is your charge circuit working correctly, rec reg/stator 
these go bad can cause your battery to go bad.
also bad earths will do it.
When I installed the new battery I did check that the charging voltage was reaching a healthy figure, which right now I don't remember the value.
When I took off the tank, a while back, I did notice that a few connectors had some corrosion deposits ( the green stuff) . I treated these with electrical contact cleaner. I gave the same treatment to the other connectors in this area even those without corrosion. I guess I need to go through all of them.
I still would like to know what error 0171 stands for.
I also have not managed to erase the fault on the display. The methods known to me are:
1. Toggle the main switch rapidly at least five times.
2. Disconnect the battery terminal.
It seems, despite what people state, the ECU does manage to retain information after switching off and even disconnecting. Alternatively error 0171 is being triggered each time I turn on the the ignition switch.