Greidy
Newly Enlightened
What is the best wiring diagram and source of power to run all five in the same circuit?
Do I need a current regulator? Resisters?
Thanks
Do I need a current regulator? Resisters?
Thanks
5 1W Luxeon emitters amber how?
- Thread starter Greidy
- Start date
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INRETECH
Flashlight Enthusiast
Lux Luthor
Flashlight Enthusiast
Greidy,
You need to be more specific about what you're trying to do. There are a lot of ways to power them, and they can be wired together in either series or parallel (or a combination) depending on what voltage you have to work with. There is also the question of how hard you want to drive them.
Perhaps if told us what you want them for, we could be of more help.
You need to be more specific about what you're trying to do. There are a lot of ways to power them, and they can be wired together in either series or parallel (or a combination) depending on what voltage you have to work with. There is also the question of how hard you want to drive them.
Perhaps if told us what you want them for, we could be of more help.
duffahtolla
Newly Enlightened
- Joined
- Jun 3, 2002
- Messages
- 104
I'd be really carefull about hooking a direct drive to a car.
Flashlight Batteries are mostly fine since their internal resistance buffers the voltage as the current loads go up.
Thats why the confusion about two Luxeons in parallel not eating up twice the current. They *would* if the power source could supply the needed current and keep the specified voltage for that heavy a load.
Car batteries are powerful beasts designed to supply massive current when needed so they could easily handle (toast?) a luxeon string. You would still get some buffering, but the current would have already exceeded the limits for Luxeons. In addition, if the car where running, the alternator would punch up voltage and then keep it there, no matter what current load it needed. There would be NO buffering.
What normally works elsewhere with portable battery packs, would very probably go POOF! in a car.
Be sure to use a rated resistor.
I could be wrong with all of this, but it's still better to err on the side of caution.
Flashlight Batteries are mostly fine since their internal resistance buffers the voltage as the current loads go up.
Thats why the confusion about two Luxeons in parallel not eating up twice the current. They *would* if the power source could supply the needed current and keep the specified voltage for that heavy a load.
Car batteries are powerful beasts designed to supply massive current when needed so they could easily handle (toast?) a luxeon string. You would still get some buffering, but the current would have already exceeded the limits for Luxeons. In addition, if the car where running, the alternator would punch up voltage and then keep it there, no matter what current load it needed. There would be NO buffering.
What normally works elsewhere with portable battery packs, would very probably go POOF! in a car.
Be sure to use a rated resistor.
I could be wrong with all of this, but it's still better to err on the side of caution.
INRETECH
Flashlight Enthusiast
One of the largest overlooked problems in running anything off a car is the incredible high voltage spikes when starting the engine
The starter in a large "big block" can draw upwards of 800A during cranking, while this is happening, it can put back short pulses of very high voltage into the electrical system
My brother runs a 460cu + .030 in his 9000lb Monster truck and he uses a Optima Battery
Always run your voltage from your car into some inductors, caps and a zener-diode to protect the semiconductors.
They do not like voltages above their rated specifications - if even for a few milliseconds.
A few inexpensive parts can protect you from a lot of damage to your expensive LEDs, like a surge protector on your computer
Nominal voltage in a car is supposed to be 12v, but most of them seem to run 13.8-15v, again - make sure that you put protection in your circuit for this
I always run aux power fused to my mobile radio DIRECTLY from the battery, the cigarette lighter is the WORST place in a car to get electricity from.
We in the NorthWest Ham community have standardized on the 15A Anderson Power Pole connector for all of our radios, and it makes it very nice when you want to hook up someone elses radio, no more adapters.
For more information, and purchasing them - please checkout:
http://www.dcpwr.com/
Mike
http://www.inretech.com
The starter in a large "big block" can draw upwards of 800A during cranking, while this is happening, it can put back short pulses of very high voltage into the electrical system
My brother runs a 460cu + .030 in his 9000lb Monster truck and he uses a Optima Battery
Always run your voltage from your car into some inductors, caps and a zener-diode to protect the semiconductors.
They do not like voltages above their rated specifications - if even for a few milliseconds.
A few inexpensive parts can protect you from a lot of damage to your expensive LEDs, like a surge protector on your computer
Nominal voltage in a car is supposed to be 12v, but most of them seem to run 13.8-15v, again - make sure that you put protection in your circuit for this
I always run aux power fused to my mobile radio DIRECTLY from the battery, the cigarette lighter is the WORST place in a car to get electricity from.
We in the NorthWest Ham community have standardized on the 15A Anderson Power Pole connector for all of our radios, and it makes it very nice when you want to hook up someone elses radio, no more adapters.
For more information, and purchasing them - please checkout:
http://www.dcpwr.com/
Mike
http://www.inretech.com
INRETECH
Flashlight Enthusiast
To run any number of LEDs in a series arrangement, total up the voltage of all the LEDs in series
If your input voltage is greater than that voltage, you will need to "get rid of it" using a resistor
The formula is simple Ohms law:
Resistance = Voltage / Current
Thus if you had 5 LEDs, and you wanted to run them off 12v, you would need to break them into smaller groups - since 5 x 3.5v = 17.5 v
Assuming a 12v system - 3 x 3.5 would be 10.5v, you would need to "get rid" of 1.5v, and the resistor would be approx 4 ohms
Its also important to guage the resistor for the proper size, and again - thats Ohms Law
Power = Current ^ 2 * Resistance
.350 * .350 * 4
About 1/2 Watt, but to be on the safe side - always purchase the next larger resister, say a 1w or 2w
These formulas will help you get a good start on the problem, but not always the perfect solution - the operating voltages of the LEDs change as their current and temperature
I have a 7 ohm 25W wirewound Pot which I use to get things "on the money"
Math Rules
Area of a circle ?
Pi R Squared
No, Pie are round - cornbread are square
Mike
www.inretech.com
If your input voltage is greater than that voltage, you will need to "get rid of it" using a resistor
The formula is simple Ohms law:
Resistance = Voltage / Current
Thus if you had 5 LEDs, and you wanted to run them off 12v, you would need to break them into smaller groups - since 5 x 3.5v = 17.5 v
Assuming a 12v system - 3 x 3.5 would be 10.5v, you would need to "get rid" of 1.5v, and the resistor would be approx 4 ohms
Its also important to guage the resistor for the proper size, and again - thats Ohms Law
Power = Current ^ 2 * Resistance
.350 * .350 * 4
About 1/2 Watt, but to be on the safe side - always purchase the next larger resister, say a 1w or 2w
These formulas will help you get a good start on the problem, but not always the perfect solution - the operating voltages of the LEDs change as their current and temperature
I have a 7 ohm 25W wirewound Pot which I use to get things "on the money"
Math Rules
Area of a circle ?
Pi R Squared
No, Pie are round - cornbread are square
Mike
www.inretech.com
Lighthouse
Enlightened
- Joined
- Oct 1, 2002
- Messages
- 254
Without going into a long dissertation about surge suppression and transient voltage surge suppression, the commentary in the posts above about surge suppression is very valid, whether you're dealing with A/C line voltage in a building, from a generator, OR DC battery voltage in a vehicle.
Yes, one can hook up all kinds of electronic equipment, crank up the engine and have the sensitive electronics keep running up to a point, however, the damage done is cumulative and will eventually cause grief of some sort down the road, UNLESS the transient voltages are properly addressed.
Unless your voltage source is completely free from any motor loads <or other inductive loads>, spike generating equipment <such as printers, fax machines, copiers etc.> as well as alternator/generator induced transient voltages /spikes, a surge suppressor is strongly suggested.
Additionally, there are other factors that can give electronic equipment fits as well, relay contacts opening and closing <starter contactor, headlight relays, etc.>
Interesting sites to learn more about some of these issues are:
www.MikeHolt.com
www.omegaps.com
www.itvss.com
www.dranetz-bmi.com
Hey Inretech,
Nice job on the Ohm's law tutorial.
BTW, Thanks for the grin, it's been a while since I've heard that joke in your last line. "Pi are round" ROTFL.
Regards,
LH
Yes, one can hook up all kinds of electronic equipment, crank up the engine and have the sensitive electronics keep running up to a point, however, the damage done is cumulative and will eventually cause grief of some sort down the road, UNLESS the transient voltages are properly addressed.
Unless your voltage source is completely free from any motor loads <or other inductive loads>, spike generating equipment <such as printers, fax machines, copiers etc.> as well as alternator/generator induced transient voltages /spikes, a surge suppressor is strongly suggested.
Additionally, there are other factors that can give electronic equipment fits as well, relay contacts opening and closing <starter contactor, headlight relays, etc.>
Interesting sites to learn more about some of these issues are:
www.MikeHolt.com
www.omegaps.com
www.itvss.com
www.dranetz-bmi.com
Hey Inretech,
Nice job on the Ohm's law tutorial.
BTW, Thanks for the grin, it's been a while since I've heard that joke in your last line. "Pi are round" ROTFL.
Regards,
LH
Andre
Newly Enlightened
Depends on what your power supply is. If you're using them in a car, you probably could just wire them in series, and add a resistor. In series they'll need something like 13+ volts. A car supplies something like 14.4 volts. There's a formula (yes, I'm too lazy to look it up and can't remember it) to calculate what size resistor (how many ohms) you'd need. (You might be able to get away with direct drive since running 5 amber 1W Luxeons at max voltage is just about 14 volts, but you'd want to double-check that.)
If you're powering it off batteries, you may need to power them in parallel instead of series. (The odd number makes it a bit more difficult - if there were 4 or 6 of them, you could have some type of series/parallel combination.) A current regulator may be useful here, but it could still be done with resistors as well, probably not as efficiently.
If you're powering it off batteries, you may need to power them in parallel instead of series. (The odd number makes it a bit more difficult - if there were 4 or 6 of them, you could have some type of series/parallel combination.) A current regulator may be useful here, but it could still be done with resistors as well, probably not as efficiently.
INRETECH
Flashlight Enthusiast
Yes, it is sad - when someone goes out and purchases an expensive 2-way radio or expensive CD-player; installs it in their car - and it "dies"
Not to mention alternator "whine" when talking to people on the 2m bands, when they improperly connect their radio to their car.
Mike
www.inretech.com
Not to mention alternator "whine" when talking to people on the 2m bands, when they improperly connect their radio to their car.
Mike
www.inretech.com
Greidy
Newly Enlightened
Thanks guys for all the responses.
I am intresting in running these for now on AA's just as a temporary source of power for testing the application.
I at a later date will be running these on 12V sealed lead which I will have to build a current limiting circuit.
So the Question is can I run say five 1w's on say three AA's in series and then another three in parallel with those without a resister for short periods of time?
Thanks
I am intresting in running these for now on AA's just as a temporary source of power for testing the application.
I at a later date will be running these on 12V sealed lead which I will have to build a current limiting circuit.
So the Question is can I run say five 1w's on say three AA's in series and then another three in parallel with those without a resister for short periods of time?
Thanks
Jonathan
Enlightened
I think that you suggested that you want to run _amber_1W LS LEDs. The amber LEDs have a lower voltage drop than the whites, and 3AAs will be far more voltage than you need. Use the equations that INRETECH posted (but use the lower Vf of the amber LEDs, not the 3.5V that he mentioned), use the 2 parallel strings of 3AA cells and you suggested, but put resistors in. Its a good simple temporary solution.
If you are going to try direct drive, start with _2_ AA cells in series. The Vf range for the ambers is as low as 2.31V, and 4.5V would be well beyond that.
-Jon
If you are going to try direct drive, start with _2_ AA cells in series. The Vf range for the ambers is as low as 2.31V, and 4.5V would be well beyond that.
-Jon
Greidy
Newly Enlightened
Thanks will try it.
INRETECH
Flashlight Enthusiast
The most usefull tool you can have, is a CURRENT METER - as you are trying different combinations, measure the current of each string - and make sure its under 350ma
Mike
www.inretech.com
Mike
www.inretech.com
M
Mark Hannah Surplus Electronics
Guest
Just so ya know, we have a resistor calculator on our website at http://www.markhannahsurplus.com/led-resistorcalc.htm just for reference.
