Promoting electric cars is often a grassroots effort, with owners acting as some of the most enthusiastic (and effective) spokespeople.

But what about one of the biggest way automakers themselves typically promote their wares? How do electric-car makers compare in terms of television advertising?

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Perhaps not surprisingly, the maker of the world's bestselling electric car is also one of the biggest spenders when it comes to advertising.

According to data from research firm iSpot (via Autoblog Green), Nissan has spent $22 million on Leaf advertising so far this year, plus around $400 million for the balance of its vehicle lineup.

2015 Nissan Leaf

It also kicked in additional $9 million for the new "Kick Gas" campaign, which began with a television ad November 3. Nissan says it helped prop up drooping electric-car sales last month.

It also seems to have attracted attention from a wide array of viewers.

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The ad aired on NBC, CBS, and Fox, and researchers found that viewers of college football, Gladiator, and The Rachel Maddow Show were the most engaged by it, based on analysis of online activity.

Kia has also been heavily promoting its Soul EV with a strangely-sexed up version of the hamster-themed ads it's been running for the gasoline Soul.

The Korean carmaker spent about $15 million on TV ads, even though the Soul EV just went on sale in the U.S. in October--and still isn't available in every state.

2014 Chevrolet Volt

Chevrolet, meanwhile, has kept the purse strings tight when it comes to advertising the Volt extended-range electric car.

It apparently spent just $2 million on Volt TV ads over the past couple of years--although 62 online ads have been released.

Right now, though, the Chevy is a lame duck. The redesigned 2016 Volt is primed to make its debut at the 2015 Detroit Auto Show in January, and has already been teased numerous times.

Maybe the new version will make a bigger impression on the small screen.

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