R/C cars LiPo Batteries

Quick Fixes to RC Car Battery Issues

Published: June 18, 2019


Categories: R/C Cars

Is your car running very slowly, not running at all, or suddenly stopping? You probably have a battery issue. These problems can plague novices and pros alike. This article deals with the most common car battery issues and quick fixes.

What Battery Do I Have?

Most batteries have a printed marking indicating what type they are. We’ve listed the different types below:
⦁ Lithium-ion polymer: Lightweight, high energy density, needs smart charger, consistent powerful discharge, most volatile option.
⦁ Nickel Cadmium: Memory effect issues, rechargeable, not very environmentally friendly.
⦁ Alkaline: Most AA batteries are alkaline. Alkaline batteries are not rechargeable.
⦁ Nickel Metal Hydride: Easy maintenance, solid recharging (can be topped off).
Cheaper RC cars normally come with low-cost batteries of the last variety, while higher end models usually aren’t sold with batteries or chargers. If you go for a costlier model, you can buy batteries and a charger separately or reuse the existing hardware.
Now, let’s get to the most common issues!

Issue 1: Reading Battery Labels Incorrectly

Reading battery labels can be a daunting task. Below, we’ve listed three commonly seen labels and how to decipher them.

LiPo Battery 4200

The number reflects the rating: 4200mAh/31.1Wh. At the end of the label, you’ll see the number 7.4, which indicates 7.4v LiPo technology.

NiMh Battery 7.2

7.2 indicates the voltage. The description of the batteries should always list the capacity in mAh and in watt hours, which is the capacity divided by the voltage. Capacity of 1800 mAh is on the lower end. If you’re looking for longer operation time, we recommend replacing a lower-capacity battery with a higher-capacity one, like 4700mAh.

Nano-Tech LiPo 35-70c

This number refers to the fact that you can discharge the battery up to 35C for an extended period of time and up to 70c for short surges. A 3-cell option is great for a high-load vehicle.
Quick fix: Read labels carefully (now that you know more about them) and make sure you’re using the same connector and dimensions. Misreading labels and using different connectors and sizes is a common cause of pesky problems.

Issue 2: You Didn’t Switch the RC Car On!

You’d be surprised at how often this happens. Sometimes, the issue is something as simple as not switching the car and the transmitter on, if the latter is equipped with a switch.
Quick fix: On certain vehicle models, it can be hard to see the direction of the batteries. Use a flashlight. If the car still won’t switch on and you want to check inside, make sure the switches are in the off position first.

Issue 3: Batteries Are Missing, Old, Damaged, or Installed Wrong

Check to see if the batteries are facing the right direction and well-seated in the right slots. If the car still won’t start, try some fresh batteries or a more expensive brand. Make sure your battery pack is fully charged.
If the battery compartment has been exposed to air and moisture or the car hasn’t been used in a while, there might be rust. Clean the contacts and replace the batteries. Also, check the RC and transmitter.
Issue 4: Are You Taking Good Care of the Batteries?
Your battery life depends on maintenance. Are you using and storing them properly? If you want to get the most out of them, here are a few things to keep in mind.

Low-Voltage Detection

Most modern vehicles have a low-voltage cutoff, a low-voltage detection system, or what is known as “LiPo mode.” These are different terms for the same mechanism; one that decelerates or stops your vehicle when your batteries need changing. If you’re using a LiPo (lithium-ion polymer), always select this mode. Otherwise, you risk over-discharging it. This will limit the battery’s life span and performance at best and lead it to “balloon” (swell up) at worst. In the latter scenario, you’ll need to throw it away.

If your low-voltage cutoff system is adjustable, set it to 3.3 volts per cell. This will make sure you get the most out of the battery. Your car will tend to slow or stop sooner in a run, but the additional runs you get over its extended life span will more than make up for this.

Are You Keeping The Batteries Clean?

Make sure you address issues like bum connectors, worn insulation, frayed wires, and damaged shrink wrap promptly regardless of what battery type you’re using. You may be faced with a short circuit if you don’t.
Are You Storing Them Right?

If you’re using LiPo batteries, know they should be about 50% charged when you’re not operating the vehicle. If you aren’t planning on using the car for a week or more, don’t store it fully charged because its voltage and overall capacity will start deteriorating, and the process is irreversible.

Why Do They Take So Long to Charge?

Probably because the charger didn’t cost very much. Some examples of low-output chargers include those usually included with the car and those that connect to the balance port. As a result, a battery with capacity of 330mA will take up to 12 hours to charge fully. This isn’t optimal and we’d suggest spending a bit more on an intelligent charger.
Why Should I Spend So Much on Batteries?
You’ve heard you shouldn’t cut corners when it comes to quality, and it’s true. But why? Like the British say, “We’re not rich enough to buy cheap goods.” Cheap batteries will be depleted soon, their life span is short, and before you know it, you’ll have to invest in new ones. A quality battery, on the other hand, will let you and your loved ones enjoy the car long-term without compromising on performance. Quality batteries are rechargeable, durable, and robust. They also take less time to charge.

Final Tips
Before you buy any battery, check the vehicle plug carefully to see if it’s the right fit. Always make sure you can have it exchanged in case something doesn’t work out.