Bottomfeeder

I'm loving the illumination provided by my DIY 20W halogen set-up. But the run time is maxing out at about 2:15, and my commute is 2:30. I'm looking for a 15W spot bulb to try as a compromise between intensity vs run time. But I have a question about when to turn the light off.

I'm running a 14.4 Watt, 5000Ah NiMH battery. And like I said, it begins to dim at around 2:15. It will run down pretty quickly from there. Is there any harm in allowing it go nearly dead before disconnecting it and recharging? Or should I turn it off as soon as I notice the light beginning to dim?

DanO

edzo

turn off when you notice it getting dim.

cyccommute 

For your application, you might want to get a charger for work and top the charge before you go home. Dropping to a 15W will increase your run time, too. And with a MR16 bulb, you would still get a lot of light...not insane amounts, just mildly crazy amounts

Nickel chemistry batteries can stand deeper discharge than other batteries but there is a limit. If you go much below 1V per cell, you risk cell reversal and damage to the battery.

Giro

Alternatives are (obviously) a larger capacity battery or (slightly less obvious & more expensive) a good dynamo ("generator") such as the Son LINK.

BikeForums has threads on using a dynamo to keep a battery charged (example threads LINK1 LINK2 LINK3). If enough of your biking is in daylight with the light off, you might not even need to use a charger regularly.

ovrrdrive

Why not put a 15W MR16 next to the 20 watt MR16 and put in a toggle switch to flip between the two?

That way you could flip back and forth depending on what kind of light you need and hopefully gain enough run time to make it home.

An even better solution would be to try one of those LED MR16's linked in this thread on them:

https://www.bikeforums.net/electronics-lighting-gadgets/360023-mr16-led-type-bulbs.html

That should give about the same light and make the battery last 3 to 4 times longer. I'm probably going to try one of them too.

Chris_F

I'm curious what kind of beam pattern those things put out. Making a ton of lumens per watt is cool but directing it where you need it is even cooler.

cyccommute 

It might last 2 to 3 times longer but the output would be about 85% less. MR16's pump out amazing amounts of light.

ovrrdrive

According to the specs of the one linked in the thread that uses the Cree XLamp XR-E LED Bulb, the lumens are the same on that particular one. I'd have to see it in person (and probably will) but it looks like a win/win bulb.

https://www.eliteled.com/products/lig...3x1w-mr16.html

The only drawback is the price, and even that's doable.

cyccommute 

Bottomfeeder's overvolted MR16 halogen is pumping out 1550 lumens. That's more light output than a 100W tungsten light bulb. It's more than twice as much as you get out of a 13W HID. It's stunning how much you get out of an overvolted halogen

This is what I get out of 5 halogens pumping out 4200 lumen. I'll admit that I've gone over the top and I wouldn't expect anyone to carry around that much light. The MR16 I added this year puts out almost as much light as the 3 other lights I have on my bar. It's a stupid amount of light but I'm having fun with it...and it was pretty cheap to make.

bmclaughlin807

I'm coming by your house and stealing your lights.

ovrrdrive

When you overvolt the MR16 output goes from 240 to 1550 lumens?

That's pretty incredible...

I have an over-volted MR16 on my bar and I agree the light is very impressive, but I had no idea that it was that much. It would take 4 CREE X-RE's at full output to equal that amount...

Chris_F

Do cars flash their high beams at you requesting you turn down your light?

cyccommute 

That's the best thing about halogens and about their only advantage over other systems. Over-volting causes them to run hotter which means that their light output is much higher. In the past, I ran 6V MR11 systems at 7.2V and noticed that they were very bright. I then got a 6V battery (it was cheap) and noticed a drastic change. This year I decided to play with the MR-16 and noticed that the light output is even higher for the same wattage.

I have noticed that the light on concrete or blacktop surfaces is very bright with the MR16...much brighter than the MR11 bulbs. Dirt surfaces, oddly enough, are about equal.

cyccommute 

Try it, Bub! One shot for the heat ray and I'll melt your eyeballs

cyccommute 

I don't have them aimed that high. But cars do wait an astounding amount of time for me at intersections

jens5

Stuart. Could you, in detail describe your set-up and how you put it together?

Thanks:
Richard

Bottomfeeder

Yea. Let's see a picture of that system Stuart.

DanO

Chris_F

I came to an intersection in my car once and saw three lights bobbing and waving towards me in an awkward motion. They were too low to be a road bike so I simply HAD to wait to see what it was. Slowly they weaved and bobbed and eventually an unsteady guy on a recumbant passed me. One helmet light, and two handlebar lights. I had a good laugh at that (probably had to wait a full minute for him to get there too.)

Bottomfeeder

By the way... getting back to the OP... Does anyone know if a 15 watt MR16 halogen spot bulb even exists? I've been searching high and low and the only thing I can find are 10 watts.

I Don't really want to chop my wattage in half. So for the time being I'll be using one of my old Cateye EL500's when there's streetlights a plenty and saving the halogen for when I get out in the boonies.

Unless anyone can hook me up with a 15 watt bulb, that is.

DanO

cyccommute 

Battery Space says they have them.

cyccommute 

I don't have the details for the MR16 yet because that system is in a state of flux right now. I just ordered a set of Optronics Driving lights and will be changing them out when they get here. What I currently use is a Hampton Bay pinhole back track light I got from Home Depot. I changed the wiring and added a switch to the back of the light. I also lined the back with foil tape to reduce the light coming from the back of the unit. The whole unit isn't waterproof (hence the Optronics). For a mount I used a mount off of an old Vista VL-500 lamp. It works perfectly.

For batteries, I use RC car batteries in 3.3, 3.8 and 4.5 Ah ratings. Each lamp has it's own pack (that's 4 packs all together), that are made of two 7.2V packs wired in series.



The connectors are Dean's Ultra Connectors but there are others that are easier to make up the harness. The wire is 18 ga speaker wire from Radio Shack.

I carry the batteries for the frame lamps in Cage Rockets that I can use on any bike.







The MR11 lamps are Niterider lamps which have proved very rugged for years and years.







I have several mounts and just move the lamps from bike to bike. The helmet light is another Niterider with the pack kept in a Camelbak.

The handlebar mount is either a SideTrak or the Performance SpaceBar. I did replace the original bar on both with a 1" aluminum tube which fits the light mounts better. I picked up the tubing at my local hardware store. I did widen the space bar this year to take all the stuff I want to cram on there. The MR16 lamp hangs below the bar while the Niteriders are above the space bar.

cyccommute 

Those photos were taken at 1/60th shutter speed by the way. No timed exposure.

Bottomfeeder

Thanks. I'm ordering 2 or 3 of them today.

DanO

ovrrdrive

That link is for an mr11 not a mr16. They don't list a 15W mr16 from what I could see...

I'm pretty sure I saw an MR16 15w spot at Big Lots last weekend though, but they only had one and the package had been opened. It was only like $1.50 though...

cyccommute 

You're right. I misread it.