My battery was totally shot but the battery symbol never came on so it probably isn't indicating a battery problem.
The symbol shows if the current from the alternator INTO the system is lower than the current demand from the system (engine, sensors, lights etc.) including the needs of the battery after a start. In this case the battery provides the difference.
On a healthy system the output from the alternator is sufficient to run the bike and charge the battery.
If the alternator output is too low, then you are using stored energy from the battery to run the bike and that is what the symbol is telling you.