MBP Early 2011 running slow on battery but works fine when on charging

When on battery the laptop runs slow (no matter which app ur working on) but it works fine once the charger is connected. Apple does not support repairs for this old laptop now. I checked with a local repair shop and they said its the keyboard which is a problem here. According to them, the battery is good. Im still not convinced that the keyboard could be a problem here. Can anyone shed some light on this for me. Any help would be appreciated. Thanks

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Hi Mayer, thanks for responding. yeah the battery is weak but can u see anything else in the screenshots that can help me. Also at the same time i’m trying to get back to my old hard-disk. This problem might have started after changing to the new SSD. If the problem still persists with the old hard-disk then yeah its the battery for sure. Thanks once again