# Beginner: Need help to make a 14.4V battery pack.



## terratec (Nov 20, 2009)

Hello, I like to power a 20W halogen light using 1.2 AA Nimh's. I need around 4000-5000mah using 14.4V. A 14.4V battery pack is quite expensive. I like a cheaper way.

I learnt about series/parallel battery.










Would i have to have 2 rows of 12 batteries end to end or 2 rows of 6 to make 14.4V 2400mah? I guess 12 still. of course this is impratical.

I understand battery holders are series. Is it possible i can connect 2 together to make parallel to get 14.4V. Is it a case of just wiring the black and red of both holders to each other. If so, how do i go about charging the lot? Besides i don't see battery pack holder for 12 AA.

If i can't do that. Is it possible to buy eg. 2 x 7.2V 2500mah battery packs and connect them together using a Y connector to get a total of 14.4V 5000mah?

I would rather be able to do it without a soldering iron if possible.


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## lidarman (Jan 12, 2004)

terratec said:


> Would i have to have 2 rows of 12 batteries end to end or 2 rows of 6 to make 14.4V 2400mah? I guess 12 still. of course this is impratical.


Two rows of twelve batteries for your final spec. 1 row of 12 =14.4 v, 2400 mAhrs if the spec of a cell is 1.2 v 2400 mAhr. Voltage increases with series wiring and capacity at a given voltage increases with parallel wiring. You need to do both here to get the voltage and capacity you specified.



terratec said:


> I understand battery holders are series. Is it possible i can connect 2 together to make parallel to get 14.4V, If so how?


Well that depends. It depends on the design of the holder.



terratec said:


> If i can't do that. Is it possible to buy eg. 2 x 7.2V 2500mah battery packs and connect them together using a Y connector to get a total of 14.4V 5000mah?


Well yes. but no. If you buy 2 7.2 volt packs you have to wire them in series. A y connector is a parallel connector. But you can buy the packs.
I'd still consider buying a 14.4 pack? Not sure they are really more expensive when you realize the issues. Personally, I wouldn't mess with building a pack unless you just like the fun of it. If you have to buy 24 cells, you are going to pay a lot and put a lot into it. You can buy 5000 mAhr cells but they are at least $5 each.

http://www.batteryspace.com/144vbatterypackseries.aspx

http://www.cheapbatterypacks.com/?menu=660F3530DE&sid=50001 You can specify the geometry with this company.

Are you replacing a pack and already have a charger...NiMH or NiCad?


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## El34 (Jan 11, 2009)

This page may be of help
I have info on this page that explains the series parallel/mah deal.
http://www.el34world.com/Misc/bike/BatteryWiring.htm

The series stack is the same mah as each battery in the stack
Putting another stack in parallel to the first stack adds the two stacks mah together


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## terratec (Nov 20, 2009)

Right so 2 rows of 12 1.2 2400mah end to end would make 14.4V 4800mah. 

Maybe that would just fit along the top tube? j/k. Shame, soldering end to end makes the soldering easier.

Thanks alot. The thing is, I am in the UK. I have no charger. The price of 14.4 are not cheap. I see 7.2V alot cheaper, thats why i had the idea of putting 2 together. 

I trying to avoid soldering all together using tape and clips etc. I know i need to connect the main wires to the bulb etc. as well. If i have to resort to buying a soldering iron i will but like to avoid for this one off DIY job.

I like to use lithium for lighter but i heard you need some extra circuitry, which i think is beyond me as a beginner at this stage.


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## terratec (Nov 20, 2009)

So the ones in this video.






What configuration are they in?

Series/Parallel?


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## El34 (Jan 11, 2009)

That's allot of batteries man, and a ton of weight.

I have a 12volt series 4/3 sanyo Ni-Mh pack here that will drop you to the floor and that is only 10 batteries, but it is 4500mah because the cells are large.

3.6v litium ions are cheap from DX
You get way more bang for your buck
You get way less weight because you use less batteries.
Don't know about 14.4v lithium chargers, that may be an issue.


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## lidarman (Jan 12, 2004)

terratec said:


> Right so 2 rows of 12 1.2 2400mah end to end would make 14.4V 4800mah.
> 
> Maybe that would just fit along the top tube? j/k. Shame, soldering end to end makes the soldering easier.


There once was a light/battery like that called the night stick. The battery was a tube that fit on the top tube.

I don't see how end to end is easier if you solder them. It's only easier if you put them in a tube like a long flashlight and just solder the ends...maybe that is what you mean.

Then yes, it might be a long tube if that is the geometry you choose.

Good luck whatever you do.


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## terratec (Nov 20, 2009)

I got the idea of making it easier for soldering from the video but i see obviously it make it too long for 14.4V. So i was interested in getting 14.4V from battery holders or 2x7.2V. Looks like the only pratical way is to buy a 14.4V from model shop. If i going to order overseas then i might as well get P7/MS and wait longer time for delivery.

I was cautious about lithium as i heard they can explode with charger.


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## terratec (Nov 20, 2009)

On second thoughts, the weight of 14.4V using AA Nimh's will be seriously heavy, over 2lb.


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## lsocoee (Oct 29, 2009)

I would definitely be looking into lithium rechargeables from Deal Extreme. 

I've been contemplating a piece of long piece of PVC and just sliding all the batteries in. Maybe I could do a cutout in the side so that I could easily remove the batteries and then put a quick piece of tape to seal it up. 3" of duct tape per ride...that seems like a pretty cheap/easy way for a watertight battery door.


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## bikeny (Feb 26, 2004)

Sometimes it's fun to do a DIY project, but sometimes it is just not worth it. If I were you. I would just get a Magicshine light and go ride. It will be a ton lighter than a 12 cell battery and will be brighter as well. It will probably cost you about the same as well, seeing as you would have to buy batteries, holders and a charger.

Mark


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## HEY HEY ITS HENDO (Feb 23, 2008)

click on the link and take a good look around,
........ some good cheap stuff an only a quid postage charge
lead acid battery and small charger is the cheapest solution
http://www.component-shop.co.uk


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## OldMTBfreak (Apr 8, 2006)

I think you would be better off to buy a NiMH battery from Batterysource. I would get a 14.4 [email protected] battery made of "C" cells. Battery cells in parallel do not do as well (the difficulty is matching the indiviual cells). This will be heavier than Li-ion, but cheaper.


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## terratec (Nov 20, 2009)

bikeny said:


> I would just get a Magicshine light and go ride. It will be a ton lighter than a 12 cell battery and will be brighter as well. It will probably cost you about the same as well, seeing as you would have to buy batteries, holders and a charger.
> 
> Mark


Yes Yes, but came to the conclusion from research that a 20W 12V MR16 IRC overvolted at 14.4V will give me more like 25W 900+ true lumens of white light, which would be stronger than a MS which is reportedly much less than it's spec of 900 lumens, and give me 2 hours + with 5000mah. Plus having the fun of trying/replacing the bulbs at a cheap price and using 35W. I was all enthusiastic to solder, when seeing the price of battery packs. I found certain attractive outdoor and pond lights with MR16 lights already in them at my local DIY store. I also came to conclusion it not worth doing if it less than 14.4V due to the extra oomph you get overvolting. I understand you always get less amps/h with battery holders due to resistance.

Thanks for the suggestions.

Alot of power drill batteries are 14.4V. You can get lithium chargers to cover 14.4V to 18V.

Don't i need with lithium, some extra configuration like a driver like LED's to stop the current dipping or something? This is what put me off LED's.

I saw from http://www.component-shop.co.uk 14.8V 3200mAh lithium and only 365g  but quite a price and still not enough duration.

One here for 4400mah , that would do. http://www.batteryjunction.com/tenergy-14-8v-4400.html

Into the realm of laptop batterys.

Those lead acid batterys are even heavier.

I see the C and D batteries with bigger amps but they still 1.2v so i still need 12 so heavier right.

Another thought was get 2xP7 that last for an hour, and carry spare batteries. I would of course need a charger and batteries but be brighter for the same price of MS.


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## El34 (Jan 11, 2009)

I have never seen a Halogen bulb that compares to the SSC P7's LED's running at 2.8 amps

I ride with a bunch of guys that have all kinds of lights.

The P7 LED's blow away everything and every high end expensive light I have seen.

The P7 light is very white and way brighter than the yellow Halogen lights.

Are you calculating this on paper or have have you seen the two trypes of lighting side by side?

Not only that, but the Li-On battery packs in use are half the size and weight.

Just asking, because I know many people like to calculate results.


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## terratec (Nov 20, 2009)

lsocoee said:


> I would definitely be looking into lithium rechargeables from Deal Extreme.
> 
> I've been contemplating a piece of long piece of PVC and just sliding all the batteries in. Maybe I could do a cutout in the side so that I could easily remove the batteries and then put a quick piece of tape to seal it up. 3" of duct tape per ride...that seems like a pretty cheap/easy way for a watertight battery door.


Right so that means instead of buying an expensive 14.4V lithium battery pack. The max 18650 lithium i see is 1500mah on one site for now and there 3.7V. So I just need to have 4 soldered end to end in 3 rows for 4500mah. Much more compact space, not to mention the weight saving. 12 18650 lithium batteries = price  Tell me it still a good saving...

I only see 18650 chargers for 2 batteries on DX.


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## terratec (Nov 20, 2009)

I see you can get 18650 upto 3000mah individual.

Check this mother out. Shame on the price.
http://www.batteryspace.com/li-ion18650battery185v52ah96whwithtrail-techfemaleplug.aspx

I see where it's all at. The polymer.
http://www.batteryspace.com/capacity4000mah-5200mah.aspx


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## OldMTBfreak (Apr 8, 2006)

96WH in 470grams...nice battery; nice price.


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## terratec (Nov 20, 2009)

What about these 26650's. I would only need 4 in series for 14.8 giving 4000mah, so much cheaper.

http://www.batteryspace.com/limnnirechargeable26650cell37v4000mah10arated148wh.aspx

Sounds too good to be true. Where's the catch?


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## terratec (Nov 20, 2009)

It says on batteryspace.com.

"Li-Ion battery pack can be used on halogen bike light, but you have to make sure PCB on Li-Ion battery pack can pass through higher higher initial current ( 3 time higher than normal current)"


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## terratec (Nov 20, 2009)

El34 said:


> I have never seen a Halogen bulb that compares to the SSC P7's LED's running at 2.8 amps
> 
> I ride with a bunch of guys that have all kinds of lights.
> 
> ...


It is calculation and from lots of different sources. P7 will have more white light but not more lumens. You may of not seen a Halogen overvolted past 12V.










Here is one example.
https://www.candlepowerforums.com/vb/showthread.php?t=221282

I heard if you get the specific IRC versions and stick aluminium foil at the back to stop light going backwards.


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## terratec (Nov 20, 2009)

Quote.

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 â€“ 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 doesnâ€™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 donâ€™t take up much space.


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## El34 (Jan 11, 2009)

If Halogens were superior, we would all be using them now instead of LED's.

High end light makers would be using them also.

Halogens were superceded by HID and HID's were superceded by LED in the bike lighting evolution

I am only throwing out info based on all these lights I have owned over the years.
I would never go back to HID and Halogens are a distant memory to me now.

The current LED's are blowing away HID and Halogen in performance.
You can go with Halogen's, thats your personal choice, you may be happy with them, many people are.

This is just my personal take on the history of bike lighting


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## jeffj (Jan 13, 2004)

The problem with making one big battery as diagrammed at the top of this thread (you are essentially making two battery packs and hooking them together) is that each 'pack' will likely charge and discharge at different rates causing them to get out of sync. If you're using a peak charger, it may sense the voltage drop on one side while other is not fully charged. Eventually, the side that is not getting fully charged will discharge past 0.9v per cell far enough ahead of the other pack that it may get so completely discharged that some cells could reverse their polarity.

If you were to be able to separately peak charge each pack and then hook them together when in use, then the above would not apply.

You can find nimh D cells up around 13,000mah. C cells can be had up to around the 5,000mah to 6,000mah range.

Soldering wires or tabs to cells is easily done with a 40watt iron using a 1/4" chisel tip. I use a dremel to rough up the surface, pre-tin the cells. Try not to keep the hot iron on the cell for more than five seconds without letting it cool off a bit. Once you get the hang of it, it's pretty easy. A jig to hold the cells (even tape can work if necessary) makes it easier too.


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## terratec (Nov 20, 2009)

El34 said:


> If Halogens were superior, we would all be using them now instead of LED's.
> 
> High end light makers would be using them also.
> 
> ...


Don't misunderstand me. I agree with you. Halogens produce alot more heat. I didn't want to go down the LED route due to soldering, heatsinks etc. Halogens were a compromise of big light with a simpler construction for me.

I was put off from the long waiting time of delivery from say DX. I can't find cheap battery packs here in UK.

I'm sure you seen this all before. I tempted to concede and get 2 Magicshine's.


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## El34 (Jan 11, 2009)

> I tempted to concede and get 2 Magicshine's.


Not a bad way to go right there.
Two is a good idea also


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## OldMTBfreak (Apr 8, 2006)

I used li-ion batterys and ran OV'ed halogens for 5 or 6 years. They worked ok. The large battery was my main gripe. Now, I've switched to LED's; I'm not going back. Even though I did like the pattern and throw of the halogens. The 12 volt bulbs ran at 16.8 volts put out lots of light.


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## terratec (Nov 20, 2009)

terratec said:


> What about these 26650's. I would only need 4 in series for 14.8 giving 4000mah, so much cheaper.
> 
> http://www.batteryspace.com/limnnirechargeable26650cell37v4000mah10arated148wh.aspx
> 
> Sounds too good to be true. Where's the catch?


They LiMnN, unsafe without a PCB.

LiFePO4 are safe and safer than Li-Ion.


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## terratec (Nov 20, 2009)

8x 3.7 Li-On 18650 @ 2400mah = £47 $80
A battery pack about the same.

It cheaper to buy a battery pack than 10x LiFePO4 26650 Cell: 3.2V 3400 mAh

Add on charger, leads, cable, plus the lamp head unit
That be another £30.

:madman: 

I get the MS's, no way MS putting out 900 lumens more like 650 at those amps.

Thanks.


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## terratec (Nov 20, 2009)

OldMTBfreak said:


> The 12 volt bulbs ran at 16.8 volts put out lots of light.


That what i was considering, run them even higher upto 18V. As the bulbs are quite cheap it be so worth it. or enough to run 2 lights.

The newer MR16 have now a bulb life of upto 18000 hours! It be worth doing now using lighter batteries.


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## ash240 (Jun 2, 2007)

*Don't bother*



terratec said:


> That what i was considering, run them even higher upto 18V. As the bulbs are quite cheap it be so worth it. or enough to run 2 lights.
> 
> The newer MR16 have now a bulb life of upto 18000 hours! It be worth doing now using lighter batteries.


Soldering iron prices start from a few dollars. If you are talking about Halogen then you have no real idea. Buy a commercial product and forget trying to be smart. 
High output Halogen = short life span (you mentioned this without seeming to understand the point, riding at 20+kph and going lights out is bad news.) . Add the out of spec running (vibration as an example) and you have no real idea how long it's going to last. Halogen cannot compare to LED and if you think they do you have not seen decent LED lighting. 
LED's give you TOTAL control over beam shape and brightness plus exceptional run time.

You can buy most of everything from DE then just get a decent controller. Housings are really easy to make (25mm square alloy with a heatsink) and in the time you have wasted looking at Halogen you probably could have had them by now AND while you waited for stock to come in learnt how to solder!

If you want to play around with Halogen then do so but if you want REAL lighting go LED.
Having spent some time prototyping Halogens before you should have a good hard look for special purpose bulbs. Xenon encapsulated units as a start IF you can find a source which does not force 000's in one order. I found some REAL gems but couldn't actually buy them. Don't forget some way to dim them too  BIG lighting means you need a second lower brightness light OR that you can dim the main light in many situations.


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## OldMTBfreak (Apr 8, 2006)

Dimming is important. When you are following in the dirt and dust, if you can't dim the glare is terrible. For the halogens, I used a mosfet 2 light controller. I only used one channel of it. I think it was a LightBrain. For the LED's, I use a Taskled controller. The LED's are so much better than the incandescent bulbs. The fact to remember is this, incandescent bulbs are 10% efficient (90% of the energy input is disapated as heat). LED's are 90% efficient!!!!!!!!!!!!!!!! So, more light for same energy.


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## El34 (Jan 11, 2009)

I have 12 volt halogen desk lamps here.
I can't keep enough bulbs on hand.
They burn out left and right.

The filaments get brittle.
Move them the wrong way and out they go.
There's not too much I like about Halogen lamps.


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## OldMTBfreak (Apr 8, 2006)

It's time for LED replacements.


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## Jim Z in VT (Sep 9, 2007)

As a convert to the DIY LED world I hate to say this. LEDs are better in pretty much every way, but.....halogens are fine :eekster: with a few disclaimers:

The light is yellower than LEDs (even at 20% overvoltage) so the apparent brightness is less than what you'd expect from the predicted lumens. Your expected 900 lumens will look more like the 600-ish lumens from the much maligned MagicShine light. But 600 lumens _is_ plenty of light to ride by.

And as mentioned, efficiency is terrible compared to LED lights, so you need to drag around a big battery to get adequate runtime.

And, they get frikken' hot! So mount them where you're not going to accidentally lay your hand on the bulb or housing. My 14.4v dual halogen gets WAY hotter than any of my LED lights.

But....some of the other arguments don't hold water:

Bulb life I've found to be a non-issue. They say 20% overvolting cuts bulb life to 5% of nominal. Say your bulb is rated for 2000 hours (most are more), so 100 hours overvolted. How many night rides is that? I have a dual MR-11 halogen set-up I bought in 1995....used it regularly for 5 seasons, put it away for a decade, then used it regularly until last year when I started building with LEDs. Still loan it out fairly often to lightless friends, and it's still going strong on it's original bulbs. I wouldn't push the voltage more than a 14.8v lithium pack though....I've popped bulbs experimenting with 18+ volts.

Dimming....well, you should run a 2 bulb setup in case one does quit (redundancy is smart whether you're running halogen or LED) so run one 12w and one 20w bulb, and you've got low/med./high levels just by switching on one or the other or both bulbs. This also extends your runtime by letting you run at lower wattage when you don't need full blast mode, like while climbing or stopped for a safety meeting.

LEDs are great; better in every way. But if you can sort out an appropriate battery at a good price, You can build a bright light pretty cheaply and very simply with halogens.

Still though.....when you think about it....lithium battery, charger, and 650 lumens ready to plug and play from that MagicShine light.....at that price.....hmmm....:yesnod:

JZ

(Doug, sounds like you need new desk lamps.....I have 2 here that are going on 20 years with the original bulbs  )


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## El34 (Jan 11, 2009)

Yeah, I think it is the cheap hologen replacement bulbs I bought. 
Not sure why they give me so much trouble.
The bulbs are two pin 12volt bulbs.
At the time, radio shack was the only place I coule find the bulbs


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## bikeny (Feb 26, 2004)

terratec said:


> Quote.
> 
> 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.


I am not sure where you are finding your information, but an overvolted halogen in definately NOT more efficient than and HID. There is no way an overvolted 20W halogen will put out twice the light of a 13W HID, that is just silly. As others have said, you could make a decent light using halogens, but it will be heavy, have a yellowish light, and be very prone to bulb failure. For the same amout of work you could make an LED light that will be brighter, lighter weight, and have a much nicer light.

You seem to be a little scared of LEDs. It is not rocket science. You need some LEDs, buy them mounted on small PC boards, you need an appropriate driver, and you need the right batteries. The only difference is the driver. The money you save by needing smaller batteries will pay for the LEDs and driver. There are plenty of simple DIY setups poted here that would be easy to follow. There are also plenty of people that sell housings for specific setups and you just need to follow their instructions.

I think in the long run you will be much happier with an LED setup.

Mark


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## ash240 (Jun 2, 2007)

JimZinVT
Bulb life I've found to be a non-issue. They say 20% overvolting cuts bulb life to 5% of nominal. Say your bulb is rated for 2000 hours (most are more) said:


> To get a decent amount of light out of halogens people tend to use the higher output units that already have a short life. Not 2k hours. In the hundreds plus these are MUCH more sensitive to vibration when run at higher V. Now, if you do want to use the crappy long life ones then your % of life will be higher at the cost of lower output.
> Early failure IS a real issue, just because you have not seen it does not make it less so
> 
> Your suggestion that he runs well over 40 Watts to of lighting to work around single light failure is reasonable. He could also then pick a spread beam for the low wattage and a medium focus for the higher wattage. If he's happy running over 40 Watts though. He does need to calculate battery life and think about it. Most of my rides are well above two hours. I can run under 15 watts of dimmable LED's and beat his 40+ watts of Halogen easily.


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## yetibetty (Dec 24, 2007)

terratec, if you are a bit scared of getting the LED thing wrong then it maybe worth having a look at cutter electronics LED kits, that way you will get the LED/ driver combo worked out for you.

Link here http://www.cutter.com.au/categories.php


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## Jim311 (Feb 7, 2006)

Well, here's my 2 cents as someone who runs an overvolted halogen and is pretty happy with it for the cash.

Here's my setup:

Niterider "Trail Rat" with a 12v 20 watt bulb in it, a drop in conversion, and bulbs are cheaply available at Home Depot.

Battery: 14.8v lithium setup, 4000 mah

I get over 3 hours of run time with it, and it's pretty bright. The above diagram states that it ought to be putting out about 600-650 lumens which I think is probably correct. I paid next to nothing for the Trail Rat housing, and about 75 dollars for the battery and charger. I have been running this setup for several years now, still on the original bulb. I will probably swap it out pretty soon, I carry a spare in my pack most of the time. I know LED is superior but prior to the creation of the Magicshine nothing else really compared brightness wise for what I have dollar wise into the setup. You can buy these old Niterider housings on Ebay all day long for cheap, and the batteries are pretty easily available from a variety of people. With lithium packs the weight is about the same as 8 AA batteries, really not an issue to me. Now that the Magicshine is out though I doubt I would go this route unless I already had most of the parts.


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## terratec (Nov 20, 2009)

Here is a 12V MR16 Xenon (normally 500 lumen) @ 20V(1000 lumen) Halogen against a P7.


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## womble (Sep 8, 2006)

Interesting revived thread. OP- what did you end up doing?

I used to use an 12V halogen (MR11 or MR16) run off a 14.4V pack but along with everyone else moved to DIY LED.

The LED system is lighter and cooler, and it's definitely more satisfying to the inner geek part of me.

Howvever, I certainly wouldn't pan halogens. They might be 'old tech', but they
- are dead easy to build (no drivers, no switches necessary, no delicate soldering required)
- are incredibly cheap to build
- have a much more comfortable colour of light output than LEDs
- could not be damaged by water (no electronics). I once ran it fully submerged in a bathtub

I never had to change a bulb once, but in any case they cost around $1 and are still available all over the place.

I'm not moving back to halogen as I'm happy with my LED systems. And I think that buying a commercial/proprietary halogen system is silly. But building a halogen system still makes plenty of sense.

Edit:

Hmm... I just re-read this thread. Looks like there are two issues raised here. Halogen vs LED and NiMH vs varioius Lithium chemistries.

Whilst these can be treated independently, I am also of the opinion that if you're pursuing the low-tech halogen route, it makes sense to run NiMH as it's also cheap and simple.

If you're going with lithium chemistries, safety and charging becomes a more complex consideration. You want to be thinking about balanced charging, voltage protection via PCBs and fuses and if you're going to go this far, then you may as well take the small additional step of LEDs, optics and drivers. I'd be *extremely *wary of building a halogen system and then just whacking on a load of unprotected Li-ion round cells, or a Lipo. That'd be asking for trouble.


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## mattthemuppet (Jul 16, 2004)

I have a halogen set up that's pretty old that still works well - Osram IRC bulb (50mm one, MR1?), lightbrain, 13.2V NiMh pack, even though it's 6+yrs old. Lots of 24h races, weekly nightrides in all sorts of weather and terrain. Downsides are weight and light output vs. runtime. I'm currently building up a twin XP-G light that will weigh 2/3 of my halogen, put out 50-100% of the light and run for twice as long. 

It will also cost more than twice as much too 

As to the OP lighting desires - if you're not comfortable with a soldering iron I would simply buy a Magicshine or equivalent. The price is phenomenal for the whole package. If you are comfortable with a soldering iron, skip halogen and NiMh and go straight to LED and Li-ion. No point in wasting time on old tech, it's not like it'll save you all that much money.


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