The Micromax Bharat 5 Plus features a 5000 mAh battery which not just provides the phone with lots of power, but has OTG support, so it doubles as a powerbank for all your electronic needs. If you go to the store and search for a powerbank to charge your phone, you are likely to get one of those 5000mAh powerbanks devices. I actually have one at home, but it's 10,000 mAh, not 5000mAh. I use it in trips where I take lots of photos and videos, and the phone's battery itself isn't enough to power the device for a long time. This is especially true if you plan to use the GPS for a long time.
This is why an external powerbank is such a good option. However, here you probably won't need a powerbank, as the phone itself comes with plenty of power and you can use it to charge up other external devices as well, like your second phone, a digital camera, etc.