DS Lite wont charge via usb, only on mains adapter?

Ive had my ds lite since 2006, still working fine and charging on the mains, but ive bought a usb charging lead for holiday usage, and when connected to the laptop and lite, its power light goes orange for 2 seconds once then off again.. and thats it! Is it possible for a ds lite to charge via usb1 and usb2? The usb lead states it works with all ds versions including the lite, but now im not so sure-cheap amazon job. As the ds still charges using the same connection using a mains plug ok, I dont think its a faulty ds connection. The ds lite uses the same size of connection as the standard ds, but does anyone know if some usb charging leads only work for the standard ds, or what is likely to be wrong? I have an original ds lite, model USG-001. thanks for any help

While I don't have a usb charger for my DS-Lite, as far as i know your cable should be charging it fine.
The DS-Lite charger i have outputs 5.2V and 450mA.
A Standard USB 2.0 port outputs 5V to 5.25V and 100mA up to a maximum of 500mA if needed (this has changed with USB 3.0)
The only problem you may have is that this maximum of 500mA is usually shared across multiple USB ports on your PC, (educated guess-->) usually 2 or 4 ports depending on the chipset.
Try moving the plug to a different port. You could also buy a USB2.0 PCI card and use that, they should be quite cheap now with USB 3.0 taking over.
Or you could buy a USB 3.0 PCI card which supplies 150mA up to a maximum of 900mA.
You could also try a 'powered' USB hub, but in your case it kinda defeats the point, may as well use the charger instead.

thanks for that-i dont think the other 3 ports make a difference, I think 2 out of the 4 are usb2. Searching earlier, some users complain on other sites at the light going out halfway or going out in 2 seconds, as with my one-perhaps its an issue with the device requiring that extra 0.2V, although it doesnt sound likely? Another user was concerned about the lites requirements and that usb could damage the device (ill have to find the link). I think it was to do with usb not recognising the lites requirements and sending it too large a current? It stated the ds had an out of the ordinary requirement, which I assume is why there arent any official USB charging leads. I do have a mains plug which works fine, I just thought a usb lead would be easier if carrying around on holiday,eg with any laptop. I might give it a go on another laptop or on a desktop in future to see if that makes a difference, but as with the mains charger the ds lite is definately working ok :) thanks