Which dollar-store batteries stand up to big-name brands, and which should you avoid?

A CBC Marketplace test of double-A disposable batteries found that while major brand names deliver on their marketing promise to be long-lasting, batteries bought at two leading dollar stores did surprisingly well and provide good value for cost-conscious shoppers.

But the test also found that not all dollar store batteries are created equally and certain types of batteries did not perform well, with experts warning that they should be avoided despite their low cost.

Marketplace, teaming with researchers from Ontario Tech University in Oshawa, Ont., tested 240 double-A disposable batteries from six brands. The brands tested were Energizer, Duracell, Canadian Tire's Noma, Walmart's Great Value, E-Circuit from Dollar Tree, as well as Panasonic batteries from both Dollarama and Dollar Tree.

In the tests, which simulated different energy drain levels, Energizer and Duracell lasted the longest. But it was E-Circuit alkaline, a brand imported by and sold at Dollar Tree, that held its own against the more well-known brands, lasting nearly as long and costing only $1.25 for a pack of four. 

The researchers used the different drain scenarios — low, medium and high — to simulate real-life uses. They said the low-level drain is similar to the continuous use of a computer mouse or TV remote control. The medium drain is similar to continuous use of a remote-controlled toy or gaming controller, while high drain is like a high-powered flashlight. 

Ontario Tech engineering assistant professor Xianke Lin, who supervised the test, noted that the results, while surprising, should not be used as a proxy for all battery performance because the test can't perfectly simulate how batteries are used in real life.

Still, the E-Circuit's value comes into focus when comparing price per battery and capacity. Based on what Marketplace paid, the average price per E-Circuit alkaline battery was just 31 cents.

"Usually people think it's cheap and shouldn't have the best value, but [E-Circuit alkaline] turns out to be the best capacity per dollar you spend," said Lin, of Ontario Tech's faculty of engineering and applied science. 

E-Circuit's ultra alkaline battery performed even longer overall, though at a higher price point.

Panasonic's Alkaline Plus batteries purchased from Dollarama and Dollar Tree also performed well in all three simulated drain tests.

While dollar store alkaline batteries offered surprises, another type sold at those stores, carbon zinc (or zinc carbon) did not do well in the tests.

Those carbon zinc double-A batteries are recommended for low-drain devices and are a common feature in dollar stores. In a test simulating the continuous use of low-drain devices, the E-Circuit and Panasonic carbon zinc batteries lasted six hours and 55 minutes and seven hours and 45 minutes, respectively, while the other brands' alkalines all lasted in excess of 20 hours. 

Despite the E-Circuit and Panasonic carbon zinc being branded as "Super Heavy Duty," they were anything but, according to experts.

"It's incredibly confusing," according to Columbia University engineering associate professor Dan Steingart, who studies the capacity and energy efficiency of disposable batteries.