Anyone keeping track of the battery's soh

Darrell Hayes said:
Here is where my SE landed in 6 months of checking SOH at the end of every month. Still seems to be dropping rather rapidly. At this pace I'll be getting a new battery when the car reaches about its 4th B-day.
date mi capacity(Ah ) SoH
6/27/2022 50 97.2 100
7/31/2022 445 96.4 99
8/27/2022 1010 95.8 98
10/2/2022 1875 95.5 98
11/4/2022 2454 94.7 97
11/30/2022 2837 94.8 97
12/30/2022 3222 93.6 96
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Jeez, that's worse than mine.

How do you charge? How do you use your car?

I am trying to do 80-20 charging and usage. My EVSE has a timer I can set on its web interface. Mostly, I do daily 38mi commutes and often 1-2 miles at lunchtime. 2 days easily fits in 80-20 the summer. Below freezing, it does not.
I have noticed that my car needs to float at 100% occasionally, or capacity will drop. Try leaving yours plugged up for a few days.
 
I certainly don't know much about the inner workings of things, but the SOH is just read out on the OBDii port & I would guess is the first indicator of the need for a new battery. Certainly the Electrified app is just a tiny smidgeon of all the data that is available. I'm guessing that there are other diagnostics that would be required for a new battery. I would also guess, that like most things battery related, SOH is an estimate that will vary a bit form measurement to measurement. I doubt that it is as inaccurate as the GOM, but who really knows? Only time will tell ...
 
I'm almost always between 30 & 70%, aside from a 100% charge every week or two. Always Level 2 charged at home. I think I saw 36° once, but it never really freezes here in Socal. Only about 125mi per week. I'm certainly not stressing it at all. I guess I could try a week of continuously charging to 100% to see what happens
 
I’m curious if the old charging to 100% guidance was the correct one in the end.
The new in Teslas LFP batteries they recommend charging them to 100%. Less deg but not as good in the cold nor can they dump out huge voltages.
 
Darrell Hayes said:
I'm almost always between 30 & 70%, aside from a 100% charge every week or two. Always Level 2 charged at home. I think I saw 36° once, but it never really freezes here in Socal. Only about 125mi per week. I'm certainly not stressing it at all. I guess I could try a week of continuously charging to 100% to see what happens
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When I first started doing 8020, I was doing a car timed 100% charge about once a week. So it only spent a few minutes at 100% That seemed to have a bad effect on the SOH. Switching to a floated 100% charge by having an untimed charge start at bedtime seemed to recover a few %. I was mostly concerned with the cold snap knocking out power.
I suspect that our partial charging regimens are only causing a temporary loss. It's just the cells getting a little unbalanced and the BMS reducing available capacity to keep them in their happy zone. 100% charges should fix that.
 
My car’s at 22,200 miles, and mi3 says the SOH is currently 100%. Battery capacity shows 97AH. I last checked in April 2021 and it said 99AH, but from this thread it looks like that number can fluctuate, so those two data points probably don’t mean much. I’m still glad to see it hasn’t dropped 10% or anything crazy. This car is already aging much more gracefully than my Spark EV.
 
fizzit said:
My car’s at 22,200 miles, and mi3 says the SOH is currently 100%. Battery capacity shows 97AH. I last checked in April 2021 and it said 99AH, but from this thread it looks like that number can fluctuate, so those two data points probably don’t mean much. I’m still glad to see it hasn’t dropped 10% or anything crazy. This car is already aging much more gracefully than my Spark EV.
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How do you charge? How far do you discharge?
 
pictsidhe said:
How do you charge? How far do you discharge?
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I have a 3.3kW L2 charger and I plug in most of the time when I get home. I’d guess the car has spent ~80% of its life plugged in and sitting at 100% SOC. I don’t often discharge below 50%, and have rarely taken it below 25%, pretty much only on road trips with lots of L3 charging.
 
Anyone secretly hoping SOH drops below 80% so they can get a fresh battery before warranty expires?
 
yoomini said:
Anyone secretly hoping SOH drops below 80% so they can get a fresh battery before warranty expires?
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Are you looking to justify your penchant for pushing your SE hard? I'm certainly doing nothing to prolong the life of my SE's battery.

My 2000 Honda Insight's battery lasted until after I got my 2006 Insight. Then my 2006 Honda Insight's NiMH battery expired in 2014, two months after the warranty period. Honda graciously paid for the replacement battery, but I had to pay for the labor. The replacement battery lasted only 5 years and I did the swap myself. That's possible when the battery weighs just 70 lbs. I used to work on my ICE cars so it felt good to finally get my hands into my Insight. Unlike the olden days, however, I finished the job as clean as when I started.

In an interesting parallel, when changing my Insight's battery, I was able to shield a wire that was causing static on my AM radio. Now, thanks the fellow SE forum members and Bimmercode, I was able to activate the secret AM radio in my SE--one that MINI likely disabled to prevent possible static from the car's electrical drivetrain. I love my AM radio and experience no static.
 
Hey gang - brand new here (2021 SE, ~35,000km) and super interested in this discussion about monitoring the battery. What’s the consensus on best apps to do this? It’s my first EV so talk to me like I’m 7…. ;-)
 
I'd like to piggyback on this....

Where can I find info on the abbreviations GOM, SOH, etc.
I've been enjoying my '23 since October 22. It's my first EV and my knowledge is very limited. I researched prior to my purchase decision & honestly I barely understand the basics. I'm using the EVSE that came with my MINI. Charge about every other day at the max. I had a dedicated circuit installed by electrician.
 
SoC = State of charge. Current battery level of your vehicle.

SoH = State of health. Battery health, 100% = no degradation. A small amount is normal and expected especially in the first couple of years, then it holds steady.

GOM = Guess-O-Meter. The in-car estimate of how many miles are remaining based on the last 30 miles (?) or so. GOMs are useful in many EVs, but the MINI’s software is pessimistic and random. Just learn to ignore it and follow the battery %. Use the top button on the turn signal stalk to display %. MANY threads on this.

Apps: mi3 seems to be pretty good. You will need a Bluetooth OBD adapter to access the data. Recurrent is a website that connects to the car over the air. I have two MINIs and find it to be unreliable as they are estimated by that site to be in very poor condition. I took one of them on a trip the other day and squeezed out 145 highway miles with relative ease. So.. :)
 
Thank you, polyphonic!

Will look into that software (and yes, that GOM is all over the map I noticed. In fact I almost didn’t buy the car because when I got in it at the dealer 50% battery was showing only 50ish km left. They assured me a couple drives and charges would bring it more in line and that proved true).

Just a note on battery analysis - I just had my annual service check at BMW and they provided nothing of the sort. Brake fluid flush, cabin filter change, and an “all good” from the service dept. I think a SOH printout would not be too much to expect for an EV, no?
 
polyphonic said:
SoC = State of charge. Current battery level of your vehicle.

SoH = State of health. Battery health, 100% = no degradation. A small amount is normal and expected especially in the first couple of years, then it holds steady.

GOM = Guess-O-Meter. The in-car estimate of how many miles are remaining based on the last 30 miles (?) or so. GOMs are useful in many EVs, but the MINI’s software is pessimistic and random. Just learn to ignore it and follow the battery %. Use the top button on the turn signal stalk to display %. MANY threads on this.

Apps: mi3 seems to be pretty good. You will need a Bluetooth OBD adapter to access the data. Recurrent is a website that connects to the car over the air. I have two MINIs and find it to be unreliable as they are estimated by that site to be in very poor condition. I took one of them on a trip the other day and squeezed out 145 highway miles with relative ease. So.. :)
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Thanks for the info!
 
Do we have any authoritative info on what metric the SOH number is derived from, or if it is actually the number used to determine warranty claims? It seems like it could be based on estimated capacity, total internal resistance, cell IR variance, cell balance, pack IR, or any other number of factors.
 
There is no standardized way of measuring/estimating SoH as far as I know. Generally there is a capacity fade (consumer products & EVs) and a power fade (industrial machinery). You can lose cathode material, anode material, and/or lithium inventory (into the SEI layer) which makes things really complex.

Suppose for one EV the graphite (and silicone) anodes of the battery packs are degraded and another EV has a degraded cathodes (NCM, LFP, or other metal oxides) in the entire battery pack. The one with degraded anodes will probably charge slower and show lower voltages (can't stuff in more electrons), and the one with degraded cathodes might not discharge as fast (lower current) because there is a backlog of lithium ions. If there is channelling in the SEI layer (too many SEI things to name) for example, you could theoretically show zero capacity degradation at 100% SoC, but experience some reduced performance with DC fast charging or reduced acceleration (in extreme cases).
 
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