It's one of the major questions for any electric-car buyer: How long will the battery pack last?

And what would it cost to replace it if I do need a new one sometime down the road?

Now a new video looks at that question, comparing the different thermal-management technologies in the batteries of the new 2018 Nissan Leaf and the Chevrolet Bolt EV electric car.

DON'T MISS: Chevrolet Bolt EV electric car: what's inside the battery? Teardown video shows all

The presenter is John D. Kelly, a professor in the Auto Technology department of Weber State University in Ogden, Utah.

It's one of several electric-car videos he's done, including a recent pair on the removal and disassembly of the Chevrolet Bolt EV lithium-ion battery pack.

His presentations tend to be methodical, direct, and easy to follow, with a lot of detail presented in high-quality video.

Prof. John Kelly on battery life in Nissan leaf, Chevy Bolt EV [video: Weber State University, Utah]

The most recent presentation, running a bit over 7 minutes, is simpler than previous videos. Much of it is Kelly lecturing, in front of a Bolt EV on a lift.

He covers a lot of ground, though, starting with the active thermal management—meaning both heating and cooling—of GM's battery packs in first the Chevy Volt plug-in hybrid and then the Bolt EV electric car.

Then he dives into the history of the passively cooled Nissan Leaf batteries, though he doesn't delve into the specific history around capacity loss in some pre-2015 Leaf packs.

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He notes that the second-generation 2018 Nissan Leaf has a page in the owner's manual that discusses issues that affect the temperature and life of the battery.

That advice includes not storing the car in hot environments, and not recharging the battery right after the car is used—which may be a surprise to owners who come home, plug in the car, and forget about it until the next morning.

It also discourages frequent use of the fast-charging capability.

Prof. John Kelly on battery life in Nissan leaf, Chevy Bolt EV [video: Weber State University, Utah]

He goes through a partial list of the factors that Nissan says can affect Leaf battery life, as covered by the manual.

Then he looks at the considerably fewer warnings that Chevrolet offers in its own manual on factors that affect the Bolt EV's battery life.

Kelly's summary concludes Chevrolet's thermal management of its batteries is "far superior" to that provided by Nissan in the Leaf, both the previous generation and the new 2018 version.

READ THIS: Tesla Model S battery life: what the data show so far

Broadly, it now seems safe to suggest that electric-car batteries with active liquid cooling (and heating) seem to have lower rates of capacity loss—especially under extreme conditions—than do those that use only passive air cooling, such as the Leaf's.

Aggregated data from batteries in the Tesla Model S, for instance, suggests that capacity loss is only on the order of 10 percent even after 100,000 miles.

Hat tips: Brian Henderson, Nikki Gordon-Bloomfield, Dave Tuttle



