I think this might be in the wrong section.....
But to answer your question, the current draw (amps) limitations will most likely be in the battery holder and not the batteries themselves. If you are using the 4-AA holder that comes with most radios, those contacts do not like much more than 1-2A continuous before they begin to heat up and melt things.
If you have the pack assembled with something thicker (say braid or battery bars), then you should be save with a 3A bulb discharger. Just make sure you disconnect the pack AS SOON AS the bulbs go dim to avoid damaging the first cell that discharges completely.
M03R, M04L, TT-01R Type E, Midnight Pumpkin,
Lunch Box, CC-01 Wrangler, SC10.2FT,
SC10B, Traxxas Slash