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I-Pace’s Changing Coasting and Braking Regen - Mike Mas
To help new I-Pace owners - More fully understand why the I-Pace brakes feel different at times, I thought a short article focusing on coasting and braking regen would be beneficial. Unlike a gas powered car, where the brake pedal always retains the same feel and braking response, the I-Pace’s braking abilities “at times” will change according to the lithium batteries charge.
Some I-Pace owners have trouble - Adapting to the I-Pace’s brakes. I have witnessed owners taking their car to a shop to change brake pads thinking there was brake problem when in fact, the brakes were working as designed. Even worse, I recall one owner selling his I-Pace, since he could not get used to the brakes.
The truth of the matter is - The I-Pace brakes will change its feel and response to pedal travel. This “feel” or changing brake response is the result of the fact the first 20-30% of brake pedal travel applies only “regen” braking, using the cars weight or kinetic energy as a power source to turn the electric motor as a generator, to both slow the car and develop regenerated power to recharge the battery. The remaining brake pedal travel uses the cars service (disk) brake. Therefore, the I-Pace has two separate braking systems; regen and disk brakes, working separate of each other but on the same pedal. However, at times when regen is not allowed, this initial brake pedal travel does not apply regen braking making the brake pedal feel somwhat non responsive.
Changing Brake Response - The reason the I-Pace brake pedal “at times” is changing response, is due to the simple fact the “battery control module” (BCM) does not allow braking nor even coasting regen to take place when the battery is at full charge or slightly below full charge. Therefore, at full charge, you’re only using the service disk brakes to stop the car. This means roughly for 25-50 miles after a full charge the brake pedal is constantly changing its feel and response. Each mile the charge declines, it increases regen slightly. the On my I-Pace, I do not achieve full regen braking until my range drops to around 185 miles. Therefore, from 220 to 185 miles, my braking regen will proportionally change and increase as the charge / range declines. This means the brake pedal is constantly changing it’s feel and response during this time. However, once the charge/range gets below 180 miles, the braking and coasting regen remain the same
Coasting Regen - Coasting regen which is accomplished by letting off the accelerator to achieve regen braking, operates on the same principles as the brake pedal regen. For this reason, the BCM also limits coasting regen as it does braking regen to prevent over-charging the lithium battery so at full charge the car easily coasts. For this reason, even if you select “high coasting regen” in the menu, if the battery is close to full charge, there is no coasting regen braking allowed.
Over-Charging - This cut-off and/or limiting of regen by the BCM occurs to protect the battery from over-charging. A typical example of why this is needed, lets say your home was located on top of a large hill or mountain. If you fully charged the battery overnight, then in the morning you jumped in the seat and headed down the mountain for a 20 -30 minute ride to the bottom using both coasting and braking regen to slow the car, this would severely over-charge the battery past its safety buffers which could damage the battery and or its health.
Battery Buffers - In brief, lithium batteries can easily last 15-20 years or more, provided they are charged and discharged properly. If you prevent fully charging and fully discharging a lithium pack, it improves its longevity and health. For this reason, most lithium batteries to include the I-Pace, use a low and high charge battery buffer. While Jaguar does not like to disclose much information of their batteries or system, most EV packs use a 5% upper and a 5% lower buffer to prevent the pack from ever being fully charged or discharged. With this in mind, getting back to the I-Pace’s brakes, this is why the BCM does not allowed regen at or near full charge since it will exceed this important safety buffer which assures the owner his pack will last the life of the car. Enjoy!
Stay Safe - Mike
To help new I-Pace owners - More fully understand why the I-Pace brakes feel different at times, I thought a short article focusing on coasting and braking regen would be beneficial. Unlike a gas powered car, where the brake pedal always retains the same feel and braking response, the I-Pace’s braking abilities “at times” will change according to the lithium batteries charge.
Some I-Pace owners have trouble - Adapting to the I-Pace’s brakes. I have witnessed owners taking their car to a shop to change brake pads thinking there was brake problem when in fact, the brakes were working as designed. Even worse, I recall one owner selling his I-Pace, since he could not get used to the brakes.
The truth of the matter is - The I-Pace brakes will change its feel and response to pedal travel. This “feel” or changing brake response is the result of the fact the first 20-30% of brake pedal travel applies only “regen” braking, using the cars weight or kinetic energy as a power source to turn the electric motor as a generator, to both slow the car and develop regenerated power to recharge the battery. The remaining brake pedal travel uses the cars service (disk) brake. Therefore, the I-Pace has two separate braking systems; regen and disk brakes, working separate of each other but on the same pedal. However, at times when regen is not allowed, this initial brake pedal travel does not apply regen braking making the brake pedal feel somwhat non responsive.
Changing Brake Response - The reason the I-Pace brake pedal “at times” is changing response, is due to the simple fact the “battery control module” (BCM) does not allow braking nor even coasting regen to take place when the battery is at full charge or slightly below full charge. Therefore, at full charge, you’re only using the service disk brakes to stop the car. This means roughly for 25-50 miles after a full charge the brake pedal is constantly changing its feel and response. Each mile the charge declines, it increases regen slightly. the On my I-Pace, I do not achieve full regen braking until my range drops to around 185 miles. Therefore, from 220 to 185 miles, my braking regen will proportionally change and increase as the charge / range declines. This means the brake pedal is constantly changing it’s feel and response during this time. However, once the charge/range gets below 180 miles, the braking and coasting regen remain the same
Coasting Regen - Coasting regen which is accomplished by letting off the accelerator to achieve regen braking, operates on the same principles as the brake pedal regen. For this reason, the BCM also limits coasting regen as it does braking regen to prevent over-charging the lithium battery so at full charge the car easily coasts. For this reason, even if you select “high coasting regen” in the menu, if the battery is close to full charge, there is no coasting regen braking allowed.
Over-Charging - This cut-off and/or limiting of regen by the BCM occurs to protect the battery from over-charging. A typical example of why this is needed, lets say your home was located on top of a large hill or mountain. If you fully charged the battery overnight, then in the morning you jumped in the seat and headed down the mountain for a 20 -30 minute ride to the bottom using both coasting and braking regen to slow the car, this would severely over-charge the battery past its safety buffers which could damage the battery and or its health.
Battery Buffers - In brief, lithium batteries can easily last 15-20 years or more, provided they are charged and discharged properly. If you prevent fully charging and fully discharging a lithium pack, it improves its longevity and health. For this reason, most lithium batteries to include the I-Pace, use a low and high charge battery buffer. While Jaguar does not like to disclose much information of their batteries or system, most EV packs use a 5% upper and a 5% lower buffer to prevent the pack from ever being fully charged or discharged. With this in mind, getting back to the I-Pace’s brakes, this is why the BCM does not allowed regen at or near full charge since it will exceed this important safety buffer which assures the owner his pack will last the life of the car. Enjoy!
Stay Safe - Mike
