The 40KWH Battery Topic

[evtifosi]

First time in a while that we have charged to 100%, so I did a check on the battery and we gained a tiny bit in the AHr reading since the summer.

Summer we were at around 104.3 AHr, now I am at 106.31 AHr

[DaveinOlyWA]

First time in a while that we have charged to 100%, so I did a check on the battery and we gained a tiny bit in the AHr reading since the summer.

Summer we were at around 104.3 AHr, now I am at 106.31 AHr

That is a pretty healthy chunk

[evtifosi]

We don't drive it too much right now (pandemic and all), and it lives in a even cooler place than it did originally. The first two years the car was in Hayward right by the bay, so pretty mild. Now though being in Santa Cruz it is a bit milder and easier on the battery...

[DaveinOlyWA]

We don't drive it too much right now (pandemic and all), and it lives in a even cooler place than it did originally. The first two years the car was in Hayward right by the bay, so pretty mild. Now though being in Santa Cruz it is a bit milder and easier on the battery...

Yeah the temperature makes a difference theory is being blown up right now. Guessing it simply has to be a lot hotter than previous packs to make a difference. I am in winter and my Jan 2021 adjustment was more than double my Oct 2020 adjustment (downward) but my 40 kwh did the exact same thing. In its 2nd year, it went up .78% July 2019 and no change Oct 2019 and yeah, we had a bit of an early onset Summer.

Another way to look at it is during Winter when I do more level 2 charging at home, driving less I am getting the bigger drops but summer when DCing more and driving a lot more, I got no drop and even an increase?

This all rather unusual to say the least.

[evtifosi]

Maybe it is happier living in our house. I did a complete paint correction, ceramic coating and thorough engine and interior cleaning when we bought it...

I am just happy to have the better range (moving from a 2015).

[danrjones]

I have continued my experiment in regards to HX. I have never let my battery SOC outside the 30% to 70% range the last month and my HX continues to slowly drop. It isn't dropping as fast as it did in the summer and fall, so the rate of change could be still related to temperature. Or it could be that my HX is low enough that it doesn't have the ability to quickly move down right now.

If anyone is willing, what would be nice is some other data. Ideally it would be a couple folks who have a higher HX, then go four weeks always keeping your SOC above 30% and below 70%. Even better, when the car is sitting, try to leave it close to 50%. I know most folks probably can't do this due to work and commute, but maybe someone can. I need to take my car into my dealer pretty soon so that means a 100% charge. I fully expect that to spike my HX up.

Some of my recent readings:
(Date / SOH / AMPHr / HX)

12/18/2020 90.04 103.94 103.55
12/28/2020 90.04 103.94 103.52
1/12/2021 90.02 103.92 103.52
1/15/2021 90.02 103.92 103.41
1/22/2021 90.02 103.92 103.37
1/24/2021 90.02 103.92 103.33
1/28/2021 90.02 103.92 103.3

[DaveinOlyWA]

I have continued my experiment in regards to HX. I have never let my battery SOC outside the 30% to 70% range the last month and my HX continues to slowly drop. It isn't dropping as fast as it did in the summer and fall, so the rate of change could be still related to temperature. Or it could be that my HX is low enough that it doesn't have the ability to quickly move down right now.

If anyone is willing, what would be nice is some other data. Ideally it would be a couple folks who have a higher HX, then go four weeks always keeping your SOC above 30% and below 70%. Even better, when the car is sitting, try to leave it close to 50%. I know most folks probably can't do this due to work and commute, but maybe someone can. I need to take my car into my dealer pretty soon so that means a 100% charge. I fully expect that to spike my HX up.

Some of my recent readings:
(Date / SOH / AMPHr / HX)

12/18/2020 90.04 103.94 103.55
12/28/2020 90.04 103.94 103.52
1/12/2021 90.02 103.92 103.52
1/15/2021 90.02 103.92 103.41
1/22/2021 90.02 103.92 103.37
1/24/2021 90.02 103.92 103.33
1/28/2021 90.02 103.92 103.3

When I first got mine, I was 100% DC charging and Hx skyrocketed. NCTC expires, so now I am 100% AC with SOC range from 20 to 45% and Hx dropped steadily but only to 111 and has been in a holding pattern for almost 2 weeks. (I was over 120)

With all that, I am not sure Hx really deserves all that much scrutiny. I will say if you prefer a higher Hx, do a half dozen DC sessions. That seems to bump it up for nearly every one.

[danrjones]

When I first got mine, I was 100% DC charging and Hx skyrocketed. NCTC expires, so now I am 100% AC with SOC range from 20 to 45% and Hx dropped steadily but only to 111 and has been in a holding pattern for almost 2 weeks. (I was over 120)

With all that, I am not sure Hx really deserves all that much scrutiny. I will say if you prefer a higher Hx, do a half dozen DC sessions. That seems to bump it up for nearly every one.

Sorry, I forgot to mention, I've done multiple short DC sessions at the station near me. But I always stop before hitting 70% SOC. Did not seem to impact my HX. Sample size of one (just me) and its during winter (and short session) so my pack doesn't get hot, so hard to draw conclusions.

[DaveinOlyWA]

When I first got mine, I was 100% DC charging and Hx skyrocketed. NCTC expires, so now I am 100% AC with SOC range from 20 to 45% and Hx dropped steadily but only to 111 and has been in a holding pattern for almost 2 weeks. (I was over 120)

With all that, I am not sure Hx really deserves all that much scrutiny. I will say if you prefer a higher Hx, do a half dozen DC sessions. That seems to bump it up for nearly every one.

Sorry, I forgot to mention, I've done multiple short DC sessions at the station near me. But I always stop before hitting 70% SOC. Did not seem to impact my HX. Sample size of one (just me) and its during winter (and short session) so my pack doesn't get hot, so hard to draw conclusions.

I haven't charged to above 70% either. In most cases, I was only charging to 45-55% (the knee on 200 amp stations)

I guess my real question is what is the desirable Hx? Because I see ones with high Hx still getting relatively large chunks on adjustment day while others with Hx in high 90's or low 100's getting no adjustment, very small adjustments or positive adjustments.

Now there is always exceptions so all my comments should be taken as "majority" observations.

[danrjones]

When I first got mine, I was 100% DC charging and Hx skyrocketed. NCTC expires, so now I am 100% AC with SOC range from 20 to 45% and Hx dropped steadily but only to 111 and has been in a holding pattern for almost 2 weeks. (I was over 120)

With all that, I am not sure Hx really deserves all that much scrutiny. I will say if you prefer a higher Hx, do a half dozen DC sessions. That seems to bump it up for nearly every one.

Sorry, I forgot to mention, I've done multiple short DC sessions at the station near me. But I always stop before hitting 70% SOC. Did not seem to impact my HX. Sample size of one (just me) and its during winter (and short session) so my pack doesn't get hot, so hard to draw conclusions.

I haven't charged to above 70% either. In most cases, I was only charging to 45-55% (the knee on 200 amp stations)

I guess my real question is what is the desirable Hx? Because I see ones with high Hx still getting relatively large chunks on adjustment day while others with Hx in high 90's or low 100's getting no adjustment, very small adjustments or positive adjustments.

Now there is always exceptions so all my comments should be taken as "majority" observations.

I have no idea what HX is desirable (good question) or if it is good to be low or high, or makes no difference. I was just doing an experiment because I could.

My HX is lower than yours and yet my SOH is not better, and for my mileage (about 8700 miles total), one could say my SOH is worse.
Right now my best guess is that SOH is primarily related to age, secondarily related to climate and cycles. But the BMS could also be hiding the real answer.