NiMH batteries offer a lighter alternative to lead-acid batteries and hold more energy per unit weight. This type of battery provides a good balance between performance and price, making them a popular choice for many electric wheelchair users. NiMH batteries have a lower discharge rate and can perform better in colder temperatures. They are also more environmentally friendly, as they contain no toxic metals like cadmium or lead. However, NiMH batteries can self-discharge faster compared to lead-acid batteries, which means they may require more frequent charging if not used regularly.