Chevy Bolt EV Forum banner
  • Hey Guest, welcome to ChevyBolt.org. We encourage you to register to engage in conversations about your Bolt.
1 - 12 of 12 Posts

Registered
Joined
2,129 Posts
See also this video of charging from 12% to 97% on the same kind of charger.

Some notes:
  • After 30 minutes, it reaches 53% (41% gained), or 97.5 miles of EPA range gained (charging rate, 195 mph).
  • After 45 minutes, it reaches 69% (57% gained), or 136 miles of EPA range gained (charging rate, 181 mph).
  • After 60 minutes, it reaches 80% (68% gained), or 162 miles of EPA range gained (charging rate, 162 mph).
  • After 75 minutes, it reaches 89% (77% gained), or 183 miles of EPA range gained (charging rate, 146 mph).
  • After 90 minutes, it reaches 97% (85% gained), or 202 miles of EPA range gained (charging rate, 135 mph).
 

Registered
Joined
5,054 Posts
Discussion Starter · #4 ·
See also this video of charging from 12% to 97% on the same kind of charger.

Some notes:
  • After 30 minutes, it reaches 53% (41% gained), or 97.5 miles of EPA range gained (charging rate, 195 mph).
  • After 45 minutes, it reaches 69% (57% gained), or 136 miles of EPA range gained (charging rate, 181 mph).
  • After 60 minutes, it reaches 80% (68% gained), or 162 miles of EPA range gained (charging rate, 162 mph).
  • After 75 minutes, it reaches 89% (77% gained), or 183 miles of EPA range gained (charging rate, 146 mph).
  • After 90 minutes, it reaches 97% (85% gained), or 202 miles of EPA range gained (charging rate, 135 mph).
Yes, that was Jeff's initial plug in. It took me three tries at this station before it was working at > 125 A. But hey, it was free and I was in the neighborhood. :D

I did notice that the numbers on the station (I couldn't get the video to come out) were slightly different than what was displayed on TorquePro and the DIC.
 

Registered
Joined
2,129 Posts
What does this high current do to battery longevity? And will the Bolt limit its current intake to a non-harmful level?
The Bolt is very conservative. When driving the car, regen can dump power into the battery at 70 kW, but the max fast charging rate is only 54 kW, and only until the battery is 55% full, at which point it reduces further.

GM's strategy frustrates some people because they (think they) would be happy to trade shorter battery life for faster charging.

Other people worry about their batteries even without fast charging, cautioning others not to operate the electric windows on a hot day, or run the headlamps at night lest it use additional electricity and hasten the demise of the battery. These folks believe the best thing is to discharge the battery to about 40%, and then never drive the car, keeping it instead at a climate-controlled vault at 60 degrees, plugging in once a month to top up (back to 40%, savagely pulling out the plug mid-charge to prevent their Bolt from over-indulging in harmful charge).

But there is no evidence at this time that any particular strategy for charging has any noticeable effect on battery life. Perhaps in a few years, those who have spent time babying their batteries will be crowing over those of us who just enjoyed driving our Bolts without worrying too much about such things 鈥 or perhaps they'll be telling us to wait a few more years and then their zeal will pay off. We'll see.
 

Registered
Joined
1,989 Posts
I was finally able to log a session on a >125 A charger, the ChargePoint Express 250 at ChargePoint's headquarters in Campbell, CA. The 150 A charge current maintained until 54% (the step down will commonly occur at 51% battery).

https://youtu.be/r6Mk-pQPVRA
* The CE 250 (supposedly, according to spec) will provide up to 156A - just a tad more than 150A (if the car draws it).

* I have read reports that imply that there *may* be both a temp and a SoC (%) trigger for the Bolt's "step down". 150A (or 125A) fast charges, when started at higher SoC (like 30%) will ramp down slightly later than fast charges started at much lower SoC (say, 10% or lower). Some suppositions I have read postulate that might be due to higher temps at a given SoC in the latter case. Although nobody knows ... maybe it's "55% -or- some-sliding-scale-time-based-algorithm-once-50% reached". Or something else.

Edit: I did find interesting that the bat temp started in the low 80s (?82?), and stepped down fairly soon after 86.0 F was reached (reached around 51%, stepped down around 54%, still at 86.0F). The temp remained constant at 86.0F up to around 71% (at which point charging stepped down to ~24 kW) - finally bat temp dropped to around 84F at around 75%.
 

Registered
Joined
5,054 Posts
Discussion Starter · #8 ·
What does this high current do to battery longevity? And will the Bolt limit its current intake to a non-harmful level?
In theory, it could result in additional battery degradation over time, but the difference between 125 A and 150 A wouldn't be significant. The Bolt EV's peak charge rate is right around 1 C, which is conservative by most EV standards. However, the battery cell specs call for no more than 1 C recharging, which is probably a result of the energy density being higher relative to the power density. But, that is also likely why GM was able to get the cell price down to $145/kWh (supposedly $130/kWh at high enough volumes).

Would you pay $5,000 more for a 60 kWh Bolt EV that charges at a peak 1.5 C rate (i.e., 90 kW)? It might be worth it, but probably not until Electrify America and Recargo install a lot more >100 kW charging locations.

* The CE 250 (supposedly, according to spec) will provide up to 156A - just a tad more than 150A (if the car draws it).
Yes, but given the fluctuations with the readings, it might not be apparent. Also, because this was a first charge, I didn't turn on the climate control during the first 54%. I will next time.

The vent was blowing cool air during charging when the rate (at 150 A) was <50 kW; however, it was acting a bit differently than it does when the charging rate is reduced for battery conditioning during a 125 A session. It's possible that the rate was lowered because of the battery temperature, not the power draw from battery conditioning. In either way, it was a dip that recovered in a matter of seconds (why it is different than the 125 A chargers).

All in all, this CPE 250 seemed to communicate a lot better with the Bolt EV in terms of fluctuating power.

* I have read reports that imply that there *may* be both a temp and a SoC (%) trigger for the Bolt's "step down". 150A (or 125A) fast charges, when started at higher SoC (like 30%) will ramp down slightly later than fast charges started at much lower SoC (say, 10% or lower). Some suppositions I have read postulate that might be due to higher temps at a given SoC in the latter case. Although nobody knows ... maybe it's "55% -or- some-sliding-scale-time-based-algorithm-once-50% reached". Or something else.
I might have made that assertion about battery temperatures; however, I wonder whether there could be another culprit. The Bolt EV's charge rate seems a bit frenetic at times (you see this most after the initial step down to 105 A). Sometimes, it dips below 105 A, and sometimes it spikes up to 110+ A (and I don't think it's due to battery conditioning). It's almost as though it's testing the waters with different charge currents. If the EVgo stations (and other older chargers) get one signal to reduce the charge current, they might never return to the original 125 A. This ChargePoint station appears to offer less, and when the Bolt EV asks for more again, it simply ramps back up. This could also be why I consistently hit 46 kW on ChargePoint chargers whereas it happens much less frequently on EVgo and others.

Again, just a theory.

Edit: I did find interesting that the bat temp started in the low 80s (?82?), and stepped down fairly soon after 86.0 F was reached (reached around 51%, stepped down around 54%, still at 86.0F). The temp remained constant at 86.0F up to around 71% (at which point charging stepped down to ~24 kW) - finally bat temp dropped to around 84F at around 75%.
Yes. I haven't noticed a significant effect on charging rates due to battery temperatures in the 80s. The Bolt EV seems fine with it until the battery temperatures hit the 90s, at which point active thermal management engages with gusto. In this session, the outside temperature was only in the 60s (it makes me wonder about which sensor TorquePro PID is drawing data from), but the air being vented into the cabin was much cooler.
 

Registered
12/16 build, 2017, white LT
Joined
14,900 Posts
I, personally, don't care if they ever go beyond 50 kW chargers, as long as they are at every place they sell diesel. Then I can hop in the car, and drive until it is down to a bar or two, and pull off at the next intersection for an 80% fill. If it takes 20 minutes or 45 minutes is pretty immaterial. If I am driving long distance in my car, it is because I am not in a hurry.
 

Registered
Joined
2,129 Posts
For fun, I combined details about this charger and miles gained with my model for Bolt efficiency at different speeds to work out best driving speed and charging options (assuming suitably placed chargers!) for different trip lengths.

We'll assume that you start from full and stop to recharge at about 12% remaining (to allow some buffer for the unexpected), meaning you only have 88% of the battery available to use (52.8 kWh). I'll also assume that charging takes an extra ten minutes over and above the time spent charging (to get to the place, get plugged in, etc.). Finally, I'll occasionally include Level-2 charging, assuming 10% charge gained per hour.

250 Miles

At 70 mph in a fossil-fuel car, you could cover 250 miles in 3.6 hours. In a Bolt, with 150 amp charging available, you could:

  • Drive at 57 mph, avoid stopping entirely, taking 4.4 hours total 鈥 47 minutes longer than the 70 mph ICE.
  • Drive at 70 mph, stop once for a 16-minute charge, taking 4 hours total 鈥 25 minutes longer than the 70 mph ICE
  • Drive at 80 mph, stop once for a 30-minute charge, taking 3.8 hours total 鈥 14 minutes longer than the 70 mph ICE

300 Miles

At 70 mph in a fossil-fuel car, you could cover 300 miles in 4.3 hours. In a Bolt, with 150 amp charging available, you could:

  • Drive at 46 mph, avoid stopping entirely, taking 6.6 hours total 鈥 136 minutes longer than the 70 mph ICE.
  • Drive at 69 mph, stop once for a 30-minute charge, taking 5 hours total 鈥 44 minutes longer than the 70 mph ICE
  • Drive at 76 mph, stop once for a 45-minute charge, taking 4.9 hours total 鈥 35 minutes longer than the 70 mph ICE
  • Drive at 85 mph, stop twice for a 30-minute charge, taking 4.9 hours total 鈥 34 minutes longer than the 70 mph ICE

350 Miles

At 70 mph in a fossil-fuel car, you could cover 350 miles in 5 hours. In a Bolt, with 150 amp charging available, you could:

  • Drive at 32 mph, avoid stopping entirely, taking 11 hours total 鈥 361 minutes longer than the 70 mph ICE.
  • Drive at 46 mph, stop once for a 90-minute level-2 charge, taking 9.3 hours total 鈥 256 minutes longer than the 70 mph ICE
  • Drive at 60 mph, stop once for a 30-minute charge, taking 6.5 hours total 鈥 90 minutes longer than the 70 mph ICE
  • Drive at 66 mph, stop once for a 45-minute charge, taking 6.2 hours total 鈥 69 minutes longer than the 70 mph ICE
  • Drive at 71 mph, stop once for a 60-minute charge, taking 6.1 hours total 鈥 66 minutes longer than the 70 mph ICE
  • Drive at 76 mph, stop twice for a 30-minute charge, taking 5.9 hours total 鈥 56 minutes longer than the 70 mph ICE

400 Miles

At 70 mph in a fossil-fuel car, you could cover 400 miles in 5.7 hours. In a Bolt, with 150 amp charging available, you could:

  • You can't avoid stopping to charge (according to my model).
  • Drive at 52 mph, stop once for a 240-minute level-2 charge, taking 12 hours total 鈥 373 minutes longer than the 70 mph ICE
  • Drive at 52 mph, stop once for a 30-minute charge, taking 8.4 hours total 鈥 159 minutes longer than the 70 mph ICE
  • Drive at 59 mph, stop once for a 45-minute charge, taking 7.7 hours total 鈥 119 minutes longer than the 70 mph ICE
  • Drive at 63 mph, stop once for a 60-minute charge, taking 7.5 hours total 鈥 106 minutes longer than the 70 mph ICE
  • Drive at 68 mph, stop twice for a 30-minute charge, taking 7.2 hours total 鈥 89 minutes longer than the 70 mph ICE
  • Drive at 74 mph, stop twice for a 30- & 45-minute charge, taking 7 hours total 鈥 79 minutes longer than the 70 mph ICE
  • Drive at 78 mph, stop twice for a 45-minute charge, taking 6.9 hours total 鈥 74 minutes longer than the 70 mph ICE

450 Miles

At 70 mph in a fossil-fuel car, you could cover 450 miles in 6.4 hours. In a Bolt, with 150 amp charging available, you could:

  • You can't avoid stopping to charge (according to my model).
  • Drive at 49 mph, stop once for a 300-minute level-2 charge, taking 14.4 hours total 鈥 478 minutes longer than the 70 mph ICE
  • Drive at 44 mph, stop once for a 30-minute charge, taking 10.9 hours total 鈥 266 minutes longer than the 70 mph ICE
  • Drive at 52 mph, stop once for a 45-minute charge, taking 9.5 hours total 鈥 189 minutes longer than the 70 mph ICE
  • Drive at 56 mph, stop once for a 60-minute charge, taking 9.1 hours total 鈥 163 minutes longer than the 70 mph ICE
  • Drive at 61 mph, stop twice for a 30-minute charge, taking 8.7 hours total 鈥 134 minutes longer than the 70 mph ICE
  • Drive at 67 mph, stop twice for a 30- & 45-minute charge, taking 8.3 hours total 鈥 114 minutes longer than the 70 mph ICE
  • Drive at 71 mph, stop twice for a 45-minute charge, taking 8.1 hours total 鈥 102 minutes longer than the 70 mph ICE
  • Drive at 78 mph, stop three times for a 30-, 30- & 45-minute charge, taking 8.0 hours total 鈥 94 minutes longer than the 70 mph ICE


500 Miles

At 70 mph in a fossil-fuel car, you could cover 500 miles in 7.1 hours. In a Bolt, with 150 amp charging available, you could:

  • You can't avoid stopping to charge (according to my model).
  • Drive at 46 mph, stop once for a 360-minute level-2 charge, taking 16.9 hours total 鈥 588 minutes longer than the 70 mph ICE
  • Drive at 35 mph, stop once for a 30-minute charge, taking 14.9 hours total 鈥 465 minutes longer than the 70 mph ICE
  • Drive at 45 mph, stop once for a 45-minute charge, taking 12 hours total 鈥 293 minutes longer than the 70 mph ICE
  • Drive at 50 mph, stop once for a 60-minute charge, taking 11.2 hours total 鈥 243 minutes longer than the 70 mph ICE
  • Drive at 55 mph, stop twice for a 30-minute charge, taking 10.4 hours total 鈥 195 minutes longer than the 70 mph ICE
  • Drive at 61 mph, stop twice for a 30- & 45-minute charge, taking 9.8 hours total 鈥 162 minutes longer than the 70 mph ICE
  • Drive at 65 mph, stop twice for a 45-minute charge, taking 9.5 hours total 鈥 140 minutes longer than the 70 mph ICE
  • Drive at 72 mph, stop three times for a 30-, 30- & 45-minute charge, taking 9.2 hours total 鈥 122 minutes longer than the 70 mph ICE
  • Drive at 76 mph, stop three times for a 30-, 45- & 45-minute charge, taking 9.1 hours total 鈥 116 minutes longer than the 70 mph ICE

700 Miles

At 70 mph in a fossil-fuel car, you could cover 700 miles in 10 hours. In a Bolt, with 150 amp charging available, you could:

  • You can't avoid stopping to charge (according to my model).
  • Drive at 32 mph, stop once for a 525-minute level-2 charge (overnight! sleep!), taking 31.8 hours total 鈥 1259 minutes longer than the 70 mph ICE
  • Drive at 38 mph, stop twice for a 30- & 45-minute charge, taking 20 hours total 鈥 598 minutes longer than the 70 mph ICE
  • Drive at 45 mph, stop twice for a 45-minute charge, taking 17.5 hours total 鈥 451 minutes longer than the 70 mph ICE
  • Drive at 52 mph, stop three times for a 30-, 30- & 45-minute charge, taking 15.6 hours total 鈥 338 minutes longer than the 70 mph ICE
  • Drive at 57 mph, stop three times for a 30-, 45- & 45-minute charge, taking 14.8 hours total 鈥 294 minutes longer than the 70 mph ICE
  • Drive at 60 mph, stop three times for a 45-minute charge, taking 14.4 hours total 鈥 262 minutes longer than the 70 mph ICE
  • Drive at 62 mph, stop four times for a 30-, 30-, 30- & 45-minute charge, taking 14.2 hours total 鈥 250 minutes longer than the 70 mph ICE
  • Drive at 66 mph, stop four times for a 30-, 30-, 45- & 45-minute charge, taking 13.8 hours total 鈥 230 minutes longer than the 70 mph ICE
  • Drive at 69 mph, stop four times for a 30-, 45-, 45- & 45-minute charge, taking 13.6 hours total 鈥 216 minutes longer than the 70 mph ICE
  • Drive at 72 mph, stop four times for a 45-, 45-, 45- & 45-minute charge, taking 13.4 hours total 鈥 205 minutes longer than the 70 mph ICE
  • Drive at 76 mph, stop five times for a 30-, 30-, 45-, 45- & 45-minute charge, taking 13.3 hours total 鈥 196 minutes longer than the 70 mph ICE
  • Drive at 79 mph, stop five times for a 30-, 45-, 45-, 45- & 45-minute charge, taking 13.2 hours total 鈥 192 minutes longer than the 70 mph ICE

Some lessons from this (entirely theoretical) exercise.

  • Drive as fast as you like. You will actually get there quicker, although there are diminishing returns so it probably isn't worth getting a ticket.
  • But slowing down does save significant energy.
  • Don't charge longer than 45 minutes unless there is some compelling reason鈥攖wo 30-minute stops beat a 60-minute stop, even factoring in modest time to stop.
  • It absolutely is slower driving the Bolt, but not so much slower that long trips are impossible.
 

Registered
Joined
1,989 Posts
I will point out that you just made my point - thank you.

As I said, the Bolt is a fine car for traveling up to (say) 350 miles (one refueling stop). You'll probably want to stop at least once for a significant amount of time anyways to eat. Leaving full, with one stop is about a 6:1 drive-charge time ratio. And you'd probably be stopping anyhow to eat, so it's not really adding an hour. The limitation is just having a reduced selection of restaurants to choose from (unless you are picnic'ing - then, it doesn't matter).

The Bolt is NOT the car for me to drive 500 or 600 miles. I just am not going to add 2 or 3 hours to an already long trip that 2 or 3 charging stops require (in a perfect world where the DCFC is exactly where I need it to be and it is available for me to use immediately).

That doesn't bother some people - more power to you (yes, pun intended). ;)
 
1 - 12 of 12 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top