Winter EV Range + Aging Batteries

[TomEV]

One of the local EV club members has operated a small electric vehicle (personal mobility vehicle on steroids...) for a couple of years. Over time, he has kept records on battery performance, daily range and battery temperature at the start of the drive.

He found that his batteries follow a fairly straightforward performance curve at various temperatures -

Temp - Fred's Range
100 - 17
90 - 15.8
80 - 14.5
70 - 13.3
60 - 11.6
50 - 9.8
40 - 8.1
30 - 6.3

My battery pack turned three years old in August. When new, it could get about 24 miles on a charge on a 70f day.

Recently, the range has been more along the lines of 15 miles or so - but the air temperature has been around 45 degrees.

Extrapolating Fred's data - here is the projected Citicar range VS temp estimate...

Temp -Fred - %of 70F -Citicar Projected
100 -17 - 127.82% - 30.68
90 - 15.8 - 118.80% - 28.51
80 - 14.5 - 109.02% - 26.17
70 - 13.3 - 100.00% - 24
60 - 11.6 - 87.22% - 20.93
50 - 9.8 - 73.68% - 17.68
40 - 8.1 - 60.90% - 14.62
30 - 6.3 - 47.37% - 11.37

Perhaps the lead-acid pack isn't doing as bad as I thought! ~15 miles is about what the table predicts at 45f...

[MetroMPG]

That's good info, thanks!

[Angmaar]

Very interesting. Has it been driven below 30*F?

[TomEV]

Not in Alameda... Normal daily temp here in winter is about 50. Summer is about 65.