AG lithium batteries for airplanes have nothing to do with NiCd's being obsolete or even useless, the energy density of a NiCd is so low that the only worse chemistry for a battery I can think for an RC plane is lead acid batteries. I don't however hear you complaining about the toxicity of lead acid batteries on the forums, you do however seem hell bent on spreading misinformation about NiCd chemistry.
And it's not so much the weight for RC cars that's the advantage, it's the control of the center of balance. The main body of the car tends to still be made out of high strength light weight composites, the cars weight is brought up with the batteries but the real advantage is that the extra weight of a flat pack NiCd pack for an RC car moves the center of gravity so low in the car that it dramatically increases handling, otherwise you'd just use lithium batteries and lead weights. The peak power put to the ground on an RC car is vastly larger than for an RC aircraft so the NiCd chemistry as well along with the weight makes it the ideal solution, even the best of the best of the BEST Lithium packs can't hold a shadow to the short circuit current of the same capacity NiCd. The only use I could think of Lithiums for in RC cars would be for endurance races... which is really a boring sport from an RC perspective.
And the chinese solar lights again? Really what does that have to do with anything? The Chinese still make products with lead based paints for children's goods, you can't blame stupidly poor application for a flaw in the inherent usefulness of the chemistry itself.
AG, the proof is in the pudding so to speak. Even within the European Union (2006/66/EC) so called ban on NiCd batteries there are exceptions, like medical uses, alarm systems, emergency lighting and power tools. So again your statement of NiCd's as being obsolete is completely out of place. They're still used in those types of devices because for their particular needs NiCd's fill the roll required.
Hopefully this doesn't derail ADW's question too much but I feel someone has to set the record straight about audioguru's statements which differ so very much from reality. This is not the first time he's posted in this manner as well on this topic.
For actual information purposes I would like to reference this thread. As I described how to go about testing individual cells for pack matching and determining the condition of pretty much any cell. As Kiss said you really need to consult the graphs provide from the maker of the battery, however in many cases such information is not available so empirical testing (as described in the thread) is the only way.
https://www.electro-tech-online.com/threads/nicad-battery-testing.116620/