CMOS batteries are no more expensive than watch batteries, as that's what they are. They are the same thing. Three or four bucks (or five, like don suggested above (was writing at the same time)). You can get one at Walmart. You just have to know which one to get, and will have to look up how to replace it. Your computer manufacturer's website should have a tutorial on how to change the battery, and will probably tell you what battery you need, too. Or, if you can get the old one out, just buy the same thing. Hopefully replacing it won't be very hard.
The main battery, on the other hand, probably just pops in, like you said, so it's an easy thing to do. It most likely has some type of mechanism for holding it in place, but it should be easy to figure out. This battery powers the whole computer, but the CMOS battery is the one that keeps the clock going, especially when the computer is off.
Is the thing with the wires coming out of it the battery itself? If so, talk about proprietary. Again, if so, that's rotten, as it appears you may have to buy their specific battery, rather than the tried and true, easy, simple button cell batteries that most other computers use. I mean, it's still a button cell battery, per se, but made in such a way that it has to be their configuration of it. That's just rotten.
Then again, I hope that's just some type of cover, and you can take that off, replace the simple battery, and replace that cover. If not...again...rotten of them.
I'm glad the battery for the HP is easy to find and not particularly expensive, but it would still be nice if one could just pop into their Walmart or Rite Aid or something and get one.
I'm glad my laptop, notebook and desktop all use the same battery. Well, not the same battery, but the same kind. LMAO.
No doubt. The Chinese batteries are junk, as are a lot of the other cheaper batteries. I stick mostly with the name brand or product branded batteries. They may cost a little more, but you know what you are getting. I made the mistake of buying some batteries from Amazon that were very nicely priced for a laser bore sight, but they died within five minutes. The money saved was certainly not worth it. Now, when I read reviews for products on Amazon, I make sure they are from verified buyers. I learned that lesson very quickly. Not all cheaper batteries online are junk, but nine times out of ten, they are.
I bought the four pack of button cell batteries only because my old 2007 Dell Dimension E521 desktop, which I was putting Linux Mint on to give away, was having clock problems. I knew the other three computers that I do still use have the same battery, so I figured I would just have them on hand if they die, as well. For eight bucks, it was worth it.