Is it harmful for phone or battery if I use the original charger of lumia 640 4 charging lumia 535?

[WPCentral Question]

The original charger of lumia 640 is 750 mAh and for lumia 535 it's 550 mAh. It takes about 4 hour for my lumia 535 to get fully charged using its own charger, Is it normal? I already tried hard reset but nothing changed. I think If I use lumia 535 charger, It will be charged faster. Is it true and safe to use?
anyone has suggestion for a good and faster charger?
Thanks

 

[rhapdog]

Using a charger with more mA capabilities will assist your phone in charging faster. There are times that it can also reduce your overall battery life, which shouldn't be a problem if you plan on replacing the phone in 2 years.

There are smart chargers which will detect what your phone can handle and deliver the most optimal charging current for your device. I find for my Lumia 640, I can get a much faster and a safe charge as high as 1200mA. My 520 came with the lower mA as well, but it charged fine with the 750mA charger with no ill effects that I am aware of.