Can iPod 3rd complete with iPods classic battery & hard drive?

I have a 3rd iPod and i have replace the battery two years before. But now, the battery only can play few hours. Also, i have a iPod classic 5 years ago but the battery still strong which can play over a day.

I have check on Internet and i know the main reason is the power consumption of iPod 3rd much higher than iPod classic. So, if i can replace a new set of iPod classic hard drive & battery on my iPod 3rd, it would be a better solution. The size of these two iPod quite same and "i think" the hard drive size is not a big challenge. But i worried about the connector between this two generation iPod, is it possible to connect them?

I really like the Ipod 3rd design and i hope to use it daily. Please give me any advice and comment.

Thanks !