Postby EVguru » Wed Jan 09, 2008 10:38 am
Thundersky cells with Cobalt chemistry have indeed been well proven. However the Manganese cells have had internal corrosion problems, particularly if layed on their side. They can die in just months in some cases. Aparently the Iron Phosphate 'power' cells also have the same problem, to what degree I don't know.
The company got a very bad reputation in the US early on for shipping defective cells and doing nothing about it, but it isn't in theory the same company any more, but we have defective cells again and the same bad attitude.
Now I hear that they are increasingly reluctant to sell in small quantaties and are going to be phasing out the Cobalt cells! My peak power requirements rule out the Cobalt cells in any case.
Doing business with China is often difficult and the Lithium cell market is in a period of rapid change, development and expansion. There's no effective patent or design protection system in China and products can be copies of copies of copies. There are dozens of factories, often with several brand names, dozens of re-branders and/or middlemen, and probably hundreds of sellers. You've got to be dealing with the factory or you've got little chance of getting the same thing twice.
I'm not against Chinese products and I've recently bought both a TIG welder and a Plasma cutter (via ebay outlets). In the case of the TIG I researched for over a year as to who was worth dealing with, but I'm very happy with the functionality and the build quality.
Kokam had a proven product in one application area, which they developed into others. Their prices have come down a lot and they're looking like a very viable option.
Paul
http://www.compton.vispa.com/scirocco/
http://www.morini-mania.co.uk
http://www.compton.vispa.com/the_named
Some were pleased some disapointed, the bigger cells def seemed better than the smaller ones.
