Leaf Owners Complain The Summer Heat Is Taking A Toll On Battery Pack Performance

Ouch. There's now some independent analysis that says the Nissan Leaf wilts in the heat.

Led by Leaf owner Tony Williams, a group of Nissan EV owners tested a dozen Leafs in Phoenix last weekend. The group put the Leafs on a pre-planned route at pre-determined speeds to measure their fully charged ranges and to find out if extensive heat has led to premature degradation of the car's battery capacity, according to posts on the My Nissan Leaf forums and Green Car Reports.

The group found that half the Leafs tested had, at "full" charge, battery-capacity indicators showing just 10 out of the original 12 bars and averaged slightly less than the 73-mile single-charge range certified by the EPA. One Leaf had just eight bars showing – indicating about a third of the battery capacity was gone – and went just 59 miles before petering out. And one Leaf, purchased new only a month ago, was already missing a battery-capacity bar.

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cidflekken - 9/20/2012 6:56:56 PM

+1 Boost

Phoenix heat will eat away a battery's life like nobody's business. Had to change the battery in my car (non-hybrid, non-electric) 3 times in 3 years, as do most of my friends here. Not good news for the Leaf. I wonder how the Volt is doing.

vdiv - 9/21/2012 11:14:17 AM

+1 Boost

The Volt has an elaborate thermal management system that uses glycol/water based coolant (basically antifreeze) to maintain the battery cells at a certain temperature range. It uses the air conditioning and electric/engine heat when available to do so. The Volt also has much larger buffer on the lower and upper ends of the 16 kWh battery capacity so only about 10 kWh are used. Those buffers are automatically adjusted during the life of the car so battery degradation does not affect the usable capacity as much. There hasn't been noticeable degradation observed yet. GM also warrants the usable battery capacity not to drop below 70% (7 kWH) for 8 years/100,000 miles.

Nissan didn't warrant a minimum capacity. The Leaf's battery is air-cooled.

There may be reasons other than battery degradation for the diminishing range of the Leaf. Though less likely the power inverter and motor may not be losing efficiency, the friction brakes may have gotten stuck (seized calipers are a common occurrence in disc brakes). Nissan is still investigating.