I2 trim piece LEDs

[Dwarf84396]

Originally Posted by ryan_walters

See post #1 and #3 above. If you're asking which charger, I have RC chargers that peak-detect charge NiCd, and NiMh.

Do you have any specific recommendations for RC chargers? And, I'm guessing, I should expect to have to pay around $50 for a good charger?

... ... I just had a crazy idea, do you think it would be possible to steal from the Segway's AC input, and have the RC charger onboard ...

And, even more questions, just because I'm still a bit unsure of my electrical abilities...

Battery View.jpg

Would this be correct?

Ok, and now to the LEDs:
I was looking at Hebei I.T. for LEDs (probably 520MW7C for white and 510PR2C for red). The only problem with Hebei is that you have to have a 25$ minimum order ... and that the LEDs are 11.8c per unit for white and 16.7c per unit for red ... it would take more than a few to get that minimum order fulfilled!

But, onto some calculations... given that battery pack above, and considering all LEDs are wired in parallel (with the packages shown below), would the resistors be proper values?

LED Info.jpg

Ok, hopefully that will be enough for the time being ... I'd just want to get all of this right before I decide to try to purchase anything ...

[ryan_walters]

Originally Posted by Dwarf84396

Do you have any specific recommendations for RC chargers? And, I'm guessing, I should expect to have to pay around $50 for a good charger?

... ... I just had a crazy idea, do you think it would be possible to steal from the Segway's AC input, and have the RC charger onboard ...

Any charger that can charge 4 AA's will work as long as you dont have to 'insert' them into the charger. I can have a look later.

I wouldn't touch the segways charging circuitry. It is possible, but not something I would mess with. Not worth it.

Originally Posted by Dwarf84396

Would this be correct?

Your battery setup above gives you 6v at 4.6ah. Putting cells in series increases your voltage only. Putting them in parallel increases your capacity only.

You're ok to run parallel packs like this during discharge, but they should be charged separately, NOT in parallel. Kind of a hastle. I would just use bigger cells if you need more than 2500mah of a AA NiMh.

Originally Posted by Dwarf84396

Ok, and now to the LEDs:
I was looking at Hebei I.T. for LEDs (probably 520MW7C for white and 510PR2C for red). The only problem with Hebei is that you have to have a 25$ minimum order ... and that the LEDs are 11.8c per unit for white and 16.7c per unit for red ... it would take more than a few to get that minimum order fulfilled!

But, onto some calculations... given that battery pack above, and considering all LEDs are wired in parallel (with the packages shown below), would the resistors be proper values?

Ok, hopefully that will be enough for the time being ... I'd just want to get all of this right before I decide to try to purchase anything ...

Those LED's look pretty good if they've only $0.12 and $0.17 each.

As for resistors, according to the datasheets,

for the white one (520MW7C), with NiMh 4AA source voltage, use 91ohm 1/4w 5%

for the red one, I'd use the 520PR2C in your list. It has a higher viewing angle, which would be more what you want for rear lights. Also, the lower the angle (tighter beam), the higher the mcd brightness number all things being equal. Think of the mcd as an intensity rating, which will be inflated with a highly focused beam.

520PR2C: with 4AA source voltage, use 150ohm 1/4w 5%. OR because the red led's need less than half of the voltage we have, you can save a little power by running two LED's in series, with a different resistor to compensate. Use 68ohm 1/4w 5% ONLY if two are in series. In the first case, one red led draws 30ma max. In the second case, two red leds draw 30ma max, saving power, but you have to run them in pairs.

I came up with the resistor values based on forward voltage versus current graphs on their datasheets, and based on max voltage you'll get hot off the charger (6v max, 4.8v nominal for 4xNiMh). Feel free to use higher resistor values if you want, they just won't be quite as bright.

[Dwarf84396]

Originally Posted by ryan_walters

Your battery setup above gives you 6v at 4.6ah. Putting cells in series increases your voltage only. Putting them in parallel increases your capacity only.

You're ok to run parallel packs like this during discharge, but they should be charged separately, NOT in parallel. Kind of a hastle. I would just use bigger cells if you need more than 2500mah of a AA NiMh.

Ah, ok. The only reason that I was looking a such a bigger set of rechargeable batteries is just to improve battery life, but, taking a look at it, if I was to run 16 white LEDs at 20mA and 4 sets of two red LEDs at 30mA, I'd still have a run time on the 4 NiMH batteries of 5 1/4 hours, which is more than enough... and, hopefully, 16 front facing white LEDs should provide enough light coupled with one of the 5W LED Dinotte headlights from Segway

[ryan_walters]

Originally Posted by ryan_walters

I don't have pictures of the batteries, but I simply took 4 AA NiMh that I had lying around here, carefully (quickly) soldered them in series (end to end) with about 1/2" between. Then put them into some heavy duty heatshrink to protect them. With the space between the batteries, they can still curve to the shape of the LSF, and the heatshrink also stops the wires from fatigue. I found they still moved around inside the LSF, so I wrapped some foam around the heatshrink to give them a little more size.

I re-wired some of the led wiring to a slightly thicker gauge. I had the batteries out anyway, so here's some pictures:

Click for fullsze:



Click for fullsze:

[ryan_walters]

I finished up the 'ground effect' downwards pointing LEDS.

I did end up using the luxeon star 'blue' led at 16 lumens. It turns out (to my eyes at least) that there's a fair bit of green in it. I would have been better off with the 'royal blue' instead.

While they do have to be heatsunk, they don't need alot of heatsink. In the below picture, after 2 hours of them being on, and aluminum is just barely above ambient temperature. The resistors I oversized on purpose. I only 'needed' 1w, but used 2w. They get a little warm, but you can very easily 'hang on' to them indefinately.

Click for fullsze:


I took a picture from above, with all the lights in my room off. You can see how even the fenders are slightly visible from 'ambient' light from the leds. I think the AA batteries were nearing the end of their charge in this picture too, as the red leds on the back were a little dim. The battery insulation blocks some of the 'middle' coverage both front and back, as it sticks down a bit more than the batteries themselves. Should be a little better in the summer.

Click for fullsze:

[Dwarf84396]

Just wondering, but do you have the aluminum screwed directly into the spacer piece?

[ryan_walters]

No, just exterior double sided foam mounting tape. Very strong once it's pushed on. I'll probably end up bending the aluminum to get them off.

[Dwarf84396]

Ah, cool.

<randomIdeaMode>Would it be possible to have a small aluminum square on the front and back of the fenders, and have some of those 1W White and Red LEDs mounted? ... (me and my random ideas)</randomIdeaMode>

[ryan_walters]

Yes, I suppose, but I think they'd be too bright. The ones I have are too bright to be comfortable to look at directly. There's quite a bit of light coming out of the led, which is a very small area. That makes the light concentration very high in that one spot. Pointed at the ground, you don't see the actual led's light until after it's hit the ground.

In comparison, an HID light puts out more light, but the area that emmits the light is much larger and therefore not as intense when looking at it.

Plus in the daytime wouldn't they look kind of strange on the front / back of the fenders? My leds don't really stand out in the daytime.

[BillPaxton]

Ryan, where are you sticking the batteries? I powered mine with 9v's but it was just not practical. I really just want to put two white luxions on the front of my fenders and reds on back, but I don't know where I will put all the batteries. I also may do some Karl style toggles on my handlebar, so maybe I can put them in a cylendar and stuff them into control bar somehow.. gonna take alot of wire & solder...

Originally Posted by ryan_walters

Yes, I suppose, but I think they'd be too bright. The ones I have are too bright to be comfortable to look at directly. There's quite a bit of light coming out of the led, which is a very small area. That makes the light concentration very high in that one spot. Pointed at the ground, you don't see the actual led's light until after it's hit the ground.

In comparison, an HID light puts out more light, but the area that emmits the light is much larger and therefore not as intense when looking at it.

Plus in the daytime wouldn't they look kind of strange on the front / back of the fenders? My leds don't really stand out in the daytime.