123001 charge telltale light lit while engine is running
123002 battery flat after extended period of non-operation
123003 charge telltale light lights up sporadically

 

What's the context of the descriptions? I'm not sure what the "123001/2/3" numbers are, but the descriptions are pretty self-explanatory. the "telltale light" is just another term for the dash indicator that lights up when you're having electrical/battery problems.

 

Depending on the age of your Battery, it may not be recharging completely and may need to be replaced.

I would start there ................................