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Electronics Noob Question

Discussion in 'General Electronics Discussion' started by evanado, Jan 17, 2014.

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  1. evanado


    Jan 17, 2014

    I've recently gotten into a little bit of electronics because I am very interested in 12v outdoor lighting and 12v solar/wind chargers in general. I run a landscaping company, and I do a lot of low voltage outdoor lighting. Recently, I've even begun making my own custom lanterns and blah blah blah, enough intro. Thats me. Jack of all, master of none.

    So, I've also been making these power-pack/flashlights out of cigar boxes and very small SLA batteries.

    Anyway, as you can see, this is the first one I built. Its a battery, a swithch, an LED array, a barrel jack (to charge it) and a 12v-cigarette port, so that you can plug your phone/ipad/whatever charger into it.

    My next model will have a USB module as well.

    Now. My issue.

    I want to be able to charge the pack, FROM a car. So, yes, double male ended 12v cord, from the cigarette lighter in your car, to the power pack itself---Btw, I built this from my necessity to work in the middle of nowhere, and yet still needing to have my phone on me at all times.

    I want the pack to have two 12v ports [one in, one out] and a 5v usb module.

    Okay. So heres where my studies have lead me:

    So, from the [in] 12v port, first, solder this module: (LM317)

    Then I adjust the voltage up to compensate for the NEXT module:

    This one, I can adjust the voltage AND the current to exactly what I need to charge my little SLA battery, and it APPARENTLY shuts off and changes the LED indicator color to notify me when it's charged. I'm aware charging voltage is higher than the desired charge level.

    Will that work?
    Last edited: Jan 17, 2014
  2. evanado


    Jan 17, 2014

    I'm aware that there are some off-the-shelf products that would do exactly what I'm asking, seemingly. I have one.

    I'm interested in it being one unit, with the charger and module inside. It's just a lot more attractive that way. There should even be enough room inside the box itself to store the double-male-ended cord needed to do this. The other way to charge it is with a standard sla charger. [which is how the proto-type works] As you can see in the top picture, theres just a barrel jack there I charge through.

    And by the way, here is the USB module I intend to use. This is a step-down module, not a charger. In no way do I intend to charge the battery THROUGH this port. I intend to use this port to charge other devices that have internal charging modules. (Iphone, droid, etc.)
    I am fairly confident this module will work for what I am doing, but please. If you see something wrong, let me know. Did I mention I'm a total self-taught amateur? No classical training whatsoever. Be patient with me!

    I realize I'm not even close to the caliber of electronics people that pass through this forum, but any help I can get is much appreciated.

    Thank you all in advance.
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