User avatar
Ingineer
Posts: 2741
Joined: Fri Oct 15, 2010 1:09 pm
Delivery Date: 13 Jul 2011
Leaf Number: 6969
Location: Berkeley, California
Contact: Website

Re: Actual LEAF Pack Capacity

Wed Feb 23, 2011 1:46 pm

AndyH wrote:
Herm wrote:This is great news because it reassures us that the pack will be long lived, if you only charge up to 80% of usable then even better, the car will rust to death before the battery fails. Can you now access actual cell temperatures during use?.. should be handy to decipher the CAN bus.

Any ideas on the actual energy density of the cells with this new data?
The module weight is on the AESC website (3.8kg). It appears that AESC's 66Ah number on their site is the consumer capacity rather than ultimate. This is common for battery vendors, but not universal, so it's good to have confirmation.

http://www.eco-aesc-lb.com/en/bmodule.html

Reserving 10% top and bottom gives the best capacity/life ratio - so routine charges to 95% should put us into 150,000 mile pack life territory...
66Ah is likely correct. The Battery ECU dynamically calculates this value and keeps a record of it to use for the other calculations. The car I logged was reading 67.568Ah.

-Phil
Easily Learn Electricity HERE! - - - - Website: http://evseupgrade.com/[/size] - - - - Like us on Facebook: EVSE Upgrade

edatoakrun
Posts: 5222
Joined: Thu Nov 11, 2010 9:33 am
Delivery Date: 15 May 2011
Leaf Number: 2184
Location: Shasta County, North California

Re: Actual LEAF Pack Capacity

Wed Feb 23, 2011 1:49 pm

AndyH wrote:
Herm wrote:This is great news because it reassures us that the pack will be long lived, if you only charge up to 80% of usable then even better, the car will rust to death before the battery fails. Can you now access actual cell temperatures during use?.. should be handy to decipher the CAN bus.

Any ideas on the actual energy density of the cells with this new data?
The module weight is on the AESC website (3.8kg). It appears that AESC's 66Ah number on their site is the consumer capacity rather than ultimate. This is common for battery vendors, but not universal, so it's good to have confirmation.

http://www.eco-aesc-lb.com/en/bmodule.html

Reserving 10% top and bottom gives the best capacity/life ratio - so routine charges to 95% should put us into 150,000 mile pack life territory...

By "Life" do you mean 80% of original capacity?

If so, LEAF battery probably good for another "lifetime"-mine.
no condition is permanent

AndyH
Posts: 6388
Joined: Fri Apr 23, 2010 3:43 pm
Location: San Antonio

Re: Actual LEAF Pack Capacity

Wed Feb 23, 2011 1:53 pm

Ingineer wrote:
AndyH wrote:
Herm wrote:This is great news because it reassures us that the pack will be long lived, if you only charge up to 80% of usable then even better, the car will rust to death before the battery fails. Can you now access actual cell temperatures during use?.. should be handy to decipher the CAN bus.

Any ideas on the actual energy density of the cells with this new data?
The module weight is on the AESC website (3.8kg). It appears that AESC's 66Ah number on their site is the consumer capacity rather than ultimate. This is common for battery vendors, but not universal, so it's good to have confirmation.

http://www.eco-aesc-lb.com/en/bmodule.html

Reserving 10% top and bottom gives the best capacity/life ratio - so routine charges to 95% should put us into 150,000 mile pack life territory...
66Ah is likely correct. The Battery ECU dynamically calculates this value and keeps a record of it to use for the other calculations. The car I logged was reading 67.568Ah.

-Phil
I don't doubt it's correct. ;) But are you suggesting it's total or end-user capacity?

I'm thinking end-user.
Because...
- The Leaf uses 48 modules
- AESC says 66Ah at 7.5V nominal
-- 66Ah*7.5V*48 modules is 23.76kWh - close to the known user Leaf pack size

AndyH
Posts: 6388
Joined: Fri Apr 23, 2010 3:43 pm
Location: San Antonio

Re: Actual LEAF Pack Capacity

Wed Feb 23, 2011 1:55 pm

edatoakrun wrote:By "Life" do you mean 80% of original capacity?

If so, LEAF battery probably good for another "lifetime"-mine.
:lol:

Yes - batteries are rated with the same 80% capacity 'lifespan' the industry uses for solar panels.

Carcus
Posts: 28
Joined: Sat Jan 15, 2011 10:32 am

Re: Actual LEAF Pack Capacity

Wed Feb 23, 2011 2:06 pm

AndyH wrote:
edatoakrun wrote:By "Life" do you mean 80% of original capacity?

If so, LEAF battery probably good for another "lifetime"-mine.
:lol:

Yes - batteries are rated with the same 80% capacity 'lifespan' the industry uses for solar panels.

AndyH, (or anyone else with an opinion), ...

I will likely drive my Leaf (assuming I go ahead with the purchase) not more than about 8,000 miles per year and charge to 80%. So I'm thinking the calender will take my battery out before cycles do.

Any guess as to how long (in years) before a Leaf used in this manner will hit the 80% capacity mark?

P.S. I know it's still a bit of a guessing game at this point. I'm just asking for an educated guess.

AndyH
Posts: 6388
Joined: Fri Apr 23, 2010 3:43 pm
Location: San Antonio

Re: Actual LEAF Pack Capacity

Wed Feb 23, 2011 2:20 pm

Carcus wrote:AndyH, (or anyone else with an opinion), ...

I will likely drive my Leaf (assuming I go ahead with the purchase) not more than about 8,000 miles per year and charge to 80%. So I'm thinking the calender will take my battery out before cycles do.

Any guess as to how long (in years) before a Leaf used in this manner will hit the 80% capacity mark?

P.S. I know it's still a bit of a guessing game at this point. I'm just asking for an educated guess.
Very roughly and loosely based on other parts of the lithium family, 8-10 years looks very reasonable.

Carcus
Posts: 28
Joined: Sat Jan 15, 2011 10:32 am

Re: Actual LEAF Pack Capacity

Wed Feb 23, 2011 2:48 pm

AndyH wrote:
Carcus wrote:AndyH, (or anyone else with an opinion), ...

I will likely drive my Leaf (assuming I go ahead with the purchase) not more than about 8,000 miles per year and charge to 80%. So I'm thinking the calender will take my battery out before cycles do.

Any guess as to how long (in years) before a Leaf used in this manner will hit the 80% capacity mark?

P.S. I know it's still a bit of a guessing game at this point. I'm just asking for an educated guess.
Very roughly and loosely based on other parts of the lithium family, 8-10 years looks very reasonable.

Ok. Thanks.


And from what I've read, the degradation won't necessarily be linear? I'm thinking the drop from 80% to 60% will happen quicker than the drop from 100% to 80% ?

User avatar
Ready2plugin
Posts: 672
Joined: Tue Jul 27, 2010 8:08 am

Re: Actual LEAF Pack Capacity

Wed Feb 23, 2011 5:07 pm

Okay....glad we have a number! I'm not an engineer, so in non-tech speak :D , charging to 100% 5 days a week, and once at 80% to cover the weekend should have what affect on the life of the battery?

Herm
Posts: 3765
Joined: Sun May 23, 2010 3:08 pm
Delivery Date: 29 Aug 2012
Location: Timbuktu, Mali

Re: Actual LEAF Pack Capacity

Wed Feb 23, 2011 5:17 pm

Carcus wrote: And from what I've read, the degradation won't necessarily be linear? I'm thinking the drop from 80% to 60% will happen quicker than the drop from 100% to 80% ?
The calendar life could be longer than 10 years, perhaps even 20 years.. I believe it depends on the stability under high voltage of the electrolyte. Capacity fade from 80% to 60% will be very quick.. but the pack will retain most of its ability to deliver power (not energy) almost unchanged.. that is why these old packs will work out very well for grid stabilization duties, they will still be able to deliver 90kw of power long after they are retired..

User avatar
Ingineer
Posts: 2741
Joined: Fri Oct 15, 2010 1:09 pm
Delivery Date: 13 Jul 2011
Leaf Number: 6969
Location: Berkeley, California
Contact: Website

Re: Actual LEAF Pack Capacity

Wed Feb 23, 2011 5:25 pm

AndyH wrote:
Ingineer wrote:66Ah is likely correct. The Battery ECU dynamically calculates this value and keeps a record of it to use for the other calculations. The car I logged was reading 67.568Ah.

-Phil
I don't doubt it's correct. ;) But are you suggesting it's total or end-user capacity?

I'm thinking end-user.
Because...
- The Leaf uses 48 modules
- AESC says 66Ah at 7.5V nominal
-- 66Ah*7.5V*48 modules is 23.76kWh - close to the known user Leaf pack size
I would agree; "usable" capacity for the Leaf.

The battery manufacturer usually specifies Ah from 100% SOC down to a certain voltage per cell. On most Lithium Ion types this is 2vpc, but I would guess the usable capacity in the Leaf is not this low. So I suspect the dynamic calculations are to this as yet undermined number. Since I now have all the tools to monitor this, all I have to do is get in a Leaf, run the pack down and see where this occurs.

It's on my list! =)

-Phil
Easily Learn Electricity HERE! - - - - Website: http://evseupgrade.com/[/size] - - - - Like us on Facebook: EVSE Upgrade

Return to “News & Main LEAF Discussion”