Mobile ad-hoc networks are deployed in different fields and it can be effective in applications that depend on the inter-node interaction such as search and rescue, surveillance, and battlefield reconnaissance. Due to this importance, in this article, we have reviewed the latest energy optimization solutions for mobile ad-hoc networks (MANET). Since the typical layered inflexible architecture is unable to handle the features of MANETs, battery consumption is the primary concern in the context of MANETs. Along with this, authors proposed categorizing energy optimization solutions into seven categories: techniques based on load balancing adaptation algorithms, methods based on multicast algorithms, and schemes based on the radio state adaptation algorithms, position-based routing protocols, schemes based on proactive algorithms, energy efficient reactive protocols, and techniques based on control of transmission energy algorithms. The authors reviewed the suggested resolutions in every domain, providing details on the methodology utilized, metrics for performance assessment, and the advantages and disadvantages related to each suggestion. We believe that the review presented in this article will be been sufficiently useful for researchers to optimize energy consumption for MANETs. Dummy text.