ON-BOARD POWER SUPPLY UNIT FOR CYCLE

Onboard electrical power supply unit (1) for a vehicle, comprising: - an elongated battery of electrical accumulators (2) according to an elongation direction (I-l), - a charger (3), fixed to a first end of the battery of electrical accumulators, having an outlet connected to said battery of electrical accumulators, and having an inlet comprising an electrical connection cable (4), of which a first end is fixed and permanently connected to the charger, and of which a second end is free and provided with a male plug (10) for connection to an external source of electrical energy, - a plug receptacle (5), provided at a second end of the battery of electrical accumulators (2) and shaped to receive and retain said male plug (10) in a rest position in which the electrical connection cable (4) runs alongside said battery of electrical accumulators (2).