Can 2 HP notebooks have interchangeable batteries?

[webmonkey]

Hello:
I have 2 HP laptops/notebooks as shown above. Usually find them at garage sales, check them, add anti virus software and give them to kids.

One has what seems to be an original battery (mfg date: 2013/08) and the other has what seems to be generic HP battery (Model:CQ42). The older battery doesn't hold a charge and sometimes won't even charge. The newer one charges and will last maybe an hour.

They seem to be the same physically as they both fit into the other notebook fine. I then crossed fingers and powered both units on and they ran fine (with the newer battery).

Dare I buy a new battery (eBay/wherever) and do some more testing. If all works fine then buy another of the same.

Thanks

[WAWood]

@webmonkey 

If you had bought the generic battery on eBay, you would not have been the first victim of folks selling worthless junk.

Batteries are like car tires in the respect that, even though several are the same size, that is no way of ensuring that they are of the same quality.  So, even though the generic battery fits and works, that says nothing about its value or ability to hold a charge.

I have repeatedly replaced batteries in laptops and in every case, I make record of the specific HP part number for the battery.  I use this when searching for replacements. If there is an image of the battery at the website, I compare that to the one in the laptop.  If they do not match, I do not buy it.   I have never ended up with a low-grade battery as a result.