RC Car Batteries 101: A Guide to Type, Sizes, and Prices


RC Car Batteries 101

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Anyone that has ever driven a high-performance remote-controlled car knows that they are tons of fun. One of the key components in these vehicles is the battery. The batteries of RC cars decide their power and runtime. These bundles of chemical energy are what allow people to rip through tracks with their RC cars.

There are many different batteries that you can use to energize your car. You have to consider the battery type, the size of the battery, and the price of the battery when choosing the right one for your RC car.

Note: The battery you need will depend on your car, so keep that in mind if this list looks overwhelming.

Battery Sizes Prices (on Average)
Alkaline D $12.99 (pack of 12)
C $7.50 (pack of 4)
AA $4.50 (pack of 4)
AAA $13.00 (pack of 24)
N $4.00 (pack of 2)
9 Volt $11.00 (pack of 8)
Nickel Cadmium AA $9.00 (pack of 8)
4/5 Sub C $14.00 (pack of 6)
Sub C Sub C
Nickel Metal Hydride AA $27.00 (pack of 16)
AAA $11.00 (pack of 4)
4/5 Sub C $7.00 (pack of 3)
Sub C $5.00 (pack of 1)
Lithium Ion Polymer 100mAh $11.50 (1 piece)
500mAh $15.50 (1 piece)
1300mAh $13.50 (1 piece)
2500mAh $15.50 (1 piece)

Note: The brands and different sizing of some batteries will have different prices than mentioned above. Prices can also vary depending on if you purchase online or at a local store. 

In this article, the information in the list above will be discussed in greater detail. Later in the article, you will be introduced to battery chargers and how to choose the one you need.

What Kind of Battery Does my RC Car Use?

Most batteries will have some sort of printed mark or sticker on them to let you what type of battery they have or what kind of technology they use. They also have labels that show their capacity and voltage which are very important to know for your RC car.

Some RC battery types that are commonly used:

  • Alkaline: These batteries are not normally rechargeable. It is a basic battery, like a AA or AAA, that is commonly used in your home.
  • Ni-Cd: Nickel Cadmium. This battery is rechargeable, but it is relatively unfriendly to the environment and banning these batteries has been proposed in some areas.
  • NiMH: Nickel Metal Hydride. It is very easy to maintain and can be recharged.
  • LiPo: Lithium-ion Polymer. It is much higher in energy density than the others but has a lighter weight. It also provides a stronger discharge but is more volatile than other batteries which means it needs more intricate chargers and can be more dangerous for beginners.

You can expect many of the lower-quality model RC cars to have a NiMH battery. Higher-quality models usually don’t have batteries or chargers included in their packaging. They enable customers to use their own hardware or buy the battery type they prefer.

Capacity

Your RC car’s capacity tells you how long your RC vehicle will run per charge. This measurement is most often shown in milliamps or mAh.

The number on the label (3300, 4000, etc) will show you the capacity in milliamp hours. This can generally be shortened to “mAh”. The greater the mAh number, the longer your car will be able to run on a single charge. However, the higher the capacity, the longer the battery will take to fully charge as well. 

Consider this: If a battery is rated 5000mAh, this means it can keep a steady 5-amp load for an entire hour. The number 5 comes from 5000 because a milliamp is just 1/1000 of an amp. A 6000mAh battery can hold a 6-amp load for an hour, but it could also hold a 5-amp load for approximately  one hour and twenty minutes. 

Voltage

The voltage of your RC car will tell you how much power and speed can be delivered to your model. The more volts your car has, the faster it will be.

Keep in mind that the vehicle system of your RC car can only hold a certain amount of voltage. If you exceed that voltage, the system may shut down. This is because of “overvoltage protection.” If there is too much voltage, there is a chance that it will fry the electronics within the vehicle and it can even fry the battery as well. 

Make sure you look at the speed control specs of your car because the voltage of a battery pack is decided by how many cells it contains. Many NiMh batteries have around six or seven cells and one cell usually spends about 1.2 volts. You will see these sold as “6-cell” or “7-cell” packs.

LiPos work with the same principle, but one cell of LiPo spends about 3.7 volts and LiPo packs have fewer cells for a given voltage. The most common setups are 2-cell 7.4-volt packs and 11.1V packs of 3-cells. Check your power system’s specifications to see how much voltage your RC model can handle.

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How Do I Choose the Best Battery for My RC Car?

By now you should know the basics of batteries, but you still need to find the right battery for your RC car. There are a few key variables to consider when choosing your perfect battery:

  • Connector Type: Look at what type of connector your Electronic Speed Controller, or ESC, needs or the connector your current battery shipped with. Refer to the guide above if you’re having trouble.
  • Cost: If a battery has already been included with your RC car, it has usually been selected by the manufacturer for a good balance of production cost, weight, and performance. However, many owners choose to buy batteries for their own needs.

Lots of batteries have smaller capacities which are a lot cheaper and can give you a longer runtime if you buy many of them. If you choose to do this, you can avoid the higher weights and price, you just have to change them more frequently.

  • Compatibility: You must make sure your ESC is compatible with your battery; otherwise, it’s useless. The battery cells (2S, 4S, etc.) and chemistry (LiPo, NiMh, etc) must be compatible. You can find this out in the instruction booklet or manual of your model from the manufacturer.
  • Dimensions: The obvious limitations to your battery and model are the dimensions of your battery tray. Some models have a setup with a clamp that can be configured so that they are more effective. Some people don’t even use a battery tray; they use Velcro straps that can secure their battery to the chassis.

Keep in mind that, if you put a heavier and larger battery in your car, it will undoubtedly change the handling and performance of your car as it shifts the center of gravity.

So, Which Charger Should I Buy?

There is a wide selection of smart chargers on the market. They all have different balance boards, battery leads, and other accessories that allow them to be compatible with different battery types.

Generally, the higher end smart chargers will have a better capacity to discharge, balance, and storage charge batteries. These are all critical functions that will keep your batteries at peak performance and prolong their life.

Here are some examples of the top RC chargers on the market today:

Traxxas EZ-Charger

The Traxxas EZ-Charger is compatible with cars that use LiPo or NiMh batteries. If you have iD batteries, you should charge them with EZ-Peak chargers for optimal results. This charger is made to be used with an upgraded system that has integrated balance cables.

Features of this charger include:

  • Automatically optimizes charger settings
  • One button LiPo storage charge
  • Charge progress indicator
  • Cooling fan
  • Advanced mode for manual settings

Tenergy

The Tenergy charger is compatible with cars that use NiMh, NiCD, or LiPo batteries. This is the most versatile battery charger because it works with nearly all battery types and has many useful features.

Features of this charger include:

  • Comes with multi-charging harness
  • Data storage
  • Cyclic charging
  • Useful for all battery pack types

Overlander

The Overlander charger is compatible with cars that use 8-cell NiMh or 6-cell LiPo batteries. It is a very fast charger that has more specific requirements for the batteries that it can charge. It also has lots of features that keep your batteries efficient and well cared for.

Features of this charger include:

  • Fast charging output
  • Storage modes
  • Lithium battery balancing function
  • Internal resistance checker
  • Delta-peak sensitivity

Essentials for Charging

If you plan on buying a powerful 5000mAh battery to extend your runtime, be aware that, with a bundled charger, you will have to wait a day before you can race again because of the massive amount of time needed to recharge. Having an intelligent charger can make all the difference; you can get your batteries charged and be back to racing in a fraction of the time.

First, you should make sure you get a charger that matches your battery type. If you are using two types of batteries, there are chargers that you can set up for either type. If this is the route you take, then make sure the correct charger configuration is set up before you hit the start button.

By far, the most important feature to look for in your charger is amperage. This is because the higher the amperage, the faster it can charge your battery. The output is displayed in milliamps.

Imagine you have a 300mA charger: this charger would take one hour to fully charge a 300mAh battery. However, if your battery is a 3000mAh, then it would take 10 hours to charge. Getting a 4-amp charger would let you charge this same 3000mAh battery in about 45 minutes. So, you can see why the charger is so important.

Safety Rules for Charging.

  1. Use the right connector: Never try to rig up your own connections with exposed clips or wires; this could cause a short circuit and damage your battery, charger, and, in some cases, it will start a fire.
  2. Use the right charger: Under no circumstances should you ever use a NiMh charger with a LiPo battery and vice versa. If you try this the batteries will catch on fire. A LiPo charger must be used with LiPo batteries and NiMh chargers can only be used with NiMh batteries.
  3. Keep an eye on your batteries while they’re charging: You can do a lot of things while your battery is charging. All you have to do is be in the same room. Most of the time the battery charges perfectly fine, but there is a slight chance that there can be damage to your RC gear and property so it is a good idea to keep an eye on them.

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How Should You Maintain Your Batteries?

It should go without saying that you need to treat your batteries correctly to get the most life and performance out of them.

LiPo Batteries

These batteries are very sensitive, so you need to take certain precautions when handling and charging them. These batteries need a charger that can use a balance lead that lowers the current at the peak cell voltage. LiPo batteries can be charged at high rates but the safest rate is 1C.

The general rule for charging a LiPo battery is 1 times the battery’s capacity. Try not to leave the LiPo battery unattended. When these batteries aren’t being used, you should keep them in LiPo safe bags.

To maximize LiPo battery life, it is recommended to store them with 3.8v per cell. Some chargers even have a storage charge function to accomplish this, such as the Emax Digital Battery capacity checker.

  • Store your LiPos at 50% charge: When your LiPo batteries aren’t in use, they should be stored at about 50% charge. Any battery that is stored at full charge for more than 10 days will begin to experience a degradation of capacity and voltage.

If you store a pack that is depleted, you won’t have to worry about it as much. It can be stored for about three weeks at this point. After this, it will start to discharge to a point of being overcharged. It is advisable to get a charger that has a “storage charge” function to keep it at 50% capacity all the time.

  • Use low-voltage detection: Newer vehicle systems have a low-voltage detection system. Essentially they slow down or stop your vehicle to alert you that your LiPo pack has to be recharged.

If you don’t select this mode and recharge when it tells you, you run the risk of over-discharging the battery. At the very minimum, this will reduce your performance and take a big chunk of life away from your battery. In the worst-case scenarios, your battery will swell, and it must be thrown out. If this happens, take it to a hobby store so they can dispose of it properly.

  • Keep your packs clean: All batteries can benefit from this. You must repair your NiMh and LiPo promptly and quickly. This includes frayed wires, damaged shrink wrap, worn insulation, etc. If you aren’t able to do this you’re asking for more damage and short circuits.

NiMh Batteries

Although NiMh batteries are one of the most robust batteries, they can still become damaged from overcharging. It is a good idea to buy a high-quality charger to not make these mistakes. They need to be kept in a cool location, and they don’t have to be fully discharged before you recharge them. 

Alkaline Batteries

Alkaline batteries are very hardy batteries because they are usually used in power transmitters. If you aren’t planning on using your RC car for a while, it is recommended that you remove them from your controller for safety.

What Do Battery Labels Mean?

Lots of batteries have very weird markings on them that can be hard to decipher. To learn how to read the markings and information on your battery, you can look at the batteries linked below and their explanations.

HPI Plaza NiMh Battery This example is well labeled. You can see all the core values. This is a 7.2-volt battery with an 1800 mAh capacity and made with Nickel-Metal Hydride chemistry. All these figures are pretty common for a bundled battery. The lower ends of capacity will be around 1800 mAh for a stick pack. If you wanted to have a longer run time, you would swap out the battery for something like 4700 mAh with the same dimensions and connector.
Absima LiPo Battery The 4200 value on this battery shows that the capacity is 2300 mAh. At the end of the label, you can see the 7.4 voltage and the 25 burst rate.
Turnigy Nano-Tech LiPo Battery This example has a ton of information to unpack. On the left you see a 35-70C label; this means that the battery can be discharged continuously for up to 35C and for short surges up to about 70C. On the right, you can see a 3-cell selection has been marked, which means it runs an 11.1-volt setup. This is a high-end battery, so it would be perfect for a high-load RC car.

What Does the “S” Mean?

NiMh and LiPo packs are usually referred by how many cells they have in a pack like 2-cell or 3-cell. You may also read that some LiPo packs will be designated as 2S,3S,4S, etc. The “S” stands for series and this means the cells contained in the pack are connected in “positive to negative”.

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In some instances, the LiPo packs will be connected in series as well as parallel. This will be shown with the letter “P.” A 2S2P LiPo pack, for example, would have two pairs of LiPo cells inside. Both pairs would be wired in parallel (2P) and the two pairs would be wired together in a series (2S). Most RC cars are wired together in a series and referred to as 2S, 3S, and 4S.

What Are Battery Connectors?

All the battery connectors that are used are geared towards a different purpose. There are many different kinds, the following are some of the most significant ones.

  • Tamiya Connector: This is the most common battery connector because it is found in most NiMH batteries. It has a white or sometimes translucent appearance and may feature a lever that unlocks it before it is pulled apart. These connectors are keyed to help installation, but the connectors can also be forced, so make sure you have the right polarization by checking the wire colors. Keep in mind that these connectors are not designed to be used for high current applications such as those in big burst rate LiPo batteries. They may easily overheat if put in these situations.
  • Deans/T Connectors: These connectors can be easily identified as short and chunky. They are also used in lots of high-current applications and can be found in Absima LiPo and HPI Plazma LiPo batteries. They have short plug bodies made of plastic with sprung flat tabs that have continuous contact pressure with the metal prongs. They are also keyed in a way where they only connect one way around.
  • XT60 Connector: These connectors are very common among drone pilots because they are easy to use and they’re keyed so there are no incorrect connections.
  • Traxxas Connectors: The are high-current connectors that are keyed to avoid wrong connections. They also have textured plugs to help removal. Keep in mind that Traxxas has an iD connector with a balance connector makes charging simpler. You can recognize these iD charges by their flat octagonal connector.
  • Molex Picoblade Connector: This connector features two miniature pins on their batteries for micro drones and their HPI Q32 models. Their main objective is to be used on low current chargers like USB powered chargers. Be extra careful when you’re connecting these batteries because the small plugs can be forced together in the wrong way.
  • Bullet Connectors: These connectors are usually referred to as “banana plugs.” Instead of batteries, they are usually found on charger adapters. There are various sizes of diameters that can support these connectors. The higher diameters can handle higher currents, just make sure they are positioned the correct way when they’re plugged in.
  • JST RCY Connector: Most transmitters have these connectors; they are the best for rechargeable battery packs.
  • Balance Connector: Multi-cell batteries have these connectors. They have multi-pin plugs to provide a connector for every cell terminal in the battery so that the voltage can be managed and manipulated individually. When this happens, the charger can discharge a certain cell to balance out the pack. Many beginners forget to connect the plug to the charger when the balance is charging. Keep in mind that there are some chargers that can fill your battery with this type of low current connection.

How Many Amps Do You Need?

You may now be thinking that more amps are better. Why shouldn’t you just get a 10-amp charger and full-throttle your battery to full charge in three minutes? In terms of mathematics, this method makes perfect sense. However, batteries aren’t that simple. If you tried to charge the battery that fast, it would start smoking.

When you charge your battery at lower amps, it extends its life. This means it can be fully charged more times before it finally stops working.

A general rule to keep in mind is that LiPo packs should be charged at the same rate as their capacity. Say you had a 4000mAh battery, at a maximum, you should charge it with 4 amps. Simply take the battery capacity and divide it by 1000 to find the optimal charging rate.

You can charge LiPos at a higher rate of “1C,” but the life will also be reduced. If you had a 5000mAh battery and you charged it regularly with 10 amps, you would only get 100 uses out of it whereas you would have had 200 uses from charging it with 5 amps.

NiMH packs are much more tolerant of higher-amp charging but it is better to get in a routine of charging between 1-1.5C. If you only charge at a higher rate a few times in extreme circumstances it won’t hurt the battery life very much but be careful not to do this too often.

What Is LiPo Balancing? Is It Worth It?

If you buy a LiPo charger you must make sure that it has the ability to balance the cells in the pack while it is being charged. To be “balanced,” the cells in the pack have the same voltage.

A 2-cell 7.4-volt pack is considered balanced if both cells can provide 3.7 volts. Packs that don’t have balanced cells will have voltages that drift and will only last for a few charge and discharge cycles. This matters because LiPo cells can’t handle being overcharged as well as other batteries.

Fortunately, it is very easy to balance your charger. All you have to do is keep the balance plug plugged into the charger. In some chargers, there is a built-in balance plug port, and on some LiPo packs there is a tiny white connector that is known as the “balance plug.”

It is wired so that the charger can read all of the cell’s voltage individually, and it can charge it according to its individual needs.

Learn More

If you are wanting to learn more about the different types of RC batteries and how that applies to your vehicle then check out the video below. It is all about understanding RC batteries.

The Takeaway

Now that you know all of this new information, it’s time to go shopping for your best batteries and chargers. Gather all your key information, such as manufacturer, model name and number, before beginning your search. Jot down your budget and requirements and then refer to the list again. You’ll have your new battery and be racing your car in no time!

Matt Robbs

I love to spend time with my wife and 3 kids. There is no better way to get them off the couch and outside than for us to grab the RC cars or boat and enjoy the sunshine!

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