The important aspect of this project is the current draw and the supply voltage. Conventional (ordinary) AA/AAA/C/D cells do not provide for extended power although you can probably make them work if you purchase enough. Missing in this instance is the ability to recharge.

For rechargeable batteries, your best options may be to look for a source of 18650 cylindrical lithium cells and a charger. The ampere-hour capacity of the cells vary and you can connect them in series to get the voltage level you require. This is the same type of battery commonly used in laptop computer. I enjoy to dismantle (carefully) dead laptop batteries to cycle (charge/discharge) to find individual cells capable for various projects, including LED flashlights.

Another advantage of this type of power source is light weight and compactness.

Amazon sells an 8-bay charger that can handle the 18650 cells as well as other chemistries. Depending on the power requirements for your lights, you may be able to configure a source that will run on a single set for the required period of time.

Amazon is being used in this example as a representative source. Batteries and chargers of this type are common enough to be found in many other resources. For easier wiring, one would also search for "18650 battery holder." Some models of the holder are designed for high current and may be a more suitable choice for your project. This type tend to ensure good contact between cells, avoiding overheating and resultant damage.

No representation is being made for the quality of the referenced products.