Bad CMOS batteries!

[PDP-Fan]

What's up with CMOS batteries today? It seems they don't last longer than 2-3 years anymore. I remember times when 20 years old systems still had their first CR2032 inside and it was still good.

But even worse is the design decision to prvent servers from turning on when that battery has failed. I had BL460c Gen8 and ML350 Gen10 that totally refused to turn on when the CMOS battery was dead. At least the BL460 signaled it with a red blinking LED, the ML350 just keeps blinking green...

Problematic battery brands are:
- KTS
- Newsun
- JHT

Good brands:
- Renata (Swiss)
- Panasonic (also best lead acid batteries)
- Varta
- Maxell

I just wonder... do you experience the same? Are you constantly changing CMOS batteries on relatively young systems?

[Suman_1978]

Hi,

Here is an article from outside.

Thank You!
I work with HPE but opinions expressed here are mine.
HPE Tech Tips videos on How To and Troubleshooting topics

[PDP-Fan]

Hi Suman

Thanks for the link to the article. The information it provides may be ok but after reading the intro, I doubt that it is researched properly. Maybe it's only a typo...

"Unfortunately, the CMOS battery is a component that is only found in laptops."

If you make it "...that is NOT only found in laptops..." it would be correct. I mean we are talking about servers in this forum and they all have CMOS batteries, as we know.
The experience I made with batteries in the last years is similar as with electrolytic capacitors 10-20 years ago. Cheaper fake/clone products entered into the market and into the mainboards of many computer manufacturers. I replaced so many capacitors, I can't even count them....
Now it seems to be the tiny batteries that fail prematurely and in a unusual way. I found many batteries that show 3V on the multimeter but when connected to a load (an LED in that case) the voltage drops almost to zero. This is caused by an increase of the internal resistance in the battery. Without load it shows full voltage but as soon as a current flows, the voltage drops.

So what can we do?
Let's hope the manufacturers are aware of this problem and start to buy better batteries again. Although the issue will not have such a large impact as the capacitor cancer, but it's annoying anyway. A good CMOS battery should last 10 years or more.

30 years ago, they were able to make such batteries... which are still good today! (in some cases)