Thanks Satinder sirji for drawing my attention to this thread :
Here is what my knowledge about batteries :
My selection of batteries is based on following principles
1. Service life : How many times a rechargeable cell / battery can be run through charging and discharging. Here Li Ion > NiMh > Nicd > alkaline(rechargeable)
2. Capacity : Here the top two are almost equal. NiMh >= Li Ion > NiCd > Alkaline NiMh sometimes do carry more power than LiIon but weighs much more and is slower to charge.
3. Memory effect : Some batteries lose their memory charging reference point meaning if they are charged before they are completely discharged they lose their capacity over time. here Li Ion > NiMh > Ni Cd > Alkaline
4 : Charging Speed : Li Ion > Ni Mh > Ni Cd > Alkaline. I read earlier that if you charge the NiMh cells faster they discharge faster, though I have not any kind of proof or experience about it in practical life.
If some one knows better I will be en-lightened
Some factors which our community as travelers have to look for
Weight : Li Ion is best by a big margin
environment friendly : Here also Li Ion is the better amongst all.
Capacity during extreme temperatures : Li Ion maintain their charge better in very low temperature but still they discharge faster, experts advise to keep them closer to body so body heat will keep them warm and efficient.
Another factor to consider is drawing voltage output : here Ni cd and Ni Mh are limited to 1.5 volts while Li Ions can deliver a lot more.
All these factors have led to popularity of Li Ions by manufacturers.
Now coming to concerns of Satinder Paaji:
Can we charge Li Ions with power banks
epends upon the model and make of bank + adapter + battery. also the link you posted shows two AA cells to charge the original equipment battery, how much they can help you is my concern.
Here we need help of an expert who can calculate well between mAh / Volts and all those numbers (pardon my knowledge as being a doctor I am better off with biology
)
My suggestions would be:
Purchase a battery grip for your camera + extra batteries and for emergency charged NiMh batteries. Because almost all battery grips allow adapter to fit in AA cells in place of LIon and most likely 3 AA take place of One Li Ion.
In general a Li Ion should power Nikon D90 for around 600 - 800 shots depending upon conditions.
While 6 AA cells will give around 25-30% less shots afaik ( I may be wrong here need some inputs)
Will post again about chargers / rechargeable batteries later.
Feel free to ask clarifications / suggestions / corrections.
