Section 5.4: Batteries #

Ah, batteries—the lifeblood of portable ham radio! Whether you’re operating from a mountaintop or preparing for emergencies, these portable powerhouses keep us on the air. But like any good superhero, they come with their own kryptonite. Let’s dive into the world of batteries and learn how to harness their power safely and effectively.

Types of Batteries #

First off, let’s meet our cast of characters:

Lead-Acid Batteries: The old reliable. You’ll find these in cars and as backup power for your shack. They’re like the dependable workhorse of the battery world. They’re rechargeable and can deliver high currents.
Lithium-Ion (Li-ion): The star of modern handheld radios. They pack a punch in a small package, but they can be a bit temperamental. These are rechargeable and have a high energy density.
Lithium Iron Phosphate (LiFePO4): The new kid on the block. They’re safe, stable, and last forever (well, almost). Also rechargeable, they’re known for their long life and safety.
Nickel-Metal Hydride (NiMH): Often found in AA or AAA sizes. They’re the eco-friendly option and were extremely common before Li-ion batteries caught on and became ubiquitous. Rechargeable and a good alternative to disposables.
Nickel-Cadmium (NiCd): The classic rechargeable. Once the go-to for cordless phones and older handheld radios. They have a nominal voltage of 1.2 volts per cell, just like NiMH batteries. However, they can suffer from the “memory effect” if not fully discharged before recharging. Due to environmental concerns over cadmium—a toxic heavy metal—they’ve been largely replaced by NiMH batteries. You might still come across them in older devices, but they’re becoming less common.
Alkaline: The one-hit wonders. Great for emergencies (you can buy them at the store!), but once they’re done, they’re done. These non-rechargeable batteries have a nominal voltage of 1.5 volts per cell, providing a bit more oomph than their rechargeable counterparts.
Carbon-Zinc Batteries: The old-school disposables. These are some of the earliest types of dry cell batteries. Non-rechargeable with a nominal voltage of 1.5 volts per cell, they have a shorter lifespan and lower capacity compared to alkaline batteries. Think of them as the great-grandparent of modern batteries—important historically but less relevant today.

A Note on Voltages #

It’s worth noting that batteries of different types may have different voltages per cell, even if they are the same size! Always check things out before connecting them!

Battery Safety Tips #

Now, let’s talk safety. Each of these battery types has its own quirks:

Lead-Acid Batteries:

These guys can produce hydrogen gas, especially when charging. Always use them in well-ventilated areas. You don’t want your shack turning into a blimp!
They contain sulfuric acid. Treat them like you would a grumpy cat—with respect and protective gear.
The terminals can deliver a whopping amount of current if shorted. Remove your jewelry and use insulated tools. Trust me, you don’t want to be the human fuse in this circuit! (and do not ask me how I know the melting point of sterling silver jewelry…)
Each cell in a lead-acid battery produces about 2.1 volts. So, a typical “12-volt” battery actually measures around 12.6 volts when fully charged.

Warning: Avoid creating sparks near a charging lead-acid battery. The hydrogen gas it emits is flammable, and a spark could lead to an explosion — not the kind of bang you want in your shack! For this reason many people prefer to avoid keeping lead-acid batteries indoors.

Here’s a real-world cautionary tale: I once tried to connect lead-acid batteries in parallel for a battery bank. Long story short, I mixed up the connections and ended up with a smoking cable hot enough to melt rubber. The moral? Always double-check your connections and use fuses!

Lithium-Ion Batteries:

Overcharging is a big no-no. It can lead to overheating or even fire. Stick to the charger that came with your radio.
If they get punctured or damaged, treat them like a ticking time bomb. Dispose of them properly and quickly.
They’re not fans of extreme temperatures. Kind of like Goldilocks—not too hot, not too cold.
Each cell in a lithium-ion battery produces 3.7 volts, so if you see a “12 volt” lithium-ion batter it is probably using some electronics to get the voltage where you want it.

One more cautionary tale for you; my 11-year-old son was playing with some 18650 Lithium-Ion battery cells on his bed one day not long before we started this book. We suspect he somehow accidentally shorted out the cells, but all we know for sure is one minute he was happily playing with the motor he stripped off of a motorized scooter and the next minute the battery casing was on the other side of the room and there was a melted spot the size of a soft ball on his quilt and a nasty smell in the air.
Fortunately everyone was okay, the house wasn’t burned down, and the only real damage was to some bedding, but be careful! They tell us that batteries don’t really explode, but Lithium-Ion batteries truly have been known to “vent with flame”.

Lithium Iron Phosphate (LiFePO4) Batteries:

These are the laid-back cousins of Li-ion. Safer, but they still prefer their own special chargers.
They’re not fans of charging in extreme cold. Think of them as the battery equivalent of a person who hates getting out of bed on a winter morning.
Each cell in a Lithium Iron Phosphate battery produces about 3.2 volts. A typical “12v-volt” battery is actually 12.8V and will usually be charged to 14.6V to get to full capacity.
Over or undercharging a single LiFePO4 cell can ruin it!

How Long Will Your Battery Last? #

When you’re out in the field or during a power outage, knowing how long your equipment can run on a battery is crucial. This is where understanding your battery’s ampere-hour (Ah) rating and your equipment’s current draw comes into play.

To determine how long your battery will last, you can use the following method:

Battery Life Calculation: Divide the battery’s ampere-hour (Ah) rating by the average current draw of your equipment.

This method will give you an estimate of how long your equipment can run before the battery is depleted.

For example, if you have a 12Ah battery and your radio draws an average of 2A:

\text{Battery Life (hours)} = \frac{12 \text{Ah}}{2A} = 6 \text{ hours}

This means your battery could power your equipment for about 6 hours under these conditions. Keep in mind that this is a rough estimate and actual performance can vary based on factors like temperature, battery age, and usage patterns.

Note: For some batteries, particularly lead-acid batteries, the battery might not last as long as the calculation suggests if you’re drawing a lot of current due to something called Peukert’s Law. Basically, the harder you push the battery, the less total capacity you’ll get out of it.

General Battery Wisdom #

Use the right charger for each battery type. It’s not a one-size-fits-all situation.
Be careful when leaving batteries charging unattended—if your charger malfunctions, you could end up with a dangerous situation.
Store batteries in a cool, dry place. They’re not wine; they don’t get better with age and heat.
Keep battery terminals covered when not in use. Accidental shorts are no joke and can be extremely dangerous.
Don’t mix old and new batteries. It’s like pairing a marathon runner with a couch potato in a three-legged race — the new batteries can end up overcompensating, which might cause them to overheat or leak.
Be mindful of what you connect to it! Charging or discharging a battery too quickly can cause it to overheat, release toxic gases (outgas), or even, in extreme cases (we’re looking at you, Lithium-Ion!), explode.

Emergency Preparedness #

For emergency preparedness:

Keep a stash of fresh batteries for your go-kit.
Regularly test and cycle your rechargeables. If you never use them, you’re likely to find they aren’t working when you need them!
Have a plan for charging during extended power outages. Solar chargers can be a ham’s best friend.

Final Thoughts #

Batteries are incredible tools that let us take our hobby anywhere. But they demand respect. Treat them right, and they’ll keep your radios powered and your conversations flowing, whether you’re ragchewing from your backyard or providing emergency communications after a disaster.

Stay safe, stay charged, and happy hamming!