Good Third Party 170W chargers for W520/W530?

[TheDeepThought42]

Hi guys,
I just got my W530 and was wondering if you have any suggestions for cheaper 170W power adapters than the one Lenovo sells. I like having 2 chargers just so I can leave one at home and keep one in my bag at all times without worrying about forgetting it. Thanks!

[ZaZ]

I picked up OEM chargers via eBay fairly inexpensively. I think they were like $20 shipped, though they were the 65w adapters. That's if you don't mind them coming from China.

[K_Wall_24]

I picked up OEM chargers via eBay fairly inexpensively. I think they were like $20 shipped, though they were the 65w adapters. That's if you don't mind them coming from China.

From what I gather, those shouldn't charge it at all unless it's off, and even then, won't really do anything. Correct me if I'm wrong though.