5 Best Laptop Batteries - June 2022 - BestReviews NinjaBatt Battery for Acer Check Price Trusted Brand These replacement batteries promise better-than-new power for Acer laptops. Fits Acer laptops. Six cell lithium-ion battery rated at 48 wH/4400 mAh/ 10.8 V. Boasts stated full capacity. Fits OEM specifications. Built-in protection against short circuits, overheating, and overload.