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Discussion Starter · #1 ·
I had bought a niterider classic select light on ebay some time ago. Batteries finally need replacing.

my choices:
Stay with 6V 10w/15w/25/ & replace NiCd with NiMh, larger size batteries for greater capacity. Larger NiMh batteries should give me a longer ride.
or
Switch to 12V system: replace halogens 15w/20w/35w. Brighter light.
Would 12v mean a longer ride but 12v=10 batteries (but smaller size batteries due to bulk & weight, etc ?)
Any suggestions for fewer batteries yet maintain capacity

During the year, I do most of my riding in the city except when I ride the dark back roads when my scout unit does an overnight and goes to summer scout camp.

Appreciate input. Any advantages/disadvatages in staying with 6V? switching to 12V?
Thanks
 

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I have never used halogens, so this idea of mine might be daft.....

I would be tempted to keep the 6v bulbs and use a 7.4v li-ion battery, plus suitable charger.

If in the future you go LED then you will have a battery and charger that is commonly used and could come in handy.
 

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Brightness depends on power, not voltage. The 12V system will be brighter, but that's only because the bulb is a higher wattage.

Runtime depends on the amount of energy in the battery, divided by the power consumption. Energy is volts * amp-hours. A 6V,10AH battery (60watt*hours) will have the same runtime as a 12V,5AH battery if they are powering bulbs of equal wattage.

If you are happy with the brightness of your existing bulbs, then I recommend just buying a replacement battery. Otherwise, if you want more light, I highly recommend looking at an LED light with lithium-ion batteries. LED's consume 1/5 as much energy for the same light output. Lithium batteries are 1/2 the weight of equivalent NiMH batteries. This combo enables you to use a battery that is 1/10'th as heavy as a NiMH battery in an equivalent halogen light.
 

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desolder said:
Brightness depends on power, not voltage. The 12V system will be brighter, but that's only because the bulb is a higher wattage.
At a first level analysis that is 100% true. However, looking a little deeper it's not quite true. In general you will find that 12 volt halogen bulbs are a little more efficient than a six volt bulb. Usually the 12 volt bulbs are about 5% to 10% more efficient at turning electricity into light than a 6 volt bulb. Using your typical G4 based bulb rated at 2000 hours a 20 watt 6 volt makes 300 lumens while a 12 volt makes 350.

Like desolder said, LED's are the way to go. At about 7 times the efficiency at turning electricity into light there is not much reason to drop cash into a halogen setup. Using that 300 lumen 20 watt 6 volt bulb as a comparision, a single XP-G R5 bin LED at about 850 milliamps will make that same 300 lumens. It will do that using only 2.75 watts vs. 20 for the 6 volt halogen.
 

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yetibetty said:
I have never used halogens, so this idea of mine might be daft.....

I would be tempted to keep the 6v bulbs and use a 7.4v li-ion battery, plus suitable charger.

If in the future you go LED then you will have a battery and charger that is commonly used and could come in handy.
Good suggestion

I used to Run my 6V bulbs off a 9.6V RC Battery but the bulbs didn't last long. A 7.4V (8.4v fully charged) Should still give good brightness. I found 10W bulbs to be best, giving 288 lumens off the 9.6V pack! The newer, (Hot by vistalite) were better than standard bulbs.
 

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Instead of spending a lot of money on a battery, you might want to consider just buying a new light - one of the magicshines...
 

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12v halogens are easier to come by than 6v. Local hardware store vs online ordering.
I'm going to LED and have no use for my 6v 5ah SLA and charger. If you were close i'd give it to you.
 

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vroom9 said:
At a first level analysis that is 100% true. However, looking a little deeper it's not quite true. In general you will find that 12 volt halogen bulbs are a little more efficient than a six volt bulb. Usually the 12 volt bulbs are about 5% to 10% more efficient at turning electricity into light than a 6 volt bulb. Using your typical G4 based bulb rated at 2000 hours a 20 watt 6 volt makes 300 lumens while a 12 volt makes 350.
And..

If you compare a 12watt light system in both 6 and 12V versions, the 6V system will be drawing 2 amps and the 12V system will be drawing 1 amp. Desolder is correct in that both systems are using the same power, but you tend to experience other inefficiencies at the higher current levels of the 6V systems.

The wiring, connectors, and switches tend to have fairly similar resistance values in both systems. Therefore you lose more power in those components at the higher current of the 6V system due to resistive loses. Yes, they can use thicker wire in a 6V systems, but the wire size is also limited by flexibility issues so there doesn't tend to be that much difference in practice.

Batteries also are less efficient at higher discharge currents relative to capacity. That wouldn't make any difference if the 6V system used 8 amp-hour batteries and the 12V system used 4 amp-hour batteries, but again as a practical matter, it doesn't usually work out that way. There just isn't that much selection in battery capacity in the cost effective sizes.

So converting the system to 12V will tend to give a marginal boost in runtime assuming you stay with a similar wattage bulb. But, as a practical matter, you will likely end up with a bigger battery pack. If you go with NiMh batteries, by far the best cell is the 4/3A that come in 3800-4500mah range. You also want to stick with a high quality cell like Panasonic or Sanyo. Cheap no-name nimh cells are really bad compared to the name brand. I use to build all my packs with Sanyo cells from batterystation.com. So with nimh you would likely end up with either a 5-cell 6V 4500mah pack or an 11-cell 13.2V 4500mah pack. 11 cell because all 12V MR11 bulb can be run at 13.2V with long life and much more light.

There are also huge differences in the quality of MR11 halogen bulbs. The bulbs used by companies like Niterider and Jet are many times better than cheap no-name bulbs. I've never found a source for these high quality bulbs other than buying the replacements from Niterider or Jet.

If you're coming from a Nicad system you'll probably have to buy a new charger if you go with anything besides another 6V Nicad pack. Once you add up the costs of a battery pack, a charger, possibly a new bulb if you go 12V, I really have to go with what others have said, It would probably be better to put money into a modern LED based light. The only somewhat cost effective way to keep the existing system going would be to buy 5 Sanyo nicad 5000mah D-cells with solder tabs from batterystation and rebuild the existing pack.
 

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Discussion Starter · #9 ·
Greatly appreciate the input.
I plan to buy a MS. The cost of changing to a 12v system (new batteries, bulbs, charger) will cost almost as much as an MS.
I'll most probably pick up a 7.2v pack for the Niterider Classic/Select & give it to my son. I already have a NIMH smart charger.
Thanks for the help.
 
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