old Laptop CMOS batteries still holding charge just fine, should be replaced/removed anyway? \ VOGONS

old Laptop CMOS batteries still holding charge just fine, should be replaced/removed anyway?

Topic actions

Post a reply

First post, by HaldrynHotel

Posted on 2021-10-17, 04:57

HaldrynHotel Offline

Rank Newbie

Rank: Newbie
Posts: 12
Joined: 2021-10-10, 05:38

Hello!, a new Vogons user here!, but i was following this forum around 2010, but never joined until 11 years later.

Recently adquired some Pentium (Normal/MMX) laptops in eBay, and a Pentium III laptop (Toshiba Satellite 2800-S202), those laptops, once i started first time, the BIOS CMOS was reset, returning bad checksum errors, but once i fixed their settings it works just fine, a couple of days and weeks the time and BIOS configuration is still there, those laptops i own are from the mid-late 1997.

If those CMOS batteries even still holds a charge for a while, are still prone to leak and should be removed soon as possible?.

Thanks.

Reply 1 of 3, by dormcat

Posted on 2021-10-17, 05:24

dormcat Offline

Rank Oldbie

Rank: Oldbie
Posts: 688
Joined: 2021-05-05, 21:59
Location: Taipei, Taiwan

Toshiba Satellite 2800 series use rechargeable NiMH batteries for RTC:

In terms of leakage they are safer than NiCd or alkaline batteries, but there's still a small degree of risk, particularly if they have been depleted over long periods. I'd suggest replacing it with modern lithium batteries at your earliest convenience.

Reply 2 of 3, by HaldrynHotel

Posted on 2021-10-17, 05:36

HaldrynHotel Offline

Rank Newbie

Rank: Newbie
Posts: 12
Joined: 2021-10-10, 05:38

dormcat wrote on 2021-10-17, 05:24:

Toshiba Satellite 2800 series use rechargeable NiMH batteries for RTC:
2021-10-17_131001.gif

In terms of leakage they are safer than NiCd or alkaline batteries, but there's still a small degree of risk, particularly if they have been depleted over long periods. I'd suggest replacing it with modern lithium batteries at your earliest convenience.

What about the 1997 laptops?, i do have a three of them, 1 standard Pentium, the others are MMX:

Toshiba Tecra 500CDT
Compaq Presario 1620
Dell Latitude LM M166ST

Those three laptops holds the CMOS battery charge just fine for a couple of days or weeks, i didn't left powered off for long periods of times since i like thinkering with them, the last two of them i couldn't find any documentation of what kind of batteries they use, the Tecra i assuming uses the same batteries from a Toshiba Satellite 110CT i have that i removed the batteries which they started to leak and corroded some of the traces, thankfully it was just getting started and didn't affected the functionality at all.

Reply 3 of 3, by dormcat

Posted on 2021-10-17, 06:24

dormcat Offline

Rank Oldbie

Rank: Oldbie
Posts: 688
Joined: 2021-05-05, 21:59
Location: Taipei, Taiwan

HaldrynHotel wrote on 2021-10-17, 05:36:
What about the 1997 laptops?, i do have a three of them, 1 standard Pentium, the others are MMX: […]
Show full quote

What about the 1997 laptops?, i do have a three of them, 1 standard Pentium, the others are MMX:

Toshiba Tecra 500CDT

Compaq Presario 1620

Dell Latitude LM M166ST

I'm not too familiar with those models but I managed to find some video and manuals:

How To Remove the BIOS Battery From a Vintage Toshiba 550CDT Laptop
Battery pack at 6:32 looks like those cordless phone batteries wrapped in epoxy.

How to Replace the CMOS Battery In a Compaq Presario 1000/1200 Series Laptop
CR1220 lithium battery at 8:30 has minimal leakage risk and can be easily purchased and replaced.

Dell Latitude LM Service Manual page 4-18
"Allow time for the CMOS battery to recharge" hints the battery should be rechargeable but no additional details could be found.

Each of them requires tools and time to disassemble, though.

Go to top of page Go to top of page

Back to General Old Hardware

Main menu

Common searches