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6 Reasons Why Your RC Car Battery Won’t Charge

Gadgets can be really cool when they want to cooperate, but sometimes they can be downright frustrating. RC cars are relatively popular but can pose a lot of issues if they are not taken care of properly or adequately equipped with the necessary elements.  

Why will your RC car battery not charge? The battery will not charge because of a discrepancy within the circuits that may require minor maintenance. Rather than going out to buy a new battery, there is also the possibility of it not being a battery issue, but rather something wrong with the charger itself.

Since an RC car, for the most part, is a toy, it should not take as much time or money to fix the issues as if it were a real (electric) car. Most issues found can be resolved as long as you know what possible ailment it is. Here are 6 reasons why your RC car battery will not charge:

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1. Overcharged Battery 

Especially with LiPo batteries that already do not last long, overcharging a battery can really hurt it. Pay attention to the voltage, and the exact amount of time it takes to fully charge it. Once it has been charged, take it off. Do not let it sit there longer than it needs to, or else it can cause permanent damage. 

The symptoms of an overcharged LiPo battery begins when it expands, is swollen and/or shaped oddly. If you take notice of this, you should throw it out right away and get a new one. If the battery was never taken off of the charger in time after the initial swelling, the battery will then proceed to catch on fire, resulting in acidic fumes and major destruction.

2. Severed Connection

Check the wires to make sure they are all intact and connected where they need to be. Refer to a diagram if you are not sure what the connection is supposed to look like. If you had to take stuff apart before to fix another issue, then either that was not the main issue, or you have connected something to the wrong place, and it needs to be switched.

If you have had your model for a while and use it often, it is likely that the wires are beginning to fray and will need to be repaired before you can use it again. There should be low resistance; if it is still not charging, then you might have to seek the help of a more experienced person. 

3. Incorrect Voltage

New batteries may take some time to break into, give it about 3 charges until it reaches its “peak” voltage. Use a multimeter or a voltmeter to check the voltage, if it still has not reached where it should be, use a storage discharger, and then try charging it again.

Keep an eye on the ESC voltage cutout so that it does not go below the designated voltage. If you are not planning on using the car any time soon, take the batteries out and store them elsewhere to prevent corrosion or over-discharging.

“Overvoltage protection” occurs when the RC vehicle is supplied with an overabundance of voltage way higher than the necessary limit, causing the entire thing to shut down or fry out the system.

4. Not Charged Long Enough

Each brand and model may differ in how long it takes to charge. For a 7.2 voltage battery, it takes about 3 hours to fully charge. Anything less than that will result in decreased driving time, leading you to believe that the RC car is not holding a charge or charging at all. 

5. Water Exposure 

Low levels of humidity would not do too much damage, but if your RC car has been submerged or doused in water, then that will create some complications. RC cars are not built to withstand moisture like RC boats are. Be careful to not drive it into any bodies of water or store it near any kind of splash zone.

6. Bad Wiring

If wires are not where they are meant to be, then this could be why you are experiencing problems with the charging. Sometimes you may have to solder the wires when you first receive the RC car, especially with the models that take LiPo batteries.

Charging Precautions

Along with battery maintenance, in order to ensure the RC vehicle’s longevity and safety, you also need to take certain charging precautions. If you do not have problems with charging now, you want to make sure that you never do. And while the problem may end up being inevitable, there are still steps you can take to delay it as long as possible. 

When wanting to make sure of the tools or accessories you will need to accommodate your RC vehicle, the determining factor is most often the battery. Because there are different types of batteries, each requires a different level and method of maintenance so that there are no charging issues in the future. 

Along with each of the accessories, you will need to look out for and have an understanding of the various functions needed to produce the best result, there is with the least amount of resistance or complications.


There should always be a label on the battery that lets you know which battery it is you purchased or that came with the model when you first got it. The type of battery will determine what charging method it will require. The higher-priced models are more likely to take LiPo batteries, but will not come packaged with them or the charger. 

While the cheaper models take a NiMH or, in some cases, a Ni-Cd battery and will come with the charger already packaged. The labels will also tell you the watt-hours and mAh (milliamp hours) which is the unit that measures the overall electric power that it accumulates as time passes by and it is continuously recharged.

If you have a LiPo battery pack, do not, under any circumstances, use a different charger for it. Each charger is made specifically for the element of the battery. If it is a LiPo battery pack, then you will want a charger made for lithium-ion polymer, not Nickel Metal Hydride or Nickel Cadmium. This also avoids a fire since lithium-ion polymer is both sensitive and extremely flammable.

However, there are quite a bit of chargers that will allow you to charge more than one type of battery and also charge many at a time. So, if you have more than one RC model of differing calibers then it might be worth investing in a single ambiguous charger. I have given the names of a few in the last section of this article.


Hook up the proper connector if the charger and battery do not already share one. If you do not know how to do it, seek out someone who can. Careless wires will do you more harm than good, especially if the clips or wires are exposed. Clips and wires that are exposed can also start a fire.  


Do not leave your RC vehicle of any sort unattended while charging; this also goes for an RC vessel or RC aircraft. You do not want to take a chance of you forgetting about it and it overcharging. Once can be enough for it to combust and start a fire that you or whoever else is in the vicinity, may never walk out of. Wherever you charge them, make sure it is at room temperature.

Pay attention to how long it takes for the vehicle to fully charge, so for the times that you absolutely must walk away from it; you can set an alarm to remind you to check and see if the batteries have begun to swell. 

Some people place a smoke detector directly above the charging area or even a baby monitor to keep track of any kind of weird sounds coming from the battery. While the best thing to do is to keep watch over it first hand, we are human and have other things to do.


The capacity is typically portrayed in mAh (milliamp hours). The higher the milliamp hours, the higher the duration of run time with each charge, but it will also take more time in order to charge it. For the total amount of milliamps, divide the mAh by 1,000 because it is 1/1000 of an amp.

Voltage (Detection)

The cells determine the voltage of batteries packs. For LiPo, they have about 3.7 bolts per single cell but come in packs of 2 or 3. That is overall 7.4 volts or 11.1 volts. For NiMH, they are 1.2 volts but have about 6 to 7 cells which would be a total of 7.2 volts or 8.4 volts. Each RC model is designed differently, and some have the capability to use packs with more cells.

When using LiPo batteries, switch on the low-voltage detection to tell you when the pack needs to be recharged. If this detection is not on, you may over-discharge the battery. When this happens, the batteries will lose power capacity and lifespan, and they may also become swollen.

If you are able to adjust the setting to stop at 3.3 volts or more, you will be able to obtain the greatest number of runs, but less run time during each session. However, each run will be regained the more runs you have throughout the battery’s lifespan.

If this battery is damaged in any way, refrain from using it or if it includes a cell with a voltage more than 3.3v (less than 9.9v for a 3-cell or 11.1v battery). Also, do not charge LiPo batteries if they are still in the car. By acquiring a balance connector, you are enabling the ability to reach and monitor each cell individually. Be sure the cell count is the correct one, or else it will not be a good outcome. 

Charging and Discharging

Charge on a level surface that is not wood, carpet, or cloth. Only charge one pack at a time, and no more than one. By charging multiple at a time, it can result in the inability to recognize the battery and charge incorrectly. The rating of the Ah will give you a clear indication of what amps to charge at. 

The amps are going to be how quickly the current will move inside the battery. It is advisable to charge them at the same rate as the mAh or on 1C—the faster you try to charge, the more likely you are to lessen the life of the battery. Each cell should be balanced out with the rest of them before charging.

LiPo’s are known as a dangerous good because of the high density mixed with the type of electrolyte it contains; they are highly flammable. Both their charge and discharge rates are high, another reason why this is the most popular battery, and they do not have a memory effect like the other rechargeable batteries. 

Improper care to the LiPo battery can really alter its efficiency and life expectancy, which is why it is important for you to take extra precautions when handling this type of battery pack specifically. A LiPo battery needs to be charged with both a power and balance lead to make sure that every cell that is in the battery pack is charged to the same voltage.

Suppose that you did everything properly and things still go wrong, for these cases, it is best to prepare in advance by setting up fire protection around the area you are charging in. You can use a fireproof charging bag, a metal box with a bag of sand on top, or have a class D fire extinguisher at the ready.

Once is enough to make a LiPo battery swell, whether from overcharging or over-discharging. Some might still try and use it depending on how badly it swells, as long as it can still fit into the car physically, but the safest thing to do is to get rid of it.

The batteries that do not come in protective plastic are the ones left vulnerable to accidental puncture by a tool or other sharp objects. They are also more likely to become damaged in a crash, and if this occurs, you will definitely want to inspect the battery when it is charging to make sure it still «is.

Here is a short video of what can happen if you do not follow the correct procedure and your battery explodes or catches fire. 

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 Top RC Chargers 

Here are some top chargers. Most are able to charge different types of batteries whether they are lithium or Nickel-based, so you do not have to worry about having to purchase separate chargers. Plus, they can charge more than one at a time among other cool features to make sure that your charging experience is as safe and reliable as possible.

–               Passport Ultra Force 220W Touch Battery Charger for $139.99 – This is compatible with both lithium packs 1 to 6 cells and nickel-based batteries 1 to 15 cells. It can also charge smartphones and tablets. An XH balance board, power cord, and charge cord come in the package.

–               Passport Duo 400W Dual AC/DC Charger for $269.99 – Possesses 400W and can charge two batteries up to 10-amps each at the same time. It can also charge both lithium and nickel-based packs up to 15 cells. It comes with a pair of JST-XH balance boards and banana-to-EC3 adapter cables and a power cord.

–               Prophet Sport Quad 4 X 100W AC/DC Charger for $239.99 – Takes on 1S TO 6S lithium batteries and 1 to 15 Nickel-based batteries. You can also charge 4 individual 10-amps each channel. This charger features reverse polarity, over-temperature protection, short circuit, and low input voltage.

–               Pulsar Touch Competition Charger for $189.99 – A backlit blue touchscreen and five customizable charging profiles. A 12-amp charge rate, compatible with 8-cell Nickel batteries and 4S sized lithium packs. It also features a LiPo balancer that detects and balances out the difference in the cells, giving the battery an elongated lifespan.

–               Advantage Touch Duo HV AC/DC Charger for $249.99 – Colored 4-inch touch screen with 200W mixed power supply that gives charge currents of 10A. It also has the capability to charge, discharge, balance, cycle, or store any mixture of batteries all at the same time.

–               Reedy 1216-C2 Dual AC/DC Competition Balance Charger for $174.99 – You can charge both 1 to 6S lithium packs, and 1 to 15 cell Nickel-based packs up to 12-amps. You can store 10 different charge profiles on a channel. 

–               Venom Pro Quad 100W X4 AC/DC 7A LiPo/ LiHV/NiMH Balance Charger for $229.99 – Possesses two 2.3-amp USB ports for charging, 5 button control interface and a backlit LCD screen. It supports both lithium and nickel-based packs.

–               H4 DC/DC Four-Port Multi-Charger for $274.99 – Encased in aluminum, this charger features a backlit LCD screen. Channels with 8-amps for both lithium and Nickel-based batteries. The lithium is up to 6S sized packs and the Nickel-based is up to 12 cells and allows each output to have temperature sensors installed. 


No matter what problems you are having with your batteries, please be sure to be safe. There are many options out there for batteries, and which ones are the best for you. Be sure to check all your connections and make sure you are charging them properly. You will never want to leave the batteries unattended while they are charging, or around any surface that is flammable. Although you may think it is no big deal and it will never happen, there is always a small chance it could happen to you.