Batteries are the power sources for a quad. We FPV-ers use different types of batteries such as LiPo, Li-ion and LiHv. To properly charge this kind of batteries you need specific charger. In this guide we're orienting on best lipo chargers we tried and tested.
A typical LiPo battery on the paper should last for as much as 200 charge and discharge cycles. Even though a 1500mAh, 100C battery can theoretically provide 150A (the current capacity of a battery is calculated by- battery mAh/1000 and multiplied by the discharge of the battery) of current, these batteries cannot be charged at the rates they are discharged.
Batteries are delicate components, are flammable and if mishandled can catch fire. The battery behavior, discharge current and life cycle, depends on how the battery is treated. A mishandled battery, charging at high currents, for example, might make the battery not perform as expected. In today’s guide, we are going to do just that, explore top chargers for batteries and learn how to care for our LiPo batteries.
LiPO Battery Charging Basics and Terminology
There are a few terms you must familiarise yourself with before diving into the guide.
mAh (spelled as milli Amp hour) - This number denotes the battery capacity of the battery. It is quite similar to our phone batteries, where a larger number means a larger capacity. Higher capacities come at the expense of increased weight.
A larger capacity battery will increase the overall weight of the quad which might cause the quad to feel slow and sluggish and smaller battery capacities will result in a lighter quad that feels agile and nimble in the air.
C rating - C ratings of a battery define the amount of current a battery can safely deliver. Higher the C rating of a battery, the higher the discharge current by it. But the C rating has become just a number and a marketing gimmick manufacturers use nowadays and make false claims about these numbers.
Battery connector - A connector present on the battery help it connect to the quad Flight controller and provide power to it. The type of battery connector present on the battery depends on the voltage and current carrying capacity of the battery.
A smaller battery typically uses a JST or a JST PH 2.0 connector and slightly larger batteries use XT30 and XT60 connectors.
Parallel charging wires - Parallel charging wires or leads are a group of wires present on every battery that allows a battery to be charged. Three 1S batteries are connected in series to give one 3S battery. The balance charging wire helps the individual 1S batteries to charge independently.
Battery charging current - This probably is one of the most important factors and calculations to be made before charging a battery without damaging the battery itself.
As a general rule of thumb, a 1C charging rate is considered ideal. 2C charging rates are also fine, but anything higher might reduce the battery’s life in the long term. For example- A 1500mAh 100C battery can be safely charged at 1C (1.5A) or 2C (3A). Any advanced chargers have the option to change the charging currents depending on the battery themselves.
Factors to consider
Some major factors that differentiate a charger that will last you a long time and a charger that will work for a while and die. Let’s find out what those factors are, continue to read below.
Number of Charging ports
Charging ports are similar to our wall sockets where we plug in our chargers. Similar to this, we plug the batteries into our sockets aka FPV charger ports. FPV Chargers draw power from the wall and charge our batteries at a controlled rate.
Since not all batteries are the same, by different I mean different capacities, voltages, they would need different charging needs. FPV chargers with 2 charging ports which are essentially 2 chargers, can do just that- charge dissimilar batteries.
But do you need 2 charging ports? Maybe. FPV chargers are things that don’t get replaced often and tend to stay with us for years and are just as critical as a Flight Controller to ensure the batteries don’t get stressed. Not only do dual charging port chargers are expensive than single charging port chargers, but they are also quite bulky. Single port chargers like the ISDT Q6 are so small that they can be slid into one’s pocket.
If the upfront cost matters to you, then you could pick a single port charger and use a parallel charging board, more on this below, and charge multiple batteries from the same charger.
Max Charging Current
Max charging current means the max current a charger can provide. A bigger battery requires a larger charging current. In the world of FPV, the most commonly used voltages are 4S and 6S. For a 1000mAh 6S battery, the typical charging current at 1C is 1A and at 2C is 2A, the same goes with 4s batteries. So we really do not require a large max current rating if you are going to charge a single battery at a time.
We can charge multiple batteries at a time if the charger has 2 charging ports, but most chargers come with a single charging port. There is another way to charge multiple batteries from this single charging port- Parallel charging boards. More on parallel charging boards below.
Battery Type Support
The most commonly used type of battery is LiPo (lithium polymer) battery. But we do use other kinds of batteries like LiHv (High Voltage LiPo), Li-ion (Lithium Ion) and some ancient batteries like NiMH (Nickel Metal Hydride) to power other peripherals such as FPV goggles and such. Some people even use Lead Acid batteries to charge batteries on the field.
If a charger only supports one type of battery chemistry, you really would be bound to that type of battery chemistry. If all your charger support is LiPo, then you would have to use LiPo batteries to power your miscellaneous. But the downside to using LiPo is the lower cycle count (The charge and discharge cycle) typically 200 compared to the 600 of the Li-ion batteries.
Some chargers like the ISDT Q6 weighing in at a mere 100g are so small that they fit into your pocket and some chargers like the SkyRC Q200 charger that weighs at a not so light 1.3kg or just over 45 ounces. Portability matters when you have a small workspace or you plan to field charge your batteries.
But the Q6 (on the left) and the Q200 (on the right) are chargers of 2 totally different spectrums. The Q6 does not come with an integrated power supply, while the Q200 comes ready out of the box meaning to say it can be plugged to the wall socket out of the box with no need for external power supplies and other hassles.
Are you saving up space buying a Q6? Probably not, as the size of the Q6 with a power supply comes to more or less the size of the Q200. But why buy a Q6? Because of the cost, while the SkyRC Q200 costs $175 the Q6 ($60) with the power supply ($24) comes to around $84 which is less than half of what the Q200 costs.
Max Voltage Support
Max voltage support is the maximum voltage that the charger can charge. Mostly we use a maximum of 6s batteries i.e. 22.2V. Most professional-grade chargers support up to 6s batteries and you should be good.
Some basic chargers like the one on the left might support a maximum of 4s and if you ever make the decision of advancing through the hobby and switch to 6s you will have to shell out extra cash. A disadvantage to these types of chargers is that they inaccurate to some extent and they do not offer the users the option to tweak the input current and the option to discharge the battery.
Parallel Charging Boards
I probably mentioned parallel charging boards like a dozen times already. What are parallel charging boards? Parallel charging boards are components that help to charge multiple batteries from a single charging port. Not all chargers have multiple charging ports and charging 10 batteries requires a lot of time (roughly an hour per battery) from a single port. Hence we have parallel charging boards.
The parallel charging board works by splitting the current coming from the charger to all the ports on the board. For example, if a parallel charging board has 5 ports and 5 batteries are connected, then the current coming from the charger is divided into all the 5 ports.
But there’s a small catch to it. Only batteries of similar voltages and capacities can be charged together as the charger views all the 5 batteries as 1 single larger battery. If batteries of different capacities are connected, then the battery with a smaller capacity might get overcharged and get damaged in the process.
Power Supply Basics
Traditionally we are used to taking any charger, our phone charger for example and hooking it up to the wall socket and expect the phone to charge. That should be the same case with FPV chargers right? Well, kind of. Some chargers come with integrated power supplies, some don’t.
As mentioned earlier, Chargers like the ISDT Q6 pro or the Q6 plus do not come with a built-in power supply and need an external power supply to provide power to the charger. Now let’s talk on more technical terms. Every charger has something called a power rating. The ISDT Q6 is rated for a maximum power of 300W (spelled as 300 watts). Power is the product of voltage and current.
Power = Voltage x Current
To exploit the full potential of the Q6, the power supply must be able to provide at least 300W of power. A power supply generally has a fixed voltage and a maximum rated current. For example, if a power supply has a fixed voltage of 12v and can provide a maximum current of 10A then the power rating of the power supply is 120W (12v x 10A). Suppose if the maximum current was increased to 20A then the power rating 240W (12v x 20A).
So we can just buy a 12v 30A power supply and be done with it right!! No. To higher charge voltage batteries, 5s or 6s then a 12v power supply would not be sufficient. But, a 24v power supply can provide 300W of power with a current rating of 12.5A.
Also, higher current rating power supplies require beefier internal components and tend to be expensive than lower current rated batteries. Hence as a general rule of thumb, a 24v power supply with at least 10A of current rating would work well for most setups.
Our pick for a power supply
Field charging Batteries
Field charging batteries might be one of the most practical and cost-effective approaches to flying longer in a single flying session. Of course, you can buy lots of batteries to fly without having to wait for batteries to charge but then again, a 4s battery costs $40 and buying 20 batteries easily pushes the investment on batteries to $800 alone, with a well spec’d quad costing around $250.
With advancements in technology taking place every day and better batteries being developed, the technology available today might be outdated 1 year down the line. Hence a significant investment in an immature system is not recommended. Hence buying a small number of batteries often is a wiser choice.
There are many ways to charge a battery on the field. Some methods include buying a large 4s or 6s 20,000mAh or higher capacity battery. This is the most practical and viable approach. Field charging is a lot safer than charging the batteries in your home, as you don’t have to worry about the batteries exploding or catching fire.
The Energy Density of the larger battery plays a role in how much smaller batteries can be charged. A 6s 20,000mAh battery has an Energy Density of 504Wh (25.2 x 20) and a 4s 1500mAh battery has an Energy Density of 25.2Wh (16.8 x 1.5). So technically a 6s 20,000mAh battery can charge 20 (504 divided by 25.2) 4s 1500mAh battery.
Another method would be to use a mini generator to charge the batteries, but a generator costs a lot of money with a decent generator costing around $950 from Honda and tend to get noisy. Some people use their car batteries to charge their LiPo’s. But if the car battery is discharged enough, then you won’t be able to start your car and will need some towing.
FPV chargers are long-time investments that stick around for a while and investing in a good quality FPV charger would benefit the user in the long run and eventually save money. A bad FPV charger cannot charge your battery and will slowly damage batteries and kill your investments slowly. Lastly, if you plan to field charge batteries you will just have to charge one larger battery and go to the field rather than buying a generator and worry about lugging that thing around.