Just for future reference, if you ever don't have spacers, you can stack pennies together and put them at the negative end of the charger/battery to create your own spacer.
Caution, you can probably only charge one battery at a time this way. The pennies may be large enough that trying to charge two batteries side by side would cause the pennies on one battery to contact the pennies on the other battery, and that would NOT be good.