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RC planes are a ton of fun to use but they also require a decent amount of expertise to make sure that your plane stays in the air rather than crashing.
One piece of information that anyone who flies an RC plane needs to know is how long the battery will last. Certainly the last thing that any RC plane pilot wants is for the battery to die mid air as that means they then have to try and land the plane without crashing it and without any power.
In general RC plane batteries last an average of 8-10 minutes of flight time before needing recharged but this depends on the battery as well as the wind conditions and how hard you are flying the plane (just going in circles or constant diving and climbing).
If you are looking to know the total time that a plane battery will need to be replaced with a new one then that is certainly longer than 10 minutes (obviously). Again it does vary depending on how well you maintain the battery as well as if it is stored properly and what kind of battery you use.
Most RC plane batteries last an average of 2-3 years depending on the variables mentioned above as well as how often you use the plane. The more often you use the plane the quicker your battery will need to be replaced as most batteries will last a certain number (300-500) of charge/discharge cycles.
How to calculate your RC plane’s flight time
There is a calculation so that you can know your flighting time for your battery and plane. You do need to remember that this is still just an estimate as strong headwinds can decrease the flight time significantly.
First of all, you have to translate your battery capacity into amp-hours. To convert milliampere-hours to amp-hours (mAh to Ah), take your battery capacity and divide it by 1000. For example, 2200mAh/1000=2.2 Ah
You can’t fly with a LiPo battery until it is completely flat because of the Low Voltage Cutoff (LVC). Your flight time depends on 80% charge of your battery. This is your battery discharge time. So, simply multiply your battery capacity in Ah by 0.8. For example 2.2Ah x 0.8= 1.76A.
The final thing you have to know is the Average Amp Draw. You can find out how much your multiple or single motor draws by using a measuring tool during a bench test.
The formula is:
Flight time = (Battery Capacity x Battery Discharge / Average Amp Draw) x60
For example, suppose I have a 3000mAh battery after convert into amp-hours it becomes 3.0 Ah. Discharge capacity 2.4 Ah. My average amp draw is 20A. So my RC plane batteries will last a maximum of 8.4 minutes.
How to choose the best battery for your RC plane?
Development of the modern Lithium Polymer (LiPo) battery is most user’s first choice because of how much electrical power is in such a small, lightweight package.
First things first right?
Choosing the best LiPo battery for your RC plane is a challenge. First I am going to describe to you how you can choose the best battery for your RC plane.
First, you must have an idea of the voltage and amp requirements of the motor/prop combination that you intend to use. Before purchasing a battery think about these points
- Physical size
- Charging Rate
We will go a little bit more in depth into each of these things below so you can pick the best battery for your RC plane in the future.
LiPo cells have a nominal voltage of 3.7v per cell. It goes up to 4.2v when fully charged. Even after it has been discharged it should never be below 3v. A LiPO battery is typically made with multiple cells. If the LiPo battery pack is listed as being 3S this means it is 3 cells x 3.7v (per cell) which is 11.1v total.
Weight is very important because if your battery weight increases then your RC plane’s weight will increase too (novel concept right?). A 25c 2000mAh battery can weigh 6-9 ounces and this weight varies depending on the model and brand.
A 1600 mAh battery weight will often be the same as 2000mAh batteries so you want to find the most powerful battery that you can that is also the lightest. Even a few extra ounces can make a big difference in your plane’s performance so weight is an important factor.
Capacity is a very important factor to consider because it is directly related with your battery’s performance. Capacity is measured in mAh (Milliamp/hour) or Ah(Amp/hour). A higher capacity battery can run your plane for longer.
Every RC plane model has a different size battery compartment. It is very important to only buy a battery that will fit in the battery compartment on your plane. All batteries are not the same size so you will want to measure the compartment before you ever head to the store.
Because many RC models have different sized battery compartments then there are a variety of battery sizes on the market to choose from so make sure you get the right one.
Soldering battery connectors can be a real pain, so it is a good idea to try to find a battery connector that you like, and stick to it. If you decide to build another plane in the future you can use the same batteries and that allows you to swap batteries easily.
Charing rate is important to know because a slower charge is always better for the long term health of your battery. Some batteries show a “C” rating for charging and some show 2C. 2C rating batteries charge faster than 1C. If you can’t find any rating on your battery then play it safe and charge at 1C.
Discharge is the amount of power that the battery can supply in your power system. It is an important number to consider when buying a new battery. For example, a 20c battery can discharge 20 X 2000Mah that means 40,000 mAh.
Best Battery for RC planes
When choosing the best battery for your plane you have to consider the nominal voltage of 3.7v for each cell. 3850 mAh or 3.85Ah battery can give you a standard flying time. You should also consider the discharge rate because this represents the maximum current that the battery can draw.
In this case, 65C is the maximum continuous current=65 x 3.85A=250 Amps. The 130C number is the burst current=130 x 3.85A=500.5 Amps. The charging rate is also important. It is true slow battery charge is good for battery but excessively slow is not good for your patience! With the charging rate, the higher the number, the faster the battery can be charged.
If you going to buy a battery then consider each cell is at least 3.7v, Capacity is 3850mAh, discharging rate is high around 65C and the charging rate is 1C. Of course, match your battery compartment and find a better battery connector that you can use regularly. By considering these factors you can get the best battery for your plane that can give you maximum flying time.
How to keep your plane batteries from exploding
It is true LiPO batteries have a lot of benefits because they have a high energy density in relation to their size and weight, with a higher voltage per cell. LiPO batteries discharge at a slower rate too which means it can hold a charge longer.
Unfortunately everything about LiPos isn’t great, there is a bad side too. If they are not charged or used properly then they can smoke and catch fire!
Thankfully this is unlikely but it can and does happen especially if you ignore the warning signs and continue to use your battery. In order to keep your batteries from exploding, you have to follow some instructions.
Don’t ignore swelling
This is the biggest thing that people don’t know or realize. When your RC plane’s batteries start to swell up that means your should stop using them IMMEDIATELY! I cannot stress this enough!
If your batteries are swelling stop charging them and purchase new ones. If you don’t want to take a chance on your RC plane bursting into flames during flight you should NEVER use batteries that have swollen in the past.
If you are not going to use the battery for a few days then you should be sure to store it with a 40% charge. LiPo charges will have a storage option on them so it will charge the battery to that point or even deplete it to the right point as well.
If you want to store the battery then you should store them at room temperature and it is better if you store them in a metal box or fireproof LiPO storage container as well.
Overcharging your battery can cause permanent damage to it so you should never overcharge your battery more than 4.2V per cell. Discharging your battery below 3V also can be the cause of permanent damage.
Use a balancing charger
In order to charge your battery properly and avoid overcharging it, you should only ever use a LiPo balancing charger. That will help keep you and your battery safe while it is charging.
Avoid extreme heat and cold
At the time you are charging batteries or storing them you should be aware of possible heat issues. Never charge or store your batteries in direct sunlight and keep them out of places that get excessively hot (such as sheds or garages in the summer).
Hopefully now you know all about how long your RC plane batteries will last between charges as well as what the total lifetime of your RC plane batteries will be.
As with everything the better you maintain and take care of the batteries the longer they will last. When you do have to replace the battery it is important to get the right size, power, etc. that will work with your plane properly.
RC plane batteries are at a risk of exploding/fire but that happens rarely and shouldn’t happen at all if you make sure to never use the batteries if they have begun to swell at all.
The most common cause of fire is people still charge and use their batteries after they start to swell which in turn causes them to ignite or explode.
If you follow the simple safety guidelines mentioned above you shouldn’t ever have to worry about that happening to you or your plane.