What happened to my Regen?

[nosuchthing]

I not only noticed my regen has turned into a real laggard, but also my cruise control being out of whack going downhill. It does not hold the speed. This is something new. Now I have to watch it because if set to 64 on flat ground, car actually speeds up to 70 downhill. That could spell trouble because we all know where the cops like to set their radar guns...

I wonder if this undesirable phenom has something to do with that last update and its "interesting results."

 

[brettcgb]

Besides preheating the cabin, any other way to easily great up the battery in cold weather?

Some cars have a cold weather package that includes a 300W battery heater that activates at -4F (-20C), deactivates at 14F (-10C). The car should be plugged in and powered. If not, the heater will not be activated if battery charge falls below 30%. The heater may activate while driving. (2012 Owners Manual, page EV-5)

When you say cabin, do you mean garage, or passenger compartment? I don't think the passenger compartment heating makes a difference.

FYI - The battery pack weighs 600 pounds, and is air-cooled. There's nothing easy about heating or cooling this pack. 300W is not a lot of heat for something this massive - the only reason it works is that there's no airflow in your garage. I suspect that when driving, normal operation tends to warm the battery, but may not make up for air-cooling.

 

[TomT]

More correctly, it is ambient cooled. There is no air cooling or cooling of any kind per se.

FYI - The battery pack weighs 600 pounds, and is air-cooled.

 

[brettcgb]

I not only noticed my regen has turned into a real laggard, but also my cruise control being out of whack going downhill. It does not hold the speed. This is something new. Now I have to watch it because if set to 64 on flat ground, car actually speeds up to 70 downhill. That could spell trouble because we all know where the cops like to set their radar guns...

I wonder if this undesirable phenom has something to do with that last update and its "interesting results."

This is another symptom of the same problem.

Cruise control depends on regen to provide the drag that an ICE naturally provides. Without regen, your car is essentially in neutral, and coasts like crazy. You have probably noticed this in ECO mode at high SoC (>80%).

 

[brettcgb]

FYI - The battery pack weighs 600 pounds, and is air-cooled.

More correctly, it is ambient cooled. There is no air cooling or cooling of any kind per se.

I'd accept that. The battery pack is essentially a closed flat can with electrical connections, and more cans inside. I've never figured out if there's even much air flow around it when driving.

 

[nosuchthing]

Cruise control depends on regen to provide the drag that an ICE naturally provides. Without regen, your car is essentially in neutral, and coasts like crazy. You have probably noticed this in ECO mode at high SoC (>80%).

You might say that, but why is it happening now? Should I be taking the car to the dealer? Is there a fix? Should I be in D?

 

[brettcgb]

Cruise control depends on regen to provide the drag that an ICE naturally provides. Without regen, your car is essentially in neutral, and coasts like crazy. You have probably noticed this in ECO mode at high SoC (>80%).

You might say that, but why is it happening now? Should I be taking the car to the dealer? Is there a fix? Should I be in D?

Cruise control gets fixed when regen gets fixed....
Regen gets fixed when the battery gets fixed....
Until then, keep an eye on your speed and apply braking as needed.

You're just now because you're driving down steep hills and cruise control is no longer able to apply sufficient drag (using regen) as before. I've not noticed cruise control issues as I'm driving on mostly level streets, but I have noticed the regen issues.

I've noticed less drag coasting down, and ended up stopping past where I intended several times. Same issue. I'm adjusting....

 

[DaveinOlyWA]

Brett; i can pretty much guarantee that your batteries were warmed up a least more than a few degrees. the average i see for a charge of that depth is 5-10º and once (last night) they warmed up from 45ºF to 58ºF for charge from 17 to 68%

Dave - I expect you're right. Unfortunately, the only indicator I have is the dash board bargraph, and that's so vague that it's practically useless for this kind of experiment.

I've considered purchasing/building instrumentation that reads out such data, but I've got almost exactly one year left remaining on my lease. I don't yet know if I would lease another Leaf or other EV, or return to ICE. I wouldn't purchase my current Leaf if newer technology was available for lower cost.

On the other hand, I expect to be losing my 4th battery bar sometime in the next 2 to 4 months, resulting in battery repair or replacement (the dealer service manager told me that the entire battery is replaced with new - I don't know that I believe that). That would be an interesting time to have such instrumentation.

It would be a good learning experience to build my own, but I'd be starting from scratch WRT CAN bus. I'm an electrical engineer working with microcontrollers and laptop Li-ion batteries are not unknown to me. I design circuits, lay out PCBs, write code (C and assy for PIC18)... and I can solder!

Can someone suggest instrumentation that reads out battery status (SoC, Volts, Amps (charge, discharge, regen), temperatures, cell voltages), and offers data logging support?

a year is a long time and I would agree that any significant investment in equipment I would not do either but if you are an Android user, LEAF Spy is a great option.

it allows you to chart a TON of info and its no more than $14.99 for the deluxe SW, about the same for the bluetooth dongle and if you are a Droid user, that would be all the investment. it really boils down to a weeks worth of gas savings in your LEAF

here is what is logged and its all abbreviated its just a paste of the header titles;

Date/Time Lat Long Elv Speed Gids SOC AHr Pack Volts Pack Amps Max CP mV Min CP mV Avg CP mV CP mV Diff Judgment Value Pack T1 F Pack T1 C Pack T2 F Pack T2 C Pack T3 F Pack T3 C Pack T4 F Pack T4 C (all 96 voltage pairs) BatVolt VIN Health Raw 12 Bat Odo(km) QC L1/L2 TP-FL TP-FR TP-RR TP-RL Ambient

but its great info to play with. examples? ok...hold on...

ok, hottest temp on sensor one from sept 30 to dec 30th 84.2ºF on 12/1/13 at 9:05 am

highest voltage measurement on CP1; 4.121

it goes on and on

 

[brettcgb]

Brett; i can pretty much guarantee that your batteries were warmed up a least more than a few degrees. the average i see for a charge of that depth is 5-10º and once (last night) they warmed up from 45ºF to 58ºF for charge from 17 to 68%

Dave - I expect you're right. Unfortunately, the only indicator I have is the dash board bargraph, and that's so vague that it's practically useless for this kind of experiment.

Can someone suggest instrumentation that reads out battery status (SoC, Volts, Amps (charge, discharge, regen), temperatures, cell voltages), and offers data logging support?

a year is a long time and I would agree that any significant investment in equipment I would not do either but if you are an Android user, LEAF Spy is a great option.

it allows you to chart a TON of info and its no more than $14.99 for the deluxe SW, about the same for the bluetooth dongle and if you are a Droid user, that would be all the investment. it really boils down to a weeks worth of gas savings in your LEAF

here is what is logged and its all abbreviated its just a paste of the header titles;

Date/Time Lat Long Elv Speed Gids SOC AHr Pack Volts Pack Amps Max CP mV Min CP mV Avg CP mV CP mV Diff Judgment Value Pack T1 F Pack T1 C Pack T2 F Pack T2 C Pack T3 F Pack T3 C Pack T4 F Pack T4 C (all 96 voltage pairs) BatVolt VIN Health Raw 12 Bat Odo(km) QC L1/L2 TP-FL TP-FR TP-RR TP-RL Ambient

but its great info to play with. examples? ok...hold on...

ok, hottest temp on sensor one from sept 30 to dec 30th 84.2ºF on 12/1/13 at 9:05 am

highest voltage measurement on CP1; 4.121

it goes on and on

I do use Android (lucky for me!) KitKat Ver 4.4.2 (google ed).

I'd heard of LeafSpy and the bluetooth dongle, and was seriously considering them.

Any other tools?

 

[dgpcolorado]

Besides preheating the cabin, any other way to easily [h]eat up the battery in cold weather?

Besides charging, just driving will heat up the LEAF battery; the higher the kW discharge rate the more heating (climbing hills helps). However, when the ambient temperature is much cooler than the battery, say 20ºF or more, and the speed is 40 mph or higher, the battery tends to cool down. So there is some heat transfer from the sealed battery pack to the airstream IME.

If the battery is so cold that it doesn't charge well, driving the car ought to heat it up enough to allow charging. And charging also ought to keep the battery warm. Unless one parks for an extended period in extreme cold it isn't hard to keep the battery warm enough to function normally, although the capacity will be somewhat reduced by the cold.

 

[Stanton]

I've considered purchasing/building instrumentation that reads out such data, but I've got almost exactly one year left remaining on my lease. I don't yet know if I would lease another Leaf or other EV, or return to ICE. I wouldn't purchase my current Leaf if newer technology was available for lower cost.

There's very little chance of THAT happening in the next year or so...unless it's another Leaf. Seems to me you're a prime candidate to buy out your lease and get a (free) "hot pack" battery replacement.

 

[brettcgb]

I've considered purchasing/building instrumentation that reads out such data, but I've got almost exactly one year left remaining on my lease. I don't yet know if I would lease another Leaf or other EV, or return to ICE. I wouldn't purchase my current Leaf if newer technology was available for lower cost.

There's very little chance of THAT happening in the next year or so...unless it's another Leaf. Seems to me you're a prime candidate to buy out your lease and get a (free) "hot pack" battery replacement.

I'm expecting the impending battery warranty work will be to swap in a "hot pack" battery.

 

[DaveinOlyWA]

I do use Android (lucky for me!) KitKat Ver 4.4.2 (google ed).

I'd heard of LeafSpy and the bluetooth dongle, and was seriously considering them.

Any other tools?

i would just start out with LEAF Spy and see how it goes. I think you will find there is little it can't tell you

 

[brettcgb]

Brett; i can pretty much guarantee that your batteries were warmed up a least more than a few degrees. the average i see for a charge of that depth is 5-10º and once (last night) they warmed up from 45ºF to 58ºF for charge from 17 to 68%

Dave - I expect you're right. Unfortunately, the only indicator I have is the dash board bargraph, and that's so vague that it's practically useless for this kind of experiment.
....
Can someone suggest instrumentation that reads out battery status (SoC, Volts, Amps (charge, discharge, regen), temperatures, cell voltages), and offers data logging support?

a year is a long time and I would agree that any significant investment in equipment I would not do either but if you are an Android user, LEAF Spy is a great option.

it allows you to chart a TON of info and its no more than $14.99 for the deluxe SW, about the same for the bluetooth dongle and if you are a Droid user, that would be all the investment. it really boils down to a weeks worth of gas savings in your LEAF.

Having purchased/installed an ELM327 and Leaf Spy Pro (Android), I have to agree that this was a worthwhile purchase. The log file has lots of data to play with (and I'm fairly certain I've not exhausted the possibilities). I wish I had this back last spring.

The one parameter it's missing would be HV battery current or power....

 

[DaveEV]

Thanks to edatoakrun I found a nifty bit of data that illustrates what we've been saying for a while now:

Advanced Powertrain Research Facility - AVTA Nissan LEAF testing and analysis - October 12th 2012

See pages 11 and 19 specifically:

My Notes:
Maximum regen occurs around 35 mph with a peak of ~35 kW into the battery.
Regen is disabled around 5 mph.
At 80 mph, regen is limited to a bit over 20 kW.
One can draw a straight line through those points to establish maximum regen thresholds based on vehicle speed.

 

[edatoakrun]

="drees"
...Maximum regen occurs around 35 mph with a peak of ~35 kW into the battery.
Regen is disabled around 5 mph.
At 80 mph, regen is limited to a bit over 20 kW...

However, at the April 2013 BayLEAFs meeting Nissan rep (Pike, IIRC?) stated one of the reasons for the 2013 LEAF range increase was the revision of regen to allow more energy recovery, and at lower speeds in particular.

So the 2012 Data might not be exactly right for later years.

That presentation had a lot of good tech info and was being recorded, but I've never found it.

Anyone?

 

[TickTock]

Well, my regen is officially back. Today I reached 7 total regen bubbles (3 more than are shown on the eyebrow) on my drive home. Definitely suggesting a seasonal effect.

 

[Stanton]

Well, my regen is officially back. Today I reached 7 total regen bubbles (3 more than are shown on the eyebrow) on my drive home. Definitely suggesting a seasonal effect.

What temp threshold have you recently crossed? I noticed an increase in regen as well (at least temporarily) when temps here spiked towards 80F or so.

 

[TomT]

Same here after a week of unseasonably warm weather...

Well, my regen is officially back. Today I reached 7 total regen bubbles (3 more than are shown on the eyebrow) on my drive home. Definitely suggesting a seasonal effect.

What temp threshold have you recently crossed? I noticed an increase in regen as well (at least temporarily) when temps here spiked towards 80F or so.

 

[brettcgb]

Well, my regen is officially back. Today I reached 7 total regen bubbles (3 more than are shown on the eyebrow) on my drive home. Definitely suggesting a seasonal effect.

Mine is back too, intermittently. The weather here has been spiking just about 80F. Leaf Spy says battery temperatures (4) are in the range of 72-78F. The dash battery temperature display still shows 5 bars (i.e. hasn't changed).

How do you get 7 regen bubbles? My NavSys traction power display corresponds well to the eyebrow bubbles - I can accept full-scale on both. You are suggesting you can see something more?