DRL lights controller - 0,25l/100km and cool features
 

Hi there fellows ecomodders!
I believe in energy-saving LED Day Running Lights since I did simple calculations about amount of fuel needed to supply regular lights. Last weekend I finally build my very own version of DRL lights controller, it is described here electronics engineering notes: DRLv2 light controller . I would like to ask you about hints and suggestions if my design seems to be cool or it's rather lame. If you know about features you would like to add - please write it here. If you would like to participate in tests of this circuit - write a private message to me.

I can see you have put a lot of thought into this project.

Can you post in this thread, some of your "Why Did I Build It" text from your post in Engineering Notes? I suppose European readers will understand the purpose immediately. I'm in the US and I'm still trying to understand.

1) Is this easier than building DRLs using LEDs?

2) Cars with EPES or alternator delete, running only on a dep cycle battery, will usually operate below 13V so will not activate the DRLs using the 13.5V detection circuit.

Why did I build it?
My car wasn't factory fitted with day running lights. In my country it is legal obligation to always drive with day running lights or with low-beam lights on. I once calculated that low-beam lights which consume more that 110Wats increase fuel consumption by around 0.25 l/100km (approximately 1,5 mpg US). I can prove it using a pencil and a sheet of paper. LED DRL consumes about 10Wats. According to EU law DRL lights should be automatically switched on when engine is started and they also should by switched off when low-beam lights are switched on. This automation is usually done by a simple relay connected to low-beam light and a wire which is connected to +12V simultaneously with turning on ignition. Using relay, although it's simple, has got disadvantages. Typical relay-based controller unnecessary drains car battery when engine is starting, it also needs to be connected to wire which is connected to battery positive terminal simultaneously with ignition. In my car it is not so easy access such a wire. I noticed that cars battery is quite easy accessible and project has started

1) It actually is circuit which switches DRLs on and off, I bought LED DRL lamps but I decided to build circuit which will switch them exactly when I want it and with nice smooth dimming.
2) You are right - in case of alternator deletion circuit will be fulled and won't work. Circuit is designed for not-so-devoted-ecomodders:) I was thinking a lot about deleting alternator and fitting solar panel instead but I haven't decided for that, yet. As a matter of fact I never heard about anybody who did that in my neighborhood.

Circuit was designed rather for skeptical car owners. Installing costs are not so high (all parts for controller cost about 7$, cheap LED DRL lights starts at 15$) and according to my calculation this self installed system will pay back in 10 000km ~ 6000mi). Low cost and relatively high gain should convince even regular and normal car drivers, it doesn't require special driving technique, it saves low-beam light-bulbs which I previously had to replace at least once a year.

that's so hard to think about how lights effect mpg

That's a nice circuit.
But if i understood correctly, if you have this installed, and you EOC for more than 30s, the lights are turned off?
That would need some improvement if you plant to sell that to people who use EOC :)

Actually easy... Everything consumes energy, and energy must be created from somewhere. Lights need power, and the power comes from the battery(partly), and the battery need to be charged from motor, by fuel :D

Yes, please.

One liter of diesel has 38 MJ energy.
1 J is 1 Watt during one second.
38 MJ = 38 MW during one second = 10555 W during one hour
1 L diesel = 10555 W during one hour
0,01 L diesel = 105,5 W during one hour.
If you drive at 100 km/h, that's +0,01 l/100 km.
Take 50% efficiency of mechanical into electrical energy.

That +0,02 l/100 km at 100 km/h and +0,04 l/100 km at 50 km/h.

So your +0,25 l/100 km are equal to 1320 W at 100 km/h, that's some serious lighting !

that's a very nice little board. Some time ago i thought about installing DRL and wiring was one of the issues. That makes it really easy, nice job. You said it could supply up to 30w to the led's. What is the output voltage for the led's?

Are you planning on selling those on ebay? I think you will sell a few.
You will have to redo the savings math again though. You'll better focus on low beam bulb replacement savings.

Keep it up!

recently i did some fuel consumption calculations, they are available here: electronics engineering notes: How much can DRL lights improve fuel consumption?

HypermilerAX: I see that you've forgotten about engine efficiency. In my calculations I used peek engine efficiency but in real life you can expect much lower efficiency.

astra74: I was thinking about trying to sell this circuit but I'm not sure if it's good enough. Right now I'm introducing some improvements to circuit but maybe one day, who knows...

Fair enough, with 20% efficiency that's 0,2 l at 50 km/h.

EDIT : yeah, including engine efficiency, I got the same figures as your link.

I realize the thread is over a year old, but, any interest in selling 1?
What's your price shipped to USA if you do have any to sell?