MassDeduction
Posts: 89
Joined: Tue Feb 25, 2020 3:24 pm

Re: Comparing layout of the Soul EV battery with other EVs

Sun Nov 15, 2020 5:07 pm

JejuSoul wrote:-
[...]N iro EV 64kWh has 98 cell triplets = 294 cells : 3 * 60Ah = 180Ahr : 98 * 3.6V = 352.8V
K ona Electric 64kWh has 98 cell triplets = 294 cells : 3 * 60Ah = 180Ahr : 98 * 3.63V = 356V

N iro EV 39.2kWh has 90 cell pairs = 180 cells : 2 * 60Ah = 120Ahr : 90 * 3.6V = 324V
K ona Electric 39.2kWh has 90 cell pairs = 180 cells : 2 * 60Ah = 120Ahr : 90 * 3.63V = 327V
[...]

Forgive my rookie question, but calculating the "C" rating on these battery packs, would it be based on the 60Ah, or based on the 120 or 180 Ah?

JejuSoul
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Re: Comparing layout of the Soul EV battery with other EVs

Mon Nov 16, 2020 5:39 am

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Using data for the MY2020 Soul EV from Kia Motors UK : All-New Soul EV> SPECIFICATION

Image

We see that the 64kWh Soul EV is identical to the 64kWh Kona Electric.
The current 64kWh Niro EV has the identical specs. - Kia Motors UK : e-Niro > SPECIFICATION

Soul EV 64kWh has 98 cell triplets = 294 cells : 3 * 60Ah = 180Ahr : 98 * 3.63V = 356V

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C-rate is defined as the charge / discharge current divided by the nominally rated battery capacity.
The nominally rated battery capacity of the pack is 180Ah.
A rapid charge of 64kW will have a C-rate of about 1 on such a battery pack.

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The codes for using Torque Pro can be found by clicking the link in the website icon under my user name on the left.

MassDeduction
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Joined: Tue Feb 25, 2020 3:24 pm

Re: Comparing layout of the Soul EV battery with other EVs

Mon Nov 16, 2020 1:09 pm

JejuSoul wrote:[...] C-rate is defined as the charge / discharge current divided by the nominally rated battery capacity.
The nominally rated battery capacity of the pack is 180Ah.
A rapid charge of 64kW will have a C-rate of about 1 on such a battery pack.

Generally speaking for lithium ion batteries 0.25C is the ideal charge rate (any faster will increase battery degradation, any slower will provide no significant benefit). I know that some battery chemistries tolerate faster charging more than others will, but "tolerate" isn't the same as "ideal". The rule of thumb as I understand it is that the ideal C rate would be an amperage rate that's 25% of the Ah rating of the battery. So an 180 Ah pack should ideally be charged at 45a or lower, ideally. Do you know any differently than me?

Thanks for the response. I was unclear on whether the C rate should be calculated on all three sections of the pack added together, or on the 60 Ah rating of each individual section. And you're telling me that it's based on them all together, as I understand it.

DaEV
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Re: Comparing layout of the Soul EV battery with other EVs

Tue Jan 26, 2021 6:01 am

Apologies for this but just scanning this thread and quickly looking st the last post (and the first), am I to believe that my 2018 30kWh Soul has an 85Ah battery and I shouldn't be charging it at any more than 0.25C , which is 21.25 amps or it will have a detrimental effect regarding battery degradation ?
As both a newbie and technical ignoramus I've had a home charger installed (Wallbox Plus, 7kW, 32a ) and I know I'm limited by the Souls ability to take in anymore than 6.6kW ac but I didn't realise limiting the amperage input would make any difference, other than more is better (as far as I, in my ignorance, was aware). I'm currently running it at 32amps but I can limit the amperage on the wallbox - Should I do this to help with long term battery health ?
cheers in advance,
Dave.

JejuSoul
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Location: Jeju
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Re: Comparing layout of the Soul EV battery with other EVs

Tue Jan 26, 2021 6:47 am

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C-rate is defined as the charge / discharge current divided by the nominally rated battery capacity.
The nominally rated battery capacity of your pack is 80Ah.
A 32A charge will have a C-rate of about 0.4 on such a battery pack.

I don't think there is any problem with this. This is the way I charge my car every night. I have 5% degradation after 6 years.
But there are a couple of counter arguments.
1/ Kia reduced the max charging rate for the OBC from 32A to 29A in 2016. They never explained why.
2/ I used to keep data for many cars. The 2 with the least degradation always charged at 10A.

There are too many other factors that cause degradation that I think are far more important.
Don't worry about 32A charging.
The codes for using Torque Pro can be found by clicking the link in the website icon under my user name on the left.

MassDeduction
Posts: 89
Joined: Tue Feb 25, 2020 3:24 pm

Re: Comparing layout of the Soul EV battery with other EVs

Sun Feb 21, 2021 3:07 pm

DaEV wrote:Apologies for this but just scanning this thread and quickly looking st the last post (and the first), am I to believe that my 2018 30kWh Soul has an 85Ah battery and I shouldn't be charging it at any more than 0.25C , which is 21.25 amps or it will have a detrimental effect regarding battery degradation ?
As both a newbie and technical ignoramus I've had a home charger installed (Wallbox Plus, 7kW, 32a ) and I know I'm limited by the Souls ability to take in anymore than 6.6kW ac but I didn't realise limiting the amperage input would make any difference, other than more is better (as far as I, in my ignorance, was aware). I'm currently running it at 32amps but I can limit the amperage on the wallbox - Should I do this to help with long term battery health ?
cheers in advance,
Dave.

I think the literal answer is yes, but the actual answer is more nuanced.

The generally recommended as "safe" rate is 0.5C, and frequently charging faster than that is to be avoided if possible. As you drop below 0.5C you see less charging-related battery degradation, until you hit 0.25C at which point going slower offers no further benefit. However, it's diminishing returns the closer to 0.25C you get, prior to no additional benefit whatsoever below 0.25C.

So if it's equally convenient to you to charge at 32a and 21.25a (ie., the charging is always finished with time to spare), then make the change to 21.25a. If you are frequently barely getting it charged in time, then definitely keep charging it at 32a. :)

As @JejuSoul says, there are many factors that affect degradation. Charging fast is bad, but so is fast discharge (eg. driving with a lead foot). Temperature plays a role. Charging higher than necessary, or discharging very deeply, play roles as well. If you do have to charge it high, how long it sits at a high charge before use makes a big difference, as does how long it sits at a low level of charge if you drain it low.

So I agree with JejuSoul that there are many factors at play. But I disagree that that's a reason to "charge it like you stole it". :) The reason to charge it as fast as possible is that you need it that fast, due to the frequency of your driving. The reason to drop down to 21.25a is if it's a best practice that you can implement without charging times becoming inconvenient. So it depends on your situation, IMO.
Last edited by MassDeduction on Sun Feb 21, 2021 3:34 pm, edited 3 times in total.

MassDeduction
Posts: 89
Joined: Tue Feb 25, 2020 3:24 pm

Re: Comparing layout of the Soul EV battery with other EVs

Sun Feb 21, 2021 3:20 pm

JejuSoul wrote:-
C-rate is defined as the charge / discharge current divided by the nominally rated battery capacity.
The nominally rated battery capacity of your pack is 80Ah. [...]

Wikipedia indicates that the full pack size of the 2016-2019 Soul EVs is "31,8 kWh (200 x 42,36 Ah x 3,75 V)". Where do you get 80 Ah from that? I note that the usable capacity listed on Wikipedia is "30 kWh (200 x 40 Ah x 3,75 V)". Are you doubling the 40 Ah listed (presumably because there are two sections to the pack)? If so, that's education for me in a couple of ways (including that C should be calculated on net capacity rather than total capacity).

Would that mean the "27 kWh (192 x 37,5 Ah x 3,75 V)" rating of the 2016-2017 Soul EVs mean the 0.25C rating for them is 18.75a?

I understand that other factors contribute to degradation, but I have the opportunity to charge with best practices so I might as well! :)

EDIT TO ADD: Re-reading earlier posts in this thread, it's explicit that yes the cells are paired, which effectively does double the Ah of the pack, and that yes the 2016-2017 Soul EVs are 75 Ah useable. I had no idea you calculated C on the useable portion, rather than the total. Thanks JejuSoul!

DaEV
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Joined: Wed Oct 21, 2020 10:29 am

Re: Comparing layout of the Soul EV battery with other EVs

Thu Jul 22, 2021 5:01 am

Many thanks for the responses there, much appreciated - apologies for the delayed appreciation, I get there eventually.

I've been monitoring SOH and still showing 100%. I've also started doing longer journeys, once or twice a month following easing of lockdown restrictions. These journeys are requiring 5 x DC charges from roughly 20--30% to 80-90% each way, mostly on 50Kw chargers, although I think I managed to find a 100Kw one last time.
If I continue having to make longer journeys using DC charging will this negatively impact battery life too ?

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