No, A bad battery does not affect the performance of the laptop. What it DOES do, however, is shorten the lifespan of the laptop (and its hardware).

If you are ONLY running on battery power, and are using a battery that is:

• Very low or at a critical level
• Doesn’t charge well
• Discharges too quickly

You can potentially ruin the hardware in your device. This is because the hardware has to draw a specific amount of current (amps) from the battery. The hardware will simply overheat because the fans do not have enough power to cool the hardware. Heat will cause massive damage to the hardware over time.

Another issue that could happen is a hardware power-surge. When the battery is critical (or faulty), a power surge could happen as a result of the hardware attempting to draw more current than the battery can supply. This can sometimes cause irreparable damage to the hardware.

I have seen hard-disk and CPU failures as a result of this. The hard-disk was partially corrupted, as the lack current caused a power surge, which caused the disk heads to jump and scratch the disks.

Solution:

I would suggest trying one of the following:

• If the battery compartment has a separate cover-plate, remove the battery, put the plate back on, and only use the laptop via the power adapter.
• If the battery is only critical level / low power, only use the laptop when plugged into power.
• if the battery is faulty or damaged, and the dust cover is built into the battery, stop using the laptop and replace the battery ASAP, you’re only asking for a massive hardware failure by using it.