It’s a good thing there are physics professors around to do all the complicated math when we need questions answered, otherwise how would we know if it’s worth it to buy name brand batteries? We would never know, is the answer.

Time.com checked out the work of Professor Allan from Southeastern Louisiana University, who had some burning questions about how much energy was burning how fast in cheap dollar store batteries versus the more expensive name brands. He blogged about his investigation and came up with some interesting observations.

The lure of generic brands has proved appealing to consumers with tight budgets, from cereal to prescription drugs, toilet paper to socks.

But when you’re trying to power a device, the amount of power delivered from the battery for the length of time you need it is important, and Prof. Allan found, through various mathematical equations and science-y type things, that the more expensive brand batteries like Duracell and Energizer keep up the juice longer than the cheapies.

So then it’s a question of what you’re using — a flashlight works just fine with a cheaper generic because it doesn’t need as much energy, and the fall off in power won’t affect its use too much. On the other hand, if you’ve got a Wii remote or a complicated device that needs lots of juice for a long period of time, go for the pricier brands.

And of course, when you can, buy in bulk to save even more money. No need to let that Wii remote go dead!

A Physics Professor Asks: Are No-Name Batteries a Better Value Than Major Brands? [Time]

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