Lithium has TWICE the energy of Lead/Acid because Lead cannot be fully discharged and Lithium can. Comparing a 100Ah Antigravity Lithium Deep Cycle Battery to a 100Ah Lead/Acid Deep Cycle Battery, our Lithium version will supply anywhere from 30 to 40% more usable energy. Although both batteries are rated at 100 Amp Hours, this is possible because a Lead/Acid battery can only be safely discharged to 50%-80% of its rated capacity (depending on the quality and age of your battery), or it will be damaged by over-discharge and its lifespan dramatically shortened. A Lithium battery can be safely discharged using 95% to 100% of its rated capacity, with no damaging effects.
Another area where Lithium excels over Lead/Acid is in its discharge performance efficiency. For example as the discharge current or the load on a Lead/Acid battery increases, the efficiency of the lead/acid battery decreases. Lithium batteries can be discharged at higher currents while maintaining much more of its capacity during these higher current discharges. Additionally, while the voltage of Lead/Acid batteries keeps going down as it loses energy, a Lithium battery will retain a higher, very stable voltage during its complete discharge. This means accessories and appliances will continue to operate better since they will be getting the correct voltage supply they need for proper operation.
Lithium will also provide a lot more usable energy in close to freezing weather: the capacity of a Lead/Acid battery is reduced by up to 50%, while a Lithium iron phosphate (LiFePO4) battery suffers only a 15% loss at the same lower temperature. So you have more capacity in the cold with Lithium Batteries.