In 2011 a DS8000 client changed from IBM to a different service provider in order to service his DS8000 machines.
As they were out of warranty this was a legal way to go.
Just recently the client has signed again new maintenance-contract with IBM.
Shortly after signing the contract several DS8000 boxes reported defective battery-sets.
These battery sets are needed in case of an AC power-loss to preserve client data.
What happened ?
Whilst the maintenance was done by the service provider, client ordered replacement batteries.
IBM made an offer too but the competitor had the better bid (actually he underpriced IBM by 2000€).
The battery sets delivered were old sets, produced between 2004 - 2006.
They were refurbished without following IBM high quality standards by inserting low capacity
modules and manipulating internal VPD data.
The batteries presented themselves as parts from 2011 :

Over the time the low quality sets could not sustain the DS8K internal health-checks and finally got called out
as defective.
Impacts :
-
Client impact
In a case of an AC powerloss, the data in the NVS (Non Volatile Storage) couldn't have been preserved.
The client impact would have been a loss of data.
-
IBM impact
IBM priced the new maintenance contract based on the current condition of the machines.
Having had knowledge of the real condition of the battery sets, the rate for the contract would definitely been different.
Conclusion :
Replacement parts, sold by other manufactures than the original one, should always be checked for their compliance
with the original manufacturer's specifications.
The low priced offer is not always the better one, especially when dealing with parts which are vital for data preservation.