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Losing Max miles on full charge
- Thread starter robl45
- Start date
Plug in every time you get home, and set your charge to 90%
Charles_sjc
Member
I bought my car in march 2020 M3 SR+. THE SOC of charge at 100% was 250 when new. it's now down to 237 after 3 months and I am worried because it is going down with every charge. I use chademo(Evgo) and superchargers about 50% of the time and charge to 90%. I usually stay in the range of 30-90%. any recommendations? I was thinking that the chademo Evgo charging is affecting my range because I noticed the drop-off right around the time I started using Chademo. It's only 50KWh but it does not trickle down in rate of charge like the Tesla supercharger does. I am wondering if this may be detrimental. I called Evgo and they said that the chip in the adapter will trickle down when it is required to prevent overheating. attached is SOC history...
Tam
Well-Known Member
I would agree that your car BMS (Battery Management System) would take care of how best to charge your car in a session whether it's Tesla or Evgo...
Your battery is guaranteed for 70% capacity, so you still have a long way to claim it.
There's no proof that DC fast charge is bad for your battery longevity but there's a notice on your fast rate being capped:
"Does Supercharging affect my battery?
The peak-charging rate of the battery may decrease slightly after a large number of high-rate charging sessions, such as those at Superchargers. To ensure maximum driving range and battery safety, the battery charge rate is decreased when the battery is too cold, when it is nearly full or when its condition changes with usage and age. These changes in the condition of the battery may increase total Supercharger time by a few minutes over time."
Charles_sjc
Member
understood but the car is just over 3 months old. I would hope that 30% degradation is only for warranty purposes and assuming only the worst case situation. It would be alarming to expect to have to hit that in a normal lifespan of a car. 5% battery degradation in that short period of time is normal? I've seen most comments aound that type of degradation over 3 years and that is with cars that regularly use supercharging. It seems a little unusual to drop that much over such a short period of time.
So, degradation for lithium ion batteries (like those in both your phone and your car) don't lose capacity linearly. They lose a chunk earlier in life, degrade much slower after that, and then suddenly drop off a cliff at the end of their usable life. The 30% reduction is about where this cliff would occur and really does indicate a mostly-dead-or-dying battery.
A bunch of us, I'd say most of us, will experience about 5% drop in the first 30,000mi. It should slow down a lot after that, and for past Tesla vehicles, it does.
Because this is complicated to explain and yet happens so early, EV manufacturers don't have clear messaging on this and yet it's brought up frequently by new owners. It doesn't help that the answer from Service is often "yep, it's within spec, see ya later".
Elon has said for the Long Range that he expects it to last 500,000mi. You could imply this to mean that the fleet should average out to that 30% degradation point around 500,000mi. Unfortunately, only time will tell since the Model 3 battery packs haven't been around for very long yet.
However, I have a big gripe with Tesla regarding CHAdeMO charging specifically. It does some super dumb things regarding actively heating the battery that it just doesn't need to do, but I have no avenue for feedback to Tesla for this. Are you using CHAdeMO as your primary charge method? I'd personally bet some money that frequent CHAdeMO charging accelerates wear greatly on a Model 3. I'd happily arm you with a ton of information to Tesla Service if you'd like to bring it up as a concern of your battery degradation. However, there's a large chance they'll say you're within spec.
Charles_sjc
Member
Yes! I noticed the steep decline after buying and using a Chademo adapter and was wondering if it was a contributing factor. Any information you can send would be greatly appreciated. Maybe I’ll shop using chademo and see if the decline ceases. Because it is decking right now after every charge session.
See my reply in this thread (3rd post): How hot should the batteries get while charging?
Especially the section titled "Implications for CHAdeMO Charging".
Essentially, Model 3 heats the battery a lot when Supercharging so that it can accept higher charge rates. The same logic is applied at CHAdeMO stations, even though they have a much lower maximum power. The result is that your battery is a lot hotter than it "needs" to be to be able to charge at the 50kW or so that the CHAdeMO station can provide (especially if you start charging at a low state of charge).
Your decline will probably cease for other reasons honestly. I'm betting you're mostly seeing the usual initial steep drop and it's now levelling out in terms of degradation. If my theory is correct, you'd only notice long-term, not really so immediately (other than accelerating the initial drop, which is maybe why it seemed so sudden from your perspective).
Feel free to PM me for any more details you'd like, clarifications, how to present it to Tesla Service, etc. If anything is relevant for wider discussion I'll make sure it ends up in a thread on these forums somewhere.
Charles_sjc
Member
thanks. much appreciated. and my observation also indicates that chademo charging does not drop off to trickle charge state when you get close to your stated level of 80 or 90%. it continues at the same full charge speed until the session is completed. I don't know if that is good or bad or of no consequence but I do recall Tesla supercharging sessions rapidly charging sat the beginning of a session and then slowing when you get closer to full capacity. I really hope decline in SOC is new car related and will stabilize. Having the battery lose 5% in a short three months is scary. this usually happens in the first 30K miles as you mentioned before and I would assume not in a smaller dataset of 3k miles over 3 months.
There is no difference there. The charging taper curve is exactly the same and dictated by the battery conditions.
You are seeing "this one slows but that one doesn't" because they are at very different power levels initially. The Supercharger is running at 100+ kW, so yes, of course it is slowing to 80, 70, 60, etc. as the battery has to reduce that power level. CHAdeMO through the adapter is only going to be doing a maximum of about 43-45 kW best case. That is already limited by the station and the adapter well below what the tapering curve for the battery would be for a very long time. But at some point, the state of charge will get high enough that Supercharging and CHAdeMO will both be affected by that tapering curve from about 45 kW and below and will behave about the same from then on.
You can make the same analogy by observing cars coming up to a reduced speed 40 mph zone for construction on a highway, and could say, "This car slowed down but that one didn't. I wonder why?" Well, one car was going much faster than the other, so the slower one was already below that limit and didn't need to slow down.
Electric700
Active Member
There appear to be frequent 100% charge sessions in your data, e.g. a 100% charge every 100 miles or even more frequently. Can you charge to 80%? I try only to charge to 100% twice a year for battery balancing, then drive immediately after the session completes.
You may want to talk to Tesla about the range loss during your next service appointment. You can report that you noticed drops mainly just after using CHAdeMO. There may be a chance the battery needs to be cooled better, considering the high rate of charge that CHAdeMO supports (not as high as Superchargers but it's still high).
SSonnentag
埃隆•馬斯克
Seems typical. Here's my S 100D chart for comparison. I'm not seeing the slowing of range loss the predictions seem to show, where initial losses are fast, with a tapering off of the rate of range loss over time/mileage. It looks quite linear to me.
Charles_sjc
Member
I never charge to 100%. the data that you see from my earlier post is from the Tesla Stats app and is an estimate of battery health at 100% SOC. as a rule, I charge to 80% and stay in 20-80% range.
SSonnentag
埃隆•馬斯克
Same here. I daily to 70% and on trips try to stay between 20% and 80%, with 90% charges to begin a trip when leaving from home. Supercharging past 80% is just too slow.
Charles_sjc
Member
re
only difference being that it took 40k miles for you to lose 14 miles of range! I've accomplished that with a smaller capacity battery in only 3K miles and 3 months. my curve drop-off seems to be more aggressive and is going down about 1-2 miles weekly. I'm thinking about making an appt with Tesla service but they will probably bring up the 70% threshold and discount it as not an issue.
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