BATTERY POWERED PRESSURE WASHER

A pressure washer includes a water pump, a spray gun fluidly coupled to an outlet of the water pump, an electric motor coupled to the water pump to drive the water pump, a battery module configured to provide battery electricity, an electrical plug configured to receive grid electricity from a power outlet, and a power management system electrically connected to the battery module, the electrical plug, and the electric motor. The power management system is configured to selectively provide battery electricity from the battery module and grid electricity from the electrical plug to the electric motor to drive the water pump.

BACKGROUND

The present invention relates generally to the field of pressure washers, and in particular, to the field of battery powered pressure washers.

SUMMARY

One embodiment of the invention relates to a pressure washer including a water pump, a spray gun fluidly coupled to an outlet of the water pump, an electric motor coupled to the water pump to drive the water pump, a battery module configured to provide battery electricity, an electrical plug configured to receive grid electricity from a power outlet, and a power management system. The power management system is electrically connected to the battery module, the electrical plug, and the electric motor. The power management system is configured to selectively provide battery electricity from the battery module and grid electricity from the electrical plug to the electric motor to drive the water pump. In some embodiments, the battery electricity current is at least 20 A. In some embodiments, a user interface of the pressure washer includes a battery charge indicator displaying at least one of a charge of the battery module and an estimated remaining run time. In some embodiments, the pressure washer further includes a base unit configured to support the water pump, the electric motor, and the battery module, where the user interface is a component of the base unit. In some embodiments, the user interface is a component of the spray gun. In some embodiments, the user interface is coupled to the spray gun. In some embodiments, the electrical plug is a component of the base unit and is a male plug. In some embodiments, the spray gun includes a trigger configured to control a flow rate of water through the spray gun. In some embodiments, the pressure washer further includes a base unit configured to support the water pump, the electric motor, and the battery module, wherein the user interface is coupled to the base unit. In some embodiments, the pressure washer further includes an unloading sensor, wherein the unloading sensor is a pressure sensor and the power management system is configured to stop the electric motor in response to a pressure sensed by the unloading sensor exceeding a threshold level. In some embodiments, the pressure washer further includes an unloading sensor, wherein the unloading sensor is a flow sensor and the power management system is configured to stop the electric motor in response to a flow rate sensed by the unloading sensor falling below a threshold level. In some embodiments, the water pump further includes an unloading flow path fluidly coupling the outlet of the water pump to an inlet of the water pump. In some embodiments, the water pump does not include an unloading flow path fluidly coupling the outlet of the water pump to an inlet of the water pump. In some embodiments, the power management system includes a power converter, where the electric motor is a direct current motor, and where the power converter converts alternating current from the electrical plug to direct current applied to the electric motor. In some embodiments, the power management system includes a power inverter where the electric motor is an alternating current motor and the power inverter converts direct current from the battery module to alternating current applied to the electric motor. In some embodiments, the electric motor is a universal motor.

Another embodiment of the invention relates to a backpack pressure washer including a water pump, an electric motor coupled to the water pump to drive the water pump, a spray gun fluidly coupled to an outlet of the water pump, a battery module configured to selectively provide battery electricity to the electric motor, and a backpack supporting the water pump, the electric motor, and the battery module. The backpack is configured to support a portion of a weight of the backpack pressure washer on at least one shoulder of a user. In some embodiments, the water pump is a self-priming water pump.

Another embodiment of the invention relates to a pressure washer including a water pump, an electric motor coupled to the water pump to drive the water pump, at least two battery modules configured to provide battery electricity, and a power management system electrically connected to the at least two battery modules and configured to selectively provide battery electricity from the battery modules to the electric motor.

Another embodiment of the invention relates to a handheld pressure washer including a water pump, an electric motor coupled to the water pump to drive the water pump, a nozzle fluidly coupled to an outlet of the water pump, a battery module configured to provide battery electricity to the electric motor, and a spray gun unit, wherein the water pump, the electric motor, and the nozzle, are components of the spray gun unit. In some embodiments, the handheld pressure washer further includes a receptacle configured to receive battery electricity from the battery module, wherein the receptacle provides battery electricity to the electric motor, where the receptacle receives the battery module, and where the battery module is removable from the receptacle without the use of tools.

DETAILED DESCRIPTION

A pressure washer provides a pressurized spray of water. The pressure washer includes a water pump driven by an electric motor powered at least in part by one or more battery modules. A power management system varies the flow of battery electricity from one or more battery modules to the electric motor to vary the characteristics of the pressurized spray. The power management system may connect two or more battery modules in series or parallel in order to extend the battery life of the pressure washer or the maximum rated pressure of the pressurized spray. In some embodiments, the power management system further receives grid electricity from a power outlet and selectively provides the electric motor with one or both of the grid electricity and the battery electricity. This provides a user with the option to maneuver the pressure washer without being connected to the power outlet or to connect to the standard power outlet to run for an extended period of time. Additionally, power can be drawn from both the battery modules and the power outlet to increase the maximum rated pressure of the pressurized spray. In some embodiments, the pressure washer includes a base unit that supports the battery modules, the pump, and the electric motor on wheels or a backpack connected to a spray gun by a high-pressure hose. In other embodiments, the high-pressure hose is omitted and the water pump, the electric motor, the battery modules, and a nozzle are incorporated into a single spray gun unit.

Referring toFIGS. 1A and 1B, a pressure washer100is shown according to exemplary embodiments. The pressure washer100includes a support structure102. The support structure102supports and houses the other components of the pressure washer100. In some embodiments, the support structure102is sealed (i.e., waterproof) to prevent water from entering the support structure102and damaging any of the other components inside. In some embodiments, the individual components are waterproof. In some embodiments, the support structure may include one or both of an open frame (in the manner of many conventional gas powered pressure washers) and a housing. By way of example, the support structure102may include a number of structural tubular frame members with a plastic housing that extends between the frame members. The support structure102may incorporate a device for facilitating transportation of the pressure washer100(e.g., handles, straps, wheels, slides, etc.). The support structure102may incorporate devices for storing other objects in or attaching other objects to the pressure washer100(e.g., pockets, clips, shelves, etc.). In some embodiments, the support structure102is included in a base unit that is separated from a spray gun by a high-pressure hose (discussed below) and supports a number of pumping and electrical components. In other embodiments, all of the pumping, electrical, and spraying components of the pressure washer100are components of a spray gun unit (discussed below).

Referring again toFIGS. 1A and 1B, the pressure washer100further includes a water pump110. The water pump110may be any variety of pumps capable of pumping a liquid (e.g., a centrifugal pump, a positive displacement pump, etc.). The water pump110draws in low-pressure water at the inlet112of the water pump110, and expels pressurized (i.e., high-pressure) water at the outlet114of the water pump110. The inlet112is fluidly coupled to a low-pressure water source116. In the embodiments shown inFIGS. 1A and 1B, the low-pressure water source116is a municipal water source. In other embodiments, the low-pressure water source116may be a source configured to contain a volume of liquid (e.g., a rain barrel, a bucket, an on-board reservoir, etc.). In some such embodiments, the water pump110is a self-priming pump to facilitate drawing water from a source with little or no head pressure. In other embodiments, the water pump110is not self-priming. The pressure washer100may include an inlet fitting118(e.g., a garden hose fitting, a quick disconnect fitting, etc.) coupled to the support structure102to facilitate connection to the low-pressure water source116(e.g., using a garden or other low-pressure hose). In some embodiments, the outlet114of the water pump110is fluidly coupled to an outlet fitting120(i.e., a quick disconnect fitting) coupled to the support structure102.

As shown inFIGS. 1A and 1B, the outlet fitting120is fluidly coupled to a spray gun130by means of a high-pressure hose132. The high-pressure hose132may include corresponding fittings (e.g., quick-disconnect fittings) on one or both ends to fluidly couple to the outlet fitting120and the spray gun130. The spray gun130includes a trigger134configured to control a flow rate of water through the spray gun130and a nozzle136. In some embodiments, the trigger134is biased into a neutral position by a biasing force (e.g., from a spring or other biasing member). The spray gun130is fluidly coupled to the outlet114of the water pump110such that the nozzle136is also fluidly coupled to the outlet114. The nozzle136is positioned to act as an outlet to the spray gun130(i.e. a spray gun outlet). In some embodiments, the nozzle136may be interchangeable with other nozzles having differing spray patterns and/or pressure. In other embodiments, the nozzle136is a turret that can be rotated to select between a number of different nozzles. In some embodiments, the spray gun130further includes a valve138disposed along a flow path between the outlet114and the nozzle136. The valve138is configured to variably restrict the flow along the flow path based upon the position of the trigger134. By way of example, when the trigger134is in the neutral position, the valve138may completely prevent flow along the flow path. By way of another example, the valve138may open (i.e., lessen the restriction on the flow) as the trigger134moves farther from the neutral position.

Referring again toFIGS. 1A and 1B, an electric motor140drives the water pump110. Electric motor140may be an alternating current (AC) motor, a direct current (DC) motor, or a universal motor (i.e., a motor that accepts both AC power and DC power). Battery electricity is provided to the pressure washer100by one or more battery modules142. The battery modules142may include various numbers and types (lithium-ion, lead acid, etc.) of battery cells in various configurations (e.g., some cells connected in series and some cells connected in parallel) to achieve the desired battery characteristics (e.g., amp-hour rating, voltage, weight, etc.). In some embodiments, the one or more battery modules142are contained within and/or coupled to the support structure102. In other embodiments, the one or more battery modules142are each received by a receptacle144. Receptacles144support the battery modules142and are electrically connected to the battery modules142. In some embodiments, the receptacles144are configured to facilitate removal of the battery modules142without the use of tools. By way of example, the receptacles144may include springs to bias the battery modules142out of the receptacles144and latches to selectively hold the battery modules142in the receptacles144. In some embodiments, the battery modules142are hot swappable (i.e., one or more of the battery modules142may be removed or replaced while the pressure washer100is in operation). The receptacles144may include seals to waterproof the connections between the receptacles144and the battery modules142.

The battery modules142can be used in other portable power equipment as well (e.g., string trimmers, leaf blowers, small chainsaws, vacuums, lights, radios, etc.). Employing the same battery modules142in other equipment provides the end user with additional utility from the power source of the pressure washer100when it would otherwise be off and inactive. The pressure washer100, one or more battery modules142, a charger, and one or more additional pieces of power equipment powerable by the battery modules142can be sold in a bundle or package. By way of example, the additional pieces of power equipment may include lawn mowers, chain saws, leaf blowers, and string trimmers.

In some embodiments, as shown inFIGS. 1A and 1B, the pressure washer100receives grid electricity through an electrical plug146. In some embodiments, the electrical plug146is a male plug attached to the end of a short electrical cord attached to the base unit or is a male plug that is a component of the base unit, and the electrical plug146interfaces with an electrical extension cord148. The electrical extension cord148interfaces with a standard power outlet150and grid electricity runs though the electrical extension cord148, through the electrical plug146, and into the pressure washer100. In other embodiments, the electrical plug146is electrically coupled to the pressure washer100though an electrical cord attached to the base unit, and the electrical plug146interfaces directly with the standard power outlet150to receive grid electricity. The pressure washer100further includes a Ground Fault Circuit Interrupter unit (GFCI)152that disconnects the electrical connection to grid electricity upon detection of a ground fault. In some embodiments, the GFCI152is a component of and/or is located partially within the base unit or spray gun unit. In other embodiments, the GFCI152is located along the length of the electrical cord or is incorporated into the electrical plug146. The GFCI152may include an externally accessible means (e.g., a button, a switch, etc.) of resetting the GFCI152(i.e., restoring the electrical connection to grid electricity).

The electric motor140is electrically connected to and receives electrical power from a power management system160. In embodiments that include the one or more battery modules142, the power management system160is electrically connected to the battery modules142and/or the receptacles144and receives battery electricity from the battery modules142. In embodiments that include the electrical plug146, the power management system160is electrically connected to one or both of the electrical plug146and the GFCI152and receives grid electricity from the standard power outlet150. The power management system160selectively provides battery electricity from the battery modules142and grid electricity from the electrical plug146to the electric motor140to drive the water pump110.

In some embodiments, the power management system160includes a controller or processing circuit162. A controller162can include a processor and memory device. The processor can be implemented as a general-purpose processor, an application specific integrated circuit (ASIC), one or more field programmable gate arrays (FPGAs), a group of processing components, or other suitable electronic processing components. The memory device (e.g., memory, memory unit, storage device, etc.) is one or more devices (e.g., RAM, ROM, Flash memory, hard disk storage, etc.) for storing data and/or computer code for completing or facilitating the various processes, layers and modules described in the present application. The memory device may be or include volatile memory or non-volatile memory. The memory device may include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described in the present application. According to an exemplary embodiment, the memory device is communicably connected to the processor via a processing circuit and includes computer code for executing (e.g., by processing circuit and/or processor) one or more processes described herein. The controller162is used to control the flow of electricity based on a number of factors described herein. In other embodiments, the power management system160includes circuits with components manually operated by the user (e.g., switches) and/or sensors responsive to various operating conditions to control the flow of electricity without the use of a controller. In some embodiments, the power management system160includes both the controller162and one or more additional circuits.

Referring now toFIG. 7, a block diagram600of the controller162(e.g., proportional-integral-derivative (PID) controller606) is shown. The controller162adjusts a control variable of the pressure washer100using proportional, integral, and derivative terms in a control loop feedback mechanism. As such, the controller162provides real-time responsive correction to the control function of the system160. The controller162continuously calculates an error value610indicating the difference between a set value602and a measured actual value608. The error value610is fed back into a calculation of the sum of error values over time. The controller162continues to perform this control feedback mechanism and produce outputs612to the system. In other embodiments, other feedback control schemes can be used. For example, the controller162can include a proportional-integral (PI) controller.

Referring back toFIGS. 1A and 1B, in some embodiments, the power management system160includes a power inverter or power converter164. In embodiments where the electric motor140is a DC motor, the power management system160includes a power converter164that converts alternating current from the electrical plug146to direct current, which can then be selectively applied to the electric motor140, and may be passed through the battery modules142before reaching the electric motor140. In embodiments where the electric motor140is an AC motor, the power management system160includes a power inverter164that converts direct current from the battery modules142to alternating current, which can then be selectively applied to the electric motor140. In some embodiments where the electric motor140is a universal motor, the conversion from AC to DC or DC to AC is not necessary, and the power inverter or power converter164are omitted.

In some embodiments, the pressure washer100further includes an unloading or recirculating flow path170, shown inFIG. 1A. The unloading flow path170is fluidly coupled to the inlet112and the outlet114of the water pump110. An unloading valve172is disposed along the unloading flow path170, allows flow from the outlet114to the inlet112when open, and prevents flow from the outlet114to the inlet112when closed. The unloading valve172allows the electric motor140to continue running when the pressure washer100is not spraying (e.g., when the valve138is preventing flow to the nozzle136). In some embodiments, the unloading valve172is pressure-activated and opens when the pressure at the outlet114exceeds a threshold pressure. In other embodiments, the unloading valve172is flow-activated and opens when the flow to the nozzle136falls below a threshold level. In some embodiments, the unloading valve172is mechanical and is not connected to the power management system160. InFIG. 1A, the unloading valve172is shown disposed along the unloading flow path170beyond the point where the unloading flow path170separates from the flow to the nozzle136. In other embodiments, the unloading valve172may be located elsewhere along the unloading flow path170(e.g., at the point where the unloading flow path170separates from the flow to the nozzle136).

In some embodiments, as shown inFIGS. 1A and 1B, the pressure washer100further includes an unloading sensor174. The unloading sensor174is disposed along the path of flow between the outlet114and the nozzle136. The unloading sensor174is operatively coupled to the controller162. In some embodiments, the unloading sensor174is a pressure sensor and provides a signal indicating the pressure of the fluid near the outlet114. In other embodiments, the unloading sensor174is a flow sensor and provides a signal indicating the flow rate of fluid to the nozzle136. The controller162is configured to slow the speed of or stop the electric motor140in response to this signal. By way of example, the controller162may be configured to stop the electric motor140in response to a signal from the unloading sensor174indicating that the pressure of the fluid near the outlet114has exceeded a threshold level. By way of another example, the controller162may be configured to stop the electric motor140in response to a signal from the unloading sensor174indicating that the flow rate of fluid to the nozzle136has fallen below a threshold level. In the exemplary embodiment shown inFIG. 1B, the unloading flow path170and the unloading valve172are omitted. The unloading sensor174is used to detect when there is a reduced demand for pressurized water (e.g., when the flow to the nozzle136drops below a threshold level), and the controller162reduces the speed of the motor140in response to the reduced demand, which allows for the omission of the unloading flow path170and unloading valve172. Omitting the unloading flow path170and unloading valve172reduces the cost associated with manufacturing the pressure washer100.

In some embodiments, the pressure washer100includes a trigger sensor176configured to sense the position of the trigger134. The trigger sensor176is operatively coupled to the controller162. In some embodiments that include a base unit, the spray gun130includes an electrical power source (e.g., a battery) that powers the trigger sensor176. The trigger sensor176communicates with the controller162wirelessly using radio frequency transceiver178, shown inFIG. 1A. Radio frequency transceiver178is a component of the base unit and is operatively coupled to the power management system160. In some embodiments, the radio frequency transceiver is incorporated into the controller162. In other embodiments that include a base unit, the trigger sensor176communicates with the controller162over a wired connection179, shown inFIG. 1B. The wired connection179may run along the outside of the high-pressure hose132. In some embodiments where a water pump and an electric motor are components of a spray gun unit, a wire passes from the trigger sensor176to the controller162through the support structure102to facilitate communication. In some embodiments, the power management system160controls the speed of the electric motor140in response to the position of the trigger134sensed by the trigger sensor176, thereby varying the water pressure of the spray provided by the pressure washer100(i.e., the spray out of the nozzle136). By way of example, the power management system160may stop the electric motor140in response to an indication from the trigger sensor176that the trigger134is in the neutral position. By way of another example, the trigger134may have a fully open position opposite the neutral position. The power management system160may vary the speed of the electric motor140proportionally to the position of the trigger134relative to the neutral and fully open positions. For example, the power management system160may run the electric motor140at 75 percent of the maximum speed when the trigger134is 75 percent of the way to the fully open position. In some embodiments, the pressure washer100includes the trigger sensor176in addition to the valve138, and the trigger134actuates the valve138based on the current position of the trigger134.

In some embodiments, the pressure washer100includes one or more user interfaces180configured to receive user inputs and/or display information to the user. The user interface180may be located on the spray gun130, on the base unit (e.g., on the support structure102as shown inFIGS. 1A and 1B), or on the spray gun unit (e.g., on a support structure). As shown inFIG. 2, the user interface180includes one or more of a water pressure adjuster182, an operating mode selector184, a power source selector186, and a battery charge indicator188. In some embodiments, one or more of the water pressure adjuster182, the operating mode selector184, the power source selector186, and the battery charge indicator188are present on the user interface180on the support structure102, while some are present on the user interface180on the spray gun130. In other embodiments, the user interface180includes other input devices or indicators (e.g., a power switch). In some embodiments, one or more of the user interfaces180are present on the base unit. In some embodiments, one or more of the user interfaces180are present on a spray gun (e.g., the spray gun130). In some embodiments, one or more of the user interfaces180are present on the base unit and one or more user interfaces180are present on a spray gun.

The water pressure adjuster182is operatively coupled to the controller162. The water pressure adjuster182may be any input device capable selecting between a range of values (e.g., a dial, an increase button and a decrease button, a slider, etc.). The power management system160is configured to vary the speed of the electric motor140in response to a signal from the water pressure adjuster182. Varying the speed of the electric motor140varies the water pressure output of the spray from the spray gun130. The power management system160may vary the speed of the electric motor140proportionally to the position of the water pressure adjuster182. For example, the power management system160may run the electric motor140at 75 percent of the maximum speed when the water pressure adjuster182is 75 percent of the way to a maximum speed position. By way of another example, the power management system160may stop the electric motor140in response to an indication that the water pressure adjuster182is in a minimum speed position. Embodiments with this functionality may omit a power switch.

The operating mode selector184is present in some embodiments that include multiple battery modules142. The operating mode selector184is operatively coupled to the controller162. The operating mode selector184may be any input device capable of switching between a number of different configurations (e.g., a switch, a push button, a knob, etc.). The power management system160is configured to connect the battery modules142in either a maximum power configuration or a maximum run time configuration based on an input from the operating mode selector184. In the maximum power configuration, the battery modules142are connected in parallel, allowing the current from each battery module142to combine and increase the net current applied to the electric motor140. This increases the power output of the electric motor140for a given voltage, thereby increasing the water pressure of the spray provided by the pressure washer100. In the maximum run time configuration, the battery modules142are connected in series, such that the same current flows through each battery module142. This maintains the same power output of the electric motor140for a given voltage as if there were only one battery module142, maintaining the same water pressure of the spray provided by the pressure washer100but increasing the run time before the charge of the battery modules142is depleted. An example graph800showing runtime plotted against boost pressure is shown inFIG. 9. As shown by line802, as the boost pressure increases, the runtime capability decreases. For example, at approximately 250 pounds per square inch (psi), the runtime can range up to longer than 45 minutes, but at approximately 2300 psi, the runtime drops below five minutes. As shown by line804, the boost pressure capability of the pressure washer100is in some cases limited to a maximum boost pressure (e.g., approximately 2300 psi).

The power source selector186is present in some embodiments that include both a battery module142and an electrical plug146and can supply either battery electricity or grid electricity to the electric motor140. Some embodiments include multiple battery modules142. The power source selector186is operatively coupled to the controller162. The power source selector186may be any input device capable of switching between a number of different configurations (e.g., a switch, a push button, a knob, etc.). The power source selector186allows the user to select between a battery-only configuration, a plugin-only configuration, a boost configuration, and a power combination configuration of the power management system160. In the battery-only configuration, the power management system160provides battery electricity from the battery modules142to the electric motor140. In the plugin-only configuration, the power management system160provides grid electricity from the electrical plug146to the electric motor140. In the boost configuration, the power management system160provides electrical power from only the battery module142, but at a higher current than would be possible using grid electricity from the electrical plug146. In other embodiments, in the boost configuration the power management system160provides electrical power from both the battery module142and using grid electricity from the electrical plug146. In some embodiments, grid electricity from the electrical plug146is used until maximum allowable current capacity of the circuit breaker (e.g., 15 Amps) is reached. At that point, additional current is drawn from the battery module142.

In the power combination configuration, the power management system160provides battery electricity from the battery modules142to the electric motor and provides grid electricity from the electrical plug146to the electric motor140. In the power combination configuration, the electric motor140is receiving electricity from both the battery modules142and grid electricity simultaneously. Grid electricity is limited by the current capacity of the circuit breaker (typically 15 Amps) to which the pressure washer100is connected by the electrical plug146(i.e., a grid electricity current), but by routing all of the electricity to the electric motor140through the battery module142, the battery module142can provide a current greater (i.e., a battery electricity current) than the grid electricity current (e.g., provide 20 Amps or greater) to the motor140. A higher current delivered to the motor140increases the pressure of the spray from the nozzle136and increases flow. In the boost configuration and the power combination configuration, the grid electricity is used to charge the battery module142when the pressure washer100is not spraying and the electric motor140is turned off. This enables the user to use the higher current operation for extended periods of time by automatically recharging the battery module142when the electric motor140is not in use. In alternative embodiments, dual voltage coils may be used providing more electricity to the electric motor140to increase the speed of the electric motor140in order to increase water pressure. The user may operate the pressure washer200using the dual voltage coils by moving the power source selector186to the designated position for the mode utilizing the dual voltage coils.

The configurations provide varying maximum rated water pressures at the outlet114. The maximum rated water pressure provided by the water pump110is the greatest in the power combination configuration. The maximum rated water pressure provided by the water pump110is greater in the boost configuration (e.g., 3,000 psi) than in the plugin-only configuration (e.g., 2,000 psi) and in the battery-only configuration (e.g., 1,700 psi). The maximum rated water pressure is greater in the plugin-only configuration than in the battery-only configuration.

In some embodiments, the operating mode is selected by changing the nozzle136of the spray gun130. As such, the power management system160selects the power source based on the selection of the nozzle136. Accordingly, the selection of a particular nozzle136can activate a boost configuration in which power is pulled from the battery modules142. Various nozzles include various effective flow areas (e.g., cross-sectional area or diameter) or restrictions on the flow delivered from the spray gun130. Based on selection of a nozzle136with a relatively low effective flow area (e.g., relatively high restriction of flow), the power management system160initiates a boost configuration. For example, the user can select between a first nozzle and a second nozzle. The first nozzle includes an effective flow area greater than the second nozzle. When the user switches out the first nozzle for the second nozzle during operation of the pressure washer100, the power management system160senses the second nozzle (e.g., senses the increased restriction of flow) and activates a boost configuration. In the boost configuration, the system160initiates a relatively higher current draw than in the battery-only or plugin-only configurations. As such, the power management system160draws power from the battery modules142to be provided to the electric motor140to increase the pressure of the spray from the nozzle136. In some embodiments, the power management system160senses the increased restriction of flow at the unloading sensor174described above. As noted, the unloading sensor174is disposed along the path of flow between the outlet114and the nozzle136. In some embodiments, the unloading sensor174is a pressure sensor and provides a signal to the controller162indicating the pressure of the fluid near the outlet114. In other embodiments, the unloading sensor174is a flow sensor and provides a signal to the controller162indicating the flow rate of fluid to the nozzle136.

Referring toFIG. 6, a schematic diagram showing a boost configuration500using the power management system160is shown. In some embodiments, the boost configuration500utilizes a primary power source502(e.g., grid electricity from the electrical plug146) and a secondary power source506(e.g., battery electricity from the battery modules142) to provide power to the electric motor140. A charging system504is structured to charge the primary power source502and the secondary power source506during operation of the pressure washer100. In some embodiment, the power selector508shown inFIG. 6is the power source selector186shown inFIG. 2. Accordingly, as noted above, the power selector508allows the user to select between a battery-only configuration, a plugin-only configuration, a boost configuration, and a power combination configuration. The power selector508is communicably and operatively coupled to the controller162of the power management system160(shown inFIGS. 1A and 1B) to provide an output510. The output510controls which power source is selected by the controller162. In the boost configuration500, the power management system160is configured to use grid electricity to charge the battery module142when the pressure washer100is not spraying and the electric motor140is turned off, thereby enabling the user to use the higher current operation for extended periods of time by automatically recharging the battery module142. In addition, the power management system160is configured to use the primary power source502(e.g., grid electricity) the charge the secondary power source504(e.g., battery module142) while the electric motor140is running. This may be done in both the boost configuration and in the power combination configuration. In this situation, some of the current supplied to the electric motor140to increase water pressure is directed to charging the secondary power source504(e.g., one or more battery modules142).

Referring toFIG. 8, a method700for charging the secondary power source504is shown, according to an exemplary embodiment. The method700is performed by the power management system160(e.g., controller162). As such, one or more of the components ofFIGS. 1-7will be referenced in the description of method700.

The method is initiated at702. Whether the secondary power source504is charged is determined at704. If the secondary power source504is not charged, the primary power source502provides charge to the secondary power source504and to the electric motor140at706. If the secondary power source504is charged or after the secondary power source is charged at706, the next step is determining whether a boost configuration is selected at708. The boost configuration is set by a user using the power source selector186(or power selector508). The power source selector186communicates the selection to the controller162. If the user did not select the boost configuration at708, the controller162sets a flag indicating to set no boost parameters at710. If the user selected the boost configuration at710, it is determined whether the secondary power source504has sufficient allowable energy according to preset parameters at712. The preset parameters may be set by a manufacturer of the secondary power source504or a manufacturer of the pressure washer100(e.g., programmed into controller162). If the secondary power source504does not have sufficient allowable energy, the system160displays an error message to the user to indicate insufficient charge of the secondary power source504at714. At which point, the system160sets a no boost parameter at710and controls the primary power source502to provide charge to the secondary power source502at706. If the secondary power source504has sufficient allowable energy, the system160sets boost configuration parameters at716and provides charge from the primary power source502and the secondary power source504at718. The system160routinely checks whether the secondary power source504has sufficient charge at712and controls the provision of power to and from the primary and secondary power sources502,504.

In some embodiments, the power management system160includes a circuit or module for measuring a charge of the one or more battery modules142. The power management system160may be configured to automatically switch from the power combination configuration or boost configuration to the plugin-only configuration in response to the charge in the battery module142dropping below a threshold level (e.g., 60 volts). In some embodiments, the power management system160will default to the battery-only configuration whenever grid electricity is not received from the electrical plug146. In some embodiments, while in the boost configuration or the plugin-only configuration, the power management system160automatically charges the one or more battery modules142when the total power draw of the pressure washer100drops below a threshold level (e.g., when the electric motor140is not running). By way of example, power washer usage typically involves intermittent spraying, so the one or more battery modules142are able to charge with grid electricity during pauses in the user's spraying when the electric motor140is turned off, thereby extending the operating time of the one or more battery modules142and the available time for the user to perform spraying tasks. In some embodiments, the power management system160charges the one or more battery modules142while the pressure washer100is powered off.

In some embodiments, the user interface180includes a battery charge indicator188. The battery charge indicator188is operatively coupled to the power management system160. The battery charge indicator188displays one or both of the current charge of the battery modules142or an estimated remaining run time to the user. In some embodiments, as shown inFIG. 2, the battery charge indicator188is a series of LED's with an included button. When the user presses the button, the LEDs light up, indicating the remaining charge. By way of example, if 60 percent of the charge remained, three of the four lights would be lit, indicating that between 50 percent and 75 percent of the charge remained. In other embodiments, the battery charge indicator188may include a display that indicates the percentage charge remaining. In some embodiments, the power management system160determines the estimated remaining run time. This determination may take into account the current power configuration (e.g., boost, plugin-only, power combination, or battery-only), the amount of connected battery modules142, the size of the connected battery modules142(e.g., an amp-hour rating), and the use history of the user (e.g., the average power usage of the user), among other factors. The estimated remaining run time may be indicated on a display. In alternative embodiments, the battery charge indicator188may be on the battery modules142displaying to the user via the LED lights that the battery modules142are fully charged or may be partially charged. Indicators, such as LED lights, may also be located on the nozzle, wand or gun portion of the pressure washer200to display to the user the charge level of the battery module(s)142.

A pressure washer200, shown inFIG. 3, similar to the pressure washer100is a floor-standing pressure washer including a base unit and a separate spray gun230(discussed below). The base unit includes a support structure202to house the internal components of the pressure washer200, which are similar to the components described in the pressure washer100embodiments (e.g., a water pump, an electric motor, a power management system, etc.). In some embodiments, the base unit includes wheels204and handles206or other components to facilitate transportation of the pressure washer200. A low-pressure water source216, which in this embodiment is a municipal water source, is connected to the base unit via inlet fitting218. An outlet fitting220is fluidly coupled to a spray gun230by means of high-pressure hose232. The spray gun230includes a trigger234that controls the flow of high-pressure water to a nozzle236similarly to the pressure washer100. The trigger234may additionally control a valve238disposed along a flow path between the outlet fitting220and the nozzle236. Battery electricity can be supplied to the pressure washer200by one or more battery modules242that are received by one or more receptacles244. Grid electricity can be supplied to the pressure washer200though electrical plug246which connects via an electrical extension cord248to a standard power outlet250. The pressure washer200includes a GFCI252disposed along the outside of the support structure202near the electrical plug246. The pressure washer200additionally includes a trigger sensor276and a user interface280to provide the user more control over the operation of the pressure washer200. A floor-standing pressure washer like the pressure washer200allows the user to use the spray gun230without having to support the weight of the base unit.

A pressure washer300, shown inFIG. 4, similar to the pressure washer100is a backpack pressure washer including a base unit and a separate spray gun330(discussed below). The base unit includes a support structure302to house the internal components of the pressure washer300, which are similar to the components described in the pressure washer100embodiments (e.g., a water pump, an electric motor, a power management system, etc.). The base unit includes a backpack304that supports at least a portion of the weight of the base unit and everything attached to the base unit (e.g., one or more battery modules342, described below) on one or more shoulders of the user. The backpack304may incorporate one or more straps306, as shown inFIG. 4. Pressure washer300may additionally include handles308or other components to facilitate transportation of the pressure washer300. A low-pressure water source316, which in this embodiment is a reservoir coupled to the top of the support structure302, is fluidly coupled to a water pump (not shown). Alternatively, the water pump may be connected to a water supply by a low-pressure hose. The water pump may be a self-priming water pump to facilitate drawing water from a source with a small head pressure. An outlet fitting320is fluidly coupled to a spray gun330by means of high-pressure hose332. The spray gun330includes a trigger334that controls the flow of high-pressure water to a nozzle336similarly to the pressure washer100. The trigger334may additionally control a valve338disposed along a flow path between the outlet fitting320and the nozzle336. Battery electricity can be supplied to the pressure washer300by one or more battery modules342that are received by one or more receptacles344. Grid electricity can be supplied to the pressure washer300though electrical plug346which connects via an electrical extension cord348to a standard power outlet350. The pressure washer300includes a GFCI352disposed along the outside of the support structure302near the electrical plug346. The pressure washer300additionally includes a trigger sensor376and a user interface380to provide the user with more control over the operation of the pressure washer300. A backpack pressure washer like the pressure washer300allows the user to carry the base unit on their back or shoulders instead of rolling the base unit along the ground, which may be advantageous in areas with uneven terrain (e.g., on a ladder). In some embodiments, the pressure washer300can be converted to a floor-standing pressure washer (e.g., by removing the backpack304and adding wheels). The pressure washer300is similar in size and use to a backpack leaf blower.

A pressure washer400, shown inFIG. 5, similar to the pressure washer100is a handheld pressure washer includes a spray gun unit without a separate spray gun. The spray gun unit includes a support structure402to house the internal components of the pressure washer400, which are similar to the components described in the pressure washer100embodiments (e.g., a water pump, an electric motor, a power management system, etc.). The internal components and a nozzle436(described below) are components of the spray gun unit, such that low-pressure fluid enters the spray gun unit and high-pressure fluid is ejected from the spray gun unit through the nozzle436. The pressure washer400may incorporate a handle404, straps, or other components to facilitate transportation of the pressure washer400. A low-pressure water source416, which in this embodiment is a municipal water source, is connected to the base unit via inlet fitting418. A trigger434is connected to the handle404and controls the flow of high-pressure water to nozzle436similarly to the pressure washer100. The trigger434may additionally control a valve438disposed along a flow path between the inlet fitting418and the nozzle436. Battery electricity can be supplied to the pressure washer400by one or more battery modules442that are received by one or more receptacles444. Grid electricity can be supplied to the pressure washer400though electrical plug446which connects via an electrical extension cord448to a standard power outlet450. The pressure washer400includes a GFCI452disposed along the outside of the support structure402near the electrical plug446. The pressure washer400additionally includes a trigger sensor476and a user interface480to provide the user more control over the operation of the pressure washer200. A handheld pressure washer like the pressure washer400allows the user to carry only a single spray gun unit instead of a base unit and a separate spray gun, which facilitates maneuvering with the pressure washer400. The pressure washer400is similar in size and use to a handheld leaf blower.