Batteries

Choosing battery for radio station

Power requirements determination

Rx - receive requirements, Tx - transmit requirements, Ho - hours of operation, TPR - total power requirements.

(Rx + Tx) * Ho = TPR

In radio stations each mode has own load. If receive load is 2 Amps and transmit load is 10 Amps, then Rx = Rl * Rt and Tx = Tl * Tt, where Rl and Tl are receive and transmit load in Amps and Rt and Tt are receive and transmit % of time in each mode respectively. Lets rewrite TPR formula with load coefficients ( (Rl * Rt) + (Tl * Tt) ) * Ho = TPR.

Lets assume that I plan to use radio station 80% of time in receive mode, 20% of time in transmit mode and expect 4h of operation. Substituted the coefficients ( (2A * 80%) + (10A * 20%) ) * 4 = TPR which is (1.6A + 2A) * 4 = 3.6A * 4 = 14.4Ah.

Varta D24 12V Model 560 408 054 acid battery for conventional vehicles has 60Ah capacity (CCA 540A). That battery is not recommended to powering ham radio station. Continuous load will damage this battery. In case you stuck somewhere and want to call for help using car battery it will be enough for 8h radio station usage without battery capacity damage and 16h operation to drain all from this battery. For 100% of time in receive mode with the same Varta D24 battery you can get ~30h maximum operation time.

Common battery types

Lead Acid

Wikipedia article

Flooded Lead Acid

Typical what you would see in a car or in a truck. Low cost solution. They have high max current output. Short burst of time current delivery to start the car engine. Low dept or discharge. If you put long load on them continuous periods of time, the battery will die relatively quickly. This don't make a good option for powering ham radio stations.

Sealed Lead Acid

Absorbed Glass Matt (AGM)

The AGM batteries have lower internal resistance and you can charge them very quickly. They can have a pretty high capacity and derivative low cost. Used in mobility vehicles like wheel chairs. That makes it popular for solar panel users and solar generators. Good for ham radio stations.

Gel Sealed

That batteries have gel sealed inside. Totally maintenance-free battery, you can mount them on the side or even upside down. Not sensitive to dept of discharge damage like AGM or flooded batteries. You can drain this batteries pretty far which is a bad practice, you should not do this. Good for ham radio stations.

Deep Cycle

This is a modification of AGM or gel sealed batteries which means its optimised for continuous stable current. Choose that one. Best for ham radio stations.

Lithium-Ion

Lithium-Iron Phosphate

Best choice for 12V applications (ham radio stations) or SLA battery alternative. They typically run around 3.6V - 3.7V and you can use 4 this cells. Very stable, no explosions.

Lithium-Cobalt Oxide

LCR (ICR) batteries good for flashlights, cell phones, laptops, cameras. They can be dangerous especially when damaged. Cobalt element is a little bit rare now, that makes this batteries expensive. And they generally have a lower discharge rate. They are not is capable to deliver a high continuous current like Lithium-Iron batteries or Lithium-Manganese Oxide batteries.8

Lithium-Manganese Oxide

Have a lower cost and a longer life. Moderately safe, safer than a -Cobalt and less as a stable as -Iron batteries. Lithium-Manganese devices are used in high drain devices like batteries in hybrid cars and newer laptops. They also very popular in a vape smokers market. They have high discharge rates.

Lithium button cells

There are many manufacturers and brands of button cells batteries on the market nowadays. At this moment three series of lithium button cells available almost in any marketplace now - CR series, BR series and LIR series. Whats the difference between those series?

Because lithium batteries employ substances that are very chemically stable as the active material it is possible to have more than 90% residual capacity after 10 years of storage (room temperature), more than five times greater than that of conventional batteries. The estimates rate of annual deterioration is around 0.5% for the cylindrical type BR series and around 1% for the cylindrical type CR series and the button type BR and CR series.

CR Series

Negative material Lithium (Li). Positive material Manganese Dioxide (MnO2). Reaction: Li + MnO2 -> LiMnO2.

• 3V chemistry.
• 6 different cylindrical configurations.
• 23 different button cell sizes.
• Storage temperature is up to +60C (not recommended).

The CR chemistry is preferred for higher current drain, intermittent pulse mode applications such as alarm actuation in watches or remote keyless entry systems. CR cell has higher voltage than BR during discharge. However, as a CR cell discharges, the operating voltage drops over time because of rise in internal impedance. CR type batteries are slightly less robust than the BR type when exposed to temperatures at the high end of the operating temperature range and can experience a rapid increase in self-discharge at the high end of its temperature rating.

BR Series

Negative material Lithium (Li). Positive material Poly-carbon Monoflouride ((CF)n).

• 3V chemistry.
• 3 different cylindrical sizes.
• 2 types of pin cells.
• 12 button cell sizes.
• 5 button cell sizes in Panasonic high operating temperature series.
• Storage temperature is up to +85C.

BR series batteries exhibit stable voltage over the entire life of the cell and stable performance at comparatively high environmental temperatures. The self-discharge of the BR chemistry at elevated temperatures is also superior to other lithium button cell chemistry content. Ideal for real-time clock and memory backup applications.

ML/LiR Series

The standard only describes primary batteries. Rechargeable types made in the same case size will carry a different prefix not given in the IEC standard, for example some ML and LiR button cells use rechargeable lithium technology.

Brands comparison

Sales awards signs is not nesessary means the best battery because most people do not read specifications.

To compare different batteries and find out which one is better for your device/project you can get battery specifications from data sheets. For example, some CR2032 batteries datasheets available in my location online stores.

• Maxell CR2032H
• Panasonic CR2032
• Duracell CR2032
• Kodak KCR2032
• Varta CR2032
• Energizer CR2032

In case technical problems with official sites, you can download datasheets PDF files from here.

Why GP is not in list? On GP's official site they have no specifications in manual document.

Comparison table

Datasheets has a lots of complex data and average human need something to compare prices. I think the good fields are nominal capaciy and operating temperature.

In your geolocation could be interesting local manufacturers wich offers good specifications by a lower price. Thats why I share my way of how to choose the most affordable product. If you want to buy 1-2 batteries for your watches, it could be any cell you can get on the way to your job. But if you plan to buy 10-100 batteries than it could be useful to check the table bellow.

The price in particular region can be formed by many factors. Some countries have own manufacturer production factory. Sellers don't need to import product, so it can be cost lower.

Packs

All companies lowers the price if you take more then one battery. But Duracell's price policy is different. When you buy 2 x CR2032 battery pack it might cost you 47 TL. Another pack costs 159 TL for 10 x CR2032, which is about 16 TL per cell. There is no point to buy big pack. It is most expensive battery on the Turkish market.

Kodak offers 2 x CR2032 pack for 39 TL, 5 x CR2032 pack for 45 TL and sometimes you can find 5 x 5 CR2032 pack for 178 TL (~7 TL per cell).

Varta has average cost 11 TL for one battery and they offer discount only if you will take really a lot of batteries. I found 200 CR2032 cells for 1500 TL pack which means 7.5 TL per cell.

Mods

Pay attention when choosing battery. Maxell has special CR2032HR modification which has OTR -40 +125 (deg. C), rare and expensive. Obviously, you don't need this HR mod in your watches.

Conslusion

For me the most affordable battery in Turkey is Kodak. There is no negative temperature in Antalya region and its good to store Kodak cells here without creation any artificial conditions. And if I will travel somewhere my body and clothes can generate enough warm to operate my Casio G-Shock watches over -20 (deg. C).

I'll choose Varta for my watches if I will move back to Kazakhstan. Winters in Astana can be colder then -30 (deg. C). But watches can be kept warm with body and clothes and Varta's unique STR allows to store those cells in the car trunk. Panasonic and Energizer are perfect for devices that work outdoors.

Maxell, Panasonic and Energizer could be a good choice in Arabic and North Africa countries where the temperature in summer can reach +50 (deg. C) and more.

Nominal capacity (mAh) is a good indicator of how long your lithium cell will provide energy. The Duracell cells are the most capasious. But you can get 2 x Varta cells for the same price in Antalya. Duracell is not affordable for me.