[mcguyver]

For NiCads, you should not discharge them to anything less than 1.0 volts/cell. So, if you have a 9.6v battery, it will have 8 cells and this means you should not discharge it to less than 8 volts. Discharging through a bulb, motor or other resistive loads can drain your battery all the way to zero volts if left unattended. This can and will kill it dead, and render it unrecoverable.

If you invest in a quality charger with discharge function, this would be best. Like anything, makeshift crap can work, or it can be disasterous. Decide if the risk is worth it for you, but manage your risk with paying attention to your battery and use a multimetter in parallel with the battery to ensure you don't cycle it too deep.