Battery Knapsack Sprayer

A battery knapsack sprayer is a backpack-mounted HDPE tank with an on-board rechargeable battery driving an electric diaphragm pump. It is the most widely owned plant-protection implement in Indian smallholdings because it eliminates the manual lever-pumping of older hydraulic knapsack designs while remaining far cheaper than an engine-driven sprayer.

Function

A 12-volt diaphragm pump draws spray liquid from the tank and pressurises a hand-held lance with selectable nozzles. The operator squeezes a trigger valve to release spray; pressure and flow are stable as long as the battery holds charge, giving better droplet uniformity than a hand-lever pump.

Design and specifications

A typical unit has a 16-litre HDPE tank, a 12 V x 8-12 Ah lead-acid or lithium-ion battery, a diaphragm pump delivering 0.9-3.0 L/min at 0.15-0.40 MPa (single or double motor), a four-nozzle kit (flat fan, hollow cone, flood and sanitiser) and a metal telescopic lance. Empty weight is 7-7.5 kg, and a full charge supports roughly three hours of spraying (15-18 tank-fills).

Operation

The unit is filled, the operator straps it on using padded adjustable straps, and the spray pattern is selected at the nozzle turret. Charging takes six to eight hours from a wall outlet. Compared with a 4 Stroke Knapsack Sprayer it is quieter and lower-maintenance, but cannot reach the pressure needed for tall orchard canopies that demand a Mist Blower or Portable Petrol Sprayer.

Subsidy and adoption

Battery knapsack sprayers are widely subsidised under SMAM and state plant-protection-equipment lists, with 40-50% subsidy for individual farmers. Adoption is essentially universal in Indian rainfed and irrigated field crops and in vegetable cultivation.

References

ECO 12V Battery Knapsack Sprayer. Fujiaka.
16-Litre Backpack Battery Sprayer. Sve Agritech.