Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations waross on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Tapping power from a gas engine to light an LED 9

Status
Not open for further replies.

paskee

Agricultural
Nov 8, 2012
18
Hi Guys,

I am an Agicultural Engineer (Irrigation & Water Mngt).. and I'll highly appreciate any help/advice you can share on...

I operate on a farm (in the Philippines) several gasoline (anywhere from 6 to 10HP) "pull start" (rather than battery start) engines that drive water pumps. These pumps/engines are operated during the night (it is pitch black!). While the engines/pump are in line of sight, they are located far (100-400 yards) from where we can view them. At present, we do not know wether the engines are ON or OFF unless we inspect them regularly and individually.

Since combustion in the engines is done thru "spark plugs" and a magneto, is it feasible and practical to tap some current from the ignition system to power an LED ?
If so, will it significantly degrade the engine's efficiency?

Thank you,
Paskee
PS. I can get the engines wiring diagram from the manufacturer.
 
Replies continue below

Recommended for you

One issue with motion activated mechanisms is that you need to make sure that wind cannot cause the same effect.

TTFN
faq731-376
7ofakss
 
Sure, you need to take wind direction and speed into account.

Gunnar Englund
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
 
The $10 budget makes 'lit when not running' more difficult.

I'd start with about five turns of #24 solid insulated wire wrapped around the engine's spark plug lead and just soldered to the terminals of an LED. If the LED burns out quickly, insert a resistor.



Mike Halloran
Pembroke Pines, FL, USA
 
Dead end. Too weak current, too short duration. And winding secondary around primary winding doesn't make a transformer.

Gunnar Englund
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
 
What about a nylon wind sock that gets inflated with the exhaust port of the engine? If it's sticking up in the air and waving about you know the engine is running.

"Art without engineering is dreaming; Engineering without art is calculating."

Have you read faq731-376 to make the best use of these Forums?
 
All these engines will have a wire to short out the "points" whether mechanical or an electronic module to stop the engine. A capacitance load of .047 connected to this lead should have no effect on the ignition system. Just add a full wave rectifier and small cap to extend the pulse should produce power for the LED. Add current limiting resistor selected more to extend out the pulse than to actually limit current. My experience with LED has shown that these easily "ghost" with as little as a couple microamps of current. On a really dark night these should be visable if a reflector is included to spread out the light. When this rain stops I will try this on my lawnmower.
 
HI Operahouse,

Plese tell me your what happened to the device on your lawnmower.. maybe the solution I am looking for
Thanks
Paskee
 
I tried the experiment on the lawnmower today and the results were good. I used a 3W 120V 6X6 LED assembly
which the normal power board had beenremoved because of damage. That 6X6 array in series normally starts
conducting at about 90 some volts if I remember. My power circuit was a .1uF 400V capacitor from the points
connected to the center of two 1N4005 diodes in series. The minus side of the diode string connected to ground.
The + side of the string connected to another .1uF cap filtering the output and a 300 ohm resistor going to the
+ side of the LED string. Engine was run at a fast idle and I estimate this was maybe 0.1 to 0.25W of power going
to the lamp. Not bright but clearly visable in daylight. I tried another 120V LED lamp directly across the
points but that didn't work at all. This is likely because these lamps normally contain an anti ghosting
resistor that places about a quarter watt resistive load on the lamp. This prevents household wiring capacitance
from causing the lamp to ghost on when not actually powered. It is likely a commercial 120V lamp would work
if this ghosting resistor is removed. Typically the resistor value is between 47,000 and 100,000 ohms. I
measured the AC voltage at the points and it was about 100V making these LED lamps a good match. Is the
normal line voltage there 220V?. My LED was white. If a 36 LED string could be found that might be more
efficient.
 
Thanks Opera House,

1. The normal line voltage in the Phils is 220Volts... but there is no elctric service in the farm ... we have a small generator.. but thta's it.

2. I am gald your lawnmower worked ! And if you can see the LEd during the day.. it surely will work during the pitch black of the night ! Hooray!

3. Where did you connect the LED wire? ( you mentioned points?)
Paskee
 
I was wondering about the voltage to see if locally supplied LED lamps would work like those with an E27 base. Some China made lamps are easy to snap apart plastic cases. With these you could open them up and remove the anti ghosting resistor and then you would be all set to just connect them to the points. Do you buy on ebay? Just need some comonality where we can view the same item. As this is a RE project, it might be of interest to others and we could work together on it on fieldlines.com
 
Hi OperaHouse,

1. I am US base, living in California.. so I can buy the components here.
2. Yes, I can buy at ebay, Amazon, or wherever in the het.
3. Sorry, but I still do not what connection to the points is/are..please elaborate.
4. What also is an RE project... "real experience" ?

thanks a lot..
Paskee
 
Hi OperaHouse,
I went to www. fieldlines... your description was of the schematics was good... the pictures were truncated (incomplete).. can you please send the pictures directly to me...appreciate it greatly... thanks paskee
 
The pictures are fine there. Try using a different browser to look at them.

Or right click on them and "save picture to" a file on your desktop and look at them without a browser.

You're not allowed to put your email address in these forums so I don't see how opera is going to "email you".

Keith Cress
kcress -
 
Hi Keith,

Got the pix/circuit... thanks ... I will try it as soon as I get an engine

PAskee
 
The bulb that seems to be the one I used is lights of america 2101LEDG10 - 41K MR16.
I haven't been able to find other suitable lamps with a single LED die. I did purchase
from China a lamp identical to this ebay #170942327062. The case did snap apart.
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor