A 1c charge rate should work which would be 1.5A for a 1500mAH battery.
I'm guessing they are NiHh batteries not NiCd? I was under the impression that NiCd were banned ages ago ?
Make sure you are charging in Ni mode. These batteries need what is called a Delta Peak where the voltage will go up, and then slowly start to drop off. That drop off will tell the charger when to stop.