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Is using often a Slow Supercharger also bad idea?

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Hi All,

I can use a free supercharger every day. It is a fast charger with 45 kWh power. I read a lot that constantly supercharging is bad for the battery and it causes more degradation over time. That info is based on superchargers up to 150/250 kWh.

My questions are:
- Is supercharging at 45 kWh just as bad as the normal superchargingof 150 kWh, or would this 45 kWh be mutch better than expected with the 150 kWh superchargers?
- Is a 45 kWh supercharging so much worse than 22 kWh normal charging?
- In addition, I wonder whether normal charging at 7 or 11 kWh is better than normal charging at 22 kWh.

I am wondering if someone found this out already. Din't find that info on the forums jet.

Thank you,
Kris
(I've got a Tesla Model 3 SR+ 2021, with LFP)
 
45kW of power is just about what I get when using my CHAdeMO adapter. It's theoretical max is 50 but I've never seen it go much above 45 (low state of charge and warm battery). I've been charging my 2018 LR RWD like this for over 3 years, with occasional usage of a 72kW Supercharger. I don't have home charging (Level 1 or 2) at the moment since the CHAdeMO station is much cheaper than what it would cost if I charged at home. Yes, it's a small hassle when I have to wait an hour or so at the DCFC to get 100+ miles but it's only once every couple of weeks with the small amount of driving I'm doing.

With about 27K miles on the odometer my 100% range hovers at 300 miles. It was 315 when new so that's about a 5% drop. First year I had my car I used the L2 charging at work (~7kW) so that may have helped some.

With a lower charging power, a lot more of the energy is going towards keeping the base electronics operating. My understanding is that it's somewhere around 500W just to power the car while it's charging. Using a 7kW power source versus 22kW means that more of a percentage of that power goes to keep the computers running and not getting into the battery. It's wasting a bit of electricity to do it this way and it will take longer to get to your target limit. 7kW vs. 22kW really doesn't matter to the battery's overall health.
 
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As a general rule of thumb, slower charge rates are better for your pack than higher charge rates.

Lithium plating is the concern when charge rates increase. As ambient pack temps decline, resistance inside the pack increases and the C-rate (rate of charge) the pack can accept without lithium plating also declines. If the pack gets cold enough, there is a point where it cannot accept any charge without lithium plating occurring. And lithium plating can occur at quite moderate pack temps if the C-rate is high enough.

Broadly speaking, heat is an enemy to pack longevity. But narrowly speaking, heat is your friend when charging. And the higher the charge rate, the more heat you need to avoid lithium plating. Which is why Tesla's will raise pack temp so much before (while preconditioning) and during Supercharging.

Most everyone celebrates very high charge rates while Supercharging. I'm not among them.
 
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I really wouldn’t stress about it.

The battery management system on these vehicles is very robust and isn’t going to let you just burn out your battery.

In the first year of ownership, I have put 25k on my M3P, with 7 race days, and about 45% of my charging is on Superchargers (lots of road trips). Still, I have only seen about 8% degradation. About half of that is calendar aging, typically cutting around 3-5% of capacity in the first year regardless of use, leaving maybe 4% extra due to my harder-than-typical usage.

Bottom line: Even ~4,500KWh of juice on 150 and 250Kw Superchargers, plus my other abuse, has only degraded my battery around 4% extra in 25k miles.**

I really wouldn’t stress about it.

**I imagine this level of abuse would take more than 4% off the service life of the Hellcats or the BMW M3s I was cross-shopping :p .
 
Hi All,

I can use a free supercharger every day. It is a fast charger with 45 kWh power. I read a lot that constantly supercharging is bad for the battery and it causes more degradation over time. That info is based on superchargers up to 150/250 kWh.

My questions are:
- Is supercharging at 45 kWh just as bad as the normal superchargingof 150 kWh, or would this 45 kWh be mutch better than expected with the 150 kWh superchargers?
- Is a 45 kWh supercharging so much worse than 22 kWh normal charging?
- In addition, I wonder whether normal charging at 7 or 11 kWh is better than normal charging at 22 kWh.

I am wondering if someone found this out already. Din't find that info on the forums jet.

Thank you,
Kris
(I've got a Tesla Model 3 SR+ 2021, with LFP)
Everyone else has given good responses but there's one more fact: your LFP car will degrade less intrinsically than other battery chemistries.

If you want to be absolutely the safest, charge at home with 7 or 11 kW, likely no real difference.

Generally there is no signifcant excess degradation from charge speed in the literature less than C/5, which means in their jargon, a full pack charge in 5 hours. With a 55 kWh battery (LFP), that is 55/5 = 11 kW.
 
Hi everyone,

Thank you all for the response! I really appreciate the responses I've received.

RayK, it's actually a CHAdeMO adapter I think. There are 3 outputs, so the base will be CHAdeMO. Theoretically it is indeed 50KW, but here always 44/45 KW. max.
For my home solution I will go for the 22KW, to waste less energy. Thank you!

Regaj, so the guess was correct. Slower rates are better for the pack. So I can worry less.
Thanks for the technical side. Good to know how it works.

Lindenwood, I'll stress less. Always a good tip.

Dr. Chaos, that's right! But since I can charge for free, I use that. But I'll have to wait there... Think I'll be less stressed to begin with.

ucmndd, I will!

---

I think the point of the story is to make it less stressful. Also that slower fast charging is less degraded than faster fast charging. And that while my LFP is already less degraded. So go and charge with that 45KW fast charger. Thank you all!
 
I know in the beginning constant super charger use was frowned upon, but also read people constantly using superchargers and battery was fine.

I really don’t have easy access to overnight slower charging, would constantly using super chargers be that bad of a thing?

Or is the difference negligible?
 
No, using Superchargers is certainly not a bad thing. But it is hard on your pack, especially if you use one locally and don't precondition for a good, long while before plugging in.

A pack degradation comparison between a mostly L2-charged vehicle and a mostly Supercharger-charged vehicle will very likely show a much more rapid decline in battery health with the latter.

YMMV. But, no, I wouldn't expect the difference to be negligible.
 
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