I recently purchased a 2010 Escalade which came with an extra battery in the engine area. I've never had a vehicle with a spare battery. It is still wrapped in plastic. How do I know if it is useable? And wouldn't it have to be charged occasionally so that it would be a useable spare in an emergency situation??

  • One option would be to unwrap it, disconnect your current one, and connect the secondary and attempt to start the car – Nate W Dec 26 '17 at 22:58
  • Welcome to Motor Vehicle Maintenance & Repair! :) First question - is the battery currently connected to the system? Additional batteries are often installed for high-power audio systems, and such audio systems are fairly common in that type of vehicle. That would be my first guess, but depends on whether or not it's attached. – kyle_engineer Dec 27 '17 at 1:51
  • Don’t just unwrap it and try to use it - that is poor advice and may damage it. Check it first. – Solar Mike Dec 27 '17 at 9:43

Only way to know is to check it and test it.

Is it filled with fluid - electrolyte to the correct level - just above the plates. If it does not have any fluid in it, then it may be a dry-charged battery that needs filling to be ready for use, which probably means it is in “as new” condition. Especially as you mention it is wrapped in plastic.

What voltage does it show at the moment - if it is too low then it may not recharge or recover and that means it is scrap.

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