dc power for lights

Discussion in 'Electrical' started by GTodd, Aug 3, 2012.

  1. GTodd

    GTodd New Member

    What if you use a dc/dc converter from TTi and hook it up to the white wire. input is 7.5v dc to 36v dc,out put is 0.5amp,output is 2w,output is 3.3v dc. use led's and a 9 volt rechargable battery. would that work?
     

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  2. darwin

    darwin Well-Known Member

    Check out the 53cc HS motor with a gen set on it, fix all your elec problems. Under 4 stroke I think.
     
  3. Fabian

    Fabian Well-Known Member

    Wonderful Creations has created a bespoke 12 volt lighting system for me, which will be available upon request. It does exactly what you want - a true regulated 12 volt system that charges a 4,000mAh lithium battery and also has a 12 volt cigarette lighter receptacle to recharge electronic devices.

    Spend good money and you will receive a good product.
     
  4. K-GEO

    K-GEO New Member

    Contact info?
     
  5. Steve Best

    Steve Best Well-Known Member

  6. Frankenstein

    Frankenstein Well-Known Member

  7. Frankenstein

    Frankenstein Well-Known Member

    Oh sorry you're Canadian, ehspoke and bespoke.
     
    CrazyDan likes this.
  8. Steve Best

    Steve Best Well-Known Member

    I resemble that remark...
     
  9. Rusty_S85

    Rusty_S85 Active Member

    Interesting. Ive seen the other ones that are sold that are real cheap I wonder just how good these are. I know they make AC LED bulbs. I'm throwing around ideas for a LED headlight and tail light for my build but I was looking at using like a couple AA or C cell batteries for power mounted internally to the lights but would much rather have a electrical source with a switch linking the two together.

    Looks like I got something to look into now and find more about.
     
  10. Frankenstein

    Frankenstein Well-Known Member

    My headlight is ac or dc 12v, it doesn't matter how you hook up the leads either on dc voltage.

    I don't know why they exist but they do and work just fine. If you are running some raw 12v ac from a gen then that might work. At a worst you could remove the electronic components from a suitable headlight and replace with the needed equivalent.

    A good headlight should be at least 10 watts to get a good light at 12v that's actually usable.
     
  11. Rusty_S85

    Rusty_S85 Active Member

    I'm actually looking at LED which limits my options unless I get a AC to DC converter. The LED bulbs I found that are automotive and they are AC/DC where they work either way the brightest is just .4 to .7 watts and puts out just 25 lumens. Hardly enough for a headlight not even for a tail light.

    I can get a plain old T10 wedge based LED bulb that is 350 lumens but its a 12v DC bulb. The 350 lumen one has a comparable wattage of 35 to 40 watts. This would be better for a headlight. But have to work around the whole AC/DC issue. I wonder why he doesn't design his to have a rectifier to convert it to DC. I mean it seems strange to offer a generator that is AC. No automotive vehicle out there produces AC current its all DC and while yes conventional bulbs can run off AC or DC, why would you create the issue in the first place.
     
  12. Steve Best

    Steve Best Well-Known Member

    Ok, time for some good ol' "mansplaining"...
    All modern automotive charging systems are a 3 phase AC "alternator".
    Their output is rectified to DC (usually internally) to suit the battery and other components in the system.
    3 phase is used because of its efficiency and it produces a very smooth (ripple free) DC current.
    Alternators (which produce AC) are used rather than DC generators because for a given output they are lighter,cooler and more maintenance free.

    Small motorcycles like my KTM offroad bike sometimes use a single phase alternator because they are simple, cheap and light. Because it has no battery, horn or turn signals, it can use the AC voltage to efficiently work the few incandescent lights it has. Because the voltage goes up with rpm it has a voltage regulator which is nothing more than a voltage limiter which shorts the current to ground if it goes over the 14.8v that the bulbs can withstand. To convert to DC is 1) not needed, 2) takes extra components, 3) reduces available wattage (power output) which is in short supply on small motorcycles and bicycles.

    LED bulbs typically come in 1) a DC only configuration or 2) some have an AC capability.
    You gotta test them with a meter to find which they are.
    The AC bulbs have a fullwave rectifier circuit built into them, so they are usually more expensive and generate some heat. No free rides. LED bulbs will tolerate a very wide voltage range (typically 4v-32v on an automotive LED) but if you exceed that voltage even ever so briefly, it is gone. Unfortunately AC tends to have voltage peaks that exceed its average voltage, so 12v AC can have 40v spikes in it if you don't have a voltage regulator in the system.

    I'd agree that about 350 lumens (which is about 35w incandescent) is about a minimum for a vehicle going 20-30mph at night. Still quite dim.
     
  13. Rusty_S85

    Rusty_S85 Active Member


    That's right. I don't understand why the builder of this doesn't design it to have some form of rectifier to rectify the AC current to create a DC current. You will have some ripple reguardless with the rectifier doing its job that's why the battery is supplying voltage as well to the electrical system to smooth out this ripple. Otherwise it would be pointless to use the battery for anything other than for cranking and just use the alternator for powering the system up once you are running.

    300 - 350 lumens is about where I am looking at as the LED conversion I'm looking at doing for a headlight once I find the one that I can use is going to have two bulbs. This would effectively give me a low beam and a high beam and depending on positioning in the reflector will determine the light pattern to some extent.

    Its just my sources for LED bulbs that I use in conversions on cars at work and for my own personal vehicles they only have 4 bulbs that are AC/DC compatible they aren't too expensive but the brightest one is only 35ish lumens. That might be fine as a tail light bulb as the low beam setting for a 1157 dual filament bulb is around 35 lumens. Cant use it for a brake light as the high beam is over 100 lumens.
     
  14. Frankenstein

    Frankenstein Well-Known Member

    http://www.ebay.com/itm/12V-10W-LED...50W-Outdoor-Flood-Light-battery-/192134720558

    This is basically the same product I have, from the same seller and the specs are the same for input and such, this is really easy to take apart, and there is a small board that takes care of rectifying the power. I took mine apart to waterproof it used seal all made by the same company who makes shoe goo. Anyway you could probably very easily take it apart or find a geeky enough person who would like to transplant the internals into a more fashionable lamp housing.
     
  15. Steve Best

    Steve Best Well-Known Member

    Awesome Frank! What wattage did you use and how bright is it?
    I can picture a 10w on the bicycle and a 30w on the KTM and Blaster.
     
  16. Frankenstein

    Frankenstein Well-Known Member

    10w it's pretty bright, it could be better but it's a flood light so it spreads the coverage out in front of you, not particularly the best for high speeds where things don't shine up much until you are within 20-25 feet of them, still provides good lighting in the dark since I have rather decent vision at night, especially without a windshield which can make it feel darker.

    I would like to get a good picture if my camera was better at night photos, i can say that signs light up well at a good 80-100feet but they are reflective so that should be expected.

    I'm personally thinking of turning it into a second running light, and then picking up a 30 that I could use in the darkest times at higher speeds.
     
  17. Rusty_S85

    Rusty_S85 Active Member

    See that's why I am trying to find a tail light and head light I like and then will gut it and convert it to meet my expectations. Problem is though I can either go battery with three AA batteries inside each housing or I could go with this power generator but that will limit me to 35 lumen LED bulbs or regular incandescent bulbs that aren't polar sensitive.
     
  18. Rusty_S85

    Rusty_S85 Active Member

    Well guess it doesn't matter because I just came across this.

    http://www.instructables.com/id/mini-cheap-ac-to-dc-converter/

    Using 4 Diodes the writer was able to convert AC to DC. That can also be done with LED as well I bet. But in any case use of four over sized diodes to make the rectifier could be placed in my case in head light and in tail light housings to convert AC to DC for my LED bulbs.
     
  19. Frankenstein

    Frankenstein Well-Known Member

    That's a bridge rectifier, it will work and that's what is in the lamp I mentioned just beefed up for 10 watts and has a capacitor to clean up the DC out. If you can manage to use a single high capacity battery as your mains over double a's then do it, messing with little batteries constantly is a pain.

    That wonderful creations generator only has a thing where it can get as high as 22 volts, doesn't matter how you rectify that since without a regulator that WILL blowout anything rated at the 12 that will normally feed from an automobile, voltages can get as high as 18 from a powerful alternator so many 12v can handle short runs at that voltage but anything more is usually electronic death.

    There's just no good solution for these things, either a handicapped electrical system that can't power much at all or using a separate battery that can power everything, but that means replacing or recharging regularly.

    I saw this nice lithium ion motorcycle battery at autozone or the alike, good capacity, lightweight, that would power any 12v system with relative ease, I might get it for my BT motor
     
  20. Rusty_S85

    Rusty_S85 Active Member

    See for me I don't plan to ride at night time I just want the lights to function if I mount them. So for me AA batteries mounted in each light would serve my purpose since I don't plan to ride at night. Only time would be during fall and winter if I take it to work after lunch and I have to ride home at 6pm in the dark. But only live 2 miles from home the route I take so the batteries should last me a long time.

    I just rather have the generator as I can make a box for the wiring and mounting a toggle switch to turn tail light and headlight on at the same time.
     
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