fatboy7

Nope, mine's from the 85 FSM, and has three resistors, consisting of a fixed voltage divider on the negative terminal of an op amp and an the third resistor that with the brake lights make another voltage divider on the positive terminal, the out put of the opamp goes to the base of an npn transistor, so when the opamp is railed high the transistor conductts and the warning light turns on. so when the resistor ratio on the voltage divider with the lights has more resistance relatively(resistance ratio) on the lower branch (ie where the lights are) than the fixed voltage divider the opamp rails high and the light turns on. So.....if the combination of lights are above a set threshold resistance they will trigger the warning light. the principle works the same as the above diagram though... as long as there is enough current to close the relay, the light will stay off...

Who knows what is actually on the inside.... that's just what is drawn on the schematic

Manitis' LED lights are more than LEDs, they probably some additional ciruitry to lower the overall resistance that when LEDs fail it becomes a high resistance or open circuit...

Manntis

Yup. Never claimed I stayed awake through every class, but I've certificates on the wall showing I showed up at the right tmies at least

a'ight, let's simplify (remember, I had military instructors so semantics can bog down what is actually not that difficult)

Let's say a stock bulb has 5 oms resistance.

When the resistance drops below 3 ohms, the idiot light comes on screaming your bulb is burnt out. Why they do this in addition to a simple break in the circuit is beyond me, but I'm still trying to figure out Lucas wiring's similar ability to defy reason.

Anywho, you pop an LED cluster into the socket with 2 ohm resistance, due to the more efficient light emiting properties of LED over filament. So the idiot light lives up to it's name and shines its annoying beacon on your dash.

Right now several Volvo owners are splicing into their wiring harmess and adding resistors to overcome this. My solution is to build the resistor into the circuit so it becomes plug'n'play for a reasonable price, not plug'n'cut'n'sourceouttheproperresistor'n'takeapar tinterior'n'solder'n'heatshrink'n'...

fatboy7

P=I*V. there is 26 W/bulb *4 bulbs = 104 W. so 104W=13.8V * I therefore I = 104/13.8 = 7.54 A.

V=I*R so, 13.8 = 7.54 A * R therfore R of the stock bulbs in paralell is 1.83 ohms. Now for the LED lights I=.090 A * 4 = .36 A so R = 13.8/.36 = 38.3 ohm.

If a light burns out, its filiment is destroyed, so it esentially is an open ciruit. So assuming the warning light comes on if only one light burns out..... the current that the assemly of bulbs drops 25% from 7.54 A to 5.62 A so the resistance changes from 1.83 ohms to 13.8/5.62 = 2.44 ohms. It becomes higher in resistance, not lower, so adding more resistance in series won't work on our cars. you need to put resistance in parallel, or change the checking unit. If you could make each 153.3 ohm LED light look like a 7.32 ohm light, you would have something.

Manntis

There's your problem. I've given up assuming what manufacturers (or their subcontractors) intended when wiring cars

fatboy7

But like I said earlier, just screw the warning light if you switch to LEDs.... This won't be an issue because:

1. LED lights have a Mean time between failure 10 times or more than the average incandescent bulb.

2. you have 15 LEDs in a light, so if one or two burn out, it can be noticed, and the bulb replaced unlike an incandesent bulb which will burn out completely without warning.

3. Why waste the energy that you are saving by going to LEDs by fooling the system into thinking they are incandesent? each of those LEDs are disipating about 1.2 W and are prbably about 40-50% effecient vs an incandesent that is about 95% ineffecient meaning it requires the 26 W to make the same light.

Save the alternator and battery the load, and just disable the warning light, then check your brake lights periodically (like once every 6 months or so)

fatboy7

EDIT
...assuming the warning light comes as soon as one light burns out.....

multiple lights will definately turn the light on... aka worst case scenerio.

fatboy7

Another cool, and probably illeagal alternative is to put 10-20 LED bulbs in.... and send out a blinding brake light that can be seen from space....

Manntis

it IS an issue. It occurs with many cars switching from bulbs to LEDS

No, I have 5 per light, and the previous generation I offered had 12. These are different LEDs than the tiny ones clustered in some other lights (newer design), more akin to the larger ones used in busses and trucks.

The main benefit to LEDs are the fact that they're brighter. This is a visible benefit, versus energy savings per bulb.

That's great! But as I said before rotorhead.ca is developing a plug-and-play solution for people who don't want to modify the wiring. The original design will still be available for those who do. Unless it's unsafe (headlight stickers, shoddy HID 'kits' that could start fires) or rediculous (400 lb wings, etc.) I try to stock what people want for their SAs, FBs, and FCs and do so by providing decent quality at a decent price.

A good example: the current design of my cupholder/stereo bracket unit requires minor assembly and fabrication to install. The Mark II design, which will bolt into both the 84-85 FB dash and the 86-91 FC dash, will still have a few snap-together pieces but otherwise will bolt right in. Sometimes only by creating a thing rather than theorizing can you see where the design needs refinement

Directfreak

iTrader: (2)

Very Good Point. The nice thing about LED's (besides the cool factor, is that they use less electricity than the standard bulbs.

So when your driving around town with you stock 55amp alternator, with the A/C, Radio, Driving Lights, and Wipers on all at the same time, - the car will be less likely to have a electrical consumption hissy fit when you tap on the brakes (and setting off the brake lights.)

Manntis, I still have to remove my gauge cluster to change out to the S/R Motorsports gauges. I could easily just remove the bulb for the "Stop Lamp" at that time.
So...
If possible, send me the LED's without any additional resistors, as I have a shitload of electrical components on my car, that are going to be fighting for every ounce of current that 90 amp Cosmo alternator is going to push out.

Thanks!

fatboy7

Still, with 5 lights that will on average last 10-20 yrs, the chance of all of them going out within the same 6 months to a year is slim to none...

I'm not saying don't develop a plug-n-play system, please do!! You will reach a much wider acceptance, and market with a true plug-n-play bulb. But for those, like DF that would like the extra 5-7 amps that will be in demand during braking, there is a cheap and really pretty safe alternative.

I'm just saying, you can have your cake (brighter lights) and eat it too (less energy consumed).

Manntis

I (not my supplier, but me, the insane ex-army artist) am actually experimenting with pulsing LEDs for safer braking.

The human eye is attuned to motion. Anyone who ever had a rock whipped at them knows your eyes wince and your body tenses before you consciously register the incoming object. Why? Motion causes reaction. You know from experience that incoming rocks can cause owies, and your subconscious has slipped your nervous system a memo about this to take action accordingly rather than wait for Departmant Head authorization.

A glowing light in front of you that gets brighter is not motion, but change in the amount of light. You must consciously see it, then react (depress brake pedal or downshift) to avoid rear-ending the ******** in the Mustang ahead of you who slammed on the brakes because he was so distracted by the passing teen's jiggling ***** he almost missed the stopsign.

I noticed, by accidentally looking into a strobe light as it was switched on, that the strobe setting created a momentary illusion of motion, as though the light were flying out at me.

I did some testing on voluntolds (friends were told that they'd volunteered) and isolated ceratin strobe rates. My goal is to develop an LED replacement that glows red as a running light, but when the brake is depressed it strobes for the first second before settling at a constant brighter red as is customary. This will cause the drive behind you to react to your braking faster than the normal red/brighter red bulbs. (the 1 second period is to make sure the driver sees the effect, but then drops to regualr so he doesn't fixate on your brakelights and ignore other potential road hazards)

Directfreak

iTrader: (2)

This has been around in the Motorcycle world for years.

Manntis

Pulsing non-stop, as on bicyclists backpacks, or coming on JUST when you apply the brakes? And are the strobe rates set to cause the illusion that the light is 'throwing itself at you' or just strobing? There's a narrow range (which I won't publish, for potential proprietary reasons) for the illusion to work and for it to be effective.

EDIT: I can understand you wanting energy efficiency for brakelamps, but the I highly recommend the resistors in the amber bulbs - the high rate of flashing in the non-resistor amber bulbs makes your turn signals look like they're broken or poorly riced

Directfreak

iTrader: (2)

Some work by:


Okay - Makes perfect sense. The REAR Turn Signals should have the resistors. The front Amber ones shouldn't, as they are also running lights when not blinking. Unless they can Isolate the resistor to the Blinking part only.

Manntis

Those motorcycle ones advertised appear to just flash, which would increase the CONSCIOUS processing of information (driver is more aware he's seeing brakelights come on, rather than thinking about his wife's lousy cooking)

The idea behind mine is it triggers the subconscious (Danger Will Robinson! Danger!) and the driver brakes sooner.

jalvord_2003_68_01

i think i'm gonna order a set of this led lights, is there any modicifations to make them work?

Manntis

right now they do work, but can cause the dash light to come on as discussed earlier in this thread. My guys are making the amber ones with a resistor in a few weeks, then the red ones to follow.

FJ

Interesting. I had thought the '84 and '85 models were virtually identical but it seems quite a few details are different.

Agreed. A simple voltage divider in either case.

Quote:

Manitis' LED lights are more than LEDs, they probably some additional ciruitry ...

No doubt. That's why I suggested sticking a resistor in parallel may not be such a good idea.

Right. A resistance in series wouldn't work on any car, it would simply dim the bulbs.

-John.

FJ

Ummm...Let's not. I asked for details, right?

No, it doesn't. At least, not on our cars.

Put a higher wattage (lower resistance) bulb in or put another bulb in parallel with the original bulb (effectively lowering the resistance) and the idiot light does not come on. It comes on with an increase in resistance. Looking at the diagram I posted above, how can the light come on with a decrease in resistance? It's a simple voltage divider (a relay coil in series with a resistance (four bulbs in parallel.))

Quote:

due to the more efficient light emiting properties of LED over filament. So the idiot light lives up to it's name and shines its annoying beacon on your dash.

Yes, LEDs are more efficient as they emit light without the need to heat a filament. They don't waste as much energy heating the surrounding air. As a result, they do not draw enough current to keep the Stop Light Checker relay (or opamp for the '85s) energized.
But the idiot light illuminates as the circuit sees the reduced current as a higher resistance.

Volvo? I thought this was an RX-7 specific forum...Screw Volvo.

So you still say the LEDs have lower resistance and lower current?

I repeat my previous question:
"Can you explain to me how an LED bulb can have a drop in resistance along with a drop in current, when the simplest of formulas says otherwise? "

"Luuucy...You got some 'splain'en to do...."

-John.

Manntis

I'm losing my patience.

adding leds CAUSES THE LIGHT TO GO IN MANY, MANY CARS INCLUDING OURS

Testing has shown it is caused by the lower resistance. Other manufacturers are starting to add resistors and charge an arm and a leg.

I'm working my ******* *** off to make a similar, trouble free product for the same price or lower than the 1st gen LEDs - and let me tell you it's definately not for the money. Between hosting pics and vids for people through the site I'm not even covering bandwidth.

Don't say 'no, it doesn't'. I have customer complaints to show it does; you didn't even know how many ******* 'bulbs' I have in my LEDs before you started telling me I'm wrong.

Adding a lower resistance bulb is still a BULB. It may or may not trigger the idiot light, I don't know. But adding LEDs DOES.

Manntis

BTW 80's volvos use Japanese wiring from the same supplier as Mazda, smartass.

Directfreak

iTrader: (2)

Ok - somebody explain to me the exact definition of "Electrical Resistance". or "Electrical Resistor."

I think the arguements here are over the use of that term, and something is getting lost in the translation.

At least to me.

FJ

Hmmm. Sorry about that. And here I thought we were just having a discussion, not arguing. I repeated the question in what I thought was an amusing manner (including the Volvo comment) because I wanted to know more about it, not to **** anyone off.

I never said you were wrong about the LEDs, I said lower resistance doesn't cause the light to come on. I tried it with bulbs. As the LEDs do, I was wondering why. And how they have lower resistance with lower current. Thought you may be able to shed some light on the subject. As I mentioned in the first page: I don't mind being wrong, I just wanted to understand it.

The last post was to repeat the question in the hope of figuring it out and maybe give a grin. The old Lucy line and smiley was intended to convey the fact that I wasn't being antagonistic, just looking for information.
Obviously, I was not successful. My mistake.

-John.

Manntis

Je suis trés désolé, mon ami. The weakness of text is it conveys the words, not neccessarily the meaning.

My terminology may be wrong ('semantically incorrect', I stated before) but here it is:

Volvo owners often complain about the dash light coming on after installing the LEDs in their tail lights. ANy generic LEDs, not just mine. Mazda owners who purchased mine sometimes reported the same thing (rather aggresively) while some said nothing. I queried those who said nothing and they were happy with the product except that the dash light came on. It would not happen under every circumstance (varying levels of harness corrosion from car to car, I suspect) but often enough it was something I wanted to address.

We ran some tests, including the Volvo owner's solution: to wire in a resistor into the wiring harness. The problem went away.

But asking customers with varying level of electrics expertise to cut harnesses and solder in resistors which their Radio Shack may or may not stock (ironic that Radio Shack no longer carries CB radios and their electrical components stock is all but useless), I decided that we should go with a plug-and-play solution.

So now it's a matter of hardwiring the electrics into the electronics so that normal LED operation is as seamless as bulb operation. We sacrifice some efficiency benifits when the brake pedal is applied and the resistor becomes a part of the circuit, but the benifit of greater light output is maintained and the product is self-contained.

I'm sorry for cursing in my previous posts. As you'll see from my (embarassingly numerous) posts on this board, that's rare. I once got into a discussion with my at-the-time future father in law in which he was telling me that according to his calculations, the 'safety doughnut' around a grenade blast was a myth (when a grenade on the ground detonates it does so as an expanding sphere. Some of the shrapnel bounces off the ground around it and into the air before falling back to earth, creating a very small but non-lethal 'sweet spot' in a ring around the device.)

Although he was a very intelligent University professor, I disagreed on the grounds of experience. In cold weather, my Company Sargeant Major looked like he had blue acne. Bits of wire shrapnel imbedded in the meat of the right half of his face, that his immune system was slowly pushing to the surface (it took months, and I could never figure out how our bodies know which way to push foreign objects to grow them out, but it works). He dropped to the ground when a Somalian had lobbed a frag grenade at him with about a second left on the fuse, and was more or less intact despite the grenade only being a meter or so away (frag grenades have a 10 meter lethal radius)

So on the one hand Professor Floyd had all these neat calculations showing that the blast wave would overcome the 'supposed' change in trajectory of the shrapnel, and on the other hand a certain Warrant Officer was living proof of the contrary.

Perhaps I misspoke when saying that a burnt out bulb drops the rezistance to zero. It does drop the flow to zero, as the circuit is open. But for whatever reason, the drop caused by swapping in LEDs can create an annoying dash light problem for which adding a resistor to restore the original resistance is the cure.

Does that clarify?

Keaponlaffen

why doesn't someone just hook a multimeter up to an LED light, then a regular 1156 or 1157 bulb, and see what the actual resistance of each are?




Jeff