Overvolting MR11 6v lamp

September 28, 2003

Hello all..

I have two (2) first generation Niterider MR11 10W lamp that puts out a very dull yellow light --
compared to the Vistalite "Hot" Bulb (overvolting).

The light output difference between the 10w Niterider bulb and the 5w Vistalite Hot Bulb is not
noticeable. I now use the Vistalite 5W to extend my battery run time.

Question #1: I found a Powersonic 8V 3.2 ahr SLA battery that is reasonably priced (about $20)..

I am wondering what kind of bulb life (in hours) I can expect if I were to overvolt a 6v bulb with a
8v power source? ie (MR11 bulb has normal bulb life of 2,000 hrs).

I have overvolted the Niterider bulb with 6 N-MH 1.2v AA battery pack. The results are much better..
but I am curious if I can further push the power source to 8v without burning out the bulb
immediately -- especially when a fully charged 8V battery may read an initial charge of 9V when
fully charged.

I have read that you can generally overvolt the bulb by 10% which will reduce the bulb life by as
much as a factor of 10 -- effectively reducing the bulb life to 200 hours -- I can live with that.

Questions #2:

Any comments on pros / cons of 6v light system vs a 12v light system. MR11 12v bulbs can be
purchased for as low as $1.50 with no front glass to $6.00 with front glass cover.

Any suggestions and/or comments?

Much obliged.

Nick carless since January 2000 Sparks, NV

On 28 Sep 2003 19:40:23 GMT, nlee1875@aol.com (NLee1875) wrote:

>September 28, 2003
>
>Hello all..
>
>I have two (2) first generation Niterider MR11 10W lamp that puts out a very dull yellow light --
>compared to the Vistalite "Hot" Bulb (overvolting).
>
>The light output difference between the 10w Niterider bulb and the 5w Vistalite Hot Bulb is not
>noticeable. I now use the Vistalite 5W to extend my battery run time.
>
>Question #1: I found a Powersonic 8V 3.2 ahr SLA battery that is reasonably priced (about $20)..
>
>I am wondering what kind of bulb life (in hours) I can expect if I were to overvolt a 6v bulb with
>a 8v power source? ie (MR11 bulb has normal bulb life of 2,000 hrs).

Have a look at the graph on this page to get an idea of the effects of over volting:

http://www.myra-simon.com/bike/lights.html

As you can see, you will reduce bulb life immensely by using an 8 volt battery.

>I have overvolted the Niterider bulb with 6 N-MH 1.2v AA battery pack. The results are much
>better.. but I am curious if I can further push the power source to 8v without burning out the bulb
>immediately -- especially when a fully charged 8V battery may read an initial charge of 9V when
>fully charged.
>
>I have read that you can generally overvolt the bulb by 10% which will reduce the bulb life by as
>much as a factor of 10 -- effectively reducing the bulb life to 200 hours -- I can live with that.

But you are thinking of overvolting what, 33%? I think that about 20% would be a good
practical limit.

>Questions #2:
>
>Any comments on pros / cons of 6v light system vs a 12v light system. MR11 12v bulbs can be
>purchased for as low as $1.50 with no front glass to $6.00 with front glass cover.
>
>Any suggestions and/or comments?

Ideally, you would use a lower voltage bulb with a battery capable of delivering high currents
without a drastic reduction in the nominal battery life (ie NiCd or NiMh). You can use fewer cells,
which will result in a lower battery weight.

Because the actual life of a SLA battery drops considerably when it is asked to deliever high
currents, a 12v setup would be preferred if you use this battery type. The main advantage of the SLA
is that the rate of self discharge is very slow; ideal if you use it infrequently.

Have you considered buying a regulator and making your own battery out of rechargeable 'C' or 'D'
cells? Extremely efficient voltage regulators which use Pulse Width Modulation (PWM) are available
for a reasonable price here:

http://lightbrain.8m.com/twin-plus.html#regulation

Even if you don't use a regulator to regulate down from a higher voltage (ie. 9.6v for one of the
models listed in the link), you could still make your own battery out of 6 1.2v 'C' or 'D' cells
(depending on the what you need). You can find rechargeable cells with far greater capacity than
what you will find in local stores by looking online, for example:

http://www.thomas-distributing.com

http://www.onlybatteries.com/items.asp?db=1

The drawback is that you would need a quality charger. If you already have a charger for a SLA
and/or you are planning to use the light infrequently, it may not be worth it for you to spend extra
money on NiCds or NiMhs (but you'll be back at square one, I guess).

This page has links to many other sites about bicycle lighting and is worth bookmarking:

http://audax.uk.net/lights/

--
Chris Bird

September 28, 2003

Chirs, thank you for the links. I've have visited those sites in the past..

Here is a better one for DIY lights:.

Use google search for

Starlight 78 Bicycle Lighting System

I've built DIY lights in the past.. and have spent over $1,000 in lights and lights supplies over
the last seven years.

I've posted instructions in MTBR.com in December 1999.. If you do a google search for Malibu LT9 low
voltage landscape lights, someone have posted my instructions on their web site -- and added a DIY
helmet mount.

Finally, anything that keeps my chances to stay alive riding at night, I have tried one way or
another -- in duplicates and triplicates -- but still haven't found a good combination of amount of
light, run time and/or weight.

You name it, chances I've tried it..

Cateye HL500 -- great light for its time Cateye HL1500 -- love this light -- replacement bulb
expensive with average bulb life of 25 hours. Cateye HL500II -- replacement bulb expensive. -- Love
the size and mounting options on handlebar..a keeper!!! Cateye Double Header -- huge
disappointment.. Cateye EL300 -- a huge disappointment Cateye EL110 -- great addition NiteRider 10w
& 15w pricey -- dull 10w bulb. Vistalite Road Toad - worthless Vistalite Night Stick - not durable
--bar quick cam clamp broke -- now on 3rd clamp. Cygolite Ranger 10+10 - not very bright for 20w.
Specialized Proview - great 12w bulb but switch is suspect. NiteHawk Viper - new this year but 5w
bulb was dull yellow but price was right, $20 at Performance Bicycles but now sold out. Bought
three. WANT TO OVERVOLT IT using 8.0v power source..but now was advised against it.

Also.. I've tried automobile 55w driving / fog light. Works great -- if I am riding to the
neighborhood grocery store using a 12v 7 ahr battery.

So far.. my best combination for road riding seems to be 2 Cateye LED EL110 and overvolting a 12w
Specialized Proview to 7.2v. using 6 1.2v AA NI-MH 2300 mahr batteries in a 6 cell battery holder --
with additional 6 or 12 2000 mahr cells backup PLUS a Vistalite 5W when needed or as a backup.

Still I think I can do better some how while staying away from HID driven light system.

Much obliged. Nick Carless since January 2000

nlee1875@aol.com (NLee1875) wrote in message news:<20030928154023.24119.00000286@mb-m11.aol.com>...

> I have overvolted the Niterider bulb with 6 N-MH 1.2v AA battery pack. The results are much
> better.. but I am curious if I can further push the power source to 8v without burning out the
> bulb immediately -- especially when a fully charged 8V battery may read an initial charge of 9V
> when fully charged.

8V is pushing it, that's >30% over, and if you look at the datasheet for the 8V battery, you'll see
that the voltage starts off even higher, so you're at least 40% over.

> Questions #2:
>
> Any comments on pros / cons of 6v light system vs a 12v light system.

I address this specific subject on my web site. There are several advantages to a 12V system,
including lower current, lower cost lamps, higher capacity NiMH battery packs with super-cheap AA
cells (versus the need to use more costly C or D cells to boost capacity on 6V systems).

> MR11 12v bulbs can be purchased for as low as $1.50 with no front glass to $6.00 with front
> glass cover.

Actually MR11 12V bulbs can be purchased for $2 with a cover (10W and 20W), at Ikea. I have other
sources on my web site as well. It's pretty outrageous what the bicycle lighting companies charge
for replacement lamps.

> Any suggestions and/or comments?

"http://nordicgroup.us/s78" will tell you more about bicycle lighting than you want to know.

On 29 Sep 2003 11:45:42 -0700, scharf@hotmail.com (Steven Scharf) wrote:
>I address this specific subject on my web site. There are several advantages to a 12V system,
>including lower current, lower cost lamps, higher capacity NiMH battery packs with super-cheap AA
>cells (versus the need to use more costly C or D cells to boost capacity on 6V systems).

Eh? For the capacity, why not parallel two AA packs?

>"http://nordicgroup.us/s78" will tell you more about

Nice gratuitous nudity. If there's anything better than useful information peppered with a bit of
gratuitous nudity, it must be food...maybe ravioli.

--
Rick "hmm...boobs or ravioli?" Onanian

On 09/29/2003 14:45, in article
4f153f94.0309291045.67e419bc@posting.google.com, "Steven Scharf" <scharf@hotmail.com> wrote:

> nlee1875@aol.com (NLee1875) wrote in message
> news:<20030928154023.24119.00000286@mb-m11.aol.com>...
>

>> MR11 12v bulbs can be purchased for as low as $1.50 with no front glass to $6.00 with front
>> glass cover.
>
> Actually MR11 12V bulbs can be purchased for $2 with a cover (10W and 20W), at Ikea. I have other
> sources on my web site as well. It's pretty outrageous what the bicycle lighting companies charge
> for replacement lamps.

What beam angle are these? The one's I've always seen are pretty wide for road use. 6V ones are
harder, and I've never seen 4.8 ones to be overvolted with a 6V battery.

Baird

"Rick Onanian" <spamsink@cox.net> wrote in message
news:93fhnv0r5ahf6phl1f38uakdkknm86akvb@4ax.com...

> >super-cheap AA cells (versus the need to use more costly C or D cells to boost capacity on 6V
> >systems).
>
>Eh? For the capacity, why not parallel two AA packs?

I also suggest this method. The only negative with this method is that you have to charge the packs
seperately since charging packs in parallel doesn't work. So if you plan to charge the packs
overnight then you'll need two chargers, or have to wake up in the middle of the night to swap them,
or get a charger that can charge 12 cells in series. You could also design a little timer circuit
with a relay that automatically switched packs after five hours or so. But if you're going to use 12
cells anyway, then you may as well go to a 12 (or 14.4) volt sysem.

>Nice gratuitous nudity. If there's anything better than useful information peppered with a bit of
>gratuitous nudity, it must be food...maybe ravioli.

The nudity is not gratuitous.

"Baird Webel" <bwebel@hotmail.com> wrote in message

>What beam angle are these? The one's I've always seen are pretty wide for road use.

38 degrees (wide flood). I prefer the wide flood for my pace at night, though narrow flood would
also be fine.

Narrow flood low wattage is available at:
http://www.harringtonlights.com/Spec...ow_wattage.htm

20 watt is available in spot and narrow flood at:
http://www.harringtonlights.com/Glass/mr11_lamps.htm

I'm also thinking that the MR16 lamps may be better because of the larger reflector. But it's
difficult to get low wattage MR16 lamps in the U.S..

In article <Bb7eb.8461$RW4.2936@newsread4.news.pas.earthlink.net>, "Steven M. Scharf"
<scharf.steven@linkearth.net> wrote:

> "Rick Onanian" <spamsink@cox.net> wrote in message
> news:93fhnv0r5ahf6phl1f38uakdkknm86akvb@4ax.com...
>
> > >super-cheap AA cells (versus the need to use more costly C or D cells to boost capacity on 6V
> > >systems).
> >
> >Eh? For the capacity, why not parallel two AA packs?

> >Nice gratuitous nudity. If there's anything better than useful information peppered with a bit of
> >gratuitous nudity, it must be food...maybe ravioli.
>
> The nudity is not gratuitous.

Darn right. The nudity advanced the plot of the web page in important, meaningful ways.

--
Ryan Cousineau, rcousine@sfu.ca http://www.sfu.ca/~rcousine President, Fabrizio Mazzoleni Fan Club