Aircraft and locomotive turbine engines are reliant upon batteries that must carry a great deal of starting voltage to power engines. Typically, aircraft engines require a 24-volt battery rather than the previously required 12-volt battery. This battery is lighter and requires lighter wiring, reducing the weight of the electrical system in the aircraft. Modern turbine engines do need a great deal of extra energy to start the engine and then charge the 24-volt battery to its pre-starting capacity.
To achieve this starting voltage and reduce wear and tear on batteries, a portable power supply is recommended to extend battery life. Typically, under normal stress, these batteries last for about 400 stress cycles of discharge and recharge. That means that the batteries are good for only 400 starts before needing replacement. With a power supply, the voltage can be boosted, reducing the sulfation of the battery.
The portable power supplies, themselves, can be purchased with either lithium-ion batteries or lead-acid batteries. The advantage of lithium-ion is the lighter weight and freedom from sulfation, whereas the lead-acid is less expensive. Choices are available on the market. Contact with the manufacturer can give graphs and schematics indicating the value of each.