I use up batteries (both recyclable and not) at an exceedingly slow rate. Stockpiling batteries for proper disposal is not realistic as I will do so for years, if not decades. All the more so, since I live in a very tiny place.
If I do my errands in a milk-run, stopping off at a box store to dispose of (say) a pair of AA batteries, I wondered whether the environmental cost of restarting the car was worse than simply putting the batteries in the garbage. I am cognizant that starting a car uses a lot of fuel, probably equating to 30 seconds of idling. It makes me wonder about the whole wisdom of it all.
I realize that it is a complex question, since it entails speculative quantification of complex factors. But are there any big factors that render the choice clear?
The natural follow-on question would be at what volume of spent batteries would it be worthwhile to stop the car. This is a tougher question, as it is more nuanced than simply looking for big factors that clearly indicate which of two options is better.