In November, I purchased a 2019 Bolt EV with DC fast charging capability and have just had my first experience using that feature. With outside temperatures in the 40's, I used a nearby EVgo fast charger for a half hour and according to a follow-up e-mail from EVgo, the energy charged was 11.6 kWh. From the Bolt's instrumentation, it appears that a half hour's DC fast charge added slightly more than a 1/8 increment to my battery charge level and extended the remaining range of my current charge by around 40 miles. For my future expectations, I am wondering whether that experience is pretty typical from the Forum's actual experience. Any input appreciated - thanks!
Fast charging experience
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Many things influence the amount of charge gained, three of which are:
1. How low is the charge when you plug in, and
2. Battery and/or outside air temperature
3. The rated charging capacity of the charging station.
You will experience a much higher rate of increase in the battery's capacity for a 1/2 hour charge if you plug in when the charge is down around the 1/4 mark on the green bar or lower than you will if the charge is already over half "full" when you plug in.
You will experience similar increases in rate of charge with temperatures that are warmer than 40 degrees.
If you were at an older EVgo station with a lower output capacity, the total charge received will be less than if you are at one of their newer installations where the output is, in some cases, considerably higher.
Many thanks, NoMoPetrol, good information. I did not think to check the rating of the EVgo charger I was using. My Bolt had slightly under a 1/4 charge when I plugged into the DC fast charger. The half hour's worth of fast charging got the charge to around halfway between the 1/4 and 1/2 charge marks.
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What NoMoPe said, plus another one comes to my mind: some DCFC's have two plugs, attached to the same stall, which means you may have to share the output with another car. I remember I was charging at an EVgo from <50% SoC @ already feeble 32 kWh when comrade Leaf latched onto its Chademo on the other side, and dropped me down to 24 kWh.
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Ph63: For awhile, gather some data. Before hooking up, note the SoC (State of Charge) of the battery, the outside temperature, and the time. Sit in your car at the beginning of DCFC and note the initial "power" rate being accepted by the EV's battery. IF the station posts it (usually not on a placard, but in the display) note the Volts and the Amps. All DCFC power drops off in a hyperbolic fashion. The voltage usually stays the same while the amperage falls off.
Usually, if my initial SoC is <20%, I gain 80-90 miles in the 1st 30 minutes, 60-70 miles in the second half hour, 30-40 in the 3rd, and (once I have > 80% SoC) only about 10-15 miles in the 4th 30 minute segment. I only charged to full once (it was free, it was warm, and I was learning). It took a full 2 hours. My wife and I had a leisurely supper and walked around the college town for awhile. I was back at the EVSE for the last 30 minutes and, at shutoff, the amperage had dropped from 100 amps to 5 amps. It took a l-o-n-g time to put in those last 5 miles!! In travelling since then, I never charge to >80% SoC as the time spent is NOT worth the miles gained. I try to plan to arrive at the EVSE with <20% SoC.
While traveling, time is the essential feature. Many times I do NOT want to leave home with a "full tank". I calculate the distance, estimate battery consumption, allow for outside temperature, factor in what speed I can comfortably (& safely) drive, and add a "no-range-anxiety" factor. When we did the 230 miles single charge segment east to VA (noted above), I simply drove 60 mph on the Interstate and arrived with 23 miles remaining. When I go to Columbus (165 miles) on the way to Ann Arbor, I drive 65 mph most of the way and leave home with 75% SoC (45 kWh). If I find my estimated miles remaining (Guess-o-Meter = GoM) dropping below my "safety factor", or the mi/kWH staying below 3.5, I simply slow down bit. I have never had to get my knuckles white.
Good luck and keep us posted.
Usually, if my initial SoC is <20%, I gain 80-90 miles in the 1st 30 minutes, 60-70 miles in the second half hour, 30-40 in the 3rd, and (once I have > 80% SoC) only about 10-15 miles in the 4th 30 minute segment. I only charged to full once (it was free, it was warm, and I was learning). It took a full 2 hours. My wife and I had a leisurely supper and walked around the college town for awhile. I was back at the EVSE for the last 30 minutes and, at shutoff, the amperage had dropped from 100 amps to 5 amps. It took a l-o-n-g time to put in those last 5 miles!! In travelling since then, I never charge to >80% SoC as the time spent is NOT worth the miles gained. I try to plan to arrive at the EVSE with <20% SoC.
While traveling, time is the essential feature. Many times I do NOT want to leave home with a "full tank". I calculate the distance, estimate battery consumption, allow for outside temperature, factor in what speed I can comfortably (& safely) drive, and add a "no-range-anxiety" factor. When we did the 230 miles single charge segment east to VA (noted above), I simply drove 60 mph on the Interstate and arrived with 23 miles remaining. When I go to Columbus (165 miles) on the way to Ann Arbor, I drive 65 mph most of the way and leave home with 75% SoC (45 kWh). If I find my estimated miles remaining (Guess-o-Meter = GoM) dropping below my "safety factor", or the mi/kWH staying below 3.5, I simply slow down bit. I have never had to get my knuckles white.
Good luck and keep us posted.
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Unless you absolutely need the range, there's very little need to DC fast charging if your battery is more than 65% to 75% full. At that point, you're really just "topping off." If you're traveling and want to maintain a decent speed, you'll generally want to start your charging sessions when your battery between 10% and 30%. At that point, how much energy and range you get back will depend on the speed of the charger.
The Bolt EV can charge faster than most of the chargers that are currently in service; however, faster chargers are coming online. At those faster chargers, you're typical stops will be 20 to 40 minutes, and you'll gain anywhere from 30% to 60% battery. Your range will depend a lot on your efficiency, but you could see anywhere from 50 to 150 miles of range added in a 20 to 40 minute session on those faster chargers.
Also, DCFC often charge fees based on time, so you might want to restrict your charging to under 55% (and definitely under 70%) because you will be getting the best bang for your buck that way.
The Bolt EV can charge faster than most of the chargers that are currently in service; however, faster chargers are coming online. At those faster chargers, you're typical stops will be 20 to 40 minutes, and you'll gain anywhere from 30% to 60% battery. Your range will depend a lot on your efficiency, but you could see anywhere from 50 to 150 miles of range added in a 20 to 40 minute session on those faster chargers.
Also, DCFC often charge fees based on time, so you might want to restrict your charging to under 55% (and definitely under 70%) because you will be getting the best bang for your buck that way.
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I agree, to a point. In CA (and near both coasts) DCFC is much more prevalent. If you are traveling from an adjacent state to/through WV (with NO CCS DCFC) it may well be that you drive 50-60 miles and then choose to DCFC because your destination is 225 miles further on. Unless you want to Level-2 charge for 2 hours, you may find yourself "charging early" to make the second leg a "non-stop flight"!
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Yup. I'd classify that as "absolutely need the range." After 95% battery, even when DCFC is available, I'm more likely to just use L2 or drive slower.
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Your experience isn't the typical experience, but it certainly has been experienced by others.
11.6 kWh in 30 minutes means a charging rate of about 23 kW. Gaining a bit over 1/8 of the battery means that the rate at which charge entered the battery averaged out to be about 16 kW. Either way, that's much less than half the charging rate the Bolt is capable of. So, let's talk about why this happens.
Although the car is capable of charging at 150A, but it will limit current based on battery temperature (and state of charge). We actually know a little about how it does that (source).
- -30.0 ℃ / -22 ℉ — 0 amps, car will not charge at all until battery has warmed
- -20.0 ℃ / -4 ℉ — 3 amps, very slow (1 kW, slower than home charging from a 120 volt outlet)
- -10.0 ℃ / 14 ℉ — 12 amps, slow (4.3 kW, slower than typical level-2 home charging)
- -0.0 ℃ / 32 ℉ — 30 amps (10.8 kW, finally faster than home charging)
- 10.0 ℃ / 50 ℉ — 54 amps (19.4 kW)
- 15.0 ℃ / 59 ℉ — 93 amps (33.4 kW)
- 22.5 ℃ / 72.5 ℉ — 134 amps (48.2 kW)
- 25.0 ℃ / 77 ℉ — 150 amps (54 kW, faster than almost all DCFC chargers can supply)
- 40.0 ℃ / 104 ℉ — 150 amps (54 kW, faster than almost all DCFC chargers can supply)
- 45.0 ℃ / 113 ℉ — 75 amps (27 kW)
- 50.0 ℃ / 122 ℉ — 0 amps, car will not charge at all until battery has cooled
Note, however, that (unlike the Leaf and the American edition of the upcoming Hyundai Kona, the Bolt can also heat its battery, but there is a lot of thermal mass to the battery, so it takes a while for the heater to raise the battery temperature). Thus, if you'd stayed longer, you'd have seen charging speed pick up a bit as the heater got the battery warmed up.
If we assume that the interpolation line I drew between the known points mirrors reality, at battery temperature of 45 ℉ you would have only charged at 46 amps (16.6 kW) initially. If your car had been sitting in the cold (e.g., overnight without being plugged in), it's possible that your battery was even colder.
On the other hand, driving the car warms the battery a little, and the battery has a significant thermal mass, so it's very possible for it to be 45 ℉ outside and have the battery be significantly warmer.
From your description, it seemed like you were using a DCFC charge as an experiment to test it out (and were disappointed).
In a more typical cold winter trip scenario, it'd go like this. You'd charge the car overnight while you slept. As part of the charging process after the battery is charged (which generates some heat all by itself), the car will automatically run the battery heater to raise the temperature closer to a good temperature. Before setting out, as you ate breakfast and got ready to leave, you'd use the preconditioning feature to warm the car up with wall power before setting out. One 30 minute session is great, two would ensure the car is as warmed up as can be. Preconditioning will further make sure that the battery is brought up to a good temperature.
During the trip, a mix of the thermal mass of the battery retaining the heat from preconditioning and the heat generated from using the battery will keep it at a good temperature so that when you arrive at your first charging stop you'll be well placed to charge at a good rate. The charging process will further raise the battery temperature so that further driving and charging will always see good speed.
Put simply, EV batteries don't like the cold. There are things you can do to help, but it's also possible to be caught out. It's true for all EVs. There are frustrated folks on Tesla forums, too, for example.
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Great post, @Vertiformed. It should be required reading for anyone getting an EV with DCFC capabilities.
Like @Ph63zink, I was also very disappointed with my first (and only) DCFC. It was about a month after I bought the Bolt. The temperature was hovering around freezing. I had just left my destination on my way home, so the battery was still cold. And my SOC was around 50%. I committed just about every DCFC mistake you could make. On the good side, researching why my charging rate was so bad led me to this forum.
Like @Ph63zink, I was also very disappointed with my first (and only) DCFC. It was about a month after I bought the Bolt. The temperature was hovering around freezing. I had just left my destination on my way home, so the battery was still cold. And my SOC was around 50%. I committed just about every DCFC mistake you could make. On the good side, researching why my charging rate was so bad led me to this forum.
Of course, if you just pulled off the road and connect to the charger in cold weather, the battery should already be warm, so the battery conditioning will just need to maintain the temperature. In very cold weather (-40°) it is probably is not possible for battery conditioning to maintain the battery temperature. Another reason to consider a fuel cell electric vehicle if you are in a cold climate.
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Or just buy a flying unicorn, with similar availability to an FCV, and perhaps a better refueling infrastructure.
I have 51,000 miles on my FCEV (picture attached) so it definitely isn't a unicorn.
Secondly, battery electric vehicles are a passing phase. They will be considered very quaint and interesting in a few years
Here's a good example (btw I own a 2019 Bolt as well as my FCEV):
Tomorrow I want to go and watch the launch of NROL-71 (Delta IV hydrolox) so I am taking my Mirai, because it is 230 miles from my house (one way) and I have to get right back to Hollywood to pick up my wife (who's not into rocket launches) from my son's apartment. One 5 min charge at the hydrogen station in Santa Barbara (https://m.cafcp.org/content/santa-barbara) and I'm good.
The Bolt is a fantastic vehicle for local commuting and I absolutely love it, but I recognize it's constraints and use it where it makes sense (commutes under 200 miles total).
Btw, here's an article that shows where our zero emmissions transportation future will be:
http://www.thedrive.com/tech/26050/exclusive-toyota-hydrogen-boss-explains-how-fuel-cells-can-achieve-corolla-costs
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I’m glad you’re happy with your CA based FCV, but you keep insisting that it’s a great choice in very cold climates without mentioning that FCVs and hydrogen charging stations are virtually nonexistent outside of CA.
So, what cold weather areas in the US or Canada can actually buy and conveniently refuel an FCV?
None. Zero. Nada. Zilch
Yes, there are a couple of stations in Canada. A couple, not a fueling network, as in CA.
FCVs may very well be the transportation of the future. I have no opinion on that one way or another, but please stop recommending them as the cold weather solution for anyone driving today, because it simply doesn’t exist.
If you were to say “once a decent hydrogen fueling network is set up and affordable FCVs are widely available...” as a preface, then your recommendation becomes more realistic. That is not the situation today, outside of CA, and even in CA only very limited numbers of FCVs are available, and they’re very expensive, although there are very heavily subsidized lease options from some manufacturers.
Please don’t let your enthusiasm for FCVs get in the way of painting an accurate picture of the current FCV market and charging network for cold weather climates. They may one day be an excellent choice, but not today.
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The problem is, HFC vehicles are regional use only at this point. Essentially, anything in California from the Mexican border to south of Redding is doable, but after that, no. So basically, your household's trips would look like:
- <200 miles: Bolt EV
- >200 miles within the confines of Southern and Central California: Mirai
- >200 miles but outside the confines of Southern and Central California: Bolt EV or rent a car.
Also, if HFC vehicles do start to take off, there will be a very serious issue with competition to access those fueling stations in the future. Many of California's H stations are offline at this point (especially those in the Bay Area) or can only provide a limited amount of fuel. Even the ones that appear to be full can only provide about 20 full tanks and maybe another 20 half tanks. Can you really plan a trip around that? What if the station is available on your trip out, but is empty or offline when you plan to return? What kind of notice do you get? And how long do those stations take to be brought back online?
My prediction is that, by the time H filling stations can be scaled up to support even a small number of local and regional drivers, battery technology will have improved to the point that HFC vehicles will not serve a real purpose. HFC vehicles are considerably faster than the current generation of EVs (though maybe only marginally faster than a Model 3); however, they will struggle to keep pace with the next generation of EVs such as the upcoming Porsche Taycan and a refresh of the Model S (if Tesla ever adds 2170 cells and either finishes Supercharger V3 or adopts CCS).
Still, given a HFC vehicle's contributions to GHG emissions, it seems that a vehicle like the Volt fits that use case better. And that really brings me to my biggest gripe with HFC vehicles. If HFC vehicles came with a big enough battery to travel 40 to 50 miles on electricity and a J1772 plug, I'd like them a lot better. As it is, I doubt they will ever sell in any reasonable number as light-duty passenger vehicles, and they will likely be phased out for that purpose in less than 10 years.
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The very act of charging itself also produces heat in the battery cells, so battery conditioning may not be needed at all.
Absolutely incorrect. There is a fueling network in the north east and California (where you obviously don't live) is a cold climate as well (many people live in mountain areas with significantly cold weather).
You've done punishing trips in the Bolt (I've seen them as you recorded them). You need to admit that stopping every 150 miles for 30 minutes is not a realistic mode of travel. No one except enthusiasts will ever do that. So the areas were you can go that I can't *currently* go in my Mirai are just exercises to prove you can do it, but no average person will ever do that regardless of how extensive the charging network is. That's the thing, building out a charging network doesn't solve the problem for BEVs but it does completely solve the problem for FCEVs because it is a 1MW charger (with no compromise - if you are absolutely empty you can fill to an absolutely full state of charge in 5 minutes)
That is simply false. Please do not make false statements, I make no false statements about BEVs (remember I have both types of vehicle).
Again this simply indicates that you have no knowledge of how hydrogen stations work. They are refilled when they get low and some of them are on-site electrolysis and never run out. The stations are extremely reliable.
Again, this comes back to a lack of understanding of basic physics and basic economics.
I've seen you mention the trade off between charge rate / capacity / durability that is the fundamental physics of batteries. I am sure you know that the specific energy of hydrogen is 140x that of lithium ion. A hydrogen station charges at 1MW. There will never be the ability to charge batteries at that rate in a way that is economical. It is physically impossible, and that neglects the advantage that began this conversation the fact that fuel cells do not require conditioning in either extreme heat or extreme cold. My Bolt, in order to be ready to go with a full charge whenever I decide to drive must consume GHG producing electrical energy without traveling a single mile. I don't see you accounting for your Bolts total electrical consumption as all the battery conditioning costs to figure into the vehicles driving efficiency. To be intellectually honest and to have integrity you must do that.
So, here again your response is simply false. I ask that we have an honest discussion and that you please refrain from falsities.
In fact, at scale (which neither BEVs nor FCEVs are at yet) FCEVs result in significantly lower GHG emmissions than BEVs.
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