Cache to flash power module is referencing the battery which in the event of a power outage will power your controller long enough for it to write the contents of its cache memory to a device in the controller. This way once you recover from your power outage you will not have lost any data that was in memory and had not yet been written.  On the PS6100 this "battery" is a capacitor on the board of the controller so you will potentially need a new controller module if this is bad. Old firmware may cause this message too so pull diagnostics and check with tech support to confirm. 
Dear All, I have facing undermentioned error on storage box. Critical hardware component failure, as shown next. C2F power module has insufficient hold time.   any needful advice to resolve the said issue.  Thanks and Best Regards, jafar
equallogic ps6100