update/add post

Author: RCmags

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-Sometimes its cool to try out different projects just to see if you can pull them off. One of them happened to be making a battery backup for a laptop. Now, at first this sort of doesn't make sense. Don't laptops already have batteries? Yes, they _generally_ do, but there are times when either the capacity is insufficient, or the battery doesn't work or is too much work to replace. In those cases, what can we do to run the laptop without AC power? Simple! Just "mimick" the power provided by an AC adapter with a battery! 
+Sometimes it’s fun to try different projects just to see if you can pull them off. One such project was creating a battery backup for a laptop. At first, this might seem unnecessary since laptops already have batteries. However, there are situations where the battery's capacity might be insufficient, it might not work, or replacing it could be too challenging. In these cases, you can run the laptop without AC power by mimicking the power supplied by an AC adapter using a battery.
 
-How exactly can this be done? Batteries differ greatly from AC power supplies. They have variable voltage and need a charging circuit, and the batteries need to be the right size to power the laptop a reasonable time. All of these things are true, but the project itself is not that hard. Here's an example of such a powerbank built by [GreatScott!](https://www.youtube.com/@greatscottlab):
+Batteries and AC power supplies are quite different. Batteries have variable voltage and need a charging circuit. Additionally, the battery must be the right size to power the laptop for a reasonable time. While this might sound complicated, the project itself is manageable. Here's an example of a power bank made by [GreatScott!](https://www.youtube.com/@greatscottlab):
 
 {% include youtube.html id='ZQjazsiyr8s' %}   
-<p align="center">Video 1. DIY laptop powerbank</p>
+<p align="center">Video 1. DIY Laptop Power Bank</p>
 
-It's possible to make something very similar with a few inexpesive components. These may inclue:
+You can create something similar with a few inexpensive components. Here’s what you’ll need:
 
-- __A large capacity battery__: Its possible to use any kind of battery so long as its rechargable and can safely output the power needed by the laptop. To this, one can use an inexpesive lead-acid battery, or a slightly more expensive and better performing lithium-ion battery.  For this project, we shall stick to a 12v 3S Lithium-Ion pack made of multiple 18650 cells. 
+- **A Large Capacity Battery**: You can use any rechargeable battery that safely outputs the required power for the laptop. Options include inexpensive lead-acid batteries or better-performing lithium-ion batteries. For this project, we’ll use a 12V 3S Lithium-Ion pack made of multiple 18650 cells.
 
 ![image](/img/laptop-ups/parts/battery.jpeg)
 
-- __DC-to-DC step down converter__: This component serves as the charging module for the ups. By settings its maximum current and voltage output, we can easily charge a wide range of arbitrary batteries. Whatever is used, the input voltage to this module MUST exceed the charge voltage of the battery. On the other hand, the maximum current will be limited to what's safe for the battery, and the power output of the voltage input source.
+- **DC-to-DC Step-Down Converter**: This component acts as the charging module for the UPS. By setting its maximum current and voltage output, it can charge various batteries. The input voltage to this module MUST be higher than the battery’s charge voltage. However, the maximum current will be limited to what’s safe for the battery and the power output of the voltage input source.
 
 ![image](/img/laptop-ups/parts/step-down.jpg)
 
-- __An AC-to-DC power converter__: A typical 65W charger brick from a laptop will work well. They are rated at approximately __20v__ output and a maximum current of __3.25A__. It's possible to use any similar converter so long as the voltage is higher than the fully charged voltage of the battery, and the maximum power is greater than that of the laptop plus the step-down converter at constant current.
+- **An AC-to-DC Power Converter**: A typical 65W laptop charger works well. It usually has a __20V__ output and a maximum current of __3.25A__. You can use any similar converter as long as its voltage is higher than the fully charged battery voltage and its power exceeds the laptop's requirements plus the step-down converter.
 
 ![image](/img/laptop-ups/parts/ac-charger.jpg)
 
-- __DC-to-DC step up converter__: Since the battery has a variable output voltage that changes with capacity and instantaenous current load, we need a module to regulate this variable voltage into a steady output. By assuming that our battery will always have a lower voltage than that required by the load (in our case, 20v for the laptop), we must always increase the battery voltage.
+- **DC-to-DC Step-Up Converter**: Since the battery voltage varies with capacity and instantaneous load, you need a module to regulate this variable voltage into a steady output. Given that the battery voltage is always lower than the required load voltage (20V for the laptop), the step-up converter will increase the battery voltage.
 
 ![image](/img/laptop-ups/parts/step-up.jpg)
 
-- __Some communation module or a relay__: The ups needs to switch between charging and discharging the battery, so some kind of device needs to be used to redirect the AC current into either case, depending on whether AC is available or not. To this end, a very simple solution is a relay switch and that activates with the AC current, and connects the battery to the step-down converter/charger.
+- **Communication Module or Relay**: The UPS needs to switch between charging and discharging the battery. A relay switch that activates with the AC current and connects the battery to the step-down converter/charger is a simple solution.
 
 ![image](/img/laptop-ups/parts/relay.jpg)
 
-With this combination of components we can make a system that automatically switches between AC and DC power. In the case of AC power failure, the relay will quickly switch to battery power to maintain power. However, since the relay is a mechanical device it will take a finite ammount of time to change state. This delay will cause power to the laptop to be dissabled momentarily, meaning the laptop will have to be powered by its internal battery for a short ammount of time while the UPS transitions. As a consequence, this design means we have __interrupted power supply__. Despite this drawback of a relay, it comes with some advantages:
+With these components, you can build a system that automatically switches between AC and DC power. If AC power fails, the relay will quickly switch to battery power. However, because the relay is mechanical, it takes a short time to change states. This brief delay will cause the laptop to briefly rely on its internal battery while the UPS transitions, resulting in an __interrupted power supply__. Despite this drawback, relays have some advantages:
 
-1. A relay has very little contact resistance since its just a mechanical switch. Either when its coil is powered or unpowered, the voltage drop across it is small. 
+1. Relays have very low contact resistance because they’re mechanical switches. The voltage drop across them is minimal, whether the coil is powered or not.
 
-2. There is little heat loss by the relay in its unpowered state. This is also helped by the low contact resistance since it the very low loss means even less heat.
+2. There is minimal heat loss in an unpowered relay due to its low contact resistance.
 
-By comparison, other switching methods like transistors or diodes will generate more heat when current flows through them. On the upside, being solid-state devices their switching time is instant compared to a mechanical switch. 
+In contrast, other switching methods like transistors or diodes generate more heat when current flows through them. However, they have instant switching times compared to mechanical switches.
 
-Putting all of this information together, we can assemble the components into the diagram below:
+Combining these components, you can assemble the system as shown in the diagram below:
 
 ![image](/img/laptop-ups/laptop-ups.png)
-<p align="center">Schematic of UPS circuit</p>
+<p align="center">Schematic of UPS Circuit</p>
 
-Note how overall system is fairly simple. It's essentially a pass-through for the AC-to-DC converter, and an automatic charger for the battery. Moreover, the __input voltage__ from the AC-DC converter just has to be __higher__ than the __battery voltage__, but it does NOT have to match the voltage required by the laptop. As a consequence, the we can use a ~12v converter up to a ~20v converter with this design. It's input voltage is very flexible. 
+The overall system is quite simple. It essentially serves as a pass-through for the AC-to-DC converter and an automatic charger for the battery. The __input voltage__ from the AC-DC converter only needs to be __higher__ than the __battery voltage__. It does NOT need to match the voltage required by the laptop. Thus, a ~12V to ~20V converter can be used with this design, offering flexibility in input voltage.
 
 {% include image-slider.html list=page.slider1 %}
-<p align="center">Views of the completed direct-current UPS</p>
+<p align="center">Views of the Completed Direct-Current UPS</p>
 
-As the images show above, the completed diagram shows how the assembled UPS is fairly compact and functional. It can be completely turned off by unplugging the AC-DC power supply and disconecting the battery from the rest of the circuit (via the power switch). Moreover, by addings a handle to the device it can be easily moved around. 
+As the images show, the completed UPS is compact and functional. It can be completely turned off by unplugging the AC-DC power supply and disconnecting the battery via the power switch. Adding a handle to the device makes it easy to move around. Overall, this was a relatively simple project that proved useful in off-grid situations. With a 4th-generation Intel laptop drawing around 10W to 40W, I was able to keep it running for over **16 hours**. Quite an achievement for some inexpensive modules wired together!

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+---
+layout: post
+title: "Remarks on old laptops and low spec computers"
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+slider1:
+- url: /img/laptop-ups/complete/ups-0.jpg
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+For a number of years I had the misforture of using a very slow laptop without knowning any better. What exactly do I mean by this? One of the issues with computers, from a user standpoint, is that performance is relative. You perceive something as "fast" if happens within a timeframe you deem acceptable. For example, In 1995, rending a relatively plain 3D image of a landspace would take hours. 
+
+By comparsion, almost any comercial device in 2024 can recreate that image in much less time. Despite that enourmous increase in computing power, for the people 1995, they through their equipment ran fairly quickly given their expectations of the task. The same effect can happen to anyone if they aren't exposed to something they can qualify as "better". In my case, this lack of perception came about slowly, through the use of very slow Fanless laptop from HP. More specifically, the HP15-223fm:
+
+It sported a mighty Celeron N3050 processor, 4gb of single channel RAM, and a 500gb 5200RPM hard drive. For 2005, the performance of this device would have been noteworthy, especially given its size and the __very low__ power consumption of the processor (only 6W TDP). In that era, a similar processor would easily consume 65W. That's a tremedous difference of power draw for the similar computational power.