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Frequent 50KW DC charging and the Model3

ivangr

Member
Jul 22, 2019
198
124
dunfermline
We have quite a few 50KW chargers around my work and house. I typically pop out during my lunch break and stick it on a 50KW (21-48KW actual speed) charger and charge back up to 90%.

Is this a bad idea? Will it damage the battery in the long run?
 

Andy_T_73

Member
Jul 22, 2019
176
126
Prestwick
I think the recommended is 80% unless you are going to use the charge immediately. AFAIK holding a high state of charge and not using it immediately can cause reduced capacity in the long term.
 
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widodh

Model S 85 and 100D
Jan 23, 2011
6,853
2,773
Venlo, NL
I think the recommended is 80% unless you are going to use the charge immediately. AFAIK holding a high state of charge and not using it immediately can cause reduced capacity in the long term.
90% is just fine and it's not a high SoC at all. Don't worry about it, just charge to 90% when ever you need.

I've been doing this daily for the last 6 years and it doesn't hurt the battery.
 
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ACarneiro

Active Member
Jun 20, 2019
1,352
1,092
Shrewsbury, Shropshire, UK
My understanding is that the slower charging is always better as it reduces the thermal stress on the battery.

That said, there are large numbers of people who supercharge very often and the batteries are holding up fine. Bearing in mind that SuC is around twice faster than a standard 50kW rapid charger, my impression is that whilst it will be better to charge at home you're unlikely to see significant issues with your current setup.

I would probably err on the side of keeping the charge up to no more than 80%, though, unless you're likely to need the range.
 

ivangr

Member
Jul 22, 2019
198
124
dunfermline
My understanding is that the slower charging is always better as it reduces the thermal stress on the battery.

That said, there are large numbers of people who supercharge very often and the batteries are holding up fine. Bearing in mind that SuC is around twice faster than a standard 50kW rapid charger, my impression is that whilst it will be better to charge at home you're unlikely to see significant issues with your current setup.

I would probably err on the side of keeping the charge up to no more than 80%, though, unless you're likely to need the range.


My own research correlates with this. It seems that the Model 3 has liquid cooling for the batteries which will prolong their life.
Apparently other manufacturers don't have this and it wrecks their batteries.

Soooo. I think it's fine. I'll keep pumping in those free and fast electrons.
 

widodh

Model S 85 and 100D
Jan 23, 2011
6,853
2,773
Venlo, NL
My own research correlates with this. It seems that the Model 3 has liquid cooling for the batteries which will prolong their life.
Apparently other manufacturers don't have this and it wrecks their batteries.

Soooo. I think it's fine. I'll keep pumping in those free and fast electrons.

<50kW is not even 1C for the battery. So no, charging with ~50kW won't hurt at all.

My understanding is that the slower charging is always better as it reduces the thermal stress on the battery.

That said, there are large numbers of people who supercharge very often and the batteries are holding up fine. Bearing in mind that SuC is around twice faster than a standard 50kW rapid charger, my impression is that whilst it will be better to charge at home you're unlikely to see significant issues with your current setup.

I would probably err on the side of keeping the charge up to no more than 80%, though, unless you're likely to need the range.
You might be surprised that time is also a factor. Charging slowly extends the time you are charging and that also has an effect on the battery cells.
 
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Rooster6655

Active Member
May 3, 2019
1,535
530
UK
No. The car has an inbuilt inverter so AC is converted to a DC before it is supplied to the battery.

The battery is always being directly charged with DC regardless of what you supply the the car.

Interesting so it’s more a case of the amount of kw your putting in at a time rather than the type.


You might be surprised that time is also a factor. Charging slowly extends the time you are charging and that also has an effect on the battery cells.

If ac is converted to dc then what do you suggest is the best way to charge then?
 

Roy W.

Battery running low...
Jun 3, 2019
2,307
2,319
Derby, UK
The problem is that even 50kW DC charging has a large heating effect on the battery. I know the Tesla has thermal management, but in my view it's better not to thermally stress the battery unless you need to. The Kona also had thermal management, but the manual included warnings about excessive rapid charging being bad for the battery.

Personally I'd rather pay a few pence each night to charge at home at a slow rate, than risk reducing the battery longevity for the sake of a few free Watts.
 

tsh2

Member
Aug 27, 2019
290
83
Cambridge, UK
Interesting so it’s more a case of the amount of kw your putting in at a time rather than the type.

Not so much. Traditionally, lithium cells age due to integrated thermal stress much more than integrated charge. Due to the implicit efficiency of the cell, there is much less heat generated when charging to ~90%. This kind of explains why lithium cells shouldn't be float charged (and why improved cooling has a dramatic effect at increasing lifetime). 50 kW at 10% is probably easier on the cells than 10 kW at 90% (nominal values, but hopefully you get the idea).
 

cezdoc

Member
Aug 15, 2015
479
707
Aberdeen, UK
I'd agree with what's said above but bear in mind some older S and X cars have had their maximum charge rate reduced over time and there does seem to be a connection with DC charging. I've seen a formula quoted for the S/X75 cars which relates max charge rate to number of kWh added at Superchargers - but it wasn't clear if all DC charging counted.

More recently I know of at least one owner in the OP's neck of the woods who's been affected by the "batterygate" range reduction (~10% loss of range following a software update) and did a large proportion of DC charging (mainly CHAdeMO, not Supercharging) - but Tesla have refused to say that DC charging triggered the range reduction.

Presumably the OP has access to free ChargePlace Scotland rapid charging so it's a nice bonus and won't last forever. Given the improved cooling in the Model 3 I would expect the risk of any battery damage to be less than that for the legacy S and X batteries so personally I wouldn't be too concerned but just be aware the risk isn't zero and a.c. charging is supposedly kinder to the battery cells (because, I think, it doesn't generate as much heat).
 

Torokruger

Member
Oct 4, 2019
147
91
Scotland
I'd agree with what's said above but bear in mind some older S and X cars have had their maximum charge rate reduced over time and there does seem to be a connection with DC charging. I've seen a formula quoted for the S/X75 cars which relates max charge rate to number of kWh added at Superchargers - but it wasn't clear if all DC charging counted.

More recently I know of at least one owner in the OP's neck of the woods who's been affected by the "batterygate" range reduction (~10% loss of range following a software update) and did a large proportion of DC charging (mainly CHAdeMO, not Supercharging) - but Tesla have refused to say that DC charging triggered the range reduction.

Presumably the OP has access to free ChargePlace Scotland rapid charging so it's a nice bonus and won't last forever. Given the improved cooling in the Model 3 I would expect the risk of any battery damage to be less than that for the legacy S and X batteries so personally I wouldn't be too concerned but just be aware the risk isn't zero and a.c. charging is supposedly kinder to the battery cells (because, I think, it doesn't generate as much heat).

Dont know if this would make a difference but remember the older S and X uses 18650 batteries whereas the M3 uses the new 21700 cells with slightly different technology .
 

VanillaAir_UK

Supporting Member
Jun 17, 2019
7,969
5,463
Surrey, UK
Even supercharger rapidly drops off charge rate as SoC increases.

20% - 100% - Come 30 minutes in, down to 50kW. Final 30 minutes was at 7kW or less.
20-100-SuperCharge.png

PS looks like right hand Y axis legend is wrong
 

TezzyMod3

Member
May 30, 2019
215
80
London
Sorry to hijack this but maybe relevant (slightly).

what’s the fastest you can type 2 charge? Should I plug into 22kw if available?
 

NorfolkMustard

Active Member
Apr 18, 2019
2,209
2,182
M3P w/FSD
Model 3? maximum you'll get benefit from is 11KW

If you have a choice between a 7KW and 22KW, it's more a preference on not blocking the 22KW for those who could benefit more from it (Renault Zöe for example)
 
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ivangr

Member
Jul 22, 2019
198
124
dunfermline
e
I'd agree with what's said above but bear in mind some older S and X cars have had their maximum charge rate reduced over time and there does seem to be a connection with DC charging. I've seen a formula quoted for the S/X75 cars which relates max charge rate to number of kWh added at Superchargers - but it wasn't clear if all DC charging counted.

More recently I know of at least one owner in the OP's neck of the woods who's been affected by the "batterygate" range reduction (~10% loss of range following a software update) and did a large proportion of DC charging (mainly CHAdeMO, not Supercharging) - but Tesla have refused to say that DC charging triggered the range reduction.

Presumably the OP has access to free ChargePlace Scotland rapid charging so it's a nice bonus and won't last forever. Given the improved cooling in the Model 3 I would expect the risk of any battery damage to be less than that for the legacy S and X batteries so personally I wouldn't be too concerned but just be aware the risk isn't zero and a.c. charging is supposedly kinder to the battery cells (because, I think, it doesn't generate as much heat).

good reply. I’ve rationalised things a bit. I would say most of my charging on 50kw’s is 21-34 kw. So, I think the “heat” impact should be minimal. It’s not exactly supercharger rates.

And yes, in Scotland it’s free and we pay higher taxes than the rest of the country to afford stuff like this so I’m keen to get the full benefit out of it.
 

ivangr

Member
Jul 22, 2019
198
124
dunfermline
The problem is that even 50kW DC charging has a large heating effect on the battery. I know the Tesla has thermal management, but in my view it's better not to thermally stress the battery unless you need to. The Kona also had thermal management, but the manual included warnings about excessive rapid charging being bad for the battery.

Personally I'd rather pay a few pence each night to charge at home at a slow rate, than risk reducing the battery longevity for the sake of a few free Watts.

Why do you say 50 kW has a large heating impact? Sources for that information?

A Model 3 isn’t a Kona and it’s obviously not “pence” and a few “free Watts”.
 
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Artiste

Member
Jun 17, 2019
427
311
Lancashire
T
Model 3? maximum you'll get benefit from is 11KW

If you have a choice between a 7KW and 22KW, it's more a preference on not blocking the 22KW for those who could benefit more from it (Renault Zöe for example)

I find that frustrating. I’m getting a 22KW charger installed at home and will only be able to charge at 11KW. A friend of mine has a Zoe and will be able to use MY charger to charge at 22KW :oops:
 
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