For electrical weed control to become an efficient complement to herbicides and tillage, treatment times and energy use must be reduced. Four pot experiments were conducted, testing different voltage levels (5–20 kilovolts) and exposure times (0.2–13.5 s) to find the most efficient combination for weed control. Experiments tested (1) seedlings of the annual dicotyledon Tripleurospermum inodorum and the annual grass Avena fatua, treated at 18 and 14 days after sowing, respectively; (2) adult T. inodorum and A. fatua plants, treated at 6 weeks after sowing; (3) established plants of the perennial grass Elymus repens, cut 34 days after emergence and treated 14 days after the cut; (4) E. repens plants treated 17 days after planting. Five kilovolts was equally or more effective than higher voltage levels regardless of plant size. Five kilovolts for 0.2 s resulted in 100% mortality of T. inodorum seedlings and >99% reduction of A. fatua seedling shoot biomass. Five kilovolts for >1.5 s reduced the aboveground biomass of adult T. inodorum plants by >80%, compared to control. Five kilovolts for 4.5 s reduced the vegetative biomass of adult A. fatua plants by 47%, compared to control. Five kilovolts for 0.2 s killed the shoots of small E. repens plants, reducing shoot and rhizome biomass by 75% and 28%, respectively, compared to control. No treatment significantly reduced the established E. repens plants. In conclusion, 5 kilovolts for 0.2 s effectively kills small annual weeds and forces E. repens to resprout, but established plants need longer exposure times.