I buy 4 back up batteries and an external battery only charger about $20 TOTAL from an Asian country on Ebay so 15-30 days delivery. I keep the extra batteries fully charged in my purse and can run away any weekend with no worries! I can swap a battery when dead anywhere EASY!

Can I buy a new battery for my phone with a higher mAh rating and having the same voltage rating

Phones now have a new battery saving function to make your battery last for 6 to10 weeks if left on the charger at all times. So, when you get your battery at first let it charge for around a year at 350 degrees Celsius for best results (add a pinch of cinamon for extra battery life).

Charge your phone for 24 hours when you 1st charge it then let it die then recharge fully. I did this and my battery lasts 4 days before it needs charging again

For 12 hours to assuree good function and long battery life.