In one example, an apparatus comprises a battery that has a first characteristic capability for providing continuous power and a second characteristic capability for providing intermittent power to the apparatus. The apparatus further comprises an illumination unit. The apparatus further comprises a controller that is configured to determine the total current consumption of the apparatus, determine the amount of battery current available to the illumination unit, and adjust current consumption of the illumination unit based on the determined available amount of battery current to ensure that the current consumption of the illumination unit stays below a battery safety circuit current limit.