Can a brushed RC motor handle 3S (A Full Guide)

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Brushed RC motors aren’t as powerful as their brushless counterparts, especially when it involves speed levels.

In fact, your brushed RC motor has a specific torque band and has been designed to run quite a specific battery voltage range, gearing, winding and poles. 

This article explores what happens when you use a 3S battery on your brushed RC motor.
Technically, a brushed RC motor can handle a 3S battery, but this possibility is dependent on several factors. 

Can I use 3s LiPo on a brushed motor?

You can use a 3S LiPo on a brushed motor.
However, the 3 cell LiPo offers a pretty good jump in rpm with over 37,000 rpm in the motor, and those high speeds will kill the brushes of your brushed motor faster when you use them for long and even cause the bearings to fail. 

Apart from this, 3S LiPo batteries work similarly to the 7-cell batteries used in the older days. They have more power than a 3000 6-cell NiMH battery, and their power capacity can eventually heat up and wear out your motor fast.
Regardless of this, they never blow up your RC car. 

Will all types of brushed RC motors handle 3s?

Even if your ESC can handle the extra voltage when using a higher voltage battery, you need to consider the brushes and commutator because they probably won’t escape the damage. 

In simple terms, not all brushed RC motors can handle a 3S battery.
For instance, most 540 20T brushed motors have their kV ratings tuned to 6 cells NiMh or 2S LiPos. On the other hand, the mega 550 12T 550 Brushed motors are usually rated 10.8v, which would generally suit a 2S. When you use these motors on a 3s, they will run hot and cause the brushes to damage. 

What voltage can a brushed motor handle?

Some brushed motors can last under 14v if you use stock motors and ESCs, but they won’t last that long. 

On the other hand, most brushed motors run on voltage capacity up to 8.4v, 9.6v and 11.1v, but they also don’t last long before it burns out. 

Thus, the nominal operating voltage a brushed motor can handle is between 4.8v to 9.6v

Should you limit the current?

If you’re planning to use a 3S battery on a brushed motor, you also need to consider if the gears on the transmission can handle that extra power. 3S batteries require strong transmission levels. 

As you run your RC vehicle and increase the speed, you generate more power for the wheels. For a brushed motor, these speed levels could damage your brushes and bearings. Hence, you’ll need to optimize the gearing to find the right balance between power and RPMs.
In essence, you need to limit the current. 

It’s always best to have your RC slightly underpowered than over-geared to avoid damages to the brushes, commuters and bearings.  

Will your brushed ESC be able to handle 3s?

All ESCs, whether brushed or brushless, is LiPo “compatible” as long as you run them under the maximum voltage input. 

However, a brushed ESC will not work effectively when using a 3S battery, especially during racing. While 3S batteries offer high-speed levels, running that many volts can eat up the brushes fairly quickly and burn out the ESC. 

Notwithstanding this, if you own a crawler, the brushed ESC might be able to handle the 3S. 

Read more: What ESC Can Handle 3S

How many volts are 3s batteries?

The voltage of your battery pack will determine how fast your RC vehicle is; hence, it directly affects your motor’s RPM. 

3S LiPo batteries have 3 rechargeable cells connected in series. Each of these cells has a nominal voltage ranging from 3.7 volts, in some cases, to 3.6 volts. Their maximum charging voltage range is 4.2 volts, plus a cut-off voltage level between 2.7 and 3.0 volts (this range differs from the brand model you use). 

Hence, to calculate the voltage of the 3S batteries in series, we need to sum the individual voltage drops. 

Thus, the nominal voltage = R1 + R2 + R3 (the same goes for the charging and cut-off voltage).

A 3S LiPo battery will feature a nominal voltage of 11.1 volts and sometimes 10.8 volts depending on the brand. The maximum charging voltage will equal 12.6 volts, while the cut-off voltage will range between 8.1 to 9 volts.

Will a 3s LiPo run your brushed motor faster?

If you put a 3S LiPo into a vehicle set up for brushed motors, they will run faster and at higher rpm. However, you will eventually burn out the motor. 

LiPos tend to hold voltage better under load. Hence when you drive your RC car, your motor draws more amps making the motor heat and burn electrical components. The best way to safely run your brushed motor faster with a 3S LiPo battery is to use a stock motor, ESC and smaller pinon gear because, without these, your RC car wouldn’t run longer than five minutes without them breaking. 

Conclusion

So, can a brushed motor handle 3S LiPo batteries?

The simple answer is yes, but you’ll have to consider getting stock ESCs and motors as the high nominal voltage ratings at 11.1V and speed a 3S LiPo battery brings to your RC car can easily burn out the brushes, commuters and bearings.

If you’re considering getting a new battery for your RC car that uses a brushed motor, hopefully, this article will help you select a battery that’s compatible with your brushed RC motor.