IMHO, I would just leave it. How often did you look at it anyway? You should already know about what your run time is by now. Just recharge when you think you are getting close.

What type of batteries are you using? Ni-Cad, Ni-Mh or Lithium? It does not hurt to charge Ni-Mh or lithium early. The Ni-Cads you should run down close to 1 volt per cell about once every two to three months to prevent the memory effect. That is if you are using a 12 volt system you should run the batteries down to 10 volts. "10 cells in a 12 volt pack", each cell is 1.2 volts, fresh off the charger should be 1.4 - 1.45 volts, each cell, ratings are also true for the Ni-Mh also, but they do not suffer from the same memory effect.

You do not want to pull a 12 volt pack below 10 volts as reverse polarity could happen to the weakest cell. This would ruin the pack.