The whole idea of a 4 cell is to keep the regulator in buck mode all the time. A lot of people sell these but they use older technology that is not very efficient. Here is about what you can expect running them under voltage. Rayovac LED upgrade 6V
The whole idea of a 4 cell is to keep the regulator in buck mode all the time. A lot of people sell these but they use older technology that is not very efficient. Here is about what you can expect running them under voltage. Rayovac LED upgrade 6V