get 35mpg out of my '90 Miata. I wasn't at complete zero on the long stretches of flat, open road, but fairly close. My dash currently says 3.8 miles/kwh average, so I'm getting the hang of it.

Re: Max regen - at what point do mechanical brakes engage?

Posted: Tue Aug 06, 2013 8:36 am
by dgpcolorado
Klayfish wrote:Starting to get a better grip on this, thanks for the replies. I used the energy screen this morning to try to monitor what I was doing. I typically try to maintain constant speed anyway, even when I was driving my ICE cars. Doing that always let me beat the mpg ratings for the car, and always above what most others report...for instance I can get 35mpg out of my '90 Miata. I wasn't at complete zero on the long stretches of flat, open road, but fairly close. My dash currently says 3.8 miles/kwh average, so I'm getting the hang of it.
In that case you should do well with LEAF mileage.

You have two mileage meters, the one on the dash and one on the console (you can get to it with a button on the energy screen). I suggest that you reset one daily and you can leave the other for longer periods (I reset mine monthly). That way you can get an idea of how you are doing each day, as opposed to averaging in daily trips since you got your car. I would guess, from your description of your route, speeds, and driving style, that you are probably doing better than 3.8 miles/kWh now.

Re: Max regen - at what point do mechanical brakes engage?

Posted: Tue Aug 06, 2013 8:40 am
by TomT
My experience exactly, drees. P3227 definitely has taken away some of my maximum available regen under numerous conditions... How much of this is due to how P3227 interacts with my degradation is unknown...
drees wrote:
TomT wrote:
EVDRIVER wrote:The regen is presently not pack restricted. All of this can be regulated in real time.
Considering how often I see less than a full compliment of regen circles these days, I'd question that... That MAY be true on a new pack but does not appear to be on a degraded one...
Since taking my car in for the latest updates at the beginning of July, I now often see only 4 regen bubbles and regen limited to 20-25 kW despite battery temps 75F+ until SOC gets below 70-75%. Never used to see that before unless it was in the winter when I presume battery temps were in the 60-65F range.

The car is much more reluctant to max out regen at 30 kW+ until the SOC is much lower and it's more difficult to keep the mi/kWh gauge pegged at 8.0 mi/kWh the first couple miles of my commute unless I am much more careful driving those first couple miles.

Re: Max regen - at what point do mechanical brakes engage?

Posted: Tue Aug 06, 2013 8:57 am
by DaveinOlyWA
Adding to what Drees mentioned. since the update, my LEAF "seems" to be somewhat different.

**GOM is much more pessimistic (still overestimates but not so much)

** lost about 22 GID (265ish to 243)

** regen bubbles "occasionally" slow in appearing. Yesterday, was done two full bars and only had access to 3 circles. TB's at 6 so no extremes here to mention...

** A/C seems to not settle in the "quarter KW" range as much. Now this is a huge variance due to heat, A/C setting etc. but before it would start high about 1.5-2.5 Kw for about 2 mins then drop fast to under a half Kw more often than not a bare sliver. this is not happening. now, this Summer has been one of the hottest in recent memory (we were actually a bit below average during the Scorcher of 2012) so that might be playing a part but things like moving the temp setting from 68º (my norm) to as high as 75 has not helped...

Re: Max regen - at what point do mechanical brakes engage?

Posted: Tue Aug 06, 2013 9:00 am
by TomT
This I haven't seen on mine... It appears to be behaving as it always has in the hot weather here...
DaveinOlyWA wrote:A/C seems to not settle in the "quarter KW" range as much. Now this is a huge variance due to heat, A/C setting etc. but before it would start high about 1.5-2.5 Kw for about 2 mins then drop fast to under a half Kw more often than not a bare sliver. this is not happening. now, this Summer has been one of the hottest in recent memory (we were actually a bit below average during the Scorcher of 2012) so that might be playing a part but things like moving the temp setting from 68º (my norm) to as high as 75 has not helped...

Re: Max regen - at what point do mechanical brakes engage?

Posted: Tue Aug 06, 2013 10:33 pm
by DaveEV
TomT wrote:My experience exactly, drees. P3227 definitely has taken away some of my maximum available regen under numerous conditions... How much of this is due to how P3227 interacts with my degradation is unknown...
OK, good to know at least that at least it appears to be due to the P3227 update and not due to the grabby brake update (NTB12-086).

Also seeing the same A/C power draw as usual on my car.

Not seeing max-regen very frequently is highly annoying, though.