Quick hack: The $1 C-to-D adapter | Evil Mad Scientist ...
2007-6-23 · For most D-size battery holders, putting in 3 or 4 quarters seems to be enough to make the C cell fit well. Above, you can see that we’ve used a total of seven quarters– three on one cell, four on the other. So, it’s usually a $0.75 or $1.00 adapter. So… A lot of people have look at this and remark that it’s really a $1.75 adapter.
