Srivenkat
Posts: 78
Joined: Sat Apr 21, 2018 11:27 am

60Ah vs 94Ah battery longevity

Tue Apr 23, 2019 6:29 am

I am wondering how the 2017 94Ah battery is doing in terms of degradation, now that it has been out a couple of years; search hasn't turned up anything. Any real world experiences out there?

Thanks in advance.

alohart
Posts: 1675
Joined: Sat Nov 01, 2014 7:36 pm
Location: Honolulu, HI

Re: 60Ah vs 94Ah battery longevity

Tue Apr 23, 2019 2:02 pm

A 94 Ah battery pack would experience ~57% fewer charge/discharge cycles per unit distance driven compare with a 60 Ah battery pack. One of the factors affecting the battery cell degradation rate is the number of charge/discharge cycles. Another factor is the time spent at very high or very low charge levels which could be less for a 94 Ah battery pack assuming that the owner manages charge level to accomplish her range goals. So the degradation rate of a 94 Ah battery pack should be less than that of a 60 Ah battery pack.

Other factors affecting the degradation rate are the age of the battery pack and the time spent at very high or very low temperatures. However, these factors would be no different for a 94 Ah or 60 Ah battery pack.

The cell chemistry of a 94 Ah cell must be slightly different from that of a 60 Ah cell as reflected by their slightly different voltages and different energy densities. I don't know how this affects the degradation rate.
Aloha,
Art

2014 BMW i3 Arravani Grey, Giga World, Tech + Driving Assist, Parking Assist, DC Fast Charging, JuiceBox EVSE

User avatar
MKH
Gold Member
Posts: 281
Joined: Fri Nov 02, 2018 5:48 am
Location: Dallas

Re: 60Ah vs 94Ah battery longevity

Wed Apr 24, 2019 5:19 am

Samsung SDI expects up to 4,600 charging cycles at 25ºC to End-Of-Life (EOL), for the 94 Ah i3 battery pack, which in the case of batteries is the point when capacity decreases to 80% (battery still can be used, but is generally not desirable in cars any longer).

Since the BMW i3 (33 kWh) is rated at 114 miles (183 km), 4,600 cycles would be more than 524,000 miles (more than 843,000 km).

And yes, these are stats directly from Samsung - but publishing battery specs that end up not verifiable real-world would open Samsung up to major costly lawsuits from its customer base, not to mention loss of reputation and future sales.

https://insideevs.com/news/338067/bmw-i ... 000-miles/
Mark H.
2015 i3 Rex, Capparis White, Tera World, Technology & Driving Assistant, Parking Assistant, Harman Kardon Audio System, 19 inch 427 wheels, EVoInnovate EVSE

coho
Posts: 9
Joined: Sun Feb 15, 2015 5:20 am

Re: 60Ah vs 94Ah battery longevity

Thu Apr 25, 2019 4:00 pm

I'm not sure if this info will help but my car is the BEV 94ah bought in march 2017. We've put 50,000 km onto the car. I checked the secret menu max kpa I think it's called, showed 29.5.... We charge mostly every night and put about 80 km per day onto the vehicle.

SloMoShun
Posts: 6
Joined: Tue Apr 16, 2019 9:32 am

Re: 60Ah vs 94Ah battery longevity

Thu Jun 06, 2019 11:43 am

coho wrote:
Thu Apr 25, 2019 4:00 pm
I'm not sure if this info will help but my car is the BEV 94ah bought in march 2017. We've put 50,000 km onto the car. I checked the secret menu max kpa I think it's called, showed 29.5.... We charge mostly every night and put about 80 km per day onto the vehicle.
Its because what you see is usable capacity, not battery capacity. I know that for the 22 KWH battery, what it would read for most new owners was 18.8 KWH. Mine is at 18.5 KWH with almost 20K mi on it.

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