Batteries and rechargeable batteries
Alkaline batteries are very common and perform considerably better than saline batteries. They are well-suited for most self-powered electrical equipment. These batteries can also be stored for much longer periods.
Lithium batteries have appeared more recently on the market and are used for situations requiring a greater capacity, a smaller size or less weight (lithium batteries are up to 30 % lighter than alkaline batteries of the same size), or a wider range of operating temperatures.
Not all Petzl headlamps are compatible with lithium batteries; please see the technical notices and www.petzl.com for more information.
Petzl headlamps come equipped with the following batteries:
- alkaline (1.5 V)
- lithium watch-type (3 V)
Batteries produce a continuous current by transforming chemical energy into electrical energy.
Battery insertion and polarity
All batteries are polarized, having one positive (+) and one negative (-) pole.
Batteries must be inserted correctly with respect to their polarity (follow the directions on the case). If a battery is inserted the opposite way, it will start to be charged by the other batteries. This causes a chemical reaction inside the reversed battery: within minutes it will begin to emit explosive gases and an extremely corrosive liquid. There is a risk of explosion or fire.
A weak level of light with new batteries indicates that the polarity of one or more batteries is reversed. Immediately turn off the light and veriﬁfy the polarity of the batteries.
The way batteries discharge depends on the technology and also on the quality of the parts and its construction. In general, the voltage of alkaline batteries decreases steadily towards depletion during normal use, whereas the voltage supplied by lithium batteries decreases in stages.
When used in headlamps (intensive discharge), lithium batteries supply energy like this:
- 1.5 V lithium batteries provide «regulated» lighting, i.e. constant lighting for the greater part of their cycle
- 3 V lithium batteries (watch-style) are not regulated (their lighting curve is similar to the one for alkaline batteries)
1.5 V lithium battery
3 V lithium battery (watch-style, etc.)
The capacity of a battery is expressed in Ampere-hours (Ah). This indicates the period of time during which the battery will be able to provide a given current (e.g.. 1 Ah is equivalent to 1 Ampere for 1 hour). The greater the capacity, the longer the burn time of the headlamp.
Capacity depends directly on the type of battery (alkaline, lithium, etc.), on the number of components in the battery and its construction. Each manufacturer uses his own methodology to measure capacity.
In practice, the energy provided by a battery is also linked with conditions of use, primarily to the ambient temperature and to normal use. This is why it is essential to choose the batteries according to headlamp use (power, temperature, length of use, etc.).
Petzl headlamps that offer 3 lighting levels (maximum, optimum, economic) allow the true capacity of the energy source to be best exploited by adapting consumption (discharge current) to the conditions for use. In “economic” mode, the batteries hold on to more energy than in “maximum” or “optimum” mode.
Like standard batteries, rechargeable batteries deliver a direct current (domestic power grids deliver alternating current). On the other hand, rechargeable batteries can be charged and therefore reused over and over. Depending on the type, rechargeable batteries can undergo 200 to 1500 cycles of charging/discharging.
Rechargeable nickel batteries
In these batteries, nickel is combined with cadmium (Ni-Cd) or with Metal Hydride (Ni-MH). Though extremely common at one time, Ni-Cd has been steadily replaced by the Ni-MH compound. This type offers a greater energy density, but also self-discharge more and allows fewer charge/discharge cycles. Ni-Cd technology remains popular, however, because it delivers a very strong current, significantly superior to that obtained from Ni-MH, Li-Ion or Li-po rechargeable batteries. This is why they are frequently used in portable wireless equipment, compact equipment, etc.
Ni-MH battery packs are available both in rechargeable battery format and standard format. These are designed to easily replace standard saline or alkaline batteries in every-day equipment (Walkman, camera, etc.).
Rechargeable lithium batteries
This type of battery appeared in the ‘90s and uses lithium in ionic (Li-Ion) or polymer (Li-po) form. More expensive, but lighter, these batteries are found in the ULTRA headlamp, telephones, laptops, the new generation of camcorders, etc. Rechargeable lithium batteries require a specific recharging device. They are equipped with an electronic protection circuit which controls the voltage during charging, temperature, etc.).
The electric current delivered by rechargeable batteries comes from the transformation of chemical energy to electrical energy when the battery is connected to the electric circuit of the receiver. As opposed to standard batteries, the chemical process that takes place in the rechargeable batteries is reversible (recharging phase) and requires an adapted recharging device (charger).
Battery insertion and polarity
Like standard batteries, all rechargeable batteries are polarized (one positive (+) and one negative (-) pole). It is therefore important to put the batteries into the headlamp in the direction indicated. Any batteries whose polarities are reversed will receive energy from the remaining batteries. This will appear as a recharge and could lead to an overcharge of the element.
When using properly charged batteries, a weak or non-existent level of light indicates that the polarity of one or more batteries is reversed. Immediately turn off the light and veriﬁfy the polarity of the batteries.
To recharge a battery, a quantity of electrical energy equal to the capacity of the battery is re-injected into the cell(s). The recharging process of a battery depends on its chemistry. The charge is mainly defined along three parameters:
- the voltage
- the current
- the duration
The duration of the charge (normal, accelerated, quick, etc.) depends on the type of battery and on user needs. In each case, it is important to precisely follow the charging procedure indicated on the batteries and to not go over the recommended charging time.
A battery can not store more energy than its capacity permits. If a battery continues to be fed by an electrical current, it will overcharge. The transmitted energy will therefore be released as heat. This process leads to premature wearing of the cells (see “Memory effect”) and can be dangerous.
WARNING, be careful to:
- Always use the charger that comes with Petzl rechargeable batteries.
- Always check that the charger is appropriate when using store-bought batteries.
- Always follow the charging instructions - duration of current - indicated on the batteries.
The way that rechargeable batteries will discharge depends on the chemistry used (Ni-Cd, Ni-MH, Li-Ion, etc.), on the conditions of use, and also on the quality of the parts and the assembly. In general, rechargeable batteries provide “regulated” lighting, i.e. constant lighting for the greater part of their cycle. However, the energy available decreases very quickly at the end of the cycle.
This indicates the period of time during which the battery will be able to provide a given current (e.g.. 1 Ah is equivalent to 1 Ampere for 1 hour). Expressed in Ampere-hours (Ah), the capacity of the battery directly affects the burn time of the headlamp. It varies according to the chemistry used (Ni-Cd, Ni-MH, Li-Ion, etc.), on the quantity of chemical components in the cell, and on the quality of the manufacturing.
The capacity of rechargeable batteries indicated by the manufacturer is calculated under optimal use conditions. The true capacity will vary according to the real conditions of use, particularly the temperature and the current used. This is why it is essential to choose the batteries according to headlamp use (power, temperature, length of use, etc.).
Petzl headlamps that offer 3 lighting levels (maximum, optimum, economic) allow the true capacity of the energy source to be best exploited by adapting consumption (discharge current) to the conditions of use. In “economic” mode, the batteries hold on to more energy than in “maximum” or “optimum” mode.
The “memory effect” concerns Ni-Cd rechargeable batteries and, to a lesser degree, Ni-MH cells. It is independent of the normal aging process of the batteries, which can not be altered. This phenomenon occurs when batteries are not discharged and recharged correctly (repeated incomplete recharging, overcharging, etc.), and it causes the cell to wear out prematurely.
“Degassing” is the release of gas by standard or rechargeable batteries. This reaction is provoked by inappropriate use: discharging or recharging too intensively, inverting the poles, using defective cells, getting salt water into the battery case (electrolysis of components), etc. If degassed, the battery permanently loses some of its capacity.
All waterproof Petzl headlamps are equipped with a safety feature (pellet, technical membrane or mechanical valve) which compensates for degassing of batteries.
Influence of ambient temperature
The temperature directly influences performance. The lower the temperature, the less energy the source will supply due to a slowing down of chemical activity. Lithium batteries offer a very wide range of uses (about -40°C to +60°C).
The remote battery packs of the ULTRA RUSH BELT, ULTRA VARIO BELT and DUO models can keep the batteries close to the body when outside temperatures are very low.
Petzl would like to remind headlamp users to recycle discarded lamps, bulbs, and batteries. This trash contains materials that are particularly harmful to the environment. It is therefore important to sort them for recycling separately from regular household waste. Please inquire about battery collection and recycling in your area. As an alternative, rechargeable batteries can be reused, eliminating the need to dispose of them. All Petzl lamps can run on rechargeable batteries.