Everything you should know about batteries

Grouping by size

18650 batteries are the most commonly used for sports torches, but 14500 and 26650 are also common, and 10440, 16340, 18350, 18500, 32650 batteries are also available, and even more, recently, 20700 and 21700 batteries have also started to become more common (the latter is helped by the fact that many electric bicycles have batteries of this size, and Tesla cars also have batteries of this size, and not a few of them). In practice, these numbers represent the size of the battery, for example, if we look at 18650, the first two characters represent the diameter of the cell, in our case 18 mm, and the second two characters represent the length of the cell, which is 65 mm. To make life a bit more complicated, some batteries can vary by a few mm, so even if it's 18650, it can still be 18.5 mm wide and up to 70 mm long, especially if it's protected (more on what that means later), so it's worth checking before ordering which battery will fit in which lamp, because it's not good luck if the battery doesn't fit, and it's not good luck if it "clumps" in the lamp. At Sportlampa.hu we always recommend batteries and chargers for each lamp that are guaranteed to fit, so that customers do not have to suffer such inconveniences.

Grouping by voltage

Nickel-based batteries, with a nominal voltage of 1.2 V, which in practice means that they operate between 0.8 and 1.4 V.
Lithium-based batteries, but with an operating voltage of 1.5 V, these were created to replace the previous group, operating between 1 and 1.8 V
Lithium-ion at 3.0 V (typically CR2 and CR123 sizes)
LifePO4 batteries with 3.2 V
Li-ion 3.6 V (between 2.8 and 4.2 V)

These are not interchangeable, so don't put a 3.6 V battery in a device expecting a 1.2 V device, or you'll end up with a nasty mess. A 1.5 V battery will simply twig a standard 1.2 V charger. But you can put a 3.0V battery in a charger that is wired for 3.2V, but there is no reason for a bigger difference.

Grouping by material

Currently there are two main battery types on the market, nickel based (1.2 V) and lithium based. (3,7V)

There are two types of nickel-based batteries, nickel-cadmium (Ni-Cd) and nickel-metal hydride (Ni-MH). The latter is the more advanced, with roughly three times the capacity of cadmium, but still lags behind Li-ion batteries in capacity and other important properties.

Li-ion

Lithium-ion batteries are currently the most common (we mainly sell them), for a number of reasons:

Lithium batteries are much lighter and more durable than nickel-based batteries
No memory effect
They are lighter and less expensive than conventional batteries
Even a depleted cell can deliver at least 2.8V compared to NiCd or NiMH batteries of 1-1.25V, although it is not advisable to go below 3V as this will compromise battery life, and not all chargers can bring them to life
However: unprotected ones are more sensitive, they can be overcharged, which can destroy the battery, and a sealed battery can be dangerous, so only buy a quality battery and charger from a reliable source

Protection
Li-ion batteries can be divided into two broad categories: protected and non-protected. Protected batteries have a small circuit at the bottom or top that serves safety purposes, disconnecting the battery cell from its terminals in case of overcharging, over-discharge or short-circuiting. Accordingly, unprotected batteries require more care but are cheaper than their protected counterparts. The protection is marked on the batteries with a PCB.
Importantly, protected batteries are longer, for example, 18650 protected batteries can be up to 70 mm instead of 65 mm.

Load capacity
There are high drain and low drain battery types, a number that indicates how much current can be drawn from a battery at a given moment. This is important because for many devices it is irrelevant, but for many it is only high drain that gives the right results, e.g. the Astrolux C8 can only get 1600 lumens and 600 metres of range from a high drain battery, while an average 10A battery can only get 900 lumens and 300 metres. The load range is wide, from 1 A to 100 A. Above about 15A we can talk about high load capacity, but obviously the bigger the better is the rule in this area. Warning, if you can get a very high load capacity very cheaply, don't assume that it will really know it, or that the battery is safe. Better to buy high capacity from a quality manufacturer (Sony, LG, AWT).

Continuous and maximum load capacity
For batteries, we distinguish between the above two figures because while the first one can be held by the battery until the end of its capacity, the second one can only last 1-2 seconds, so it is worth paying attention to what is written on which battery and what it is advertised as.

Li-on battery types

ICR (LiCo)

Features:

LiCoCo (LiCr) Nominal voltage: 3.7V
2C (C=capacity).Voltage: 3.Co2.1V.Co2.2C
Typical capacity: 18650 size 2200-3600 mAh

The most common battery type. Typical cell size is 2C, i.e. a 2000 mAh cell can deliver 2 X 2000 mA in one hour, which is 4000 mA or 4 A. Typical internal resistance is around 30-40 mOhm. Protected batteries are made from such cells. There is a maximum capacity of 3600 mAh, if you come across a larger one, you can be sure that the real value may be a fraction of the stated value.

INR (LiNCA):

Features:

Rated voltage: 3.7V
3.0V.Rated voltage: 3.0V.C.Load capacity: average 10-12C
Typical capacity: 18650 size 1800-3000 mAh

Due to its special mixed cathode, the internal resistance is 15-20 mOhm. It has a high load capacity, up to 50 A, so it can produce brutal light with a good quality lamp and a serious LED, but the drawback of the high current output is that it requires routine use, the shutter must be very careful, use only a specimen with intact insulation and only in a reliable device, because it can be dangerous! Fused versions are rare (Vapcell has been producing some recently). Use ONLY with a GOOD QUALITY INSULATOR!

IMR (LiMn):

Features:

Rated voltage: 3.7V.
Voltage: 3.3 VMMM: 3.5VM.Capacitance: average 6-8 C
Typical capacity: 18650 size 1600-3000 mAh

The golden mean between high current and safety. IMR batteries are both powerful and safe thanks to the special manganese-contaminated cathode. LiMn composition batteries produce only a small amount of vapour in the event of a short circuit, so they do not disintegrate the cell body in the event of a short circuit, but only swell slightly. It is also much less fussy to over-discharge and overcharge than an ICR or INR battery. Its current carrying capacity is lower than the INR battery, but better than the ICR battery. Typical internal resistance is between 20-25 mOhm.

Summary

A battery, especially Li-ion, is not a toy and needs to be handled wisely, but if you follow a few rules below, it has virtually no risk and will pay for itself many times over:

for complete beginners, a protected battery is recommended
IMR cells are recommended for those with a little more experience or minimum experience in electricity, INR batteries are only recommended for professionals or those with more experience
Do not buy an anonymous, "cheap" charger from an unknown source, as you risk your battery and/or your own safety.

The ideal battery should have a high capacity to get the most out of the lamp, be protected to protect both the lamp and the user, have a high capacity so that it rarely needs charging and come from a reliable manufacturer, as the quality of anonymous manufacturers is variable.
Two rules of thumb to bear in mind when buying a lamp, because some retailers try to attract customers with unrealistic claims, are the following two:

don't buy a 18650 battery that weighs less than 40g unless it costs pennies, because its capacity is definitely below 1500
don't buy 18650 batteries that are larger than 3600mAh, because they can't be that much, if you see one, it's definitely not 1500, especially if it costs pennies

What else should we look out for?

- It's important to check whether you need a flat design or a tapered design for your device (whether the positive end of the battery has a bulge or not), because if you choose the wrong one, it won't fit or work with your device

- Recently, batteries with a USB port have also appeared, which do not need a separate charger, but can be charged directly with a cable that plugs directly into the battery. Such batteries are usually protected and almost certainly longer than usual, so this is something to consider.