The length and quality of the cable between the charger and your phone will dramatically change the charge rate.
The longer the cable the less charge rate
The thinner the wires the less charge rate.
And as you can imagine a combination of length and crapy wire =
A lot of the cables on eBay are terrible as they are made as cheap as possible.
I have found that the coiled (spring looking) ones are almost always good as you can't make a decent 'coil' with crapy wire.
Hope this helps.
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