miles added with DCQC

[dndrich]

BoltPals:

When considering the possibility of longer range travel with our new Bolts, I want to understand if my math is right. If I have a Bolt with say 1/2 the battery drained, and I use a Chargepoint DCQC with 24 kW max, if all goes well, I would add 24 kWh in one hour? So, at about 4 miles per kWh, I would then increase range by 96 miles? Similarly, with a 50 kW EVgo charger, 1/2 hour should supply 25 kWh, or a similar amount of mileage? Is this correct?

 

[Zoomit]

Generally yes, you got it. The reality is that "50kW" 125A chargers don't actually put 50kW into your car so it's a little less. If you're at low SoC you should get about 80-90 miles in 30 minutes. Here're some graphs that show what you might expect. These are my predictions based on current, limited owner experience.

 

[Pigwich]

Your graphs are fantastic - Are you getting the data by sitting there in front of a charger with pen and paper?

 

[GetOffYourGas]

So it looks like your Bolt must be less than 20% charged to get the advertised "90 miles in 30 minutes". That makes sense, given the taper profile.

From what I can gather (no direct experience yet), with most EVs you want to keep the SoC between 20 and 80% on a road trip. Generally wait until you are at about 20% to DCQC, and then only charge up to 80%. This, of course, is entirely contingent on finding DCQC at exactly the right places. Hopefully the Bolt will sell well, and encourage a proper build out of infrastructure.

 

[roundpeg]

Very informative. Most interesting is that the "sweet spot" for a half hour of DCFC is 40-60% of charge remaining. Anywhere in that range gets you back to right around 200 miles.

 

[roundpeg]

So it looks like your Bolt must be less than 20% charged to get the advertised "90 miles in 30 minutes". That makes sense, given the taper profile.

That's true, but I thought it was interesting that charging for a half hour anywhere from between 40% and 60% results in roughly 200 miles of range.

 

[Zoomit]

Your graphs are fantastic - Are you getting the data by sitting there in front of a charger with pen and paper?

Let me be clear, these graphs are not of real car charging data. They are the output of a battery charging model I created. I've based that model, and calibrated it, by using real world charging experiences from others.

So these graphs are my prediction of how I expect the car to charge under optimal conditions. I will continue to refine my model and predictions based on what owners experience. The big uncertainty is what will change when a greater than 50kW charger is used.

 

[user 124]

So why doesn't somebody post their actual data? It is easy to record and plot by looking at the charger and recording values. I have done this for my RAV4EV but do not have a Bolt (yet).

 

[Zoomit]

One source: http://boltev.blogspot.com/2017/01/dc-fast-charge-data.html

 

[SeanNelson]

So why doesn't somebody post their actual data? It is easy to record and plot by looking at the charger and recording values. I have done this for my RAV4EV but do not have a Bolt (yet).

Yes, that would be nice but don't forget that factors such as ambient temperature may cause results to vary.

 

[mitchev]

I feel like I might have missed something, but is this assuming the charger can output a specific kW rating? I think GM said the optimal was an 80 kW charger?

 

[SparkE]

What do you mean by "this" in your previous post? ("is this assuming")

 

[user 124]

So why doesn't somebody post their actual data? It is easy to record and plot by looking at the charger and recording values. I have done this for my RAV4EV but do not have a Bolt (yet).

Yes, that would be nice but don't forget that factors such as ambient temperature may cause results to vary.

What effect concerns you? The traction battery will heat up quickly when charging, negating any impact of cold ambient temperature. Likewise, the battery thermal management system will keep it from getting too warm.

Do you have any facts or data showing the effect you postulate, or are you just making this up?

Sorry to have to be so direct, but I think that this forum needs a higher signal to noise ratio.

 

[Zoomit]

"Up to 90 miles of range in about 30 minutes of charge*

*GM estimated. Actual charge time may vary due to outside temperatures"

http://www.chevyevlife.com/bolt-ev-charging-guide/?evar25=ch_boltev_mob_charging

 

[SeanNelson]

So why doesn't somebody post their actual data? It is easy to record and plot by looking at the charger and recording values. I have done this for my RAV4EV but do not have a Bolt (yet).

Yes, that would be nice but don't forget that factors such as ambient temperature may cause results to vary.

Do you have any facts or data showing the effect you postulate, or are you just making this up?

A poster in another forum has been finding that the charge rate ramps up pretty slowly in cold weather.

 

[user 124]

A poster in another forum has been finding that the charge rate ramps up pretty slowly in cold weather.

Thanks for the link.

Those data are fairly useless because they are incomplete: battery voltage values are not listed. Therefore it is not possible to determine if the battery charges at lower current in cold weather or how big that effect is if it exists (Power = Voltage x Current).

It is too bad that people are not interested in sharing useful information on how the car charges.