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  • Convert old cordless tools to Lithium power

    You should really emphasize the need for high discharge rate batteries. If someone tried to do this with a non protected lithium battery that is not rated at a high enough discharge rate, the battery could heat up and explode. The discharge rate is the 3C or 4C you mention. Some drills can suck down a lot of current at once.

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  • Easy 5 Minutes USB Solar Charger/Survival USB Charger

    While thats great, any ICs or other parts can be purchased online, and usually cheaper than the parts that are used in this instructable. The biggest issue with this though is that its effectively useless unless you want to charge something very slowly with it powered down. The solar panel is only 200 mA, which is less than half what a normal usb socket puts out (and thats under ideal full sunlight). Most phones require 1-1.5A to charge at any reasonable rate, and will take forever to charge at 500mA on a regular usb port. At less than half of that, your phone will not actually "charge" while its on. You will continue to lose battery (albeit a little slower). A simple battery inside the housing would allow the panel to charge up a battery, which can then supply the proper curr...see more »While thats great, any ICs or other parts can be purchased online, and usually cheaper than the parts that are used in this instructable. The biggest issue with this though is that its effectively useless unless you want to charge something very slowly with it powered down. The solar panel is only 200 mA, which is less than half what a normal usb socket puts out (and thats under ideal full sunlight). Most phones require 1-1.5A to charge at any reasonable rate, and will take forever to charge at 500mA on a regular usb port. At less than half of that, your phone will not actually "charge" while its on. You will continue to lose battery (albeit a little slower). A simple battery inside the housing would allow the panel to charge up a battery, which can then supply the proper current at a reliable voltage. This also would enable you to store the sunlight even if you don't need a charge at that moment. Without some sort of regulation to keep the current and voltage stable, your device might behave strangely while plugged into this.Most importantly, if you are doing these things with your kids PLEASE PLEASE PLEASE make sure everyone is wearing safety glasses. Its one of the most overlooked things because people think "its just soldering", but there are 2 people I am acquainted with who are blind in one eye because solder was flicked into their eye while trying to desolder a wire (which is what is being done at one step in this instructable). Solder is metal at 700 or so degrees and it will do heavy damage to any unprotected sensitive body parts.

    If hes using a 5V solar panel the car charger seems to be almost entirely pointless and is only really useful for the usb port itself.

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  • rundmcarlson commented on unetity's instructable Outdoor Kitchen Island4 months ago
    Outdoor Kitchen Island

    fusion 360 has a free yearly license for personal use or startups http://www.autodesk.com/products/fusion-360/try-buy

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  • A Guide for Buying LED's on E Bay ---- Part TWO

    You need a bridge rectifier, or sets of diodes/rectifiers that bring the flow from both halves of the wave to the device, removing your flicker. This image shows what I mean: https://www.elprocus.com/wp-content/uploads/2014/0...If you really want efficient bulbs, its not hard to make them yourself. If you can etch boards and buy some surface mount LEDs, you can get many high efficiency LEDs that you simply have to solder down. The circuit that runs it can use a simple switched-mode power supply or a "joule thief" style circuit that you can control the flicker rate. If your "joule thief" flickers higher than 200Hz you won't even notice it flickering, but you are still saving some power by having it flicker.

    The reason "100W was 100W" is because incandescent is just electricity running through a long thin loop of tungsten (because resistance increases with length and decreases with surface area). The high resistance makes the tungsten hot and it glows. Since the heated tungsten always creates the same light intensity at a given wattage, there is no difference between brands. LEDs on the other hand work in a fundamentally different manner. Not only that, but there are varying degrees of efficiency in LED designs. This leads to different lumen output at different wattage.Ultimately, the use of Watts as a measurement for lightbulbs is somewhat stupid in this age. Watts only measure the power usage of the device, not its brightness. Thats why LED, CFL, and incandescent all put out dif...see more »The reason "100W was 100W" is because incandescent is just electricity running through a long thin loop of tungsten (because resistance increases with length and decreases with surface area). The high resistance makes the tungsten hot and it glows. Since the heated tungsten always creates the same light intensity at a given wattage, there is no difference between brands. LEDs on the other hand work in a fundamentally different manner. Not only that, but there are varying degrees of efficiency in LED designs. This leads to different lumen output at different wattage.Ultimately, the use of Watts as a measurement for lightbulbs is somewhat stupid in this age. Watts only measure the power usage of the device, not its brightness. Thats why LED, CFL, and incandescent all put out different amounts of light and at different watts. At one point I'm sure people only cared about how much electricity the bulb uses, but now the amount of actual light (lumens) is a far more important metric to make sure you get bright enough lights.

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