IDX says specifically in their FAQ "don't do it". Not only is it not advisable it's actually pretty unsafe. There is a lot of energy stored in these things. Better batteries and chargers have overcharge protection and monitoring built in. Are these circuits included or monitored via Dtap, Do cheap knockoff batteries and chargers even have these circuits. I don't know but I don't want to burn the house down to find out.
Most of these D-tap chargers are just 16v DC power supplies. Can you do it, sure. Is it safe, no.