This one is Compaq heavy, but don't worry we don't brand hate here.
I have been a long time collector of vintage computers before it was cool to collect them. I got started in 2003 with a Compaq Prolinea 575e courtesy of the local school. I quickly got into repairing both desktops and laptops. One of the more notable systems in the collection was the very rare Compaq LTE Lite 25E. It had a problem that is unique to this model and its other 386 counterparts. The systems will not turn on if the CMOS battery goes flat. I repaired that and found out the main battery was dead. That wasn't a big deal at the time. The 25E also survived the great computer purge of 2012. At that point, I knew this computer was special and needed to be saved. I fired it up about once a year to make sure it was still going. I did this until the pandemic.
After a lengthy shut down at my full time job due to a Covid outbreak, I decided to take a deep dive in my collection. The retro hobby was one of the last fields that didn't turn political. At that moment, I discovered the Facebook group "Compaq LTE & Armada Owners." I quickly found out there was a renewed interest in the LTE systems. For the next several months, I started documenting procedures and fixes for several Compaq portable systems and uploaded those to my YouTube channel i80386sx. Then a new hot topic came up. Batteries. Most of the users of these systems couldn't get the batteries for these systems. Most of them used Ni-CD batteries.
My first assignment was to reproduce the Compaq LTE 5000 RTC battery. Demand for these was particularly high in the UK. Options for batteries are limited outside of the US & Canada. The battery itself was easy to find thanks to a supplier in Canada. The thermostat on the other hand was very difficult to find. The Isuzu thermostat these came with from the company turned up no leads. Thanks to an aftermarket RTC battery I had on hand, I was able to cross reference a part number and found a company in Texas that had an equivalent replacement. Once shrink wrap was found, we were in business. After a little trial and error, we had 20 assembled units. Those sold out in 5 minutes.
Quickly after, a member of the Compaq LTE & Armada Owner rebuilt the battery on their LTE 5400 with great success. Since I own about 2 dozen LTE Lite systems, I decided to take a chance and attempt a rebuild on one of my batteries. I only had a soldering iron for this build. The first attempt didn't go well as I overheated a thermal fuse on it. I wasn't about to be defeated that easily. Being stubborn can be an asset when used correctly. I regrouped, purchased a spot welder, nickel strip and other tools and gave it another try. The second attempt yielded a fully functional battery. I now have a battery that can keep an LTE Lite powered for about 3 hours on a single charge. I cautiously offered my services to rebuild other Compaq batteries. I kept my list small as I wanted to be able to personally test each pack going out.
Much like others in the retro hobby, I wanted to help people and share experiences. I wasn't expecting to be building battery packs long term, but if it means helping restore these vintage systems, I will keep going as long as I'm able. I used my eBay account 80486sx to handle transactions since I started this. I've since restored RTC batteries for several Toshiba laptops and some PowerBooks. I mainly cover areas that don't have a coverage.