Above: Lead-Acid Battery packs come in a wide range of power capacities and physical configurations. Example image from |
Nickel-Cadmium Cells NiCds are a very popular form of rechargeable power. Almost any hand-held device which uses rechargeable power uses NiCds. The smaller the device, the more likely that it uses NiCds, because these cells come in a wide range of sizes-corresponding to the normal packaging for "flashlight batteries", with some in-between sizes found only in NiCd form. NiCd cells differ from the traditional non-rechargeable- carbon-zinc types, and the newer alkaline types in voltage level, both of which put out 1.5 volts per cell. NiCds put out 1.2 volts. This means that a battery supply which delivers 12 volts will require 10 cells in series hookup for NiCds, and 8 alkaline cells to deliver the same voltage. Generally, the larger the cell size, the greater current capacity. With NiCds, there is another determinant- most NiCd cells are available in different capacities within the same size level . As a rule of thumb, the greater the capacity (rated in amp/hours, or milliamp/hours) the higher the price. Lead-Acid Storage Batteries Although there have been modern improvements, this is the same type of power source which has been cranking the engines and powering the lighting systems of automobiles since the earliest days of motoring. New technology, in the form of gel electrolytes in a sealed case, have made this type more ubiquitous than ever. The ability of the battery to retain its electrolyte, even when upside down, has seen the lead-acid becoming used in applications which would have called for carbon or alkaline cells in the past. The cells which make up this type of battery have a significant advantage over the NiCd cells- they put out 2 volts per cell. Whereas it requires 10 NiCd cells in series to deliver 12 volts, a gel-cell battery requires only 6 cells to deliver the same voltage. This can make a difference in many applications. Although it is possible to buy a single 2-volt lead-acid cell, they are most commonly combined within a multi-cell package which has voltage outputs in the popular ranges: 6, 12, and 24 volts. Like the NiCds, it is also rated as to capacity in amp/hours. Again, the greater the capacity, the higher the price. The Economics Of Storage Battery Types In Relation To Bike Lighting Needs At this point, comparing the cost of NiCd and Gel types for delivering 12 volts at useful amp/hour ratings, the Gel Battery has a significant advantage. Amp/hour-wise, gel batteries cost about half of the NiCd price. Assuming that I was about to build a bicycle lighting supply, I would normally open my current Herbach and Rademan Catalog to the battery section. There are many sources for this type of product; but I have been dealing with H&R for thirty years, and have always been happy with their prices and service. They always have a wide range of stock rechargeable power sources, in NiCd and Lead-Acid types, at competitive pricing. H&R's catalog and website also feature special deals on manufacturer's over-runs, and industrial surplus. At a given time, you may find a battery pack which exactly fulfills your need at a significant saving over the stock component price in the same catalog. In our research into the current H&R catalog (4 times a year) we put together a set of power supply specifications and prices based upon stock units of the NiCd and Lead-acid types, and a pair of happy discoveries in the surplus category A Nickel-Cadmium Battery Supply With NiCds, the bigger the package, the greater the capacity. For this reason, for high-power supplies, larger cells are preferable. As NiCds pretty much follow the flashlight battery size categories, we have chosen the "C" size. While "D" cells will have inherently greater capacity, their cumbersome size makes them more problematic for fitting into a bike application. Therefore the choice of the "C" cell, which is 1" in diameter by 2" long, is purely determined by its size. For a 12 volt pack, we will require 10 cells. These cells must be wired together in series, with wire interconnects soldered to each cell. This is a fairly tedious process, although it is not onerously so. There are no stock battery clip arrays for this job, and the soldered connections will be much more reliable. A string of 10 cells stretched straight would form a tubular shape 1" in diameter by about 20" long. This would fit within the length of a typical bike's top tube or seat tube. A pouch of this dimension could be discreetly strapped to the top tube, and would work perfectly well, unless you would prefer another location and configuration. The NiCd cell string can be folded together in just about any shape you could want. Many commercial high-power battery packs for bikes come in a cylindrical package which fits into a normal water-bottle cage. If you like this package, it is as simple to do as any other pack shape. There are other locations on a bike frame where a NiCd pack may be located. Thinner arrangements- the previously-mentioned 1" X 20" or the 2" X 10" (2 rows of 5 cells) will comfortably fit into a streamliner tank area. If you prefer another area, for whatever reason, a more compactly-folded cell string will comfortably fit into the triangle formed by the seat tube and the seat stays of most bike frames. (Diagram A) When choosing NiCd cells in a given size range, there is often a choice to be made. Typically, in the H&R catalog, there are Consumer Grade and Industrial Grade types. The industrial grade have higher capacity and price. For a set of 10 NiCd "C"cells in consumer grade, the H&R price is $40 for 12 volts @ 1,200 milliamp-hours. (1.2 amp-hours) The same set of cells in industrial grade will cost $70 and deliver 12 volts @ 2,000 milliamp-hours. (2 amp-hours) In the H&R surplus specials, currently, is a pre-wired NiCd package, H&R part# TM98BAT3105, complete with charger, which delivers 12 volts @ 1,600 milliamp-hours. (1.6 amp-hour) This package costs $10.95 and measures 7"X 3" X 3 1/8". Quite a bargain, eh? If this capacity suits you, and you can fit the physical size of the pack into your setup, you're in great shape with this one. At this price, you might want to spring for some spares, always a good thing to have, in bike lighting. This package size should fit into a bottle cage. Any NiCd pack will require a charger fitted to its specifications. Getting a dedicated charger with a pre-wired pack will save considerable time on the project. A Gel-Cell Battery Lighting Pack As gel batteries customarily are made as unified packages of internal cells, they come in many different sizes and configurations. As usual, the bigger the package, the higher the capacity. We will show several packages available as stock off-the-shelf items, and one of the H&R surplus specials similar to our needs. H&R Part # Volts Capacity (amp-hours) Dimensions Price PAN-102 12V 1.2 3.82" X 1.65" X 2.05" $23.95 PAN-105 12V 2.2 6.97" X 1.34" X 2.36" $23.95 PAN-103 12V 4 2.76" X 3.82" X 4.02" $26.75 PAN-104 12V 6.5 5.95" X 2.54" X 3.70" $27.95 PAN-110 12V 12 6.91" X 3.86" X 3.70" $40.96 From this it may be seen that gel batteries have much greater capacity per dollar price, and that the physical size is certainly no greater than for a corresponding NiCd pack. The NiCd has a certain advantage, in that it may be stretched out and reconfigured. The numbers tell the story: a 1.2 amp-hour NiCd pack will cost $40. A 1.2 amp-hour gel battery will cost $23.95. This is a considerable price difference. A gel battery of 10 times the capacity of the 1.2 amp-hour NiCd pack is barely more expensive. The H&R surplus special on a gel battery pack within our performance/size parameters is their part # TM97BAT3038. It is a 12V pack of 3.2 amp-hour capacity, complete with charger. It measures 9 ¼ " X 2 ½ " X 1 ½ ". It costs $14.95. This is roughly the size of a 2" X 10" NiCd pack. Although it is a half inch thicker than the NiCd pack, it will still fit into most tank areas. As of this writing (11-15-01) the choice would appear fairly obvious. The H&R surplus gel-battery pack and charger, at $14.95 is tough to beat. It has twice the capacity of the NiCd surplus pack at a price one-third higher. Of course, if you prefer to have a pack which will fit into a bottle cage, the physical configuration may make a difference in your choice. If you'd like to mount it in the tank area, you might be more inclined to the gel pack. Either way, it's hard to go wrong at these prices. I had originally intended to include a circuit diagram for building a NiCd charger. A charger consists of a transformer to step-down line voltage to the battery pack's range, a diode bridge which turns the AC from the transformer to DC, and a power resistor to limit the output to the battery's charging level. NiCds are designed to be charged at 1/10 of their capacity. The different capacity ratings determine the value of this component. A 12V.gel battery may be charged by any small auto-battery trickle charger, so I've felt no need to include any instructions for one of those. Considering the differences of available NiCd capacities, I have decided not to include plans, but recommend that you buy the surplus pack with charger. If anyone out there wants to build a NiCd pack from cells, I will be glad to furnish a schematic with correct current-limiting resistor specification to fit your exact cell specifications. As this article will be archived, H&R's surplus pack deals are likely to have changed in the future, although they generally have something similar to both specials. . It is recommended that you go to Herbach& Rademan's web site to consult their current catalog, totally on-line in Acrobat .PDF format. Go to: http://herbach.com How Do These Numbers Relate To My Needs/Wants For My Bike Lighting Project? Good question. A battery supply's capabilities are determined by what is demanded of it. Let us take an example and do the math for it. Lighting Load: Let's say that you have light sources which add up to 30 watts. The formula is: P =VI , where Power (P) is the Voltage (V) multiplied by the current (I). We plug in 30 (watts, which is how electrical Power is rated). Voltage is 12. We get the current figure ( I ) by dividing ( P ) 30 by ( V ) 12. 30 Watts / 12 Volts = 2.5 Amps Batteries are rated in Amp-Hours. A 1 amp-hour battery will deliver 1 amp for 1 hour, before it must be recharged. Since our theoretical lighting load of 30 watts draws 2.5 amps, our bargain Gel Battery Pack of 3.2 amp-hour rating will deliver full lighting for about 1.3 hours. Good thing they're bargain-priced, because a spare may come in handy. If you'd like to just get more time- say 2.5 hours, maybe the PAN-104 6.5 amp-hour battery, at $27.95 is better for your needs. And what about that 55-watt bad boy you want lighting-up the front end?. We'll do the math again, dividing ( P ) 55 by ( V ) 12. This time we get about 4.5 amps. In amp-hour terms, this gives you about 1.5 hours of lighting from that 6.5 amp-hour pack. The bargain pack of 3.2 amp-hour will give you about 45 minutes. Perhaps, if you want to light with the big boys you should go for something like the PAN-110 , rated at 12 amp-hours, for $40.96. It's of a manageable size, at roughly 7" X 2.5" X 3.75" , which could theoretically fit in either the tank or tube/stay intersection. ( It has a shipping weight of 5.5 pounds.) That one will give you about 2.5 hours. Tail lighting draws much less power than head lighting. LED tail-light power demand is measured in milliamps, so it is pretty much negligible in calculations. Always factor in the actual power rating for your tail lamp if you use a bulb type, though. It should be fairly obvious by this time that NiCd packs are at a severe disadvantage for ultra-power lighting needs, unless your night-riding is of an occasional, short-duration basis, or if you just want the bike lighting to look kool. |
Jim Wilson: Building A Serious Lighting System For KustomBikes- Part Three: Choosing A Rechargeable Battery Lighting Pack |
Nickel-Cadmium Cells NiCds are a very popular form of rechargeable power. Almost any hand-held device which uses rechargeable power uses NiCds. The smaller the device, the more likely that it uses NiCds, because these cells come in a wide range of sizes-corresponding to the normal packaging for "flashlight batteries", with some in-between sizes found only in NiCd form. NiCd cells differ from the traditional non-rechargeable- carbon-zinc types, and the newer alkaline types in voltage level, both of which put out 1.5 volts per cell. NiCds put out 1.2 volts. This means that a battery supply which delivers 12 volts will require 10 cells in series hookup for NiCds, and 8 alkaline cells to deliver the same voltage. Generally, the larger the cell size, the greater current capacity. With NiCds, there is another determinant- most NiCd cells are available in different capacities within the same size level . As a rule of thumb, the greater the capacity (rated in amp/hours, or milliamp/hours) the higher the price. Lead-Acid Storage Batteries Although there have been modern improvements, this is the same type of power source which has been cranking the engines and powering the lighting systems of automobiles since the earliest days of motoring. New technology, in the form of gel electrolytes in a sealed case, have made this type more ubiquitous than ever. The ability of the battery to retain its electrolyte, even when upside down, has seen the lead-acid becoming used in applications which would have called for carbon or alkaline cells in the past. The cells which make up this type of battery have a significant advantage over the NiCd cells- they put out 2 volts per cell. Whereas it requires 10 NiCd cells in series to deliver 12 volts, a gel-cell battery requires only 6 cells to deliver the same voltage. This can make a difference in many applications. Although it is possible to buy a single 2-volt lead-acid cell, they are most commonly combined within a multi-cell package which has voltage outputs in the popular ranges: 6, 12, and 24 volts. Like the NiCds, it is also rated as to capacity in amp/hours. Again, the greater the capacity, the higher the price. The Economics Of Storage Battery Types In Relation To Bike Lighting Needs At this point, comparing the cost of NiCd and Gel types for delivering 12 volts at useful amp/hour ratings, the Gel Battery has a significant advantage. Amp/hour-wise, gel batteries cost about half of the NiCd price. Assuming that I was about to build a bicycle lighting supply, I would normally open my current Herbach and Rademan Catalog to the battery section. There are many sources for this type of product; but I have been dealing with H&R for thirty years, and have always been happy with their prices and service. They always have a wide range of stock rechargeable power sources, in NiCd and Lead-Acid types, at competitive pricing. H&R's catalog and website also feature special deals on manufacturer's over-runs, and industrial surplus. At a given time, you may find a battery pack which exactly fulfills your need at a significant saving over the stock component price in the same catalog. In our research into the current H&R catalog (4 times a year) we put together a set of power supply specifications and prices based upon stock units of the NiCd and Lead-acid types, and a pair of happy discoveries in the surplus category A Nickel-Cadmium Battery Supply With NiCds, the bigger the package, the greater the capacity. For this reason, for high-power supplies, larger cells are preferable. As NiCds pretty much follow the flashlight battery size categories, we have chosen the "C" size. While "D" cells will have inherently greater capacity, their cumbersome size makes them more problematic for fitting into a bike application. Therefore the choice of the "C" cell, which is 1" in diameter by 2" long, is purely determined by its size. For a 12 volt pack, we will require 10 cells. These cells must be wired together in series, with wire interconnects soldered to each cell. This is a fairly tedious process, although it is not onerously so. There are no stock battery clip arrays for this job, and the soldered connections will be much more reliable. A string of 10 cells stretched straight would form a tubular shape 1" in diameter by about 20" long. This would fit within the length of a typical bike's top tube or seat tube. A pouch of this dimension could be discreetly strapped to the top tube, and would work perfectly well, unless you would prefer another location and configuration. The NiCd cell string can be folded together in just about any shape you could want. Many commercial high-power battery packs for bikes come in a cylindrical package which fits into a normal water-bottle cage. If you like this package, it is as simple to do as any other pack shape. There are other locations on a bike frame where a NiCd pack may be located. Thinner arrangements- the previously-mentioned 1" X 20" or the 2" X 10" (2 rows of 5 cells) will comfortably fit into a streamliner tank area. If you prefer another area, for whatever reason, a more compactly-folded cell string will comfortably fit into the triangle formed by the seat tube and the seat stays of most bike frames. (Diagram A) When choosing NiCd cells in a given size range, there is often a choice to be made. Typically, in the H&R catalog, there are Consumer Grade and Industrial Grade types. The industrial grade have higher capacity and price. For a set of 10 NiCd "C"cells in consumer grade, the H&R price is $40 for 12 volts @ 1,200 milliamp-hours. (1.2 amp-hours) The same set of cells in industrial grade will cost $70 and deliver 12 volts @ 2,000 milliamp-hours. (2 amp-hours) In the H&R surplus specials, currently, is a pre-wired NiCd package, H&R part# TM98BAT3105, complete with charger, which delivers 12 volts @ 1,600 milliamp-hours. (1.6 amp-hour) This package costs $10.95 and measures 7"X 3" X 3 1/8". Quite a bargain, eh? If this capacity suits you, and you can fit the physical size of the pack into your setup, you're in great shape with this one. At this price, you might want to spring for some spares, always a good thing to have, in bike lighting. This package size should fit into a bottle cage. Any NiCd pack will require a charger fitted to its specifications. Getting a dedicated charger with a pre-wired pack will save considerable time on the project. A Gel-Cell Battery Lighting Pack As gel batteries customarily are made as unified packages of internal cells, they come in many different sizes and configurations. As usual, the bigger the package, the higher the capacity. We will show several packages available as stock off-the-shelf items, and one of the H&R surplus specials similar to our needs. H&R Part # Volts Capacity (amp-hours) Dimensions Price PAN-102 12V 1.2 3.82" X 1.65" X 2.05" $23.95 PAN-105 12V 2.2 6.97" X 1.34" X 2.36" $23.95 PAN-103 12V 4 2.76" X 3.82" X 4.02" $26.75 PAN-104 12V 6.5 5.95" X 2.54" X 3.70" $27.95 PAN-110 12V 12 6.91" X 3.86" X 3.70" $40.96 From this it may be seen that gel batteries have much greater capacity per dollar price, and that the physical size is certainly no greater than for a corresponding NiCd pack. The NiCd has a certain advantage, in that it may be stretched out and reconfigured. The numbers tell the story: a 1.2 amp-hour NiCd pack will cost $40. A 1.2 amp-hour gel battery will cost $23.95. This is a considerable price difference. A gel battery of 10 times the capacity of the 1.2 amp-hour NiCd pack is barely more expensive. The H&R surplus special on a gel battery pack within our performance/size parameters is their part # TM97BAT3038. It is a 12V pack of 3.2 amp-hour capacity, complete with charger. It measures 9 ¼ " X 2 ½ " X 1 ½ ". It costs $14.95. This is roughly the size of a 2" X 10" NiCd pack. Although it is a half inch thicker than the NiCd pack, it will still fit into most tank areas. As of this writing (11-15-01) the choice would appear fairly obvious. The H&R surplus gel-battery pack and charger, at $14.95 is tough to beat. It has twice the capacity of the NiCd surplus pack at a price one-third higher. Of course, if you prefer to have a pack which will fit into a bottle cage, the physical configuration may make a difference in your choice. If you'd like to mount it in the tank area, you might be more inclined to the gel pack. Either way, it's hard to go wrong at these prices. I had originally intended to include a circuit diagram for building a NiCd charger. A charger consists of a transformer to step-down line voltage to the battery pack's range, a diode bridge which turns the AC from the transformer to DC, and a power resistor to limit the output to the battery's charging level. NiCds are designed to be charged at 1/10 of their capacity. The different capacity ratings determine the value of this component. A 12V.gel battery may be charged by any small auto-battery trickle charger, so I've felt no need to include any instructions for one of those. Considering the differences of available NiCd capacities, I have decided not to include plans, but recommend that you buy the surplus pack with charger. If anyone out there wants to build a NiCd pack from cells, I will be glad to furnish a schematic with correct current-limiting resistor specification to fit your exact cell specifications. As this article will be archived, H&R's surplus pack deals are likely to have changed in the future, although they generally have something similar to both specials. . It is recommended that you go to Herbach& Rademan's web site to consult their current catalog, totally on-line in Acrobat .PDF format. Go to: http://herbach.com How Do These Numbers Relate To My Needs/Wants For My Bike Lighting Project? Good question. A battery supply's capabilities are determined by what is demanded of it. Let us take an example and do the math for it. Lighting Load: Let's say that you have light sources which add up to 30 watts. The formula is: P =VI , where Power (P) is the Voltage (V) multiplied by the current (I). We plug in 30 (watts, which is how electrical Power is rated). Voltage is 12. We get the current figure ( I ) by dividing ( P ) 30 by ( V ) 12. 30 Watts / 12 Volts = 2.5 Amps Batteries are rated in Amp-Hours. A 1 amp-hour battery will deliver 1 amp for 1 hour, before it must be recharged. Since our theoretical lighting load of 30 watts draws 2.5 amps, our bargain Gel Battery Pack of 3.2 amp-hour rating will deliver full lighting for about 1.3 hours. Good thing they're bargain-priced, because a spare may come in handy. If you'd like to just get more time- say 2.5 hours, maybe the PAN-104 6.5 amp-hour battery, at $27.95 is better for your needs. And what about that 55-watt bad boy you want lighting-up the front end?. We'll do the math again, dividing ( P ) 55 by ( V ) 12. This time we get about 4.5 amps. In amp-hour terms, this gives you about 1.5 hours of lighting from that 6.5 amp-hour pack. The bargain pack of 3.2 amp-hour will give you about 45 minutes. Perhaps, if you want to light with the big boys you should go for something like the PAN-110 , rated at 12 amp-hours, for $40.96. It's of a manageable size, at roughly 7" X 2.5" X 3.75" , which could theoretically fit in either the tank or tube/stay intersection. ( It has a shipping weight of 5.5 pounds.) That one will give you about 2.5 hours. Tail lighting draws much less power than head lighting. LED tail-light power demand is measured in milliamps, so it is pretty much negligible in calculations. Always factor in the actual power rating for your tail lamp if you use a bulb type, though. It should be fairly obvious by this time that NiCd packs are at a severe disadvantage for ultra-power lighting needs, unless your night-riding is of an occasional, short-duration basis, or if you just want the bike lighting to look kool. |
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Diagram A: Typical Seat Tube- Seat Stay Intersection. showing how a NiCd cell string may be folded compactly to fit into a package which fits this area. |
Above: A typical line of NiCd cells, available in standard "flashlight" sizes, and special, in-between and odd packages. |
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Above: Lead-Acid Battery packs come in a wide range of power capacities and physical configurations. Example image from |
Functional, high-intensity bicycle lighting requires an electrical supply which can deliver a large flow of electrical current. High capacity is required to give adequate usage time at these power levels. The following is a comparison of the two most commonly used rechargeable battery types, and their use in bicycle power supplies. In this article we show the choices available from a typical source, and our recommendation for two currently available extremely good deals from a specific source. |