Cold Weather Range

[MrDRMorgan]

Hi, Everybody!

In my one year's experience with my 2015 Spark EV, I've been using one of two DCFC chargers in my area when needed, either to get up the hill to my house, or after going up the hill from San Jose, on my way to Santa Cruz (where I frequently play trumpet with the symphony there).

In the case of the first charger, the 50KW unit at ChargePoint HQ, I've frequently charged up to 100% (frequently, meaning on the order of once per month on average). I've watched the numbers both on the ChargePoint app on my phone, and on the unit itself, and seen that at 80% full, the charge rate starts to ramp down to on the order of 20KW by the time I get up to around 95% full. It doesn't drop below that rate until it determines I'm fully charged and stops altogether.

In the case of the other charger, one of the two EVGo units at the restaurant at the summit of HWY17, it does approximately the same thing according to the big display on the charger: Starts at 99 to 100A, and stays there until 80% after which it slowly ramps down to about 20A right up to 100%.

Both of these post-80% charge rates are far above the Level II rates, and therefore are worth taking advantage, as long as there's no one waiting to use the charger. Since I'm usually at ChargePoint after 10pm, that's not usually not a problem. There are two chargers at the summit restaurant, and only twice have I encountered anyone else charging when I got there. (I have to use it after work on my way to orchestra rehearsal, around 4:00pm).

The one odd thing I notice, after charging to 100% is that the Battery Information screen doesn't reset as it does after a level 2 charge completion. Is that normal??

Hope this helps!

Guy Clark
Los Gatos, CA

Awesome, thanks!

Many times I have 100% charged at EVgo locations only to see the charging cycle is still going but at a very low rate. When I finally disconnected, I also noticed the Energy Info screen did not reset to zero. But, there have been occasions where, if I left the car charging on the DCFC long enough, the screen would finally reset. Now I do worry about it and only charge to 95% max.

 

[GuyClark]

I guess I've been in too much of a hurry to let the car continue after the DCFC unit says it's done to see what happens ;-). For now, since I'm unlikely to do sequential DCFC sessions on a long trip, I'll just live with the un-updated energy display and not worry too much about it.

Long trips are why I have a wife (well, that and a few other reasons! ;-) ) and I kept my old Honda Del Sol for emergencies.

Later!!

Guy

 

[MrDRMorgan]

I guess I've been in too much of a hurry to let the car continue after the DCFC unit says it's done to see what happens ;-). For now, since I'm unlikely to do sequential DCFC sessions on a long trip, I'll just live with the un-updated energy display and not worry too much about it.

Long trips are why I have a wife (well, that and a few other reasons! ;-) ) and I kept my old Honda Del Sol for emergencies.

Later!!

Guy

I believe there were comments posted on this forum that suggested quick charging to 100% could cause the battery to degrade. I would have to look through my notes but I also believe tests conducted by the Idaho National Laboratory confirmed this point. That is why I no longer quick charge to 100%. I now charge to 90 - 95% and go on my way. This saves me some money since I pay by the minute and charging is really S.....L.....O.....W from 95 to 100% and even slower to the point where the Energy Info screen is reset to zero..

If you are trying to estimate the capacity of the HV battery in your Spark EV, I am finding I get good results by slow charging to 100% until the energy info screen resets to zero and then driving 40 miles or more [could be more that 1 day to get over 40 miles] before making the capacity calculation. I then use the numbers on the Energy Info screen to calculate the HV battery capacity. My 2016 Spark EV has been ranging between 17.1 and 17.5 kWh for the last ~400 miles.

 

[CCIE]

I believe there were comments posted on this forum that suggested quick charging to 100% could cause the battery to degrade. I would have to look through my notes but I also believe tests conducted by the Idaho National Laboratory confirmed this point. That is why I no longer quick charge to 100%. I now charge to 90 - 95% and go on my way. This saves me some money since I pay by the minute and charging is really S.....L.....O.....W from 95 to 100% and even slower to the point where the Energy Info screen is reset to zero..

If you are trying to estimate the capacity of the HV battery in your Spark EV, I am finding I get good results by slow charging to 100% until the energy info screen resets to zero and then driving 40 miles or more [could be more that 1 day to get over 40 miles] before making the capacity calculation. I then use the numbers on the Energy Info screen to calculate the HV battery capacity. My 2016 Spark EV has been ranging between 17.1 and 17.5 kWh for the last ~400 miles.

I don't see why it would. The charge rate drops to around the same rate as L2-AC at the very end of the charge cycle (~3kw). It's not like it charges at 50kw until full.

 

[MrDRMorgan]

I believe there were comments posted on this forum that suggested quick charging to 100% could cause the battery to degrade. I would have to look through my notes but I also believe tests conducted by the Idaho National Laboratory confirmed this point. That is why I no longer quick charge to 100%. I now charge to 90 - 95% and go on my way. This saves me some money since I pay by the minute and charging is really S.....L.....O.....W from 95 to 100% and even slower to the point where the Energy Info screen is reset to zero..

If you are trying to estimate the capacity of the HV battery in your Spark EV, I am finding I get good results by slow charging to 100% until the energy info screen resets to zero and then driving 40 miles or more [could be more that 1 day to get over 40 miles] before making the capacity calculation. I then use the numbers on the Energy Info screen to calculate the HV battery capacity. My 2016 Spark EV has been ranging between 17.1 and 17.5 kWh for the last ~400 miles.

I don't see why it would. The charge rate drops to around the same rate as L2-AC at the very end of the charge cycle (~3kw). It's not like it charges at 50kw until full.

True. The 40 kWh Drive-The-Arc chargers have a screen that show the charge percent, volts and amps. The charge rate starts tapering off at 80% and at 90% the charging current has dropped about 50% from what it was at 80% and continues to drop until 100%.

 

[CCIE]

You can also see the kWh charge rate by turning on the car while DCFC charging is active. Charge rate will show on the power/regen meter.

 

[SparkE]

I believe there were comments posted on this forum that suggested quick charging to 100% could cause the battery to degrade.

I don't see why it would. The charge rate drops to around the same rate as L2-AC at the very end of the charge cycle (~3kw). It's not like it charges at 50kw until full.

"I don't see why it would."

A: Heat. Heat is BAD for Li-Ion batteries. Quick Charging generates heat. At 50 kW, you are charging your battery at around 2.5C (2.5x the capacity in Wh). Ever charge your NiMH AA batteries at a very high charge rate, to almost full? How hot were they? VERY. And that change rate was probably LESS than 1C (most people charge their 2100 mAh AAs at 1000 mA, or less - except for short duration, "I need to get 20% into the AAs fast before I run out the door").

With my SparkEV, (unless I need the range) I generally only charge to around 75% (if using a 40-50 kW charger) or 85-88% if using a 20-ish kW charger. Heck, I rarely charge over 85% using level-2, unless I do it soon before burning it off (except for my monthly "charge to 100% to make sure the cells are balanced"). I almost never charge to 100% and then let the car sit in the garage overnight - I tend to charge to 80-85%, then (if I need the charge) plug in the next morning an hour or so before leaving to get the last 15%. I rarely need a full charge, and it just isn't that cold here around SF (this past cold snap, down into the 35s at night and mid-50s during the day, range dropped to about 80 miles from the usual 105-115; in "normal" winter weather the range drops down to around 90 on a full charge).

 

[MrDRMorgan]

I believe there were comments posted on this forum that suggested quick charging to 100% could cause the battery to degrade.

I don't see why it would. The charge rate drops to around the same rate as L2-AC at the very end of the charge cycle (~3kw). It's not like it charges at 50kw until full.

"I don't see why it would."

A: Heat. Heat is BAD for Li-Ion batteries. Quick Charging generates heat. At 50 kW, you are charging your battery at around 2.5C (2.5x the capacity in Wh). Ever charge your NiMH AA batteries at a very high charge rate, to almost full? How hot were they? VERY. And that change rate was probably LESS than 1C (most people charge their 2100 mAh AAs at 1000 mA, or less - except for short duration, "I need to get 20% into the AAs fast before I run out the door").

With my SparkEV, (unless I need the range) I generally only charge to around 75% (if using a 40-50 kW charger) or 85-88% if using a 20-ish kW charger. Heck, I rarely charge over 85% using level-2, unless I do it soon before burning it off (except for my monthly "charge to 100% to make sure the cells are balanced"). I almost never charge to 100% and then let the car sit in the garage overnight - I tend to charge to 80-85%, then (if I need the charge) plug in the next morning an hour or so before leaving to get the last 15%. I rarely need a full charge, and it just isn't that cold here around SF (this past cold snap, down into the 35s at night and mid-50s during the day, range dropped to about 80 miles from the usual 105-115; in "normal" winter weather the range drops down to around 90 on a full charge).

Now that I started something, let me see if I can clear this up:

Reference: Idaho National Laboratory http://avt.inl.gov
Effects of Electric Vehicle Charging on Battery Life and Vehicle Performance INL/CON-14-33490
Matthew Shirk and Jeffrey Wishart
To be presented at the SAE 2015 World congress and Exhibition, Detroit, Michigan, April 21-23, 2015

From their conclusion statement: "A greater loss in battery capacity was observed for the fast charged vehicles, though the difference compared to the level two charged vehicles was small in comparison to the overall capacity loss." ...."Hotter ambient temperatures appear to have accelerated capacity loss for all vehicles in the study, thought the exact relationship remains to be seen." Testing was done using four 2012 Nissan Leaf EVs.

Extremes in temperature can cause degradation of the HV battery's capacity. The Spark EV has a liquid cooling system for the HV battery. Can this cooling system adequately protect the HV battery from extremes in temperature due to environment and / or charging?

 

[CCIE]

The leaf they used for testing doesn’t have a liquid TMS. Our Sparks do, so it’s a whole different ballgame.

 

[NORTON]

The leaf they used for testing doesn’t have a liquid TMS. Our Sparks do, so it’s a whole different ballgame.

The Leaf doesn't have any TMS cooling capabilities.
Black Leaf, parked on black asphalt at a DCFC in Tucson, after a highway run depleting most of the SOC.
So the pack is already warm/hot and now you want to DCFC it????
I imagine the only thing a Leaf can do is to limit the charge current as the pack gets even hotter and hotter.

 

[SparkE]

Re: "cold temp driving" (the original subject of this thread): stumbled across this 12V electric blanket for cold weather driving. This might be ONE answer to not losing so much winter range in a BEV (don't use the heater as much) :

https://www.amazon.com/Electric-Blanket-Tailgating-Emergency-Stalwart-BLUE/dp/B001QJQ22O/

I am sure there are other brands.

 

[GuyClark]

I guess I've been in too much of a hurry to let the car continue after the DCFC unit says it's done to see what happens ;-). For now, since I'm unlikely to do sequential DCFC sessions on a long trip, I'll just live with the un-updated energy display and not worry too much about it.

Long trips are why I have a wife (well, that and a few other reasons! ;-) ) and I kept my old Honda Del Sol for emergencies.

Later!!

Guy

I believe there were comments posted on this forum that suggested quick charging to 100% could cause the battery to degrade. I would have to look through my notes but I also believe tests conducted by the Idaho National Laboratory confirmed this point. That is why I no longer quick charge to 100%. I now charge to 90 - 95% and go on my way. This saves me some money since I pay by the minute and charging is really S.....L.....O.....W from 95 to 100% and even slower to the point where the Energy Info screen is reset to zero..

If you are trying to estimate the capacity of the HV battery in your Spark EV, I am finding I get good results by slow charging to 100% until the energy info screen resets to zero and then driving 40 miles or more [could be more that 1 day to get over 40 miles] before making the capacity calculation. I then use the numbers on the Energy Info screen to calculate the HV battery capacity. My 2016 Spark EV has been ranging between 17.1 and 17.5 kWh for the last ~400 miles.

HI, DR!

It seems to me that it's been established that the Chevy engineers took that into consideration already, so that we not only can't drain the battery below a certain percentage (~20%?) but we can't charge it ABOVE a certain percentage (~85%?). Thus, I feel relatively secure charging all the way to 100%. What I insecurity I do have, however, is range anxiety. I have established that I need to have about 30 miles on the Guess-o-meter in Los Gatos, or 40-something miles in Santa Cruz to be sure of getting home near the summit of HWY17. To that end, when I go to Santa Cruz from work in San Jose, I now always charge at the summit as much as possible (which is generally in the 90 - 100% range) in the time I have available. If I've had to drive to Stanford University or beyond, I'll HAVE to charge at Charge Point HQ, and usually do that to as near 100% as possible.

This is the second winter I've had my SparkEV, and I seem to be getting better milage this year than last, but that could be partially due to better driving weather this year, and/or my year's worth of driving experience. I'm averaging 4.9mi/KWH (with ~4kmi averaging) this year vs. 4.7mi/KWH over ~8Kmi last year. No noticeable battery degradation yet! (Knock on Wood!)

Later!

Guy

 

[SparkE]

There is NOT 40% 'reserved' in the battery pack - it is around 5-8% *total* - at top and bottom combined (based on the figures I've seen which calculate the max using the # of cells and their individual specs). Myself, I only charge over 90% (at any rate of charge) when I think I need the range, and I rarely fast-charge (50 kW) past 80% - generally I stop around 70%. (Well, except for my once-every-4-8 weeks ritual of 'time to overnight slow-charge to full to balance the individual cells'.)

By charging to 100% at the summit of highway 17, you are throwing away the energy generated when going downhill. Yes, you need about 40 on the G.O.M. to be sure of getting to the top, but end up with a lot of it back by the time you get to the bottom (or at least I do, when one-pedal driving the car in 'L'). Driving from Los Gatos to Aptos, I 'used' about 40 miles on the GOM to get to the summit, but got about 30 of them back by the time I got to the highway 1 South split. A LG-Aptos round-trip used up about 65 miles total (start-to-finish) by the time all was said and done. (Yes, I charged to 100% for that trip, but didn't charge en-route.)

When you drive to Stanford University (or beyond), consider stopping at NASA-Ames instead (CA-85 & US-101 junction, Moffit road). They have *EIGHT* 50 kW DCFCs there - and I've never seen more than 3 in use at the same time, I am usually the only one there. You don't *HAVE* to charge at Charge Point HQ, especially if you filled up at the summit - heck, you wouldn't even need to fill to 50% at the summit as it's only about 30 miles to Stanford from there and it is DOWNHILL (although I understand wanting to "be safe" and charging to 70%).

 

[MrDRMorgan]

There is NOT 40% 'reserved' in the battery pack - it is around 5-8% *total* - at top and bottom combined (based on the figures I've seen which calculate the max using the # of cells and their individual specs). Myself, I only charge over 90% (at any rate of charge) when I think I need the range, and I rarely fast-charge (50 kW) past 80% - generally I stop around 70%. (Well, except for my once-every-4-8 weeks ritual of 'time to overnight slow-charge to full to balance the individual cells'.)

By charging to 100% at the summit of highway 17, you are throwing away the energy generated when going downhill. Yes, you need about 40 on the G.O.M. to be sure of getting to the top, but end up with a lot of it back by the time you get to the bottom (or at least I do, when one-pedal driving the car in 'L'). Driving from Los Gatos to Aptos, I 'used' about 40 miles on the GOM to get to the summit, but got about 30 of them back by the time I got to the highway 1 South split. A LG-Aptos round-trip used up about 65 miles total (start-to-finish) by the time all was said and done. (Yes, I charged to 100% for that trip, but didn't charge en-route.)

When you drive to Stanford University (or beyond), consider stopping at NASA-Ames instead (CA-85 & US-101 junction, Moffit road). They have *EIGHT* 50 kW DCFCs there - and I've never seen more than 3 in use at the same time, I am usually the only one there. You don't *HAVE* to charge at Charge Point HQ, especially if you filled up at the summit - heck, you wouldn't even need to fill to 50% at the summit as it's only about 30 miles to Stanford from there and it is DOWNHILL (although I understand wanting to "be safe" and charging to 70%).

Thanks for posting the "how I got there" information. One of my "bucket list" test trips is to drive from Manteca to Santa Cruz over hwy 17, down to Watsonville, over to Gilroy and back home to Manteca. I see, from these postings, that is will be doable. I also am planning to make a trip to Reno over I-80 and back and I want to stop at Donner Lake along the way. My wife and I have already driven to South Lake Tahoe and back and now there are even more DCFC chargers in South Lake Tahoe as well as along hwy 50.

 

[SparkE]

One of my "bucket list" test trips is to drive from Manteca to Santa Cruz over hwy 17, down to Watsonville, over to Gilroy and back home to Manteca. I see, from these postings, that is will be doable. I also am planning to make a trip to Reno over I-80 and back and I want to stop at Donner Lake along the way. My wife and I have already driven to South Lake Tahoe and back and now there are even more DCFC chargers in South Lake Tahoe as well as along hwy 50.

As I mentioned, you need about 40 miles on the G.O.M. to be sure of getting to the summit, but you get a lot of it back on the way to the bottom. There are two CCS/Combo DCFCs at ChargePoint headquarters in Los Gatos/Campbell (a 24 kW and a 50 kW) so you could "add a shot" quickly if needed (they are located about 2-3 miles before heading up into the mountains). Heck, there may be a third DCFC by the time you do the drive, as they have been fiddling with a brand new "Express 250" DCFC (62 kW). I haven't been there for 2 weeks so I'm not really sure if it is working yet (and it might be reserved for testing for the foreseeable future).

Also as mentioned, there are EVgo DCFCs at the summit. You might want to stop there anyways - there's a restaurant and "something funky" up there (used to be a roadhouse, but I haven't stopped there in the last 30 years - oops, I just dated myself). But if you had enough juice to make it to the top and didn't stop at CP in Los Gatos, you could do a quick fill (personally, I wouldn't go past 70%, since you ARE going to get quite a few miles back on the way down in 'L' at 50 mph).

Since you already mentioned that you have an EVgo subscription, leaving Manteca full ...

Well, you know about the EVgo DCFCs in Livermore (quite a few!), there are two DCFCs at the Walmart in San Jose (near US-101 & I-280) and another two near CA-87 & CA-85 (also 2 DCFCs at a Walmart). There's ChargePoint in Los Gatos/Campbell (off CA-17), the two DCFCs at the summit of CA-17. There are two locations (total of 3 CCS plugs) in Watsonville, and the 4 plugs in Gilroy. I imagine that from Gilroy you are going to take US-101 back up to (East) San Jose and then I-680 back to Livermore, as the DCFC opportunities along 152 (to Los Banos) are pretty ... non-existent.

Since you already have an EVgo subscription for other reasons, you wouldn't really count the monthly fee into the cost of this trip. It's just 10c/minute. With all the EVgo DCFCs down along that route (every 20 miles or so) you can just fill up until the charge rate drops below 40 kW (around 80%/70 miles of range), then back on the road!

It sounds like a fun trip. Have you already visited "the mystery spot", and "Roaring Camp Railroad" (an actual, restored 1890s steam locomotive) in Felton? There's the Santa Cruz boardwalk, the beaches from Santa Cruz down through Aptos, moss landing, elkhorn slough (tidal marsh with seals, otters, cranes, herons, and sometimes whales and orcas). Heck, you could REALLY make a day (or weekend) of it and head down to Monterey/Pebble Beach/Carmel! The DCFC infrastructure is solid all along the entire route, with multiple locations/plugs/choices close to one another (longest stretch is Watsonville-Monterey at 30 miles).

 

[MrDRMorgan]

One of my "bucket list" test trips is to drive from Manteca to Santa Cruz over hwy 17, down to Watsonville, over to Gilroy and back home to Manteca. I see, from these postings, that is will be doable. I also am planning to make a trip to Reno over I-80 and back and I want to stop at Donner Lake along the way. My wife and I have already driven to South Lake Tahoe and back and now there are even more DCFC chargers in South Lake Tahoe as well as along hwy 50.

As I mentioned, you need about 40 miles on the G.O.M. to be sure of getting to the summit, but you get a lot of it back on the way to the bottom. There are two CCS/Combo DCFCs at ChargePoint headquarters in Los Gatos/Campbell (a 24 kW and a 50 kW) so you could "add a shot" quickly if needed (they are located about 2-3 miles before heading up into the mountains). Heck, there may be a third DCFC by the time you do the drive, as they have been fiddling with a brand new "Express 250" DCFC (62 kW). I haven't been there for 2 weeks so I'm not really sure if it is working yet (and it might be reserved for testing for the foreseeable future).

Also as mentioned, there are EVgo DCFCs at the summit. You might want to stop there anyways - there's a restaurant and "something funky" up there (used to be a roadhouse, but I haven't stopped there in the last 30 years - oops, I just dated myself). But if you had enough juice to make it to the top and didn't stop at CP in Los Gatos, you could do a quick fill (personally, I wouldn't go past 70%, since you ARE going to get quite a few miles back on the way down in 'L' at 50 mph).

Since you already mentioned that you have an EVgo subscription, leaving Manteca full ...

Well, you know about the EVgo DCFCs in Livermore (quite a few!), there are two DCFCs at the Walmart in San Jose (near US-101 & I-280) and another two near CA-87 & CA-85 (also 2 DCFCs at a Walmart). There's ChargePoint in Los Gatos/Campbell (off CA-17), the two DCFCs at the summit of CA-17. There are two locations (total of 3 CCS plugs) in Watsonville, and the 4 plugs in Gilroy. I imagine that from Gilroy you are going to take US-101 back up to (East) San Jose and then I-680 back to Livermore, as the DCFC opportunities along 152 (to Los Banos) are pretty ... non-existent.

Since you already have an EVgo subscription for other reasons, you wouldn't really count the monthly fee into the cost of this trip. It's just 10c/minute. With all the EVgo DCFCs down along that route (every 20 miles or so) you can just fill up until the charge rate drops below 40 kW (around 80%/70 miles of range), then back on the road!

It sounds like a fun trip. Have you already visited "the mystery spot", and "Roaring Camp Railroad" (an actual, restored 1890s steam locomotive) in Felton? There's the Santa Cruz boardwalk, the beaches from Santa Cruz down through Aptos, moss landing, elkhorn slough (tidal marsh with seals, otters, cranes, herons, and sometimes whales and orcas). Heck, you could REALLY make a day (or weekend) of it and head down to Monterey/Pebble Beach/Carmel! The DCFC infrastructure is solid all along the entire route, with multiple locations/plugs/choices close to one another (longest stretch is Watsonville-Monterey at 30 miles).

Thanks for the info. I have not tried going over Hwy 17 yet but I am aware of all of the charging stations along the route over and South along Hwy 101. PlugShare is, and has been, my best friend! I could even venture as far as Monterey and then cut back to Salinas via the road to the Laguna Seca Raceway.

But, to get back on topic, I will not attempt this trip until the weather warms up a bit so I do not have to use the heater. My historical data show my lowest GOM range occurs in the winter months with the GOM range dropping about 20 - 25 miles from that recorded in late spring and summer.

 

[MechDork]

I about fainted here when it was -8 degrees fahrenheit and despite letting it warm up while plugged in it still read "42" miles max range, especially when last fall when I got it I saw 81 as the highest.

Not a big deal.. my round trip commute is only 25 miles but I was a bit concerned about it's charging effectiveness as I'm still charging it overnight with a 110v circuit while it's parked outside.

Once it's more consistently warmer out I need to clean out the garage, do a bit of brake work so I can sell my old Festiva to make room for the Spark (I named it "Skate 2.0"), and run a 220v circuit for it.

 

[MrDRMorgan]

I about fainted here when it was -8 degrees fahrenheit and despite letting it warm up while plugged in it still read "42" miles max range, especially when last fall when I got it I saw 81 as the highest.

Not a big deal.. my round trip commute is only 25 miles but I was a bit concerned about it's charging effectiveness as I'm still charging it overnight with a 110v circuit while it's parked outside.

Once it's more consistently warmer out I need to clean out the garage, do a bit of brake work so I can sell my old Festiva to make room for the Spark (I named it "Skate 2.0"), and run a 220v circuit for it.

Recently, I left my 2014 Spark EV parked outside overnight in 33 deg. F weather. The next day I saw 3% battery conditioning on the energy info screen. 3% represents about .5 kWh which isn't much. However, I do not know how effective the L1 EVSE [120 volt] is in trying to keep the battery warm in -8 deg. F temperatures - especially outside and overnight.

 

[SparkE]

It *might* be true that there is more aggressive "battery conditioning" (keeping it warm) when the Spark EV is plugged in and either 'charging' or 'full'. By 'more aggressive' I mean that the battery might be kept warmer than when it is not plugged in.

That is the case for the Bolt - but that doesn't mean it necessarily is true for the Spark. And apparently this isn't active (on the Bolt) if you have set options for "off-peak charging" and the car isn't charging because of rates (which makes some sense, as you've basically told the car "electricity is more expensive now - don't pull any from the wall").

So it *might* be a good thing to plug in the vehicle overnight in cold garages, or AT LEAST to plug the EV in when you get up in the morning, to start the battery warming.

 

[SparkE]

Recently, I left my 2014 Spark EV parked outside overnight in 33 deg. F weather. The next day I saw 3% battery conditioning on the energy info screen. 3% represents about .5 kWh which isn't much. However, I do not know how effective the L1 EVSE [120 volt] is in trying to keep the battery warm in -8 deg. F temperatures - especially outside and overnight.

First, the car does all the work, not the EVSE (which is just providing electricity from the wall instead of the battery).

Second, to be clear to all, "battery conditioning" on the energy info screen shows how much energy was pulled from the battery for conditioning - if the energy is pulled from the wall, it wouldn't show up on that screen.

Lastly, since the 120V EVSE provides about 1 kW @ 8A (default "low" setting) - let's say 800W after losses - the standard EVSE provides more energy in an hour than the conditioning in this case used all night. So, even if the car is "more aggressive" about keeping the battery warm, and uses 4x more energy, the 120V EVSE would handle it. It would, on the other hand, charge more slowly - so you'd probably want to charge at 12A if you needed a "big fill".