Bolt Charging times to optomistic

[Fivedoor]

When planning a route the software does a good job of estimating times for a Bolt charging up to around 60%, but from there on up to 100% the charge times are optimistic.  I think the software uses the same taper curve for the Bolt as it does for a Tesla, just scaled down due to the Bolts lower maximum charge rate, but in reality the Bolt has a more severe taper than a Tesla.  Observed data show that at a 150 or more amp charger the Bolt will charge at a rate of 10% every 7 min up to 50%.  From 50% to 60% takes 9 min.  From 60% to 70% takes 12 min.  From 70% to 80% takes 15 min.  From 80% to 90% takes 21 min.  From 90% to 95% takes 16 min... and that last 5% from 95% to 100% takes 30 min.  So, a charge from 10% to 95% will take an hour and 40 min... the software currently estimates 5% to 97% only taking 1 hour 20 min.  This flaw makes route planning for best time hard because you have to manually add charge stations to avoid charging much past 80%.  A 10% to 80% charge is just a hair over an hour at 64 min... anything past that gets exponentially worse as SOC rises.  It takes more time to go from 80% to 100% (67 min) than it does to go from 10% to 80% (64 min).

[Jason-ABRP]

The Bolt's charge curve is taken from real-world Bolt data, but doesn't take into account battery temperature yet.  I suspect that the top end of the curve is more heavily tapered when your battery is warm.  Something for us to work on improving!

[Fivedoor]

On 6/23/2019 at 10:47 AM, Jason (ABRP) said:

The Bolt's charge curve is taken from real-world Bolt data, but doesn't take into account battery temperature yet.  I suspect that the top end of the curve is more heavily tapered when your battery is warm.  Something for us to work on improving!

Where did you get your data?

 

Mine is from data logs of several CCS charging sessions ranging from 150 amp Electrify America, 125 amp Chargepoint and EVgo stations, and 100 amp EVgo stations and posted up on the chevybolt.org forum where they have been compared to other users experiences at CCS charging stations.  Charge times in COLD weather with a cold battery are much worse than the numbers I gave you due to limitations on charge rate at low battery temperature.  The only real difference between "mild" and "hot" charging is the first tapper point from 150 amps down to 110 amps on the high power stations takes place around 50% SOC in hot conditions and seems to hold out until 55% in mild conditions.

 

Interesting fact, even with the winter charge starting at a much slower charge rate and ramping up, both charges (winter and summer) took 135 min (2 hours 15 min) to go from 3% to 100%

 

Keith

Edited July 4, 2019 by Fivedoor

[Jason-ABRP]

On 7/3/2019 at 10:02 PM, Fivedoor said:

Where did you get your data?

 

Mine is from data logs of several CCS charging sessions ranging from 150 amp Electrify America, 125 amp Chargepoint and EVgo stations, and 100 amp EVgo stations and posted up on the chevybolt.org forum where they have been compared to other users experiences at CCS charging stations.  Charge times in COLD weather with a cold battery are much worse than the numbers I gave you due to limitations on charge rate at low battery temperature.  The only real difference between "mild" and "hot" charging is the first tapper point from 150 amps down to 110 amps on the high power stations takes place around 50% SOC in hot conditions and seems to hold out until 55% in mild conditions.

 

Interesting fact, even with the winter charge starting at a much slower charge rate and ramping up, both charges (winter and summer) took 135 min (2 hours 15 min) to go from 3% to 100%

 

Keith

That's some really interesting data! One thing that's been on my to-do list is to go and see if I've got enough OBD data yet for different battery temperatures to create a good temperature-based charging model.