When the hybrid engine is was ist kobalt in parallel both engines can propel the car alone or together. A good example would be Toyotas' Hybrid Synergy Drive (HSD). Capable of being propelled at low speeds by the electric motor, the gas engine takes over at higher speeds. This allows both engines to perform in their optimal situation.
To avoid this you can check date of manufacture and buy one that is more recently out the gates of the factory. As a workaround you can buy any netbook while it's under warranty test the battery and if it's not up lithium facts to your expectations you can send it back as dead on arrival and demand for a replace.
This can be a problem for where the battery is not used that often but is can be important when it is needed for emergencies such as power outages. As the battery does not store well over extended amounts of time, it is possible that when they are needed they will not be usable. But for things that are used and recharged on a regular basis such as for portable electrical equipment, they are very good. But there is not always a slowing amount of capacity when they are getting old and it is possible for them to just not work without any reason being obvious.
On the second point, iPOD batteries are smart charging. Now, you can't use your iPOD Nano battery to help study for a test! Rather, they're smart because they can tell the charger when they're almost full. When your iPOD is charging, it charges up to 80% capacity in no time flat. Then the iPOD battery tells the charger to slow down so the charging process goes lithium bettery stock from warp speed to snail's pace. This ensures that the battery doesn't overcharge, and makes certain that you're spending your time with your music, and not spending your cash on iPOD batteries.
Briefly relating back to overall size... many lithium 18650's will differ ever so slightly in length (measured in millimeters). This is mainly due to an added protection circuit. The circuit helps to prevent the battery from over-discharging, since Li-ion cells can easily become damaged if their power is drained below a particular voltage. The protection circuit also prevents the cell from being over-CHARGED as well. These cells are very sensitive. They must be handled carefully, gently, and as described above, must never run-down too far, or be charged over and above their threshold. They can actually explode if severely mistreated!
The bottom line, be gentle to your lithium-ion batteries. If you excessively charge the battery, with high voltages, and heavy load conditions, it will shorten your battery's life. It's best to charge at a slower rate.