zener diode IDin battery pack over-charge protection circuit

[apinkel]

I recently repacked a Panasonic Nicad drill battery pack (model Ey9106). In the process of doing so I accidentally trashed a zener diode that runs thru the datapack to an over-charge protect circuit in the charger.

So I'm trying to figure out what the specs are of this diode so I can replace it.

Attached to the final negative terminal of the battery pack there are two zener diodes in series (my understanding is that the voltage adds when these are placed in series like this) which are followed by two resistors of 226ohms and 110 ohms and then this connects to the charger.

The thru-hole diodes are orange in color with a small silver disk in the middle surrounded by a glass surface with a gold/yellow band on one end... no letters/codes. My understanding is that, unlike resistors there is no universal color codes for these which has made it difficult to determine what the values should be. I have a volt/ohm meter but I don't have a variable power source to determine what the breakdown voltage is.

The battery pack is a 2Ah, 12V pack with 10 1.2V sub c cells. Any assistance on this would be greatly appreciated.