It looks like limited charge items can be recharged by selling to a vendor and is NOT an exploit. It is explicitly allowed as a "classic mechanic".
Process:
1. Need 1 fully charged item and one that is depleted
2. Find a vendor with open slots
3. First, sell the fully charged item
4. Then sell the depleted item
5 Buy both back. They should both be fully charged.
Recharging clickies
Recharging clickies
One neuron short of a loon...