Monday, November 9, 2020

How to make your own laptop battery out of lithium-polymer cells.

Just thought this story may help others fix old laptops with batteries that no longer hold the charge.

A few years ago, sometime in 2016 or 2017 - I bought a really cheap laptop off of a Microsoft Store website. The laptop was Trekstor C11B - the cheapest Windows laptop you could get at the time, that wasn't a celeron or a chromebook. The laptop had a joke 32GB SSD and 4GB RAM, but a nice ergonomic design and a decent full HD touch screen. Later I upgraded it to 256GB SSD, but this story is not about the laptop.

It's about how to make a new battery yourself for basically any laptop brand no matter how old.

Disclaimer: the below instructions are provided for information purpose only, I'm not responsible for any of your attempts to fix something that may have failed, especially if you never soldered your own wires before. In other words - your mileage may vary and you are on your own. With that being said keep reading.

What happened with my Trekstor Primebook as it was getting older - the battery was getting bad. Eventually it became so bad that even touching the power connector would shut down the computer completely. The other weird thing was the laptop had problems coming up after abrupt shutdowns. I believe that was due to its power management when it detected no battery it wouldn't start up at first, but only after a few power button presses. Even worse, the battery started to overheat and expand to the point that the keyboard began to bulge. That was not only bad but really dangerous.

So I opened the laptop and removed the blown battery pack. This is what the original battery looked like (cooled down and deflated):

I thought I would buy the new battery somewhere. Tough luck. The manufacturer (Trekstor Gmbh) was done with laptops and was selling scooters. Nice. EBay or Amazon didn't seem to sell anything even remotely compatible. I even asked a buddy to post a 'helpme' message at (

It took me several months to realize that no one in the entire world except may be one aliexpress seller really sells that type of battery. Even so, the price was around $60USD and the shipping times where anywhere from 2 months to never. Not good. I never expected to get something from Microsoft Store and later realize that there is no support and you are on your own especially if the manufacturer is out of business. 

So I went ahead and (carefully!) cut the battery shell open to remove the external sticky plastic. Hey, don't cut the actual cells, because they may blow up in your face and start the fire(!). It's all because of lithium gel inside the battery which may combust if it touches the air. 

I very carefully cut and pulled the sticky plastic around the battery pack - on the concrete floor in the garage for extra safety - keeping the cells flat and not bending them at all. I didn't cut into the battery cells, just peeled the black plastic cover to separate the cells from the frame.

In my particular case there were two 3.8v battery cells inside the frame. Each cell is about 70mm by 110mm size and about by 3mm thick. Here is the photo of one of the cells after I cut its connectors out of the charging circuit:

It took me quite a bit of time to actually find a battery cell manufacturer in the continental US which could ship the cells. I found one on ebay (sorry no link, just a photo)

I emailed the seller to make sure the battery is as pictured and is close to 2.5mm rather than 25mm (1") thick. The other two dimensions - 75mm and 110mm were about right. As the matter of fact, the new battery was wider a bit than the original, so I had to adjust the frame before install.

I bought two battery cells each 3.8v to have 7.6v total. They came in a small box a few days later. Each cell came pre-charged to 3.8v and with the positive connector insulated. Each battery cell also had some circuit inside. Luckily, the cell+circuit size was not exceeding my specifications.

Next, I tested the charging circuit by connecting the battery frame to the computer and connecting each cell with crocodile connectors to the charging circuit on the frame. It seemed to work with no heating or bulging of any components, so I decided to move on to soldering the cells.

To solder the cell wires to the frame terminals you will very likely need an aluminum flux and solder kit (click for the product) such as the one I bought from Amazon. It was a tiny bit too expensive for my needs (I needed just a little of it), but it came with the applicator and the solder wire - which both turned out to be very useful. The actual product looks like this:

I am not too good at soldering things. Before this I soldered a few copper wires, never aluminum. So I decided to practice a bit. I tore off a small sheet of aluminum foil - food grade, nothing less. Heated up a small soldering iron (no more than 40W). Dropped a few drops of the liquid flux from the kit on the foil and used the solder wire from the kit. I figured that I need very little flux liquid and very little solder wire with just a touch of the solder iron for my purpose. The alum flux works nicely with temperatures lower that regular copper solder flux. That was good to know before trying to solder the battery cells to the terminals.

Even before soldering anything I tried to arrange the battery cells in the packs and close the frame. It turned out the cells were a bit too wide, so I cut and sandpapered off some plastic from the frame to allow its edge to overlap one of the cells. See photo:


Next, keeping my fingers crossed (imaginably of course) I first applied just a bit of solder alloy to the terminals without attaching the battery wires yet. The plan was to make sure the flux works well. Also, the instruction recommends washing off the excessive flux with water. I figured it's because the flux is purposefully acidic for removing aluminum oxidization, and leaving it on the surface may corrode the terminals over time. So.. I tried to apply just a bit of water on the terminals to wash off the flux. It removed some but not all. Dried it afterwards too with napkins.

This is what the frame with solder terminals looked like, the battery cells are not installed yet.

Next, I soldered the negative wire to the corresponding terminal on the frame, then removed the scotch tape from the positive (red) wire and soldered it to its terminal. Ditto for the second battery cell.

I immediately covered the electric terminals with sticky tape to prevent any accidental short circuit.


I arranged the cells within the frame and closed the frame. 


I used duct tape (white) to hold the cells within the frame:

The next photo shows what the 'final product' looked like before installing into the laptop:


The laptop worked right after install!

Subsequent tests showed that the full charge is enough for about 2 hours of work under medium load - screen on 90% brightness, active web browsing, etc. That's about the same when the laptop was new.

I hope that after a few drain and recharge cycles the computer will adjust and slightly improve its battery use time.

Monday, September 28, 2020

Visual Studio 2010 upgrade to 2017 - finally!

Latest update. I am gradually migrating from VS2010 to VS2017 for Web projects. So far, the 2017 is good for the task. It's still somewhat annoying when working with C# code with different keystrokes, popups and color highlighting, but it's way better with Javascript code parsing. It saves me tons of time when debugging JavaScript. While VS 2010 is still the tool I utilize for Windows Forms projects and other lightweight applications, for Web the 2017 is looking like the tool I can finally migrate to. And I'm doing just that.

Friday, February 28, 2020

AWS Monitor Portal and other projects.

As my grandfather used to say: no one will honor you if you don’t honor yourself.

So.. a few words about my recent accomplishments in the world of software development.

Many people heard about Elastic Cloud Gate for AWS, some may even use it. For me, seeing it was an unforgettable experience. A ‘nice’ ASP interface from the 90’s, small fonts, lots of clicking around. Their software does have a lot of functionality, most of which however duplicates AWS Console. Their killer feature for us was scheduling AMI backups and other standard AWS tasks such as reboots. The outdated used interface of the eCG remains their huge issue - if you ever used the eCG you would prefer to set it to the auto mode and never see again (here and here).

Meet the guy who single-handedly designed and developed a product to fully replace the eCloudGate for the company he works for, and for many customers of ours. This has not only saved our company $2,500+/mo, but also lots of support time and countless frustration moments. Not mentioning that we can now pocket some profits by offering the service to our customers.

I won’t go into many details here what my software can do especially if you are already familiar with the eCloudGate website. What is notable is that my product besides doing scheduled EC2 AMI and DR backups also helps people manage AWS WorkSpaces. Last time I checked the eCG did not do anything for WorkSpaces besides reboots.

AWS WorkSpaces are virtual Windows Desktop machines offered by Amazon AWS for individual and business needs. Users can run any software they want on them much as on their own Desktops, but without fear of ever losing data due to virus or encryption attacks. Superior recovery is not the only strong side of the WorkSpaces, their speedy performance and easy maintainability make them grow in demand in the corporate world.

In short, the company I work for helps customers migrate their networks to AWS VPCs and Desktops to WorkSpaces. Besides that, our company itself owns hundreds if not thousands of EC2 instances under many departmental AWS accounts. Thanks to me and my software we now have a centralized portal to support and manage thousands of machines… and even make some money on that.

A few ‘killer’ features of my AWS Monitor Tool:

- simple and responsive user interface (here and here),
- separate administrative, customer-level , and user-level accounts,
- remote control and scripting of WorkSpaces and EC2 instances (here),
- WorkSpace and EC2 instance support and management:  real-time ‘heartbeat’ and inventory, scheduled backups and other tasks,
- and a popular feature: users can reboot their own WorkSpaces via a Text Message (SMS) (here).

Some stats as of today: my AWS monitor database is gaining 2-3 million records daily into its SQL databases.

Drop me a note if you want to find out more..

outdated eCG interface
outdated eCG interface

Saturday, January 18, 2020

Happy New 2020 Year dear Visual Studio 2010!

Seven years seems to be a long break between posts, but I must admit during that time there were no dramatic changes in my job description, while of course there was some progress.

We all evolve in our work as in no way we wouldn't if we wanted to keep our jobs. We learn new skills and tools as the industry moves forward. But some things like an old boombox from the 80's just keep working. So why not to use it?

Today I'm here to say Hi to a venerable tool that many of us still use even though it's not as popular anymore. To my opinion it's one of the best ever created by Microsoft and it remains one to this day.

Ladies and Gentlemen - I welcome the Visual Studio 2010 to the podium!

It's quick to open.

Have you used the VS 2017 or 2019 lately? Did you notice that it takes anywhere from 30 seconds to 2 minutes just to open the environment on a fast Intel i5 computer with SSD and 8GB RAM? Guess what, the SQL 2019 Management Studio takes even longer on a super-fast Xeon server with even more memory! The dev tools that Microsoft gave birth in the recent years are bloated pieces of junk umm.. software.
Visual Studio 2010 opens in under 10 seconds.

It's simple.

Do you have to juggle between 4 or even 5 different languages in your VS 2017 just to add a few things to a web page? HTML, C#, JavaScript, TypeScript, and Angular? Don't you want a hint of Linq on top of that? Do you also have to do SQL in the same project? What? Are you not happy with that?
It kinda feels like doing a translation job for the United Nations - you have to bounce between English and Spanish, then Afrikaans' flavour of Dutch, then quickly jump to Chinese, then back to English. Gosh.. that's heavy.
Guess what, if you apply for a job and honestly state in your resume that you are fluent in German, they won't even interview you as they want the Southern Austro-Bavarian dialect of German for some reason. WTF?

It compiles code into very compact footprint.

Let me give you just a couple of examples.

1.5 years ago I completely redesigned one of my software projects, which happens to be also #1 in Google for its keyword. It has millions of users and 50-60GB of daily uploads.
That project has it all: C# with .NET 4.x, AngularJS, HTML, Android API, clean and fast SQL queries - all the cool stuff.

Guess what.. the DLL that does all of that is only 100Kb. It could fit on a 360Kb floppy!

Btw, what you see on the picture is the entire contents of the BIN directory. The project runs and stores files in S3 buckets, hence the 3 extra AWS DLLs to support that. That's all.

The other project I've done in the last couple of years and which I maintain on a daily basis incorporates quite a bit more functionality.
Well.. it has to, otherwise it wouldn't have over 120 thousand lines of code!

It does a lot of modern stuff including API access via JSON/REST protocols and it does a lot and I mean a lot of database talk. The average daily traffic is reflected in over 2 million daily SQL INSERT calls via just one server with occasional spikes in traffic. I didn't count how many SELECT queries it does, but I'm sure a lot.

That project is designed to do AWS infrastructure management that AWS console happens to do well, but there are some functions that the console does not do too well, specifically the WorkSpaces management and more. If you ever used AWS Console you know what I mean. But.. anyway.

The DLL that runs the whole thing - API and all - is 444Kb. Nice!

The only 3rd party DLLs in the BIN directory are AWS runtimes. No freakin 'scaffolding' or auto-generated junkware code.
For a comparison, a simple web-based "hello world" in VS 2017 eats up 15 to 60 Megabytes (!) of space for its BIN folder.

Do you have any questions or opinions? Do you want to discuss that? Post a comment.