My DIY 56V 20W Xenon lighting system my e-bike project

[patrick_mahoney]

I've been riding with a DIY "Home Depot" bicycle headlight based on instructions that I found somewhere on the web that looked mostly like these:
http://www.bike-recumbent.com/headlight.shtml

I used a 20W 12V MR16 halogen from Home Depot. I spray-painted it black to match the bicycle handlebars.

I used three spare 18650 3.7V lithium ion cells to make a 3s1p 11.1V 2.2Ah which I put in a plastic water bottle. I made a couple of changes to the instructions above and used a different set of electrical pipe and then a flat base. I charged the cells used the same charger as my e-bike lithium ion pack (an Astroflight 109 li-ion charger).

The final result is in the photos below - although I later zip-tied it to the frame.

 

[patrick_mahoney]

But, the problem was that an evening bicycle trip now required two charging cycles - one for the primary 44V 18Ah pack, another for the 11.1V 2.2Ah headlight pack. Also, the since headlight pulled ~1.9A (as I recall), the batteries would last about an hour before the batteries began to run low.

After two trips that had me riding the last part of the trip home without lights because I decided that I was cutting it close (I gauged it based on the riding time), I decided that the irony of having low batteries for the headlights when I had a massive battery pack behind me was too silly.

So I started planning my e-bike headlights "Mk.II".

After some thought and a lot of research, I bought two 24V 10W Xenon MR16 lights and decided to link the lights in series so that I could drive them from a 48V battery pack (full-charge on my pack is 50.4V, usually it sits around 47-48V in use). This time I'll add a fuse and a switch (before I had to unplug the pack).

The bulbs that I bought were item #882810 from this page:
http://www.sailboatstuff.com/lt_G4_MR11_MR16.html

MR16 XENON CLEAR LIGHT BULB WITH REFLECTOR. Equipped with 2" reflector and glass lens cover. 24V 10W. For $4.75 each.

With shipping for the pair of bulbs, it came to a pretty reasonable $14.70.

I bought the parts at home depot, they came out to $7.58. Then I bought a switch, fuse holder and a fuse at Radio Shack for about $5. I used some 16AWG spare wire from another project and spare connectors that I had left over from the pack build.

For reasons that I don't fully comprehend, SailBoatStuff.Com sent me 28V 10W xenon MR16's. Why 28V? I don't know. I'll call on Monday.

- update from the next day, Saturday -

The housings are painted and polyurethaned and look a somewhat glossy/shiny black. They look good. I got the lights wired up - at least temporarily. I tried out the lights and I have to say that I'm disappointed. The new 10W+10W halogen set is noticeably dimmer than the old 20W setup.

Measurements:
original: 1.5A @ 11.6V = 17.4W
new: 0.2A @ 48.7V = 9.74W

On the plus side, the power output is now about half. But on the negative side, the light is noticeably weaker. I definitely know that watts are not a great way to measure the light from a light bulb. But I don't have a light meter, so it's about the best that I can do besides my eyes. And my eyes tell me that the new bulbs are "yellower" and dimmer and have a narrow beam than my old bulb. And the watts tell me that these bulbs are not pulling much juice... a good thing except that it translates to less light.

I presume that this is because of 28V+28V=56V bulbs and the 48V battery system. I wish the guy at sailboatstuff had shipped me what I'd ordered... And I don't know why they call these "xenon" bulbs. They look just like regular halogens to me. I had been expecting a "whiter" output.

Still, if I have to live with this set up, I can. The old setup was very bright. If I cut that down a bit, but can use it all the time, I'll be content... I guess. At least 0.2A is almost negligible...

 

[patrick_mahoney]

The finished product is shown below. I haven't tried it outside in the dark yet (bad weather) but so far it's working great in the garage. The switch is nice. I added rubber "o-rings" from a cut up old vacuum cleaner belt to allow me to adjust the lights while "sticking" them in place. This system seems to work well - although we'll see if it holds up on the road.

The semi-gloss polyurethane coating came out looking really nice, I think. The headlights actually "fit" the bike pretty well - particularly for $20 headlights.

 

[Toorbough ULL-Zeveigh]

I decided that the irony of having low batteries for the headlights when I had a massive battery pack behind me was too silly.

Got that right.

What I find equally silly is parking a $300 to 1k$ HID on your bars that gets ripped off by some low-life or your first spill to the ground. Much rather put the money to a second pack for my ebike which can be used for both the motor & lighting. With the money left over can buy a whack of halogens & all I'm sacrificing is a slight reduction in efficiency. Oh yeah, & poseur status.

 

[Lowell]

I decided that the irony of having low batteries for the headlights when I had a massive battery pack behind me was too silly.

Got that right.

What I find equally silly is parking a $300 to 1k$ HID on your bars that gets ripped off by some low-life or your first spill to the ground. Much rather put the money to a second pack for my ebike which can be used for both the motor & lighting. With the money left over can buy a whack of halogens & all I'm sacrificing is a slight reduction in efficiency. Oh yeah, & poseur status.

Anyone tried using automotive HIDs? These can be had pretty cheap, plus you get a spare!

 

[Leeps]

I was under the impression automotive hids are damn expensive. Not sure if the bulb itself is cheap, but you cant just connect the bulb to the power supply it needs a driver. Maybe in a parts store theyre not so atrociously expensive?
Actually now you got me wondering what it is the driver does, maybe ill build one :lol:
Actually right now im working on a 15 watt led headlight, the driver chip is backordered like so many things in my life, waiting waiting
Joe

 

[Toorbough ULL-Zeveigh]

I believe you got it straight. Expensive for bikes too because of the driver/ballast, whatever you want to call it. Tho I see that thanx to the chinese the low end price has dropped to under $200.

Then there's the thousand dollar, german end of the price spectrum.
http://www.bumm.de/index-e.html?docu/197e.htm

 

[Reid Welch]

Then there's this for sixty bucks, DIY

http://www.instructables.com/id/E2K9BN5EDKEUBYRD9V/#previewlink


Also, in case you haven't heard before, overvolting "12V" lamps is essential to gain whiter light and greater lumen efficiency. Up to nearly 15V is fine.

Yellow becomes white, and perceived brightness jumps way up.

hth,
Reid

 

[xyster]

Halogens especially will not last very long at 15v.

 

[Reid Welch]

Yeah, that's liable to cut them from 2,000hrs to 100 hours.
But, the 20W I get from Batteryspace cost only a couple bucks and change.

Frankly I'll never not overvolt a halogen.
Bear in mind, they are 12V nominal. If we want road lighting, it's best to run them at automobile voltages, just like other 12V bulbs. And that means well above 12V.

From one of many such pages,

http://www.morcmtb.org/morcpages/howto/lights2.htm

Overvolting

The above bulbs that we are running are rated for 12 volts. We will be using them at approximately 14.5 volts, which is a 20 percent "overvolting". Without getting too technical, overvolting causes a halogen bulb to produce a LOT of light – almost twice the rated output. At this voltage, the efficiency of an MR-16 is actually better than an expensive HID. With the overvolting technique, we will be running the 20-watt bulbs at about 25 watts. Most HIDs are around 10 or 13 watts. So assuming equivalent efficiency, you can see that this light will produce about twice the output of an HID. Also, the light is a nice white color, rather than normal yellowish halogen color, or the blue light produced by HID bulbs.

However, the efficiency is at the expense of bulb life. A 20 percent overvolted bulb will only have about 5 percent of its rated bulb life. (maybe up to 10 percent, depending on which source you believe) But, that doesn’t mean you are going to be swapping bulbs on every ride. The Phillips Masterline is rated for 5,000 hours, so 5 percent of that gives you about 250 hours of night riding. Nevertheless, I usually carry a spare bulb, because they are lightweight and don’t take up much space.

 

[patrick_mahoney]

There's a lot of interesting things that can be done with 12V, but if you want to drive the bulbs off the primary power supply for the bike, I'd need to run 4 of them. I really only wanted one bike headlight, but I can live with two. But I definitely didn't want four. Lights also pull enough amps that a DC-DC converter would be expensive.

Update on the headlight project: I got all the pieces assembled, and put it on my bike. I need to get a rubber gasket to hold the lights from moving. And then I need to wire up the plugs. While messing with itm I decided to try to wire in my taillights as well - so one switch will turn on the lights.

I bought some electroluminescent (EL) wire last week for the fun of it. Not sure what I'll do with it, but it was cheap and looks like fun to play with.

http://www.vibelights.com/bili.html

I wonder if putting it on my bike (I bought 6 meters of the stuff), would make me more visible, or more of a distraction, or a combination of the two. I'm guessing the last one.

But the stuff looks neat. My daughters were walking around the house with it wound around their arms and dancing. Pretty neat stuff. I can imagine some cool possibilities for Halloween too. On the negative side, the driver/inverter/ballast thing makes a high pitched whine - gets annoying after a while.

 

[xyster]

But, the 20W I get from Batteryspace cost only a couple bucks and change.

That's where I get mine too. I'm very happy with my six MR-11's strung in series. Lights, connectors, housing and mounting only cost in total about $20. No DC-DC converter needed since they're connected to the main power line. I found out from one of those lighting sites a little too late that MR-16s, because of their larger mirror, put out like 3 or 4x the lumens for the same wattage as MR-11's. I'm not sure six MR-16's would have all fit across the front anyway.

I've since removed the single MR-16, putting it back on my scooter.

 

[fechter]

That thing must look like a UFO at night.
Next thing you know some men in black will be knocking at your door.

 

[xyster]

Next thing you know some men in black will be knocking at your door.

Great...just what I wanted to hear

 

[Reid Welch]

I've long admired your bike's headlight array. In your case, it's all good,
and only 60W drain from your huge battery supply.

The safety factor is enviable. Gotta like it.

 

[xyster]

Heck with the lights, I like patrick_mahoney's fancy house and nice looking neighborhood! Ebike party at Patrick's house!!! We'll have a backyard BBQ. BYOB!!! (Bring Your Own Bike) 8)

 

[Toorbough ULL-Zeveigh]

In Canada the highway code doesn't permit more than two headlights on a motorcycle, bicycle, or power bicycle anyway. Anyone who wants to hook in multiple lights needs to check if they have this same restriction. Mr. X, is your setup legal?

Also xyster, aren't your MR11's being overvolted to 14 volts already(84V/6)?

I think overvolted is the normal mode of operation for most flashlight & bike lights, the ones that use the PR type bulbs anyway. These bulbs are typically rated for a lower voltage in order to get out something approaching a white light during operation with saggy dry cells. Their lifespan usually ranges from 100 to 150 hours as a consequence, some of them as low as 10 to 25 hours.

Halogen bulbs have a really low resistance when cold. Since most bulb failures occur at switch-on, a softstart circuit to ramp up the voltage would prevent the cold filament from taking a current hit & lengthen their lifespan. I know that my halogens always blow during the winter when the filament resistance is even lower than normal, resulting in massive inrush current. As it stands now, my bulbs die from this current spike long b4 the overvoltage has a chance to do them in. So I'm looking for a suitable softstart circuit to limit rise-time.

 

[xyster]

In Canada the highway code doesn't permit more than two headlights on a motorcycle, bicycle, or power bicycle anyway. Anyone who wants to hook in multiple lights needs to check if they have this same restriction.

That's nuts. Imagine all the money wasted that could have gone to better causes, or back to the taxpayers, instead of writing, arguing, enacting, bureaucratizing and enforcing that nonsense. And for what? So everybody in that chain of (ir)responsibility gets more of your money.
How does your law treat LED lights, each one made up of an array of 3 - dozens or more? Let me guess, after receiving campaign contributions from LED manufacturers, lawmakers recently wasted more time and money carving an exception for LED arrays. Since lawmakers mostly just make law, at some point about a century ago, we'll all drown in lawyers needed to interpret and mesh it all.

Mr. X, is your setup legal?

LFINO. Living here in the US is only very slightly less of a socialist nightmare, so it wouldn't surprise me either way. But I haven't read anything to the effect arrays of lights are illegal.

Also xyster, aren't your MR11's being overvolted to 14 volts already(84V/6)?

You're right -- at full charge and not under load while motorin'. Most of the time they're "seeing" 76 - 80 volts.

 

[auraslip]

Hey this is really good.

I'd like to try this, but the original how to is down. Does someone have it mirrored some where?

 

[swbluto]

Hey this is really good.

I'd like to try this, but the original how to is down. Does someone have it mirrored some where?

ALL HAIL THE WAYBACK MACHINE!

http://web.archive.org/web/20080713034727/http://bike-recumbent.com/headlight.shtml

(It looks like you got lucky this time; it appears they stored the images, too.)

 

[auraslip]

My hero...swoooon