Need help with battery info

[RyanS1982]

Hello,

I recently acquired an HP 15" laptop which had a known bad battery, as it would no longer take a charge. I found a replacement and it is on order.. my question is the CMOS (RTC) battery. I found the part number on HP's support site, but I cannot find a replacement online that matches the exact part number, nor proper instructions for changing it. I know it is the coin style which has the electrical pigtails that plug into the main board, but I cannot find any information on *how* to change it.

I am assuming that is why I am getting the CMOS 502 error when I unplug it from AC power since the battery is not powering it. The rtc battery must also be at its end of life as well, correct? On/off while plugged in there is no issue, but unplugged long enough for capacitors to drain, error pops up during power on.

I only paid $15 for the laptop and charger, so buying the batteries isn't an issue considering the rest is 100% functional.

[Huffer]

Service Manual:

Manual 

See p. 104. 

RTC battery  747132-001

https://www.ebay.com/itm/324579032692?hash=item4b926afe74:g:ipgAAOSwmBZdBSRR

Above is from Germany and the shipping is high. A kind of guerilla repair is to take the yellow plastic off. See what kind of coin battery it is (CR2032 it seems). Odds are they have one at CVS or Walgreens in the hearing aid section. Very carefully peel the leads and pigtail off the old battery. A needle nose set of pliers works well. You can then reattach the leads to the good new battery and wrap the whole thing up with clear packing tape or shrink wrapped wire cover making sure the leads are on the right side of the battery (+ or -) and are held down firmly. 

Post back with any more questions and please accept as solution if this is the info you needed. 

[RyanS1982]

Alright, I will take those both into consideration. That being said, I've seen a bunch of other HP laptop rtc batteries that look similar, and my next question would be, are any of those interchangeable with the model I need?

[Huffer · Accepted solution]

The devil is in the details. The pigtails have different interfaces that plug into the motherboard. Likely some are interchangeable but there is no magic interchange chart. 

[RyanS1982]

Good to know! Thank you for the info! As soon as my new battery arrives and I swap it out, I'll see if the CMOS error comes back, i might just end up living with it considering I paid next to nothing for the laptop itself. With the new battery, I'm only into it for $40 right now (the undoubtedly aftermarket battery was fairly cheap and received decent reviews on Amazon, since HP no longer carries the factory battery) it will just be for travel and such, so I'm not expecting to do great things with it🙃