gascant
Posts: 921
Joined: Tue Nov 23, 2010 4:09 pm
Delivery Date: 13 May 2011
Leaf Number: 2209
Location: San Jose, CA

Re: Regen question

Wed Sep 07, 2011 8:59 pm

FWIW, I recently bought an SOC meter from garygid. Initially, it just showed SOC (% remaining) but, with the latest firmware update, now shows Voltage, current (directional) and Power. I was braking downhill at 45 MPH last weekend and thought I saw 40 kW of regen Power for a brief moment. Then today, having to do a rapid deceleration at a freeway off ramp, it appeared to give 44-45 kW regen Power. So, maybe the 30 kW limit indicated by the energy display in the LEAF is fictitious and arbitrary? Just sayin.... 8-)
2011 LEAF SL brilliant silver + QC
DRL's, Seat Heaters, Horn, LEDs and EVSE upgrades
Over 24,300 miles gas-free
http://sfbayleafs.org

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Nekota
Posts: 615
Joined: Sat Dec 11, 2010 11:16 pm
Delivery Date: 12 May 2011
Leaf Number: 2182
Location: Sunnyvale, CA

Re: Regen question

Wed Sep 07, 2011 9:36 pm

tbleakne wrote:

This is a very nice graph. Do you have a link to the report from which it was extracted ?


It's from a nice article from SAE on Vehicle Electrification with the chart available with the following link.

http://www.nxtbook.com/nxtbooks/sae/11EVSD0223/#/16
Res 20Apr2010 / Ordered 27Sep2010 / Delivered 12May2011

PV System

Volusiano
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Joined: Thu Feb 24, 2011 2:41 pm
Delivery Date: 03 Jun 2011
Location: Phoenix, AZ

Re: Regen question

Wed Sep 07, 2011 9:47 pm

gascant wrote:FWIW, I recently bought an SOC meter from garygid.
I guess I missed the memo that garygid sells his SOC meter. Can you point me to the thread that talks about this in more details? I'd like to learn more. Thanks.

91040
Posts: 822
Joined: Fri Mar 11, 2011 10:36 pm
Delivery Date: 06 May 2011
Location: Los Angeles, CA

Re: Regen question

Wed Sep 07, 2011 10:27 pm

Volusiano wrote:
gascant wrote:FWIW, I recently bought an SOC meter from garygid.
I guess I missed the memo that garygid sells his SOC meter. Can you point me to the thread that talks about this in more details? I'd like to learn more. Thanks.

viewtopic.php?f=44&t=5045&start=0
1st Capacity Bar loss 30k mi 16.25mo
2nd- 49k mi 25.5mo 51.5Ah
3rd- 73k mi 36.5mo 46.9Ah 71% SOH 50.9Hx
4th- 86.5k mi 43mo 42.61Ah 64% SOH 43.79Hx
5th- 101k mi 50.5mo 38.38Ah 58% SOH 37.02Hx

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drees
Moderator
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Joined: Fri Apr 23, 2010 3:51 pm
Delivery Date: 07 Jun 2011
Leaf Number: 002448
Location: San Diego

Re: Regen question

Wed Sep 07, 2011 11:50 pm

gascant wrote:So, maybe the 30 kW limit indicated by the energy display in the LEAF is fictitious and arbitrary? Just sayin.... 8-)

It's possible - gary mentioned he's seen more than 80 kW under power.

Or perhaps the two don't necessarily agree.

Or perhaps the gauges only indicate what the maximum sustained power/regen is, but lets the car go briefly over those limits in certain conditions.
2011 LEAF SL delivered Jun 2011
Stats: Jul 2015: 41k 49.4Ah 209/174 GID - 11th bar lost: 11/11/14 @ 51.56Ah 220/181 GID, 12th lost: 9/23/13 @ 55.25Ah 228/194 GID
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tbleakne
Gold Member
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Delivery Date: 03 Jun 2011
Leaf Number: 2400
Location: Claremont, CA

Re: Regen question

Fri Sep 09, 2011 5:58 pm

abasile wrote:
tbleakne wrote:If I can find a steady grade not quite so steep, with a higher safe speed, where I don't need to apply any brake pressure, I can hopefully get a higher regen efficiency reading.

The road that we use to reach our mountain town (CA-330) seems pretty good for that purpose. When there is not much traffic and the SOC is sufficiently low, it is possible to use ECO mode regen to keep one's speed down with little to no use of the brake pedal. You'll have to come visit! :D

Andrew, this sounds like an excellent plan. I will contact you to find a mutually convenient time.

I have re-edited my regen report above with some new data that now yields this estimate:
Regen efficiency = (5 clicks/7 clicks) = ~73% +- 7%.
LEAF Ocean Blue SL, "100 % Electric" decals, Delivered June 3, 2011
Sold June 2014 27K miles, 18% capacity loss, 1 bar, 5.0 mi/kWh.
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Stoaty
Gold Member
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Delivery Date: 12 Jun 2011
Leaf Number: 3871
Location: West Los Angeles

Re: Regen question

Fri Sep 09, 2011 6:11 pm

tbleakne wrote:I have re-edited my regen report above with some new data that now yields this estimate:
Regen efficiency = (5 clicks/7 clicks) = ~73% +- 7%.

I assume this is for a one way trip (energy back into the battery, not out again to kinetic energy)? If so, and if the efficiency on the way out is assumed to be 80% (motor alone is 87-95% efficient per Nissan), then the round trip would be 0.73 * 0.8 = 58%
Lifetime 5.5 m/kWh (Dash) over 43,100 miles / 50 months
Capacity Loss Predicted - 22.7% Actual - 23.5%
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SanDust
Posts: 1363
Joined: Fri Aug 06, 2010 10:54 am

Re: Regen question

Fri Sep 09, 2011 7:35 pm

Nekota wrote:The KW loss going from the battery to the wheels is described by Nissan to have an efficiency range of 87% to 95%

The graph seems to be describing the efficiency of the electric part of the drivetrain.

Herm
Posts: 3765
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Delivery Date: 29 Aug 2012
Location: Timbuktu, Mali

Re: Regen question

Fri Sep 09, 2011 9:51 pm

SanDust wrote:The graph seems to be describing the efficiency of the electric part of the drivetrain.


Yes, motor and inverter.. then you have the one speed gearbox. the differential and the two halfshafts with their universal joints. Probably 2% mechanical losses and 1% battery losses.

SanDust
Posts: 1363
Joined: Fri Aug 06, 2010 10:54 am

Re: Regen question

Fri Sep 09, 2011 11:58 pm

Herm wrote:Yes, motor and inverter.. then you have the one speed gearbox. the differential and the two halfshafts with their universal joints. Probably 2% mechanical losses and 1% battery losses.

The SAE has published a composite efficiency map for the Volt and the efficiencies ranged between 70% and 88%. The Leaf's shouldn't be that different. http://papers.sae.org/2011-01-0887

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