All the way to zero?

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Porsche

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Apr 2, 2021
Messages
129
Has anyone actually run their Spark EV all the way to zero miles, i.e., actually to the point where the car will no longer drive? If so, can you describe the sequence of events in detail? I've come close, experienced the scheduled power reduction, even the (comical) "automatically turning off the radio to save power" feature (funny how there's no way to actually turn off the radio when you want to). But all the way to zero? Does the car stop exactly at zero? Were you able to drive a little farther? how much farther? What was displayed? error message? etc.? Did the car recover gracefully when reconnected for charging? Any details would be appreciated.
 
Has anyone actually run their Spark EV all the way to zero miles, i.e., actually to the point where the car will no longer drive? If so, can you describe the sequence of events in detail? I've come close, experienced the scheduled power reduction, even the (comical) "automatically turning off the radio to save power" feature (funny how there's no way to actually turn off the radio when you want to). But all the way to zero? Does the car stop exactly at zero? Were you able to drive a little farther? how much farther? What was displayed? error message? etc.? Did the car recover gracefully when reconnected for charging? Any details would be appreciated.


Yeah I have more than a few times completely run out or driven at 1kW full throttle. The level 2 EVSE I had planned to stop along my way home was offline so I had no other choice but continue or call a tow. In one instance, the Sparkev died on a 1.2km long hill with an elevation gain of 80 meters and 2 mandatory stops that requires ~35+kW at 50km/h or ~15kW at 26 km/h with about 0.5kWh required to traverse it

The car had several warnings before it cut out and there was lots of time to make decisions. First, there is the quiet orange blinking battery warning on the dash between 10-20%, then the radio shut-off suggestion that might save 100W. BTW you'll save more power turning your daytime running lights off ~130W with halogen, 25-30W with LED. Below 10% you'll get a low battery popup on the dash with full-throttle still available. There are roughly 5 more audible warnings each with gradually more aggressive throttle remapping and power limits.

The second final warning will tell you the car has entered a battery-saving mode that has the most extreme power limit and no heating or cooling, and the final warning states out of battery. The behavior of propulsion in this last stage depends on the energy in the cells and the amount of power you're requesting. The powertrain will closely watch the BMS' reported cell voltages and request power as long as its above ~2.2V under load. I've seen minimums reported on the OBD II scanner as low as 218V and 264V at high SOC. The PID title was *Battery - Pack - Minimum Voltage (22433B). The no-load cutoff is usually 2.5V for the lowest cell. The BMS just really wants to prevent series cells from being reverse-charged and plating themselves to death under discharge. However, it's not going to damage the cells by completely exhausting them, it's rather the number of hours/days you keep the cells at this voltage that determines the extent of the irreversible chemical reactions that take away mobile lithium in the cell.

As long as your cells are well-balanced, and you are discharging at a low rate under 1C (12kW-16kW), you should be able to reach around 0.4% SOC.

Because my Sparkev died on a hill, it meant I could recover some energy. I didn't get far so I might've been able to recover 100Wh or less if i moved it. After getting out and walking around, I discovered that there was a film studio that had an operable level 2 EVSE in their parking lot at the bottom of this hill. When I got back in the car, it showed "EV Ready" despite being at a fractional SOC. I turned the car back on and heard contactors sequentially close. I don't remember if the incandescent MAP light got brighter or if it was off (indicating the 14V APU was running). It's possible the APU chooses a low setpoint at 11.9V, 12.2V or 12.9V. I also don't remember if the car gave me only fans or no fans when I played with the dial. In any case, I had 12V power steering and full brakes. I experienced quite a strong regen (reverse direction motor torque) at low speed because the pack voltage is so much lower, allowing the paltry back-EMF (reverse direction generated voltage) to give us enough of a voltage difference to allow some power to flow and behave more functionally as a brake at low RPMs.

I helped myself to their 208V @ 16.2A, charged up to 10%, and used 3% of it to get up the hill and home.

In another instance, I was able to make it up this hill, and noted power taper away with a fully pressed pedal (something you shouldnt do at low SOC). I was able to draw 30kW, which diminished to 20, then 10, and by the top of the hill I was only able to draw 6kW. This diminished further to 1kW which by then I had a small hill assisting my coast.

Does the car stop exactly at zero?
No, somewhere around 0.3-0.4% depending on cell balance and power use. I haven't tried draining further with lights, radio, HVAC, but I bet you could go lower.
Were you able to drive a little farther? how much farther? What was displayed? error message? etc.?
It's hard to say exactly because I live in an area with a lot of hills, but I would say an extra 1-2km if you really baby it after 0 indicated range on the dash. I managed to go 5.5km before it stopped, with 3km reported at the time I noted it. It REALLY depends because the BMS will signal the end of your drive when the lowest cell reaches the threshold 2.2-2.5V. I saw 0km indicated on the GOM, LOW, battery saver mode, and Out of charge. All of these were drivable and just depended on my discharge behavior. No errors.

I have a screenshot, it wasn't at the lowest point in my drive, but it was 0.9%, pretty close
DzgRXCr.png
 
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Yeah I have more than a few times completely run out or driven at 1kW full throttle. The level 2 EVSE I had planned to stop along my way home was offline so I had no other choice but continue or call a tow. In one instance, the Sparkev died on a 1.2km long hill with an elevation gain of 80 meters and 2 mandatory stops that requires ~35+kW at 50km/h or ~15kW at 26 km/h with about 0.5kWh required to traverse it

The car had several warnings before it cut out and there was lots of time to make decisions. First, there is the quiet orange blinking battery warning on the dash between 10-20%, then the radio shut-off suggestion that might save 100W. BTW you'll save more power turning your daytime running lights off ~130W with halogen, 25-30W with LED. Below 10% you'll get a low battery popup on the dash with full-throttle still available. There are roughly 5 more audible warnings each with gradually more aggressive throttle remapping and power limits.

The second final warning will tell you the car has entered a battery-saving mode that has the most extreme power limit and no heating or cooling, and the final warning states out of battery. The behavior of propulsion in this last stage depends on the energy in the cells and the amount of power you're requesting. The powertrain will closely watch the BMS' reported cell voltages and request power as long as its above ~2.2V under load. I've seen minimums reported on the OBD II scanner as low as 218V and 264V at high SOC. The PID title was *Battery - Pack - Minimum Voltage (22433B). The no-load cutoff is usually 2.5V for the lowest cell. The BMS just really wants to prevent series cells from being reverse-charged and plating themselves to death under discharge. However, it's not going to damage the cells by completely exhausting them, it's rather the number of hours/days you keep the cells at this voltage that determines the extent of the irreversible chemical reactions that take away mobile lithium in the cell.

As long as your cells are well-balanced, and you are discharging at a low rate under 1C (12kW-16kW), you should be able to reach around 0.4% SOC.

Because my Sparkev died on a hill, it meant I could recover some energy. I didn't get far so I might've been able to recover 100Wh or less if i moved it. After getting out and walking around, I discovered that there was a film studio that had an operable level 2 EVSE in their parking lot at the bottom of this hill. When I got back in the car, it showed "EV Ready" despite being at a fractional SOC. I turned the car back on and heard contactors sequentially close. I don't remember if the incandescent MAP light got brighter or if it was off (indicating the 14V APU was running). It's possible the APU chooses a low setpoint at 11.9V, 12.2V or 12.9V. I also don't remember if the car gave me only fans or no fans when I played with the dial. In any case, I had 12V power steering and full brakes. I experienced quite a strong regen (reverse direction motor torque) at low speed because the pack voltage is so much lower, allowing the paltry back-EMF (reverse direction generated voltage) to give us enough of a voltage difference to allow some power to flow and behave more functionally as a brake at low RPMs.

I helped myself to their 208V @ 16.2A, charged up to 10%, and used 3% of it to get up the hill and home.

In another instance, I was able to make it up this hill, and noted power taper away with a fully pressed pedal (something you shouldnt do at low SOC). I was able to draw 30kW, which diminished to 20, then 10, and by the top of the hill I was only able to draw 6kW. This diminished further to 1kW which by then I had a small hill assisting my coast.


No, somewhere around 0.3-0.4% depending on cell balance and power use. I haven't tried draining further with lights, radio, HVAC, but I bet you could go lower.

It's hard to say exactly because I live in an area with a lot of hills, but I would say an extra 1-2km if you really baby it after 0 indicated range on the dash. I managed to go 5.5km before it stopped, with 3km reported at the time I noted it. It REALLY depends because the BMS will signal the end of your drive when the lowest cell reaches the threshold 2.2-2.5V. I saw 0km indicated on the GOM, LOW, battery saver mode, and Out of charge. All of these were drivable and just depended on my discharge behavior. No errors.

I have a screenshot, it wasn't at the lowest point in my drive, but it was 0.9%, pretty close
DzgRXCr.png
That's a lot of very detailed information. Thank you for taking the time to write it out and it will provide some comfort in future close calls!
Question: where did you get that screen shot? Is that from some programming device?
 
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