I was looking at my neighbor's outdoor solar lights last night and I was surprised to see NiCad batteries in what is supposed to be a green product. I assume they have the cheapest charging method, which would be trickle charge.
Look at the inverse correlation between the level of Depth Discharge and discharging cycles at that article.
Besides, part II of this article finally did not answered most questions left unresolved here. This link http://blog.bestlaptopbattery.co.uk/ might prove to be more useful than what we are commenting into.
The focus of the aricle is on recharable batteries.
There is a whole peletora of non-rechable batteries that are available off-the shelf. These includes:
Carbon Zinc 1.5V
Alkaline Manganese 1.5V
Lithium Iron Disulphide 1.5V, long shelf life, high power density
Lithium Manganese 3V, long shelf life, high power density
Lithium Thionyl Chloride 3.6V, long shelf life, very high power density
Silver Oxide 1.5V, typically button cells only
As mentioned above there are regulatory requirements to consider when selecting a battery technology. There are issues with batteries based on cadmium, lead, and lithium (and mercury, of course) in a variety of markets, not just the EU. Some are environmental, some are transport-related.
If you're going to do an article about "Selecting the right battery" in 2012, consideration of environmental performance, recyclability, potential shipping constraints, and legality are of critical importance.
Why do you leave that much reserve capacity in the battery? Is it to extend battery life? Is it because the internal impedance goes up too much? I remember when the voltage gets down near 3V, the battery is going fast.
Here are a few other good characteristics of lithium ion batteries: flat discharge curve, typical voltage just about right to linear regulate for logic, and it's easy to detect charge termination. Low self discharge is important for many low power applications.
You don't have to use CC/CV charge methods for these batteries. You can pulse charge them.