LIGHT BULB OPTIONS
ON LED HALOGEN KRYPTON AND VACUUM BICYCLE AND FLASHLIGHT BULBS
We supply 4
types of bicycle and flashlight bulbs:
(a) Vacuum (b)
Krypton (c) Halogen
Their characteristics are broadly as follows:
(a) Vacuum filament
bulbs are the basic type which are best for low power lighting
where high intensity light is not required. They are the lowest
cost, but because the filaments operate at a relatively low temperature,
only a moderate light quality may be achieved. This can be a
shortcoming in cycle headlamps and flashlights if a penetrating
beam is required.
filament bulbs contain pure inert gas which allows the filaments
to run at a higher temperature, emit a whiter light, and enables
enhanced visibility for a given power consumption compared to
(c) Halogen filament bulbs contain a technically advanced
mixture of active and inert gases. The active component re-cycles
tungsten from the glass back onto the filament, enabling the
use of a hotter, brighter filament. They are the ultimate filament
bulbs producing the best combination of white light, visibility,
and safety. The glass is thicker than krypton and vacuum bulbs,
and is hardened to produce a mechanically stronger bulb. Halogen
bulbs are available in the widest power range and they provide
good colour rendering in applications such as slide viewers and
inspection lamps. Halogen bulbs with push-in and screw-cap bases
are suitable for rough and demanding conditions. They have been
successfully shock tested at 40G in the axial and lateral planes
for emergency lighting in military aircraft.
(d) LED bulbs are
a more efficient light source and provide whiter, clearer illumination
at much lower power consumption. Nicelite Super LED bulbs utilise
high performance multi-led emitters and have a lifetime of over
30,000 hours. Miniature filament bulbs last typically 25-200
hours, depending on the design and type. The lowest voltage filament
bulbs tend to have the lowest life.
We supply 5 common light
(1) Bi-pin G2.5 = T5 5mm diameter (16mm glass length)
(2) Bi-pin G4 = 8mm diameter (24mm glass length)
(3) MR11-C = 35mm diameter Reflector + Cover. 27.3
- 27.7mm front to back (excluding pins), rim thickness 1.9-2.4mm
(4) Push-in P13.5s = P13.5s flanged [Pre-focus - 'PR'], barrel diameter
9.2mm, with flange "V" notch
(5) Screw-cap E10 = E10 [MES] G31/2
, thread diameter 9.5mm
In the Nicelice
LED section there is also a non-standard oversized "CNC"
push-in base for use in Maglite® metal bulb holders.
If you are unsure of the exact bulb you require, refer to the
Bicycle Bulb Guide or Flashlight
Bulb Guide tables. There are pictures of the different bulb
bases in the Halogen, Krypton,
and Vacuum Lists.
Please consult the upgrade bulbs listed
in the Bicycle Bulb Guide or Flashlight Bulb Guide. If planning
other upgrades, please be aware that plastic parts designed for
a certain power level ('W' column)
may not tolerate the higher temperature of a significantly more
powerful bulb. In addition, avoid leaving lights switched on
in a location with little airflow where they may overheat.
Temperature problems can result from a
substantial power increase through the 3W level. For instance,
thousands of dynamo headlamps have been upgraded from 2.4W to
3W with no difficulties reported, but fitting a 6W bulb in a
light that originally had a 2.4W bulb could cause damage to the
bulb holder or reflector if they are plastic. However, if the
light is from a series capable of high power such as the Vistalite
VL4xx range (these headlamps can all run at 10W even if they
were supplied with the lowest 2W bulb), this gives an assurance
of the upgrade capabilities. Some manufacturers including Cat
Eye specify upgrades in their instructions, or on the light body.
Some headlamps can operate way beyond
their rated power. A GH44 10W
screw-cap halogen bulb was fitted into a Soubitez 825 dynamo
headlamp (rated at 2.4W) and powered at a steady 6V under test
conditions. After 4 hours with a slight airflow and at 4 times
the rated power of the headlamp, there were no signs of deterioration.
Note: The above comments relate to powering
a dynamo headlamp from a battery. A normal dynamo is limited
to a total output of little over 3W.
BEAM FOCUS: The beam from a screw-cap
bulb can often be manually focused by adjusting the amount the
bulb is screwed into the holder, if the centre contact is sprung.
The beam focus is pre-set with push-in, bi-pin and MR11 bulbs.
BULB GLASS is supplied
clear as standard for maximum brightness. We do not supply quartz
glass so there is no danger of cracking if the glass is touched,
however for best illumination keep bulb glass completely clean.
Halogen bulbs can be requested with frosted glass which diffuses the light,
and is an advantage in special applications where a very even
light distribution is required, such as slide viewers, instrument
illumination, and models. When a bulb is frosted, the glass envelope
appears to be the light source rather than the filament. The
overall intensity is lower if a bulb is frosted. Only Halogen
bulbs can be frosted due to their thicker hardened glass.
The most common bulb we supply for stereo
slide viewers is the frosted GH160V(F). However, we have been
informed by one customer who prefers GH160V (clear glass) in
a View-Master Model E as the image is more vivid than with frosted
glass. The View-Master diffuser produces an even illumination
with GH160V, which is much brighter and whiter than the original
vacuum bulbs fitted back in the 1950s.
Some Vistalite cycle lights were factory
fitted with frosted bulbs. Please note that in flashlights and
cycle lights the central beam intensity is significantly reduced
by frosting. There is an extra cost for frosted
Battery discharge time is directly proportional to the cell capacity,
and inversely proportional to the amps (A) rating of the bulb.
To calculate the approximate run-time,
divide the capacity of one cell in amp-hours (Ah) by the amp
(A) rating of the bulb, eg the expected run-time with a GH157
bulb (4.8V 0.5A) powered by 4 fully charged 2.2Ah cells is 2.2
divided by 0.5 = 4.4 hours (4 hours and 24 minutes).
The capacity of rechargeable cells is
usually indicated on the label. Alkaline cells have the following
approximate capacities: LR03/AAA = 1.1Ah (up to 0.3A max. bulb),
LR6/AA = 2.5Ah (up to 0.6A max. bulb), LR14/C = 8Ah (up to 0.9A
max. bulb), LR20/D = 16.5Ah (up to 1.1A max. bulb).
Please note: If the electrical load on
any battery is extreme, the run-time is likely to be shorter
lights powered by disposable zinc chloride or alkaline manganese,
and NiCd or NiMH rechargeable batteries, the rated bulb voltage
is lower than the fully charged or new battery voltage. This
is because the battery voltage under load is lower. Please see
the cell quantities column in the bulb lists.
A range of bulb voltages have been specified
over time and by different designers. For instance bulbs intended
for use with 2 dry cells can be approximately in the range 2.4V
to 2.8V, and for 4 dry cells they are usually in the range 4.8V
to 5.2V. If you can't find an exact replacement for the original,
rated voltages in the above ranges will normally be acceptable.
Our MR11-C bulbs are designed to be very bright and white
when run at the rated 6V. Unlike some bulbs on the market, it
is not necessary to "over-volt".
can produce excessive voltage and cause bulbs to fail prematurely.
Modern dynamos are generally better regulated, and systems designed
for Halogen bulbs usually have an electronic voltage regulator
As a general guide, a 10% increase in
voltage causes a 50% reduction in bulb life and the opposite
applies for reduced voltage. If the voltage at the bulb fluctuates,
causing flickering (from poor or dirty contacts, etc) then bulb
life can be significantly reduced, due to the resulting surge
currents. Because some electrical contacts have a thin anti-corrosion
surface, it is far better to use metal polish rather than abrasives
to clean them.
DC voltage can be reduced by approximately
0.6V by putting a rectifier diode in series in the forward direction.
2 diodes reduce voltage by approximately 1.2V, etc. If the circuit
is AC (generator), put an equal number of diodes parallel to
the first diodes in the reverse direction.
A more efficient method to control voltage
in a DC circuit is to fit a transistor series regulator, as long
as the fixed "drop-out" voltage loss is acceptable
(around 0.5V-1.0V) An additional cell can be added to the battery
to compensate, or a lower voltage bulb could be used, eg moving
from a 6V to a 5.2V bulb. With a series regulator, the light
output will remain constant until the battery voltage has fallen
to near the set voltage, and current surge at switch-on is reduced,
increasing bulb life.
MR11-C bulbs are tested before despatch
by turning them on-off-on-off-on-off at the rated 6V.
If a new MR11-C does not light, or stops
working shortly after fitting, please consult the factors below:
1. Is your battery charged?
2. Is your battery voltage 6V?
3. Was your light system working recently with the previous bulb?
4. Does the charger become slightly warm as normal during charging,
with any LED indicators showing correctly?
5. Is your battery a lead-acid type (which can quickly fail if
not regularly charged)?
6. If possible, without looking directly at the bulb, try moving
the bulb pins in the bulb holder with the switch "on"
to check if there is a contact problem.
7. You may be able to check if there is a voltage in the bulb
holder with a multimeter set to VOLTS 6V DC or higher.
8. You can test the integrity of the filament in the MR11-C with
a multimeter set to RESISTANCE (ohms). If the filament is intact
the conductivity between the contact pins will appear as a virtual
short circuit (due to a cold filament). If an open circuit is
indicated (no meter response = infinite resistance), the filament
CAUTIONS: AVOID multimeter tests with
amps (A) selected !! Short circuit must be avoided !!
AFFECTING BULBS POWERED BY CYCLE DYNAMO-GENERATORS
1. Many cycle generators produce excess
voltage at high speed, over-loading the bulbs. When one bulb
fails, voltage rises significantly, over-loading the remaining
bulb even at lower speeds. When replacing a Halogen
headlamp bulb, it's a good idea to also replace the GV601
low cost tail light bulb (if fitted - see 2).
2. Excess voltage can also occur if electrical
contact is lost, perhaps momentarily, with one of the lights.
We recommend checking the electrical connections, and connecting
the earth return terminals where fitted, rather than relying
on the mounting bolts for connection to the frame, as the connection
through the bolts can be affected by corrosion over time.
3. It is fairly common to power just the
headlamp from the dynamo, and use an independent battery powered
tail light. In this case it is preferable to fit a 3W headlamp
bulb rather than the standard 2.4W, because virtually all bicycle
dynamos are designed to supply 3W. GH103
and GH106 3W Halogen Bulbs are recommended. A common exception
is the Sturmey Archer Dynohub which has a 2W output, with bulbs
providing a 1.8W load. For Dynohub bulbs, please see the Bicycle Bulb Guide, and Nicelite
4. Output from a generator driven from
the rim or tyre is not affected by wheel diameter, eg unless
the tyre is skidding, the tread of the tyre is always moving
at road speed. The fact that a small wheel has a higher rate
of rotation is not relevant. Therefore at any speed, the power
from a rim/tyre generator is the same whether the wheel is standard
or small diameter.
5. Output from a hub generator is higher
at all speeds when fitted in a small wheel, which can seriously
over-load the bulb(s) and any electronics (such as LED standlights)
unless a suitable regulator is fitted. In this situation there
may be sufficient dynamo power to operate a 3W headlamp bulb
and a tail light, therefore reducing the tendency to over-load
the bulbs. It appears from reports coming in, that many headlamps
are having their factory-fitted regulators burnt out by the high
excess power of hub generators at high speed. We have therefore
designed the XGEN5 to control this excess power, as shown in
the Dynamo Regulator section.
XGEN5 has been proved effective in controlling hub generators
and allows the use of Nicelite LED Bulbs
Copyright Reflectalite Ltd ©2012