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JSH · 07-25-2023, 04:15 PM

Some updates on life with a 2017 Bolt.

Tires:
I switched back to summer tires last week since the winter tires were to the wear bars. My efficiency dropped from 4.8 miles/kWh to a steady 4.0. Some of that is error from the winter tires being undersized but most of it is due to wider, stickier, and MUCH better tires. That puts me back to EPA range and efficiency.

Low 12V battery = no shifting
I ran into a new problem - my car would not charge when I pulled up to the DC charger AND it would not shift from park to drive to allow me to leave the charger. A bit of time with Google says a low 12V battery will cause that. I walked over to the shop for a multi-meter and confirmed the 12V battery was low at 12.15 V. So I charged it a bit and got home OK. The 12V battery is AGM and costs $200.

EDIT: Google tells me 12V power is required to move the shift solenoid and to close the battery contactors to allow charging.

GM's HVAC design engineer need to be fired:
The Bolt's HVAC is even stupider than I thought. I had the OBD scanner hooked up to record some DC charge curves so I decided to monitor what the AC does on my way home from work. With the A/C set to more than 70F the car RUNS THE HEATER to get that magical auto temp instead of just dialing back on the AC compressor speed to reduce cooling or cycle the A/C on and off as required. No doubt that works fine with an ICE vehicle where the heat is a waste product but running the electric heater in an EV at the same time as the A/C is just plain stupid

I'll post some charge curves shortly. Likely my last DC charging experiments as the DC chargers near work now have a paywall instead of being free. The pricing is a very fair $0.15 per kWh but free is still better. Back to the 3 kW AC chargers for me.

07-25-2023, 04:15 PM	#81 (permalink)
JSH AKA - Jason Join Date: May 2009 Location: PDX Posts: 3,601 Adventure Seeker - '04 Chevy Astro - Campervan 90 day: 17.3 mpg (US) Thanks: 325 Thanked 2,147 Times in 1,454 Posts	Some updates on life with a 2017 Bolt. Tires: I switched back to summer tires last week since the winter tires were to the wear bars. My efficiency dropped from 4.8 miles/kWh to a steady 4.0. Some of that is error from the winter tires being undersized but most of it is due to wider, stickier, and MUCH better tires. That puts me back to EPA range and efficiency. Low 12V battery = no shifting I ran into a new problem - my car would not charge when I pulled up to the DC charger AND it would not shift from park to drive to allow me to leave the charger. A bit of time with Google says a low 12V battery will cause that. I walked over to the shop for a multi-meter and confirmed the 12V battery was low at 12.15 V. So I charged it a bit and got home OK. The 12V battery is AGM and costs $200. EDIT: Google tells me 12V power is required to move the shift solenoid and to close the battery contactors to allow charging. GM's HVAC design engineer need to be fired: The Bolt's HVAC is even stupider than I thought. I had the OBD scanner hooked up to record some DC charge curves so I decided to monitor what the AC does on my way home from work. With the A/C set to more than 70F the car RUNS THE HEATER to get that magical auto temp instead of just dialing back on the AC compressor speed to reduce cooling or cycle the A/C on and off as required. No doubt that works fine with an ICE vehicle where the heat is a waste product but running the electric heater in an EV at the same time as the A/C is just plain stupid I'll post some charge curves shortly. Likely my last DC charging experiments as the DC chargers near work now have a paywall instead of being free. The pricing is a very fair $0.15 per kWh but free is still better. Back to the 3 kW AC chargers for me.