RC Battery Types Explained in Plain English
Do RC battery types baffle you? Are you confused and bemused by codes and jargon? Keep reading because a little knowledge can go a long way. What about all those letters and numbers, I hear you say. Yes, they too will make a lot more sense by the end of this no-nonsense guide.
Not all RC models are equal. They come in atypical sizes, weights, shapes and with different functions. Each product also has its set of expectations and power needs. Well, the same things apply to batteries. It’s why there are so many types catering to the vast range of radio-controlled models.
Warning: Some batteries are safer than others. Be very careful when selecting batteries and chargers. Always follow manufacture recommendations and look for 3rd party independent testing. Never overcharge batteries and do not charge them unattended.
Minutes Vs. Hours
The cost of a battery depends on what it powers and who makes it. Some RC models cannot use the less expensive third-party batteries. Others have built-in types that you can’t swap. Most RC models come with a standard battery with the exception being some kit (DIY) products. It’s wise to invest in spare batteries and or upgrade from the standard ones that come with the model.
The False Economy
The better the battery is, the longer the playtime or running time. Short battery life is one of the biggest frustrations for RC model enthusiasts. Second to short battery life are long charging times. Let’s take a drone as an example: it may have 15 minutes of flight time with a battery that takes four hours to charge. Some RC models may have even less running time and longer charging times.
These are the reasons why battery knowledge is so significant. A little understanding can save users from bitter disappointment. NEVER skimp on batteries, always buy the best that you can afford. Buying cheap substandard batteries is a false economy.
The following section looks at which batteries to use for what purpose.
Don’t let the alien text above put you off. I’m not going to bore you with technicalities here. This section is just a short overview to explain the four following types and their uses:
- NiCad (Nickel Cadmium)
- NiMH (Nickel Metal Hydride)
- LiPo (Lithium Polymer)
- LiFePO4 (Lithium Iron Phosphate and A123)
Don’t worry if it still reads gobbledygook. It’s all going to make a lot more sense in a moment.
#1 Nickel–Cadmium Batteries (NiCad)
The NiCad (nickel–cadmium) battery is a rechargeable type of cell. It consists of the materials nickel oxide hydroxide and metallic cadmium element. That’s about as technical as I’m going to get.
Most of us are familiar with NiCad rechargeable batteries. They’re the oldest technology and still with us despite the alternatives. It wasn’t so long ago when all RC applications relied on the Nicad for power. Some folks continue to use them because Nicads have a low self-discharge. Furthermore, they fare well in extreme temperatures (hot and cold). They’re practically indestructible too.
The NiCad weighs more and is bulkier than newer battery technologies. It’s also unfriendly to the environment. There are other pros and cons, but I don’t want to get scientific for the sake of it. You can still use Nicads to power transmitters and receivers. Their use is dying out, though, as more efficient, cleaner alternatives advance.
#2 Nickel Metal Hydride Batteries (NiMH)
We’re more familiar with Nickel Metal Hydride in its short form, NiMH. These batteries replaced older nicads for RC transmitters and receiver packs. It wasn’t a smooth transition. The early models were rife with problems and weren’t safe options for radio-controlled systems. Well, that was then, and this is now. The latest versions are reliable, stable, and an excellent choice for RC systems.
Most of these batteries come from China and often fall short on their claims. They’re still good, but not as good as the makers claim them to be. The main issue is that they lose their charge faster than stated. NiMH batteries do self-discharge faster than alternative technologies. Despite this, they’re still good batteries for RC systems. They’re also eco-friendlier than the older nicads.
Take heed if you use hi-capacity NiMH cells. That means AA-size batteries that are over 1650mAH. It’s easy to damage these by overcharging or by charging at a current that’s too high for them to handle. There are recharging restrictions as well. They need currents of around 250mAH, so top-ups in the field are not practical. A better alternative is a quality 1650mAH transmitter pack.
OK, let’s now see if the Lithium Polymer (LiPo) can offer yet more advantages.
#3 Lithium Polymer (LiPo) Batteries
Life before the LiPo battery was heavy and sluggish, and that restricted the ability of RC models. LiPos offered a solution to these ‘weighty’ problems. RC models can now move faster, climb higher, and release their true agility. LiPos have the highest power to weight ratio around, but that’s not all. They also have an impressive low self-discharge rate compared to the alternatives.
LiPo batteries can handle low temperatures too. But they’re not perfect, despite the glowing appraisal thus far. Two downsides are the batteries intolerance to both over-charging and over-discharging. They also have a considerable fire risk. This due to the high amount of energy stored in such a tiny space. I’d never leave them to charge unattended without placing them in a fireproof box.
LiPos are an excellent choice if you use them with caution. They promise to provide any compatible RC model with maximum performance. I avoid using them with transmitters even though there are LiPo packs available. The voltage is just too high for one, and that alone could void a warranty.
Next up is the Lithium Iron Phosphate (LiFePO4) and A123 batteries. Keep reading to see why these are the best batteries today for radio-controlled models.
Lithium Iron Phosphate (LiFePO4) & A123 Batteries
Each battery on this page brought something new, something better, to the table. But none of the above technologies are without their own set of problems. What the RC world wants is a battery as safe and as durable as nicads, but with the lightweight and capacity of LiPos. Well, Lithium Iron Phosphate (LiFePO4) technology has achieved all that. I can summarize this with three points:
- Same power-to-weight ratio (well almost) as LiPo batteries
- More tolerant of over-charging and under-charging events
- Unlikely to explode and catch fire thanks to the inclusion of phosphates
Another highlight of LiFePO4 technology is the low self-discharge rates. You can also use them with compatible RC equipment without the need of regulators. They’re almost perfect but not quite. The batteries do cost a lot compared to the alternatives, though many will argue they’re worth it. They boast more life cycles, have faster charging times, and they’re safer—much safer.
Right now, there’s a limited range of available battery capacities. You must also invest in a LiFePO4-capable charger as no other type will do.
LiFePO4 Vs. A123
I’ve grouped LiFePO4 and A123 for a reason. Many people use LiFePO4 and A123 interchangeably, but they’re different. A123 is an actual brand, not another name for the technology. The A123 brand relates to a specific kind of LiFePO4 battery. They incorporate something called nanotechnology (NT). NT improves the battery’s current-handling abilities by a significant amount.
I won’t go into the technical details of A123 batteries as it’s irrelevant to the topic. Most RC models don’t need the impressive current-handling capabilities provided by this specific brand.