Blackview BV4900 Pro Correctly charging the BV4900 Pro smartphone

I have been having difficulty correctly charging my BV4900, sometimes when I charge the phone, I see a red indicator dot, or there is sometimes a blue indicator dot.

Sometimes, even no indicator dot. 

Sometimes, even after four hours of charging, the battery level only goes form 80 to 81 percent.

Also, is there a certain block charger, i.e.  5 Volt, .500 amp, 1.00 amp, or 1.200 amp that I need to use.

I have also tried different micro USB cables, and I still get super slow charging.

Thanks for any advice.