Of course, a nine volt battery is different than a 1.5 volt battery is different from a lithium battery and so on. Here I’m referring to just the class of what I think of as “regular” batteries. These are the ones you would put in a cheap flashlight. 1.5 volts. Cylindrical. 1.5 volts. Etc. And I’m just talking about the non-rechargeable ones.
So, someone tells me there is no difference between brands of battery amongst this class, aside from their packaging. He claims that in some cases, batteries from the very same factory may even end up going to different corporations and recieving different packagings. So the Energizer and the Duracel on display at my grocery store may well have been manufactured in the same batch.
Batteries are more complicated than the voltage. An important thing to consider is the milliAmpere-hour rating which is directly related to how long the battery will last. My AA digital camera batteries, for example, are rated at 2050 mAh. I vaguely remember the ordinary dollar-store AAs will only give 1700 or so.
The obligatory Wikipedia link which will explain it a lot better:
Consumer reports did a test and they found (IIRC):
1 - Name brands do outlast the no-name ones by a very small margin - maybe 5%
2 - The cost factor means get the no-name batteries
2a - but make sure they are fresh (high turnover rate) -and alkaline.
3 - High drain batteries (Durecell Ultra) do last longer in high drain devices, but have shorter life in low drain devices.
4 - One brand of AA’s have lithium batteries, they will last a good deal longer but are many times more expensive - only use if battery life is a priority (backpacking, emergency use).
My camera won’t even work if I use the dollar store batteries. I guess the mA/hour is too low? So there is definitely a difference. Among non-dollar batteries, I’ve found that Rayovacs are the best, and on the cheap end.
within a given chemistry there isn’t much difference. Assume all alkaline (for example) are within 10% of performance and buy the cheapest.
More important than the kind of battery, try to understand the battery use. Operating a motor on a toy car is quite different than running a smokedetector. Try to figure out whether your use is high current or low current, whether you want it to operate for a long period of time, or you will use it up quickly. Different batteries are best for different uses.
BTW, there seems to be almost no justification for the old Carbon Zinc batteries. Alkalines have better performance in almost all uses.
Oh, and batteries don’t really get used up, they drown in their own waste. A battery consists of two materials, say carbon and zinc (to keep it simple), connected by an electrolyte-usually a paste. A battery doesn’t die when the carbon or zinc is used up, it dies when the internal resistance of the electrolyte goes up to the point that the internal voltage can’t push the electrons through. Of course batteries are designed to pretty much use up their electrodes by the time the electrolyte resistance is a problem, but they die when the resistance is too high.