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  • Hand Built 26 Watt Portable Bluetooth Speaker

    Wow, thanks, I use these a lot

    Capacitors store power and release it fast as the amps demand it for the peaks. The power supply modules by themselves will be slower to react and the peaks will clip.

    Nice design, well thought out. Nice instructable. Can I suggest your next addition to your work space be a vice? You look like you are trimming your toenails with a jig saw, and trying to get a blood sample from your finger with a drill ;)

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  • How to Make an Automatic 12V Battery Charger

    #massimostep is correct up to a point. On the side of your battery you can see "cyclic use 14.1-14.4V",that is for deep cycle use. What you are doing at float charge (13.8V) is ok for say, a UPS for a raspberry pi, if you only unplug it for 5 minutes to plug it in somewhere else. You haven't taken more than 5% out, so you don't need absorption charge at the higher voltage. If you ran the pi all night you would be deep cycling the battery. Then 13.8V would only take the battery to about 80%. Batteries used like that might last 6 months then die. You might manually turn up the voltage till the battery voltage has been at 14.3V for half an hour. Note that due to voltage drop in the cables, what you see on your display will be higher than the voltage at the battery until the curre...

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    #massimostep is correct up to a point. On the side of your battery you can see "cyclic use 14.1-14.4V",that is for deep cycle use. What you are doing at float charge (13.8V) is ok for say, a UPS for a raspberry pi, if you only unplug it for 5 minutes to plug it in somewhere else. You haven't taken more than 5% out, so you don't need absorption charge at the higher voltage. If you ran the pi all night you would be deep cycling the battery. Then 13.8V would only take the battery to about 80%. Batteries used like that might last 6 months then die. You might manually turn up the voltage till the battery voltage has been at 14.3V for half an hour. Note that due to voltage drop in the cables, what you see on your display will be higher than the voltage at the battery until the current comes down.Nice instructable, nice production.

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  • Robotic Arm 3D Printed (DIY Initial Prosthetic Prototype)

    Great instructable, and honest. Don't give up, no prototype works perfectly

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  • Make Your Own Photovoltaic Off-Grid System

    Open circuit voltage on a 12v panel might be 22V, calculate current for that. What is the max current your led can take? Calculate R(resistance) = V / A (ohms law). Power of the resistor, Watts = V x A (the more powerful resistors are basically bigger in physical size)

    You're talking about the solar charger, but say nothing about the discharge. For best life don't run your AGM or other lead acid batteries at an average of more than 20% depth of discharge. For an 18ah battery that's 3-4ah depth of discharge. You could run a half amp led light for 7 hours , fine. But a 4A TV, only one hour... Without the led light running that day.

    AC is safer, it doesn't sustain an arc as much. DC is still used eg NZ cook straight transmission is DC, it doesn't lose power to capacitance with the ocean like ac would.

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  • Make Your Own Photovoltaic Off-Grid System

    Definitely, all sorts of things run off 12V these days. More efficient and safer.

    It's probably too smaller batteries for the loading, so the batteries fail, maybe not the inverter.

    I don't mean to pick (sorry, solar is my job :) you shouldn't run a 400W or larger inverter off the load output of the solar controller which is rated at 20A. 400W continuous inverter might surge to 800W, which is 66A from the 12V supply. A 100Ah battery won't reliably run an inverter over 240W.Re an earlier question, house mains sockets at 240V are rated at 10A typically. That's 2400W for one outlet... Don't even think about wiring a 600W or 400W inverter to this, it will end in tears! Use appropriate circuit breakers or fuses.

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  • CraigH23 commented on Magnetic Games's instructable Ferrocell, Magnetic Fields Viewer4 months ago
    Ferrocell, Magnetic Fields Viewer

    An old fashioned CRT TV displaying a plain white screen shows magnetism well, but then it stays magnetised

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  • CraigH23 commented on imsmooth's instructable Homemade Liquid Nitrogen Generator5 months ago
    Homemade Liquid Nitrogen Generator

    Excellent project. I had searched for something like this years ago, but assumed it was too dangerous, now reading this I still think that. I read an old book on electric cars from the 1960s. One design, used lead acid batteries, and liquid nitrogen. The N2 was circulated through copper pipe which at room temperature makes a good conductor of electricity to the motor, but cryo cooled it's resistance dropped much further. N2 was also cooling the motors for the same reason. At the point where the gas was released it was at a high enough pressure to run a turbine electrically coupled to the motor or battery. Basically, N2 was the fuel, the batteries were short term storage. That started my interest in cryo gas production, but I think I'll leave it to the experts now. Liquid oxygen could be...

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    Excellent project. I had searched for something like this years ago, but assumed it was too dangerous, now reading this I still think that. I read an old book on electric cars from the 1960s. One design, used lead acid batteries, and liquid nitrogen. The N2 was circulated through copper pipe which at room temperature makes a good conductor of electricity to the motor, but cryo cooled it's resistance dropped much further. N2 was also cooling the motors for the same reason. At the point where the gas was released it was at a high enough pressure to run a turbine electrically coupled to the motor or battery. Basically, N2 was the fuel, the batteries were short term storage. That started my interest in cryo gas production, but I think I'll leave it to the experts now. Liquid oxygen could be disastrous around petrol vehicles, nitrogen dangerous in the cabin. Thanks, very interesting.

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  • 6.3 kiloWatt Ground Mount Home Solar Array

    From the snow on the ground it seems your latitude is at least 45 degrees. For a grid tied unit you want to maximum the summer sun for best payback - so angle to your latitude. If living off grid latitude + 5 degrees will maximize for winter sun, the hardest time of year to get through.

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  • CraigH23 commented on marcus2015's instructable Make your own lye1 year ago
    Make your own lye

    I accidentally made NaOH while making hydrogen gas by electrolysis of water. It was going very slowly so I figured common salt (NaCl) would help conduction and speed things up. It did speed my hydrogen production up, but on smelling the strong smell of chlorine gas at the other electrode, and some school chemistry I realised that the remaining solution must be NaOH, caustic soda

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