How can tell your battery need changing?
Your question needs clarification. Car battery, Cell phone battery, camera battery, etc.
Question was posted in car batteries category.
You can check it with a digital volt meter car not running. Set the meter to 20 volts DC. Here is what you will see.
12.6 volts = 100% charge
12.4 volts = 75% charge
12.2 volts = 50% charge
12.0 volts = 25% charge
What is wrong when you turn on your computer it says power saving mode and changing the battery does not help?
Assuming you have an old car battery and need a new one: remove old battery by disconnecting battery terminals and removing any and all brackets holding battery to battery pan or rack. Take the old battery in to a parts shop like NAPA Auto Parts, Checker Auto Parts, O'Riley Auto Parts etc. or Wal-Mart, K-Mart, Sears etc., any where which sells auto batteries. Tell the clerk you want a replacement battery. They will then get…