Over the past 5 years I have used two main battery types for backpack portable operations. My first battery, weighing 2.06 kg, was a 12 V 7.2 Ah sealed lead acid battery. The more recent battery, weighing 1.05 kg is a 13.2 V 8.4 Ah Lithium Iron Phosphate battery.
Prior to the 2102 French Island trip I load tested the SLA batteries I was taking to be sure of their performance. The newest of these batteries is shown in the chart below. Last weekend I performed the same load test on the LiFePO4 battery, also shown in the chart below.
The load used was a 50 Watt quartz halogen light bulb, the battery voltage was sampled every 5 minutes and the test stopped when the battery reached its suggested minimum discharge voltage. Each battery was fully charged, on a suitable charger, at the start of the test. The temperature during each test was about 18 degrees C.
From these test you can see why I prefer the LiFePO4 battery. Longer time, lower weight, smaller size. Unfortunately it comes at a much higher cost.