BiggieJohn
Gold Member
Posts: 33
Joined: Sun Mar 27, 2016 8:43 am
Delivery Date: 25 Mar 2016
Leaf Number: 019136

replacement batteries slightly larger capacity ?

Mon Jun 19, 2017 7:18 am

I recently had my 2012 battery replaced under warranty.
Notice the Ahr is 66.14. at full charge, 395V * 66.14Ahr = 26kw

hmmmm

Screenshot_20170615-045122.png
You do not have the required permissions to view the files attached to this post.
2012 SL Nissan Leaf Glacier White #019136
2015 Chevy Volt summit white #07978

rmay635703
Posts: 345
Joined: Wed Jan 19, 2011 7:43 pm

Re: replacement batteries slightly larger capacity ?

Mon Jun 19, 2017 9:21 am

No one ever said how big your replacement could be ;)

That said 2013+ batteries are slightly bigger to start compared to 2011

alozzy
Posts: 456
Joined: Fri Jan 20, 2017 4:25 pm
Delivery Date: 18 Jan 2017

Re: replacement batteries slightly larger capacity ?

Mon Jun 19, 2017 9:31 am

Maybe because not all the kWh are useable because the BMS prevents the cells from dropping below a certain voltage.
Canadian with a US 2013 Ocean Blue SV + QC, purchased 01/2017 in WA
Zencar 12/20/24/30A L1/L2 portable EVSE
1-1/4" Curt #11396 hitch
After market, DIY LED DRLs
LeafSpy Pro + Konnwei KW902 ELM327 BT OBDII dongle
Big grin, enjoying my first BEV :D

BiggieJohn
Gold Member
Posts: 33
Joined: Sun Mar 27, 2016 8:43 am
Delivery Date: 25 Mar 2016
Leaf Number: 019136

Re: replacement batteries slightly larger capacity ?

Mon Jun 19, 2017 9:56 am

alozzy wrote:Maybe because not all the kWh are useable because the BMS prevents the cells from dropping below a certain voltage.



The old 24Kw battery had 22.5Kw usable.
I guess I need to do a full range test one of these days and make sure I have LeafSpy running the whole time to see how much gets used.
2012 SL Nissan Leaf Glacier White #019136
2015 Chevy Volt summit white #07978

Oils4AsphaultOnly
Posts: 90
Joined: Sat Oct 10, 2015 4:09 pm
Delivery Date: 20 Nov 2016
Leaf Number: 313890
Location: Arcadia, CA

Re: replacement batteries slightly larger capacity ?

Mon Jun 19, 2017 10:07 am

alozzy wrote:Maybe because not all the kWh are useable because the BMS prevents the cells from dropping below a certain voltage.


Even accounting for that, that's a pretty big buffer isn't it?

My 30kwh battery at full charge shows 394.91V and 78.96 AHr for 31.18 KWh. While usable capacity is 28 KWh, giving me a ~10% buffer. OP's buffer, assuming the same 22kwh usable capacity would be almost 20%!

Any suggestions on how to determine if OP has a bigger buffer or more usable capacity?
[2013 leaf traded for 2016 leaf S30 (7300 miles & 363 GIDs @ 1 May 2017)! ... still getting a model3 though. :D

User avatar
RegGuheert
Posts: 5421
Joined: Mon Mar 19, 2012 4:12 am
Delivery Date: 16 Mar 2012
Leaf Number: 5926
Location: Northern VA

Re: replacement batteries slightly larger capacity ?

Mon Jun 19, 2017 1:44 pm

BiggieJohn wrote:Notice the Ahr is 66.14. at full charge, 395V * 66.14Ahr = 26kw
The voltage of the battery drops during discharge. As a result, you need to multiply the Ah capacity by the *average* discharge voltage in order to get at kWh. I think the average discharge voltage is around 375V, so that gives about 24.8kWh.
RegGuheert
2011 Leaf SL Demo vehicle
2011 miles at purchase. 10K miles on Apr 14, 2013. 20K miles (55.7Ah) on Aug 7, 2014, 30K miles (52.0Ah) on Dec 30, 2015, 40K miles (49.8Ah) on Feb 8, 2017.
Enphase Inverter Measured MTBF: M190, M215, M250, S280

User avatar
Stanton
Forum Supporter
Posts: 1892
Joined: Thu Feb 03, 2011 10:56 am
Delivery Date: 01 Sep 2011
Leaf Number: 7458
Location: Plano, TX
Contact: Website Twitter

Re: replacement batteries slightly larger capacity ?

Mon Jun 19, 2017 2:24 pm

BiggieJohn wrote:I recently had my 2012 battery replaced under warranty.
Notice the Ahr is 66.14. at full charge, 395V * 66.14Ahr = 26kw


This is common for "replacement" battery packs in "old" Leafs (like mine).
If you search the threads, you'll notice that the 66.14 number seems to be some sort of default max the BMS reads...until the actual capacity falls below that number and it starts dropping just like any other battery pack.
So yes, there does seem to be a bit of a buffer at the top of the lizard packs.
2011 Blue Ocean SV w/floor mats & window tint
12v LiFePO4 battery & FIAMM 74100 horns
Wet Okole seat covers (front)
Tor's low-power heater mod
2013 sun visor
3G modem upgrade
L2 EVSE Upgrade
Battery Pack replaced (Rev E) @51 months and 41k miles

cwerdna
Gold Member
Posts: 6701
Joined: Fri Jun 03, 2011 4:31 pm
Delivery Date: 28 Jul 2013
Location: SF Bay Area, CA

Re: replacement batteries slightly larger capacity ?

Tue Jun 20, 2017 12:25 am

BiggieJohn wrote:
alozzy wrote:Maybe because not all the kWh are useable because the BMS prevents the cells from dropping below a certain voltage.



The old 24Kw battery had 22.5Kw usable.
I guess I need to do a full range test one of these days and make sure I have LeafSpy running the whole time to see how much gets used.

Battery capacity is measured in kWh, not "Kw".

kW and kWh are very different metrics. It's the same as confusing gallons with horsepower. Think of kW = horsepower, kWh = gallons.

If one charges at 1 kW (or 1000 watts) for 6 hours, 6 kWh came out of the wall. If it's at 6 kW for 1 hour, it's also 6 kWh. If it's 1 watt for 6000 hours, it's also 6 kWh.

One pays for electricity at home in cents per kWh. There are a few utilities w/residential plans where they not only bill per kWh but also have demand charges, but that's rare and complicates calculations. (Demand charges aren't unusual on many commercial plans.)

(BTW, 1 hp = ~0.746 kW. And, many .gov sites say 1 gallon of gasoline=33.7 kWh.)

'13 blue Leaf SV w/premium package (owned)
'13 blue Leaf SV w/QC + LED & premium packages (lease over, car returned)
'06 Prius

Return to “Batteries & Charging”