Batteries for your quadcopter have a few more areas of consideration than simply how long it will keep your craft in the air. This guide is to help inform you of what those considerations are, and to help you decide which is the best lipo battery for your drone and individual style of flying.
Voltage and capacity are the most important things to consider, but weight and discharge rate (also called ‘C’ rating) are almost as important.
LIPO BATTERY BASICS
As we know from Christmas mornings as kids, not all batteries are the same. After unwrapping the biggest gift under the tree, and fitting the “no-name” batteries that came free with your toy, the buzzing, and beeping, which drives parents to distraction, gets quieter and more distorted, until the batteries no longer work at all. We learn pretty early on that it is worth spending a few extra dollars on good-quality batteries so our playtime doesn’t get cut short.
Lipo Battery Size Chart
| Number of Cells | Battery Voltage | Applications |
|---|---|---|
| 1S | 3.7V | Indoor whoops |
| 2S | 7.4V | 30-75mm micro brushless |
| 3S | 11.1V | 100-220mm brushless |
| 4S | 14.8V | 220mm brushless |
| 5S | 18.5V | 220mm+ brushless |
| 6S | 22.2V | 220mm+ brushless |
Battery Voltage (Cell count)
The nominal voltage of a LiPo cell is 3.7v, cells are put together in series to increase the voltage, and the number of cells used in a LiPo pack is shown by a number followed by the letter ‘S’. So a 2S battery has 2 cells wired together in series to create a 7.4v battery, and a 3S has 3 cells to increase the voltage to 11.1v. The most common voltage for quads at the moment is a 4S 14.8v battery.
Capacity
The capacity of a LiPo has the greatest effect on flight times, the higher the capacity, the longer the flight time you will get from your craft, but the higher the capacity, the heavier the battery will be. As the LiPo is the single heaviest component on your quad, you will reach a stage where you get diminishing returns, and the battery is too heavy for your craft to carry efficiently. The most common capacity for racing drones with 5-inch propellers is 1300mAh, which seems to find the best balance between performance, flight time, and weight, but there are, of course, exceptions to this.
Discharge Rate (C Rating)
The discharge rate is shown by a number followed by the letter ‘C’, the higher the discharge rate, the better. The discharge rating shows how quickly you can safely discharge your battery. A higher C rating means that you will use less throttle input to get your craft to hover, and it will provide more amperage to the motors at full throttle, making your craft faster and more punchy.
There is a phenomenon known as ‘Voltage Sag’ – The higher your throttle input, the faster you deplete your battery, but this depletion is not linear. At very high throttle the voltage drops even faster, but as you decrease throttle, the voltage will recover, the lower the C rating of your battery the more pronounced the voltage sag will be, and the longer it will take for the voltage to increase again.
With a high C rating, the voltage drop at a very high throttle will be reduced. I recommend 45C as the very minimum to fly slowly, a 75C pack will be better for freestyle, but to get the best out of your quad, and particularly for racing you should be looking at C ratings of 80-100C and higher.
Note – Batteries with a higher C rating will usually be slightly heavier, than others with the same voltage and capacity.
Buyers tip – Some manufacturers inflate the numbers of the C rating of their batteries, which is why it is recommended to purchase your batteries from a reputable source.
Important Buyers Note – Unscrupulous manufacturers often inflate the advertised C ratings of their batteries, as such, it is highly recommended to purchase batteries of a well-known brand from a reputable retailer.
Battery Chemistry
Batteries store electrical energy by using a reaction between different chemicals, such as Lead and Acid – which is what is used for car batteries. Li-Po or Lithium – Polymers have a good power density, they can be made in various shapes, and also inherently have good discharge rates, which make them ideal for our hobby/sport.
There are 2 other common chemistry types used for drones, these are LiHv (Lithium High Voltage) and Graphene. LiHV cells have a higher nominal voltage of 3.8v per cell, which provides a little more punch at full charge. Graphene batteries are said to have a slightly longer lifespan as they build internal resistance slower than a standard LiPo or LiHv.
Batteries don’t last forever
Like propellers, LiPo batteries are consumable in the hobby, however, they should last longer than your props, as long as you treat them well! I mentioned internal resistance earlier, this is what kills your batteries over time. The more you use a LiPo, the more the internal resistance increases. Internal resistance can be thought of as a component within your battery that uses electrical energy, leaving less power for your motors.
Overcharging, and over-discharging your batteries will cause internal resistance to increase more quickly, also leaving your batteries fully charged or discharged (past 3.2v per cell) for extended periods will also cause internal resistance to build faster. Unless you are going to fly tomorrow, I would recommend that you re-charge/discharge your batteries to storage voltage, which for standard LiPo, LiHv, and Graphene batteries is between 3.7 and 3.95v per cell, most say 3.8v for LiPo and Graphene and 3.85v for LiHv.
4S BATTERY OVERVIEW (14.8V)
A 4 cell/4S (14.8v) pack is the most common voltage for flying almost any size drone (apart from micro >120mm frames) at the moment. This voltage is very versatile and provides great performance for racing and freestyle on almost any quad using 2.5” props and over.
There are now components hitting the market that will support 5S and even 6S voltages, but at the current time, these are quite specialized. A few years ago 3S (11.1v) was the most common and as such, some are slightly behind the times and suggest that this voltage is better for the beginner pilot.
However, the throttle curve can be adjusted on your transmitter and/or flight controller (FC) so that at full stick input, your model is not running at its full thrust capacity.
If you do feel that your 4S model is a bit too fast for your current skill level, rather than buying 3S packs, you can adjust the settings to slow it down to a more manageable pace, and then revert or re-adjust these settings over time, to increase the thrust of your model as you feel.
3S BATTERY OVERVIEW (11.1V)
As I mentioned above, up until a few years ago 3S was the most common voltage used in the sport, but as the skill of pilots improved and technology advanced, we saw the introduction of 4S compatible parts, until subsequently, the higher voltage became commonplace.
As you may have learned, much of the hobby is a balancing act, the most important factors to balance are the thrust generated by your motors and props, and the All Up Weight/AUW, (basically, the weight of your model, including the battery).
These days generally 3S packs are used for smaller, lighter models and motors. Models designed for 3S voltages usually have a specific reason for using a 3S pack over a 4S, namely the additional thrust from the higher voltage battery will not show as much improvement as the decrease in weight of the battery.
Of course, there are exceptions to every rule, the exceptions here are that some larger crafts with 8 inches or larger props, will use a high-capacity 3S battery.
Remember that as capacity increases, so does the weight of the individual cells that make up your pack. Some long-range craft, designed to optimize efficiency, will sacrifice the additional thrust from a higher voltage, for an increase in mAh capacity.
Spending extra on long-range components for a craft that only has a flight time of 5-6 mins is a needless expense because you won’t be able to fly to the limits of your range in 2.5-3 minutes, remember you always have to save enough battery power for your return journey!
These 3S packs have been chosen to reflect the current popularity of micro models, you will notice that the capacities of the packs in this list are lower than the 4S list above due to the limited thrust of smaller props.
2S BATTERY OVERVIEW (7.4V)
2S packs are commonly used for quads with a wheelbase of between 100-120mm, but nowadays there are quite a few craft in this size category that will happily run on 3S and even 4S voltages.
Finding information on the craft that works best with 2S packs is not that easy as smaller capacity 3S and 4S packs become more common. Some ultra micro craft such as brushless tiny whoop’s, which often run single cell (1S) packs, are now using components to support upgrades to 2S voltages.
These packs will generally have a very low capacity between 200-400mAh, which is not enough to handle the current draw of 2” or larger props. Another thing to consider with 2S batteries is the connecter that is used, I think 2S voltage has the widest range of different connecter types as you can find Walkera/LOSI, JST PH, JST RCY, XT 30 and XT 60 are all available, so make sure you order the correct type for your model.
1S BATTERY OVERVIEW (3.7V)
1S packs are where many of us start, powering a toy-grade model such as the Eachine H8 mini, blade indicatrix, or one of its many clones. There are many different non-branded types of 1S batteries which is what taught me (the hard way) that not all Li-POs are equal.
Some of the no-name brand 1S packs I bought worked fine, others, from their very first use, failed to provide enough power to sustain a hover! Due to the popularity of Tiny Whoops, there are now many well-known companies providing high-quality 1S packs and relatively cheap too.
Most of the packs listed here are available in standard Li-Po and Li-Hv chemistries, so ensure that your charger and model are compatible with your selection.