Why the replacement batteries never seems as strong or as durable as the original unit?
Like a toothbrush, flashlight, clock, solar lamp, calculator, etc.?
Think in terms of the first times you have traveled to new places. Each time, it seems like a shorter trip. Same with battery life. When first getting a new gadget to your expectations are wide open and your ability to use the product has no preconceived relative time frame. The more you use the most useful gadget, you'll have it and therefore drain more energy, there will be especially if you like the activity. The battery life is not as big as your new level of performance expectation. I recommend Eveready e-squared batteries if they have the size you need.
solar batteries rechargable rechargeable garden lights – I can replace with normal or rechargeable batteries are special?
my solar lights were dead, so I have to open and found two rechargeable AA batteries. They said Solar Lighting Power Pack 600 mAh, 1.2V. 600mA fast charge 1.5 hours, standard load 15 hours at 60 mA. NC I suppose the reverse of this question is "How can I can recharge the rechargeable batteries using the solar panel normal little garden lamps?" That would be 15pm to 60 mA.
Not be a problem if you use batteries of the same chemical (Ni-Cad). If you buy new batteries you probably have a greater capacity and so will never get fully charged, it shortens the life of Ni-Cad, due to memory "effect." You could replace batteries Ni-Cad with nickel metal hydride (Ni-MH) to prevent or reduce this. If you live somewhere where you get 15 hours of bright sunlight, will also be able to use the panels as a charger.
How efficiently plants use solar energy from solar panels?
How much energy chemicals stored in plants compare to the electrical energy stored by solar panel / batteries?
Most plants are about 1% efficient at turning sunlight into a useful form of energy it can use. Bamboo is not maybe even higher. Solar panels are somewhere around 20% efficient now, I think. The trees are much cheaper to use to collect energy if you have solar land area well.