Many businesses and organizations rely on two-way radio communications, so battery life is critical for reliable day-to-day operations. The last thing you want is for workers to lose communication when carrying out vital operations. In order to keep communication flowing, it can help to understand battery types, how to charge them, and how to take care of them for the longest life.

The 5-5-90% cycle

In the radio communications industry, we talk about radios being on a specific cycle. It is called the 5-5-90% cycle time assumption. This means that when you use a radio, 5% of your time is spent transmitting, 5% receiving, and 90% on standby.

Battery Technology

The four typical types of rechargeable batteries are the Nickel-Cadmium battery (NiCad), the Nickel Metal Hydride battery (NiMH), the Lithium-Ion battery (Li-ion), and the Lithium-Ion Polymer battery (LiPo).

1. Nickel-Cadmium

NiCad batteries are very robust. They are good for working in extreme environments, such as cold or hot weather. They are very robust for high output and deep discharge applications. On the downside, they have a charging problem called the “memory effect”. That is, if they do not get completely charged after each use, they will potentially only charge up to the last highest charge. This can shorten the lifespan of the battery.

2. Nickel Metal Hydride

NiMH batteries offer a higher capacity than Nicad batteries, but they are nearly twice as heavy. They have good deep-discharge qualities and can store nearly twice the capacity of NiCad batteries. NiMH batteries can have a weak-cell syndrome. That is when you charge a NiMH battery all the way (and testing will show that it is fully charged), but when you go to use, it dies right away. They are a good medium temperature battery. NiMH batteries do not suffer from the memory effect like NiCad batteries.

Organizations using radios with NiCad or NiMH batteries spend more money replacing or doubling up on batteries to keep operational communications up and running during working hours than they did on the radios.

3. Lithium-Ion

Lithium-Ion battery cells are known for their enormous energy density and use a liquid electrolyte. They store more energy per pound than any of the traditional NiCad or NiMH battery packs. They don’t have the memory effect that NiCad does, and they perform the best at deep discharge applications compared to NiCad or NiMH. Environmentally, they are safer to dispose of than nicad, as they don’t taint water supplies. The charge and discharge curve of li-ion is extraordinary. It can handle heavy input and output voltage, making it ideal for use in two-way radios.

4. Lithium-Ion Polymer

Lithium-Ion Polymer batteries are the next generation in battery technology and use a polymer electrolyte instead of a liquid electrolyte. High conductivity semisolid (gel) polymers form this electrolyte. Lithium-Ion Polymer batteries provide higher specific energy than other lithium battery types and are lighter in weight. Lithium-Ion Polymer batteries can provide up to 24 hours of battery life per charge in a radio under 5-5-90 conditions.

At Chierda, we use Lithium-ion and Lithium-Ion Polymer batteries that charge quickly and weigh as little as possible in a slim form factor, without compromising on capacity performance or battery life. In addition to the excellent energy-to-weight ratio, Lithium-Ion offers the major advantage of not suffering from the memory effect, so even after months of use, they can still last for significantly longer periods of use.

Charging Cycles

A charging cycle is the daily operational use and recharging of the battery. On average, most Lithium-ion and Lithium-Ion Polymer radio batteries will provide enough charging cycles to last around 18 to 24 months, depending on how the radio is used, cared for, and charged.

Another advantage of Lithium-ion and Lithium-Ion Polymer batteries is that they provide a longer charge, so they provide a longer shift which means they don’t have to be recharged as often (fewer charging cycles), which can extend the battery life.

Digital Mobile Radio (DMR) and Battery Life

In the past, two-way radio battery life could only be increased by using larger batteries or lower power technologies. DMR now offers increased battery life using two-slot TDMA (Time Division Multiple Access) technologies.

DMR radios transmit on one of two available timeslots, or half the time of a conventional analog transmission. This allows them to deliver battery life up to 40% longer than the analog equivalent on a single charge.Chierda DMR two-way radios operate in both analog and digital modes, and as a result, the battery life will differ depending on the operating mode of the radio.