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SWAGGER

Mfc-01 Help Needed Please.....

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Hi all,

Really hoping someone can help me out.

For those who know the Knight Hauler, there are two orange/amber blinkers on the the air cleaners, just begging to be lit up. Looks really easy too, they even have little holes for LED's and cover plates like all the rest of the lights. Problem is, the MFC-01 does not provide extra blinker lights for them.

I have seen it done, on a You Tube vid of someones truck. I figured, can't be to hard, just splice to more front blinkers into the two existing ones, one each side, right? Well, did that and they don't work.

First thing I did was chop off the existing front blinkers and temporarily connected up the new LED's that I wanted to add in. They worked fine, green is neg and yellow is pos. Sorted.

So then I splice in the new LED with the existing one, solder it all up really neatly and even have a neat heatshrink job done. There is no logical reason for this not to work, but it doesn't.

It's like they the new LED's are not even there, I am still at square one, ie, the originals work as they always did and both of the new ones are non functional.

I know the LED's worked before I soldered them in.

I have seen and heard of loads of people adding in extra lights, dipped, full, front, rear and so on, but has anyone here ever added in extra blinkers on an MFC-01?

It should work shouldn't it?

Thanks guys!

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Hi all,

Really hoping someone can help me out.

For those who know the Knight Hauler, there are two orange/amber blinkers on the the air cleaners, just begging to be lit up. Looks really easy too, they even have little holes for LED's and cover plates like all the rest of the lights. Problem is, the MFC-01 does not provide extra blinker lights for them.

I have seen it done, on a You Tube vid of someones truck. I figured, can't be to hard, just splice to more front blinkers into the two existing ones, one each side, right? Well, did that and they don't work.

First thing I did was chop off the existing front blinkers and temporarily connected up the new LED's that I wanted to add in. They worked fine, green is neg and yellow is pos. Sorted.

So then I splice in the new LED with the existing one, solder it all up really neatly and even have a neat heatshrink job done. There is no logical reason for this not to work, but it doesn't.

It's like they the new LED's are not even there, I am still at square one, ie, the originals work as they always did and both of the new ones are non functional.

I know the LED's worked before I soldered them in.

I have seen and heard of loads of people adding in extra lights, dipped, full, front, rear and so on, but has anyone here ever added in extra blinkers on an MFC-01?

It should work shouldn't it?

Thanks guys!

Cant 100% help but this might...

http://en.wikipedia.org/wiki/Diode

Good luck.

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Thanks for the info hedge, but I can't see why I would need a diode for this.

There is no need to block current from any direction. Both existing and new LED's are sharing common positive and negative. In theory, if one lights, both should light. I could be wrong of course, but im pretty sure I am not. I have rewired most of the dash of my (1:1 real) car, and the rear light clusters without a hitch. I used diodes on the rear lights as I added extra "slave" rear lights, that are also brake lights and can be kept on as fog lights with the flick of a switch on the dash. The diodes where to stop the current going back and making the existing lights stay in normal operation when the new ones act as fogs.......hmmm......I just don't get this.... :)

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The LED is a diode. Remove it and test it in it's own circuit. If it works there you have the polarity backwards.

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Yeah I get that, Light Emitting Diode, but I checked the polarity first and they worked. I temp fitted them for test before any soldering. I suppose there is a chance that I mixed it up afterwards.

Ill peel away the heatshrink and desolder them. It's worth checking.

It's funny, I want the polarity to be wrong so that they work, but I also don't want to feel like a twat! LOL!

Ill post back later with the result, thanks guys!

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I knew I was not going mad. I had the polarity right. It seems that there is not enough current on the blinker circuit to run more than one LED at a time.

Either the original LED works OR the new one, but not both together.

I assume this current limit is only on the blinkers as it seems most people get away with loading up loads of LEDs from the headlight circuits.

Any other ideas guys?

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There is ample current to run an extra LED off either side of the blinker circuit for the air cleaner indicators. Pretty sure the draw for one tamiya LED is only about 1.8a, you are using a 3v LED right?

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Thanks mate, that's exactly what I was just wondering, what type of LED's are most suitable. I just had a bunch of LED's in my toolbox. Don't know what voltage they are, never even thought of it until today. I'm guessing they must be automotive as I have used them in my car with no issues for back-lighting the heating and air con controls. That would make them 12V I suppose. Ill head out tomorrow and buy a **** load of 3V in in both 3mm and 5 mm and maybe in a few different colors. Ill try them out tomorrow evening and post back hopefully with good news!

Thanks again for the tip!

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Ok, I tried a few electronics stores and to my total shock, they had no LED's.

Finally I drove across the county to Maplin. They had 3 of the type of LED that I wanted. Yep, 3. Sad huh? So I tried to get some more, maybe different colour or whatever. All I wanted was some 3V 3mm LED's in white and red and amber/orange. All I managed to get was 3 red and 3 white, both 3mm but I think the guy gave me the wrong type of white ones. I am guessing that they are 9 or 12 volt as they barely illuminate even on a 5V source.

The reds work fine and I installed them on the back of my Knight Hauler this evening and spliced them off my rear aux lights. I basically made a loom that looks identical to the Tamiya LED looms, twisted pair cable with the two LED's wired in series. I added a small resistor on the first LED anode to reduce the current drawn by the two new LED's. All works fine, but the existing rear Aux lights seem to be a little dimmer now with the extra current being drawn from that circuit.

I know some people add hundreds of LED's to their trucks, I can't see that any more than 2 of these would be a good idea without dimming all the LED's down to practically nothing.

Can someone please advise me of the best exact LED spec to get and possibly where to get them? I have given up on local stores, what's a decent website to order from?

Cheers,

Swagger.

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Swagger,

LEDs by them selfs are not "12V". We need to understand the way LEDs work to connect them properly; Most LEDs are spec'ed to operate at 20mA (=0,02A) and depending on type and colour they will exhibit voltage drops of typically 1,6(red)-3,3V(white).

So the way to go about the design is first to decide on series connection (pearls on a string) or parallel (side by side). Normally it's more power efficent to go series, but the sum of the diode voltage drop cannot exeed the driving voltage less a resistor voltage drop, which is used to stabilize the current.

Example: Driving voltage 7,2V and 3 pcs of red LEDs. Total LED voltage drop 3 x 1,6 = 4,8V. That leaves 7,2-4,8=2,4V to be dropped over the stabilizer resistor. OHMS law (U [Volt]= R[Ohms]xI[Amps]) gives us U/I=R => 2,4/0,02=120ohms

You could add a 4th diode, but if the battery voltage changes (and it does), the stabilization would be insufficient. Hence, consider LED current at max and min voltages.

Now, I'm unfamiliar with the output configuration of the MFC-01, but I would assume it to be a current-limited (or even current-regulated, making the resistor superfluous) type but still operating at the 7,2 voltage. Anybody with knowledge of the actual output are welcome to chime in. At least, you can't go wrong with the calculation done in the example. If you need more diodes, you need to parallel several of the 3pcs LED series.

LEDs are available on EBAY for next to nothing. Normally specs are quoted in the actions - The voltage drop is perhaps quoted as the "forward voltage", normally at 20mA

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Mike O,

Thanks very much for your very detailed response. Much appreciated. Incredible English for a Dane, but to be fair I have a few colleagues in Denmark and I am always impressed with their English, they even kind of have American accents!

Right, I am not that good with electronics. What you are saying makes sense to me, but I may have to read it a few times and do a bit of homework to fully understand it. It is a massive help though and puts me on the right train of thought. I don't have time at the moment to work on the truck, but when I do, the next thing is to paint the body and fit some of the extras I got for it. Once that is done and the truck is "finished" I will go back to trying to light her up a little more.

Thanks again for putting so much effort into that reply, very helpful.

Swagger.

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Yeah, I'd try and wire the new LEDs in parallel, I'm working on my own lighting system and I can use 8 high power 5mm white LEDs on one regular resistor...

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That's interesting, ill try them in parallel then. 8? Wow, 2 barely worked for me.

Out of interest, what circuit are you feeding them from? Headlights, Fogs, or front aux?

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