Wind up Torch from ASDA

[Skvez]

Last night (1st Sept 2011) I took the ASDA wind up torch apart to see what the rating on the capacitor used to store the electrical charge between winds was and got rather a shock to discover that there wasn't a capacitor, it was using a Lithium Ion (rechargeable) battery.
       
Unfortunately Li+ batteries have a limited shelf life, I had expected the life expectance of the torch to be affected by use (since it's using plastic gearing and no proper overcurrent protection of the LEDs) but have a fairly good shelf life, making it reasonable for prepping but the Li+ battery changes this considerably.
The Li+ battery probably has a half life (time to loose half its capacity) of 2 or 3 years and that's assuming it gets charged nicely (which it isn't) and not overly discharged (a distinct possibility in this application).
I then took my other wind up torch apart and found it too used a Li+, it actually has a bigger battery so its poorer performance is probably due to it being over a year old already (other possible causes are a less efficient generator or LEDs).
I withdraw my recommendation to buy this as a prep.