48V DC to 12V DC converter, backwoods method, charge tractor battery, run solar tracking, ETC.

A simple low tech way of converting high voltage DC(48v) to 12v with a buffer to supply power to {solar lights} tracking and charge controller circuits. Build a charge controller with the circuit and instructions in the book Wind and {solar lights} Electricity by Andy Reynolds. Available at Lowimpact.org, youir local book shop, Camden Steam, Centre for Alternative Technology, and online.


{solar lights} & Wind EBooks
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13 Comments on "48V DC to 12V DC converter, backwoods method, charge tractor battery, run solar tracking, ETC."

  1. neil b says:

    interesting stuff… remeber em battery milk floats sort of like the future in the past 

  2. Thanks for the comment. Like modern electric vehicles the old milk floats suffered from excess weight and lack of range.

  3. Dennis Haack says:

    You seam very knowledgeable about electrical information. I know that most times when you flip a switch the light comes on. Anyway her is my question :
    What would be better ?
    Using a 12v deep cycle battery (i.e. RV battery)
    I want to charge a phone.
    Hook it up with a 12v cigarette plug in ?
    Or invert to 110v and plug in that way ?
    Which way will consume more power ?
    Thanks, Dennis 

  4. Dennis. Just thinking about it using a 12v car type charger then you are only running the regulator. If you use an inverter and then a standard charger you are using 2 pieces of equipment, each will use power to run itself. The inverter will use at least 20 watts (1.6 A) just to run. The former is the way. Hope that helps. Andy

  5. Dennis Haack says:

    Thanks, I guess that makes sense. 

  6. Dennis. Thanks for your comment. It's easy and you can make it from bits lying around. The battery does not need to be grade A, as long as it does not self discharge quickly, after all it is acting only as a buffer and is constantly being trickle charged. A pragmatic and low cost way of betting around the problem.

  7. John French says:

    Good video Andy.What is the voltage from the light bulb to the battery?

  8. ATCRyderX© says:

    I'm a rookie who is a bit confused at to whats going on here. What I want to do: I have a Mobile Home that is no longer hooked to electricity. I run everything off a 12V inverter on a marine Battery. I want to use that Marine Battery to make my normal electrical system in the trailer function. Is what I'm watching even close to that scenario?

  9. xanataph says:

    Awesome. I like to use incandescent light bulbs as resistors whenever possible for purposes like this.  Because, as you probably know, they have a big advantage over a normal resistor – they change their resistance according to current flow. This can be very handy when charging batteries as they essentially constitute a "near constant current" source. Sometimes I use them to take a feed from my main array through a small charge controller to an auxiliary battery. The bulb prevents the array from overpowering the controller. For this kind ov thing I usually use 12v 50watt Halogen reflector bulbs, or recycle car headlights that have a dead low beam filament. Uses like these seem to be the only place for an incandescent light bulb on a off-grid system. They are too power hungry to be used for their intended purpose when better options are available such as LED & CCFL. :)

  10. Monideth Pen says:

    Great video! Clear and informative. Thank you for sharing the knowledge. I assume this method is also applicable for a 36v source?

  11. IPIX360 says:

    Could I convert 96v DC (coming from the windturbine) to 48V DC battery bank? Could you help with any ideea where to start?

  12. Dan Libby says:

    interesting. What if I want to run a load that is say 10 amps @ 12 volts? Will this method work? or the bulb will burn out? Or the 12v battery will eventually discharge?

  13. Amazing video. Couldn't have explained it better. This is my scenario, i have a 48v power supply and i want to run a 12v pc fan that draws 0.3 amps. What are your suggestions or thoughts? thanks for your help

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