Opale recently announced an upgrade to their Auxiliary Motor Kit for the paraglider pilot Mike XL. The upgrade is now easier to assemble, stronger, and dampens the vibrations from the engine upon start-up. The upgraded kits are on their way, so keep an eye out for them to pop up on the site!
In the last Flight School segment we discussed the basics of batteries – key terms and what they mean. Now we are going to dive in a bit deeper and discuss the different chemistries that are out there and some of the differences between them.
All batteries, as explained previously, consist of a cathode, an anode, and an electrolyte. Through a chemical reaction (a redox reaction specifically), electrons flow through these parts creating an electrical current, which is then used to power any device that is connected to the battery circuit. The chemical makeup of the cathode, anode, and electrolyte can change aspects of the battery. This makes understanding battery chemistry a must when searching for the right battery for your airplane.
Lets take a look at the properties that will differ based on battery chemistry:
Cell Voltage - Battery voltage is a measure of the pressure from a power source that moves charged electrons (known as current) through a circuit. It is measured in volts (V). Batteries of the same chemistry will provide the same nominal voltage, but that nominal voltage will differ when comparing batteries of different chemistries.
Energy Density - Energy density is the ratio of energy stored to size of the battery cell. This can come into play when considering fuselage size and flight style. Energy density is energy stored per unit of volume, gravimetric energy density is energy per unit of mass.
Rechargeability - Some batteries are not rechargeable, and others are. The battery chemistries you will see in the RC flight industry will be rechargeable.
Self-Discharge - Even if you are not using a battery, it will still undergo chemical reactions that will result in a loss of charge. This process is known as self-discharge. Depending on the chosen battery chemistry, the amount of self-discharge over time can vary.
Cycle Life - In addition to self-discharge, batteries have a limit on the amount of times it can be charged and discharged. This is called cycle life, and again, differs based on chemistry.
Economics - Just like everything in life, based on the material inside, the cost of your batteries can be effected.
Safety - Some chemicals are very stable, others are very volatile. Battery chemistry plays a big part in how safe your battery is, and what practices should be employed.
Now that we have discussed some of the properties that can be effected by different battery chemistries, lets take a look at the chemistries found in RC Flight.
Nickel Based Batteries; (NiCd and NiMH)
NiCd – Nickel-Cadmium batteries are made with a Nickel Hydroxide (Ni(OH)2) anode, Cadmium Hydroxide (Cd(OH)2) Cathode, and an electrolyte of Potassium Hydroxide (KOH). While they are affordable, provide a large cycle life, and can charge quickly, they have a high self discharge rate and it is very hard to tell charge based on voltage. In addition, they are toxic and corrosive, so disposal is difficult. NiCd batteries also suffer from the “memory effect” which is where a battery, if not fully discharged, will “remember” the previous discharge level, loosing the ability to discharge past that level in the future.
NiMH – Nickel Metal Hydride offer many of the same pros and cons as NiCd, only it removes the toxic Cadmium and replaces it with a metal alloy hydride for the anode (which actually results in higher performance).
Lithium Based Batteries; (Li-Ion, LiPo, LiFe)
Lithium based batteries have high energy densities, making them a great choice when weight and size are of importance. In addition, they also have much lower self-discharge rates.
Li-Ion – These batteries, Lithium Ion, use a porous material for the anode (such as graphite or silicone) and an ionic lithium compound for the cathode. Multiple chemistries exist for the cathode, including Lithium Cobalt Oxide (LiCoO2), Lithium Manganese Oxide (LiMn2O4), and Lithium Nickel Manganese Cobalt Oxide (LiNiMnCoO2). The electrolyte used consist of lithium salts dissolved in an organic compound, which due to the properties of lithium as well as the compound, are highly explosive. These batteries come in a hard outer casing.
LiPo – Lithium Polymer batteries are much like the Lithium-Ion, however they differ in what the electrolyte is made of. In LiPo batteries, you will find a gel lithium polymer instead of a liquid. This provides less of a chance of the electrolyte leaking out. Although this is a safety improvement, LiPo batteries have a soft casing as opposed to their counterparts – Li-Ion.
LiFePO4 – Lithium Iron Phosphate batteries are a type of Lithium Ion battery, but this particular chemistry has its own set of properties, differing from the other Lithium Chemistries. The energy density of LiFe batteries comes in a bit lower than that of the Li-ion or LiPo batteries, but better than that of the Nickel based batteries. In addition, LiFe batteries have a long cycle-life, are more affordable and safer overall.
The DC-24 Carbon represents Jeti’s new flagship, State-of-the-art, transmitter that sets a new standard for the RC Industry. Jeti’s final touches and finishes are outstanding. The front panel of the system is made of genuine Carbon Fiber with UV stabilized acrylic clear coating and the case made of anodized, CNC cut, solid aluminum. Unfortunately, with all that being said, the demand to test drive the DC-24 radio just isn’t what it used to be. With that knowledge, we have decided to sell (at a great price) our DC-24 Carbon Titanium transmitter that was used in the program.
This is such a great video posted online by revilozone! Not only can you watch the beautiful Split 1.6 as it floats majestically through the air, you get a birds eye view from the sky as well. Not to mention the landscape is simply breath taking!
So far, in the Flight School blog segments, we have touched on electric systems; motors and esc’s. But, there is another important component – the battery. This is another task that can seem daunting when looking at all the information and the many options available. We hope that this will give a breakdown of what you might need.
A battery is a device that converts chemical energy to electrical energy. It can be used to power other devices electronically. Batteries consist of a cathode (positive electrode), an anode (negative electrode), and an electrolyte medium between the two. As we mentioned earlier, there are several type of batteries that utilize different chemicals to produce electrical energy. We are going to define the types you may encounter in the hobby, but for this segment we wont dive to deep into the chemistries just yet.
NiMH (Nickel-Metal Hydride)
LiFe (Lithium Iron)
Li Ion (Lithium Ion)
LiPo (Lithium Polymer)
The capacity of the battery determines how long you will be able to fly. This number is listed in milliamp hours (mAh). The higher capacity, the longer you can fly. Keep in mind, there are many different variables to consider when thinking in terms of how long you will be able to fly (such as what you are powering or how you are flying).
Cell Count (Voltage)
Most times there are multiple cells in the battery. These are often indicated with the number of cells, followed by a “S” or a “P”. “S” indicates that the cells are connected in series with each other (positive to negative) where “P” indicates that the cells are connected in parallel (positive to positive, negative to negative).
Each cell has a specific nominal charge measured in volts. These voltages will vary based on the battery chemistry used. The voltage will determine how fast your electric motor will spin, within the parameters of your system. The higher the voltage, the faster the motor will spin. This information will come into play when considering RPM of your motor.
Your motor will help determine your battery needs, so when selecting your battery, make sure you know your motor (and load) requirements and specifications.
LiPo battery connected in series
C-rating (Discharge Rate)
The C-rating is how fast a battery can safely be discharged. It will be listed as a number with a “C” after it. For example, some of our Jeti Pro Power Batteries are 30C. This means that the discharge rate of the battery is 30 times more the capacity of the pack. Typically, the higher the C-Rating, the higher burst energy can come from the battery. This is important in different flight applications such as 3D or racing.
There are many things to consider when looking into your power needs, but we hope this makes it a bit easier to understand. Stay Tuned! In the next segment of Flight School we will dive into battery chemistries. Check out our line of batteries here.
Esprit Tech stands behind the quality of the products we sell. That is why quality control checks are important to us. At MAV Sense, all Elite Falcon Electronic Speed Controls are factory tested and must pass quality checks before they are shipped out. Each and every ESC undergoes a full spectrum calibration before leaving the manufacturer. The speed controls must pass quality checks in regard to voltage, amperage, used capacity, and temperature. Once these requirements are met, the ESC’s are then able to be shipped to their final destinations.