TonyWilliams
Well-known member
freddms said:Without your guys advice I would not have made it. Just got home and I'm still cold. 20 degrees out. But, I made it 67 miles. Three miles out no bars.... I did not run any heat, in eco mode, I conserved everything I was aware and glad I did.
Congrats on your new ride, and welcome aboard. You learned by fire how cold affects a non-Temperature Management System battery electric car (as opposed to the Volt, which has a really good TMS).
With showing three miles on the Guess-O-Meter (GOM), you were likely at "Very Low Battery", which means that the GOM would start showing "---", which means that you only had about 3 additional miles to drive at that same economy to hit "Turtle" mode.
So, about 70 miles range total. Unfortunately, you didn't know to reset your dash economy gauge before you launched, but it would have shown about 3. Check out the Range Chart.
Your battery is now doubt somewhat degraded from sitting on a dealer's lot all summer (for a year total), perhaps some of that time at 100% charge. But, without hard data, let's make the following adjustments to your batteries based 21kWh of available (usable) energy at 70F degrees for a new condition battery:
19.95kWh = 5% arbitrary adjustment for degradation losses multiplied by 21kWh for a new 70F battery - so, 21kWh - (5% * 21kWh) = 19.95kWh available with a 70F degree battery.
17.45kWh = 12.5% loss for battery temp at 20F degrees (lose 1% per 4F/2C below 70F/20C = 12.5% @ 20F) - so, 19.95kWh - (12.5% *19.95) = 17.45kWh total usable available with 5% degradation and a 20F degree battery.
Hopefully, this all makes sense. The final issues to determine capacity are that all the cells are balanced, and the best way to do that is just charge to 100% and let the automation do its job. It can take over 4 hours, at which time it will charge up the battery a small amount after discharging the highest cells. Sometimes this can happen more than once. I recommend doing this at least once a month.
Range autonomy is always simply usable energy capacity multiplied by consumption rate:
kWh * miles/kWh = range autonomy in miles
Since we don't know your economy, but we do know your likely range and available usable kWh:
70miles / 17.45kWh = 4 miles per kWh economy
If you had run the heater.... you ABSOLUTELY would not have even come close to completing the trip. Anyway, I hope this gives you the tools to quickly become confident in your range estimating.