LiPo Batteries for Drones (Everything You Need to Know)

LiPo Batteries for Drones (Everything You Need to Know)

What battery does your drone use? It’s almost certainly a LiPo battery. These batteries are mostly utilized in toys, drones, RCs, and even mannequin airplanes and trains. Why is one of these battery the most typical selection?

Lipo batteries are the perfect factor that ever occurred to the drone group and different toy and pastime communities due to their smaller dimension and bigger capacities. These qualities are important for longer flight occasions. However, they pose a possible hearth hazard if not dealt with correctly.

It’s essential to know the ins and outs of your drone batteries to get probably the most out of them, so I’m going to debate the whole lot it is advisable learn about LiPo batteries, together with easy methods to safely retailer them and eliminate them off in the event that they get broken.

What is a LiPo battery?

LiPo stands for Lithium Polymer or Lithium-ion polymer, that are rechargeable batteries product of polymer electrolytes. In easy phrases, as a substitute of utilizing a liquid type of electrolyte, LiPo batteries use polymer, which is extra of a “sheet” that shops a cost and transmits energy to the gadget when crucial. 

LiPo batteries have a smooth shell casing, in contrast to ion batteries which have a tough shell. The polymer and the power to surround it in a smooth cowl make these batteries appropriate for RCs since you possibly can type them into totally different shapes, in contrast to with onerous shells.

Now let’s take a look at a number of the important ideas that make up a LiPo battery. I will likely be referring to the picture beneath all through the article.

Image credit score: Ingolov.com

Voltage (Nominal Voltage)

Nominal voltage is the “named” voltage, or the voltage of a battery when at relaxation. It shouldn’t be confused with the rated voltage or working voltage. For occasion, the nominal voltage of most LiPo batteries is 3.7 V, however when absolutely charged, LiPo batteries have a 4.2 voltage. And whenever you’ve discharged them to the minimal, they need to have a 3.0 Voltage.

This brings us to the labeling. You will discover most batteries labeled as 2S, 3S, 4S, or 6S. These numbers consult with the variety of cells of the batteries organized in a sequence type. So, the S stands for Series. 

You’ll discover that there’s additionally a quantity denoted by C on the battery. In the picture above, we now have 50C. But that doesn’t imply “Cells.” It means Discharge Rating, which I’ll focus on in a minute.

To get the full voltage, you add the voltage of every cell. For occasion, a 2S battery has two cells, so the full voltage will likely be 7.4V, 3S batteries just like the picture above can have 11.1 V, 4S batteries can have 14.8, and so on…

You might come throughout older batteries labeled as 2S2P, which suggests there are 4 cells; 2 in Series association and a couple of in Parallel construction. But such batteries have been phased out and changed by the newer fashions.

So, what’s the significance of understanding the voltage? It interprets to how briskly a motor can rotate, which then interprets to the facility and velocity of a drone. You might have come throughout quadcopters with motors labeled as kV. At first, I believed, and a few customers did too, that kV stands for kilovolts. Well, that’s not the case. 

kV truly stands for RPM (rotations per minute) for each volt. So, if the quadcopter has a 3000 kV, you’ll must multiply that by the battery’s voltage. For occasion, a 2S battery will produce 22,200 RPM. The extra voltage the battery has, the sooner the motors rotate and the extra energy the drone can have.

Capacity

To perceive capability, let’s use the frequent water tank analogy. The voltage I simply described is the stress of the tank. Simply put, the extra stress/pressure a tank has, the extra powerfully it would eject the water. Now, the capability would be the quantity of water the tank can maintain at a time. So, when talking of batteries, it means the quantity of cost it will probably maintain, which interprets to how lengthy the battery can final. 

The capability of a battery is measured in milliamp-hours (mAh). Our battery above has 5200mAh, however you’ll discover some batteries with capability as excessive as 12,000mAh, and a few with lower than 5000mAh. Also, 1000mAh, make 1Ah (Amp-hours).

While a battery with extra capability looks like a good suggestion because you get to make use of a drone for longer, you additionally want to think about the consequences on the general system of the drone. 

For one factor, extra capability means extra weight, and most drones can’t operate as properly once they’re too heavy. Secondly, if the motors run for too lengthy with out cooling down, they could catch hearth and even harm the whole drone.

Discharge Rating (C)

Also generally known as the “C” Rating, the discharge ranking is the quantity of cost/load you possibly can constantly drain from the battery with out damaging it. If you employ a tool that pulls extra cost at a time, you could possibly harm the battery. 

Now, our battery has a discharge ranking of 50C, which suggests you’re going to multiply 50 by the battery’s capability in Amps.

So, our battery’s capability is 5200mAh. In amps, that’s 5.2Ah.

50*5.2 = 260 A.

So, you possibly can constantly draw 260 A from this battery. Now that’s the continual ranking. 

There’s additionally a Burst Rating, which is the very best quantity of cost you possibly can draw inside 10-second bursts. Our battery above has a burst price of 100C, which suggests it will probably survive 520A blasts sometimes. This might be through the acceleration of a drone, and it’ll most frequently be greater than the continual ranking.

When shopping for additional batteries, ensure you’re conscious of the facility draw the drone wants and what you’ll be utilizing the drone for. Racing drones may have batteries with the next discharge ranking.

Internal Resistance

While the inner resistance will not be a part of the battery design, it’s important to say it. Using the water tank analogy, we are able to finest clarify resistance with a hose. A hose is meant to permit water to circulation easily. But if there’s a kink within the hose, it limits how properly the water flows—the larger or deeper the kink, the extra inadequate the water circulation. 

The identical case applies to LiPo batteries and another electronics. The greater the resistance, the much less the cost that reaches the vital elements of the drone. The purpose they’ll’t point out the resistance is that it builds up over time. 

The extra you employ the battery, a residue generally known as Li2O (lithium oxide) is deposited, including to the inner resistance to a degree the place the battery turns into unusable. When the power can’t get to the required elements, it’s transformed to warmth. Heat then results in extra oxygen accumulation inside the batteries and extra lithium oxide build-up, which causes them to swell. The second you see the battery swelling, it is best to cease utilizing it. 

Using a swollen battery generates much more warmth, and a course of generally known as Thermal Runaway takes place. Eventually, the lithium oxide build-up, oxygen, warmth, and humidity mix and explode into a hearth.

The customary measurement for resistance is ohms (Ω). 

1 milliohms (mΩ) = 1 ohm.

It’s very important to maintain checking your batteries’ resistance ranges to verify they’re nonetheless usable. Most superior chargers might help you measure the inner resistance both for one cell individually or for all cells collectively. 

Generally talking, it’s secure to make use of a battery with a resistance starting from 0 to 12 ohms. Anything greater than which means it is best to think about changing the batteries.

Why do drones use LiPo batteries?

LiPo batteries have many advantages for the drone trade since they’re small and may carry a variety of cost in a single cell (3.7 V to 4.2V). This makes it attainable to construct a large-capacity or excessive voltage battery for numerous purposes with out making the drone too heavy.

How to cost a LiPo battery?

LiPo batteries are fairly delicate. You can’t use simply any charger with them. Overcharging them might result in harm or perhaps a hearth. Unlike different batteries, LiPo batteries use a CC/CV system which suggests Constant Charge/ Constant Voltage. 

As talked about earlier, they’ll maintain a most of 4.2 V. So, when the battery has 4.2 V on every cost, it maintains that voltage somewhat than constantly throwing present pulses.

The Charger

LiPo batteries use what are generally known as balancing chargers. These are costs that be certain that every cell within the battery will get sufficient cost. Balancing chargers or chargers with inbuilt balancing may be fairly costly, however they’re price it in order for you your battery to last more. Besides, a battery with an unbalanced cost (some cells with extra cost) will increase the danger of damaging the battery and even inflicting a hearth.

The Current

Another side to think about when charging a LiPo battery is the quantity of present. Fast chargers are the norm in some units, the place they ship excessive quantities of present (amperes), charging a big battery inside a short while. You can’t do this with a LiPo battery. LiPo batteries include a price at which you’ll cost them, identical to the discharge price.

Now, our battery above has a 2C cost price. Like we calculated the discharge price, you multiply the charging price by the capability. In this case, our battery has a capability of 5.2Ah or (5200mAh).

5.2*2 = 10.4 A.

So, it is best to at all times cost this battery at 10.4 Amperes. Always test your battery to determine the appropriate cost price. You can cost with a decrease price, equivalent to a 1C price, however by no means go above what the labeling on the battery advises.

The Connectors

And lastly, it is best to be certain that the charger you’re utilizing has a connector appropriate with these in your battery. As you possibly can see in our battery above, every Lipo battery has two connectors. The yellow one goes (largely XT-60) to the drone, whereas the white plugs go to the balancing charger. Most importantly, because you’re coping with excessive voltage and amperage, the wires needs to be thick. 

How many LiPo batteries do you want to your drone?

Two to 3 batteries could be nice to your drone. While it’s attainable to have extra batteries and fly for lengthy, you danger damaging your rotors, particularly whenever you run them for too lengthy with out permitting them to chill down. 

How to retailer LiPo battery

A LiPo battery ought to by no means be saved when absolutely charged. Neither ought to or not it’s saved when beneath 3.0 V. Doing this might harm them fully. For occasion, when you retailer them at full cost, the batteries will routinely discharge themselves, and so they might find yourself with a voltage of lower than 3 V.

The optimum storage voltage is 3.8 V. Always test the batteries’ voltage earlier than storage. Thankfully most superior chargers assist you to test the voltage, so cost them if they’re beneath 3.0 V, and discharge them if the voltage is greater than 3.8 V. 

Also, to forestall fires when in storage, at all times retailer LiPo batteries in fire-resistant luggage such because the one pictured beneath.

Other storage areas equivalent to ammo luggage or firearm safes will nonetheless work so long as they’re fireproof.

How to journey with LiPo batteries

If you’re planning to take your drone with you when touring, you possibly can safely deliver 2 to three LiPo batteries. However, LiPo batteries usually are not allowed within the cargo cabin since they’re a hearth hazard. You must carry them together with your different carry-on baggage. 

Before packing the batteries, be certain that they don’t seem to be broken. You can place the batteries in a fireproof bag or a drone-carrying field with compartments for the batteries. Also, ensure you test the airline’s tips on carrying drones and batteries.

If you’re planning to journey together with your drone (and batteries!) learn our Ultimate Guide to Traveling with a Drone for extra tips about easy methods to pack and fly together with your gear. 

How lengthy do LiPo batteries final?

LiPo batteries are designed to final a minimum of 300 to 500 cycles when the whole lot is ideal. That is, retailer them within the right voltage, retailer them on the proper temperature, keep away from extra humidity, keep away from puncturing them and cost them utilizing the proper charger. 

However, it’s not at all times attainable to keep up all of those situations. That’s why most LiPo batteries common between 150 and 250 cycles. That may be wherever between 1 yr and three years, relying on how usually you employ your drone.

How to eliminate a LiPo battery

At one level, you have to to throw away your LiPo battery, which it is best to do very fastidiously. Here’s why.  As talked about earlier, the Lithium oxide and oxygen build-up trigger the battery to swell. And I discussed, continued use might harm the batteries and trigger a hearth. 

However, though you’re not utilizing the battery, it might nonetheless trigger a hearth when you puncture it. The Thermal Runaway course of might nonetheless happen, particularly if the battery remains to be charged.

NOTE: Some corporations provide warranties on the batteries. So, test that earlier than attempting any of the processes beneath.

Whether your batteries are useless or swollen, do the next earlier than disposing of your LiPo batteries:

Start by checking the voltage. The ultimate voltage for disposing of your battery needs to be 0.0 V. If it has some cost, discharge it with both of the next steps.

Make certain they’re fully discharged earlier than disposing of them. There are a number of methods you are able to do this. 

  1. You can use your balancing charger to discharge them or use them within the drone till they’re left with no cost. The latter course of is dangerous since you could possibly set your drone on hearth.
  2. Another technique to discharge it’s utilizing a salt water bathtub. Add heat water to a tray and saturate it with salt till no extra salt can dissolve. Then soak the batteries within the salty water. 
  3. You can even drain it by connecting it to an LED mild whereas the battery is dipped in sand. When the LED dims or goes off attributable to low voltage, disconnect it, and join the optimistic and damaging wires of the battery to trigger a brief circuit.

Once you’re certain it has no cost, you possibly can throw it in your common trash can or search for native battery disposal providers.

Safety Precautions

Below are some security precautions and a abstract of easy methods to prolong a LiPo battery’s lifespan.

  • Always have a hearth extinguisher close by. LiPo batteries don’t do properly in excessive temperatures and can usually lead to a hearth. While a hearth extinguisher will not be the perfect for chemical reactions such because the one in LiPo batteries, it would assist comprise it.
  • Constantly monitor your batteries carefully as they cost. It solely takes a couple of seconds of the improper temperatures for these batteries to blow up. So, when you go away them and go to the shop, or for a run across the neighborhood, you might come again to search out your total home on hearth.
  • Make certain the storage space is at room temperature. I’ll stress once more, LiPo batteries and excessive temperatures are sworn enemies.
  • Always retailer the batteries in a dry space, and ensure they don’t contact water since water facilitates the chemical reactions that trigger a hearth.
  • Always maintain your batteries clear. Using a soft-bristled brush, clear the drone, the connectors, and the drone’s battery compartment.
  • Always maintain the voltage between 3.0 V and 4.2 V, and retailer them at 3.7V.
  • Use a high-quality balancing charger.
  • Avoid utilizing metallic objects that will join the optimistic and damaging, inflicting a brief circuit. This might be when utilizing pliers through the soldering course of.

Conclusion

And there you have got it. Hopefully, I’ve coated the whole lot it is advisable learn about LiPo batteries for drones. While they provide extra advantages than different battery varieties, it is advisable deal with them fastidiously to forestall potential hazards. 

As we’ve established, preserve them on the acceptable voltage, use the right charger, keep away from too scorching or too chilly temperatures, keep away from utilizing swollen batteries, by no means go away them unattended, and ensure the batteries are discharged earlier than disposing of them. 

While it is best to take the dangers critically, these batteries usually are not one thing to scare you off although. Handled correctly, it is best to by no means must face an emergency. And don’t neglect to have enjoyable when flying your drones.

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