Longer charging time in hot weather?

B

Brian Beuchaw

Member
It's been over 100 F here for weeks, and didn't realize it would impact level 1 charging that much. I plugged it in (it's garaged and the garage has a wind turbine on it that the previous owners put in, so it's a bit cooler than outside) after a 15-minute drive home on Thu at 17:45 (it was at 31%), and unplugged it at 8:30 Fri and it only made it up to 72%. Almost 15 hours to go 41% when it's in the 90-100 F range - is that normal for how the SE charges in this heat?

It's getting taken in to MINI to replace the KLE on Friday, but wondering if they'll be able to test properly to see if it can take the full ~30A charge in this heat?

Also, I haven't done DC charging yet, assuming it will take longer too in 100 F, but wondering how much longer?
 
I average between 2-4% per hour on 110V (L1). The higher the starting %, the longer it takes.
upload_2022-7-18_15-52-48.webp
 
Level 1 appears to suffer as much as arctic climates in the heat, in that the majority of energy may be redirected to battery conditioning first. Add in the already inefficient Level 1 charging losses, as opposed to Level 2, and I can instantly see the NEED for Level 2.

Any chance in upgrading to a 16 amp Level 2 at your location. It's a marginal panel amperage upgrade, using only 20 amp breakers.... assuming there's panel space for the breakers. The 16 amp EVSE was more than adequate for Minnesota winters in an unheated detached garage, I'd imagine it would translate equally with the heat.

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Correction.... 20 amps as an add-on to an existing panel. Not a panel upgrade.

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Zim said:
Level 1 appears to suffer as much as arctic climates in the heat, in that the majority of energy may be redirected to battery conditioning first. Add in the already inefficient Level 1 charging losses, as opposed to Level 2, and I can instantly see the NEED for Level 2.

Any chance in upgrading to a 16 amp Level 2 at your location. It's a marginal panel amperage upgrade, using only 20 amp breakers.... assuming there's panel space for the breakers. The 16 amp EVSE was more than adequate for Minnesota winters in an unheated detached garage, I'd imagine it would translate equally with the heat.

Sent from my ONEPLUS A6003 using Tapatalk
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Yes, I've got a level 2 circuit installed (but the electricians need to come out and redo it, they put in a 35A breaker and 10 gauge wiring instead of 40A and 8 gauge) and a 32A Lefanev charger ready to go, but my KLE is broken, so level 2 is charging no faster than level 1 (MINI will go in Fri to get it replaced).

Thanks to the rest of y'all for your answers, didn't know that about the higher starting percentage, but that kind of matches what I've seen online when reading about DC charging (how it ramps up to max pretty quickly, but when it hits 75%, it starts to taper off).
 
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Puppethead said:
The SE doesn't start to taper until 85% or so, it has a great built-in charger.
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When it works. :-( I'm pretty bummed that mine was either delivered broken or broke right off the bat (and that MINI has no replacements in the USA), but hopefully after it's replaced I don't see the dealer for 1.5 more years... GTK about the 85%, I was just remembering a graph that someone did while doing CD charging and was fairly accurate. ;-)
 
On DC fast chargers the Mini charging speed increases the higher the state of charge gets as the pack voltage increases.
It will start at around 42kW if you’re at say 15% and will linearly increase until it hits 50kW by the time you get to 80%, shortly afterwards it will start to slow down.

As for slower charging in hot weather, I can’t say I’ve seen it on L2, in my ridiculously hot garage it charges at the full 32A just as it did in winter.
On The DC fast charger it also didn’t seem to be any slower in the 40degC+ (105F+) weather but I only did a short charge.
I will point out that when charging the Mini disables the climate system (ie no AC or heat) so that all the energy goes into the battery. If you activate “comfort cooling” manually the amount drawn from the DC fast charger won’t go up but less makes it’s way into the battery as some is diverted to cabin cooling, which means longer charging times. It may even rob some cooling from the battery during charging causing it to slow even further, not sure. You’re only likely to activate comfort cooling if you’re sitting in the car while DC fast charging in hot weather, thus giving the perception that the car charges slower in hot weather, which isn’t the case.
 
AndysComputer said:
On DC fast chargers the Mini charging speed increases the higher the state of charge gets as the pack voltage increases.
It will start at around 42kW if you’re at say 15% and will linearly increase until it hits 50kW by the time you get to 80%, shortly afterwards it will start to slow down.

As for slower charging in hot weather, I can’t say I’ve seen it on L2, in my ridiculously hot garage it charges at the full 32A just as it did in winter.
On The DC fast charger it also didn’t seem to be any slower in the 40degC+ (105F+) weather but I only did a short charge.
I will point out that when charging the Mini disables the climate system (ie no AC or heat) so that all the energy goes into the battery. If you activate “comfort cooling” manually the amount drawn from the DC fast charger won’t go up but less makes it’s way into the battery as some is diverted to cabin cooling, which means longer charging times. It may even rob some cooling from the battery during charging causing it to slow even further, not sure. You’re only likely to activate comfort cooling if you’re sitting in the car while DC fast charging in hot weather, thus giving the perception that the car charges slower in hot weather, which isn’t the case.
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Thanks for the info about not slowing down for L2 and DC. I've only charged in the evenings on L1 with it parked in the garage, so it was completely empty and idle, but good to know that...

And looking back at my charging history in the app, my concern about slower charging may be false. I'll have to run some numbers, and it may have always been this slow, but I didn't notice it because I was WFH from Feb until now-ish and just plugged it in and didn't have a need for it to be ready at 8 AM. Have to research and see if the end-time on the app is when it was unplugged or when it reached 100% (and stayed plugged in because I hadn't unplugged it yet and it may have sat there for a few hours).
 
Mea culpa, this thread can probably actually be deleted, lol....

Went back and did some math with the charging history and found that the time it takes in 100F is about what it took back in Mar/April when it was around 70F or so. 14:42 in July to charge ~16kWh, from 31% to 72%. Back in March, it took 3:10 to do 4kWh, from 62% to 72%, and in April, took 9:35 to do 11kWh, from 75% to 100%. So it appears that it's approximately an hour per kWh. As I mentioned, I had just been plugging it in at night, letting it charge and unplugging it a day or so later, not noticing how long it *actually* took to charge since I didn't have a morning deadline to adhere to. Oh well, at least now I know what the charge rate really is, thanks for all the replies humoring me. :-)
 
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