Brushless motor replacements for brushed DC motors have been in development for many years and promise to dramatically improve drivetrain performance.

A brushless retrofit has many challenges including the increased cost of the electronic commutator and the need to upgrade the battery. The brushless motor takes DC power from a battery pack and inverts into 3-phase Vrms power generating a rotating magnetic field (RMF). By comparison, the brushed motor mechanically inverts DC power into Vrms RMF using copper segmented commutator bars and graphite brushes with increased mechanical wear and electrical arcing.

Brushless motors operate with a better rate of acceleration, efficiency, reliability, top speed and regen characteristics all of which are programmable. The performance characteristics of brushless motors are a leap above its brushed counterpart. Brushless motors have been slow to come to market because of the engineering & programming complexity of the inverter/speed controller and the increased cost as well as the need to increase the battery voltage due to the difference in form factor.

When upgrading a 12Vrms brushed motor to brushless, the battery voltage must be increased by a form factor of 1.35 x DC voltage e.g., 12Vrms x 1.35 = 16 VDC Batt. By comparison, a brushed DC motor’s mechanical commutator converts DC power into ‘multi-phase’ square waves having a form factor of nearly 1.0 x 12Vrms = 12V Batt.

Brushless motors do not require mechanical commutation and are more efficient than its brushed DC counterpart by a factor of 20 to 40%, depending on the load. It creates significantly more torque, faster acceleration and since it has no mechanical connections, other than the ball bearings at each end of the rotor, maintenance is minimal. Available DC ‘brushed’ systems cannot deliver all these features.