As of my knowledge cutoff date of September 2021, here are some of the best smartphones under 10000 in India with good battery life:
Xiaomi Redmi 9 Power - This smartphone has a massive 6000mAh battery that can easily last for more than a day on a single charge. It also comes with a 6.53-inch full-HD+ display and a Snapdragon 662 processor.
Realme Narzo 30A - The Realme Narzo 30A has a 6000mAh battery that can last for up to two days on a single charge. It also comes with a 6.5-inch HD+ display and a MediaTek Helio G85 processor.
Samsung Galaxy M12 - This smartphone has a 6000mAh battery with support for 15W fast charging. It also features a 6.5-inch HD+ display and a Exynos 850 processor.
Infinix Hot 10S - The Infinix Hot 10S features a 6000mAh battery with support for 18W fast charging. It also comes with a 6.82-inch HD+ display and a MediaTek Helio G85 processor.
Tecno Pova 2 - This smartphone has a 7000mAh battery that can easily last for more than two days on a single charge. It also features a 6.9-inch full-HD+ display and a MediaTek Helio G85 processor.
Please note that the prices and availability of these smartphones may vary depending on your location and the time of purchase. Additionally, newer models may have been released since my knowledge cutoff date, so it's always a good idea to check for the latest information before making a purchase decision.
