I was wondering what is a Yamaha. I thought it was a tiny motorcycle.
But it is actually a tiny motorcycle with 4 wheels. It is not street-legal so it can have no light or any light on its rear.
Hardly tiny. That thing has a 450cc motor! Great gobs of power! The tail light serves as a brake light so people following you don't slam into you when you stop quickly on the trail (I've seen that happen - and taken the two riders to hospital with broken bones).
Yeah even if they were voltage-matched you can't put LEDs in parallel due to the negative temp coefficient of forward voltage. As was already said.
Two being in series would be more efficient- as already said.
And the mcd system (again, it was already said) gives deceivingly high number for focused beams, whereas most people are more interested in "lumens" the total visible light power it emits, biased for the human eye response (a milliwatt of green scores much more lumens than a milliwatt of red because the human eye reacts to green better). **broken link removed** that turns mcd and angle into lumens.
The 5mm T1-3/4 LEDs should not be run over 20mA. Preferably less. They won't burn up right away but the hotter junction degrades rapidly, over hours or days. And the hotter junction is less efficient anyways and doubling the current makes less than double the light output.
Size each resistor by (Vin-Vled)/(current per LED). The voltage will be 13.8V-14.6v with the engine running so like (14.4v-3.4V)/(.015)=733 ohms.
Wattage is (Vin-Vled)*(current per LED). Don't run a 1/4W resistor at 1/4W that's like a maximum when mounted ideally and the enclosure doesn't get hot. 1/8W would give an excellent safety margin on a 1/4W resistor.
Road vehicles need pollution controls, seat belts, air bags and proper lighting. Their bumper must resist a 5mph crash.
I don't think the toy will meet the requirements.
Well, here in the U.S., it veries from state to state, but in Missouri, they are illegal on the roads. And as far as I know, there's only one version of ATV we can buy over here.
I have seen a few 3-wheel open motorcycles on the roads. They had a single steered wheel at the front like a motorcycle and two driven wheels at the back on each side like a small car.
The only pics in google are 3-wheel enclosed cars in India and childs electric sidewalk toys.
Got my LEDs today and spent some time this evening calculating. Here's what I'm thinking of doing (taking into account all the advice in this thread).
I'm using 14.4V as the supply voltage, 3.2V as LED forward voltage and 18mA as LED forward current. Calculates to 444.44Ω resistors. Round up to 470Ω and I get a bit of extra safety (approx 17mA).
I breadboarded one LED at 5V with three 330Ω resistors in parallel to give roughly 16.5mA. Brightness seems fairly decent at that level. Blinding at close range when viewed straight on (still seeing spots ). They're 20 degree viewing angle LEDs, so not too bad I think.