Patent Publication Number: US-2023145755-A1

Title: Modular power charging unit for retrofitting existing aircraft monuments

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This is a divisional of U.S. application Ser. No. 16/821,580, filed on Mar. 17, 2020, entitled “Modular Power Charging Unit For Retrofitting Existing Aircraft Monuments,” which claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 62/824,957, filed Mar. 27, 2019, for “Modular Electrical Unit For Retrofitting Existing Aircraft Monuments”, the entire disclosures of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     As portable mobile electronic devices become more pervasive to use for airline personal to communicate and provide instructions to cabin catering, and to sell services onboard, the need for aircraft monuments with power supplies to charge those devices has become apparent. This need has introduced a service gap with existing aircraft monuments that were deployed prior the recent technology trends. Accordingly, there is a need to retrofit existing aircraft monuments to include power charging units. There is a further need for power charging units that are configured to enable retrofitting of components, e.g., walls, doors, etc., of these aircraft monuments in a way that does not compromise the structural integrity of the monuments to a degree that negatively affects the airworthiness certification of the monuments. 
     SUMMARY 
     Disclosed herein is a system for retrofitting a wall of an aircraft monument that is certified to withstand a load in a range of 1 g-force (g) and 9 g. The system includes a modular power charging unit and mounting hardware. The modular power charging unit includes a housing containing at least a portion of an electrical port component, a cable harness, and a switch. The housing has a plurality of screw holes and a back panel having an opening through which the cable harness extends. The mounting hardware includes a plurality of threaded inserts, each configured to be inserted into one of a plurality of mounting holes formed in the wall, and a plurality of screws, each configured to extend through a screw hole of the housing and into a threaded insert. The housing is configured to be secured to a first side of the wall so that the entirety of the housing projects outward from the first side and only the cable harness extends through a cable-harness hole formed through a thickness of the wall. Because the housing is configured to be secured in place on one side of the wall and only the cable harness extends through the wall, structural modification of the wall during retrofitting is limited to a single, small hole through the wall and a plurality of even smaller mounting holes into, but not necessarily through, the wall. As such, the structural integrity of the wall and the aircraft monument is preserved. 
     In additional aspects of the system, the housing includes a grommet surrounding the opening of the back panel through which the cable harness extends. The grommet has a maximum cross sectional dimension that enables placement of the grommet into a cable-harness hole through the wall. The cable-harness hole has a maximum cross sectional dimension that is small enough to preserve the structural integrity of the wall and the aircraft monument. In another aspect, the plurality of threaded inserts has a length less than the thickness of the wall to prevent mounting hardware, e.g., screws, from extending through the entire thickness of the wall. 
     In other aspects related to the modular power charging unit, the electrical port component may be a charging interface, or a power and electrical power outlet. The modular power charging unit may further include an indicator light electrically associated with the electrical port component and configured to illuminate only when the modular power charging unit is in a power on state. 
     Disclosed herein is a method of mounting a modular power charging unit to an aircraft monument that is certified to withstand a load in a range of 1 g and 9 g. The method includes forming a cable-harness hole through an entire thickness of a wall of the aircraft monument. The size of the cable-harness hole is large enough to allow for a portion of a cable harness of the modular power charging unit to pass through. The size and location of the cable-harness hole relative to the edges of the wall preserves the structural integrity of the wall and the aircraft monument. The method further includes forming a plurality of mounting holes in the wall, and inserting a threaded insert in each of the plurality of mounting holes. The size and location of each of the plurality of mounting holes relative to the edges of the wall preserves the structural integrity of the wall and the aircraft monument. To further preserve the structural integrity of the wall and the aircraft monument, the plurality of mounting holes may extend only partially into the wall. The method also includes feeding the portion of the cable harness of the modular power charging unit through the cable-harness hole. Next, the method includes aligning each of a plurality of screw holes of a housing of the modular power charging unit with a screw hole having a threaded insert and inserting mounting hardware through each screw hole and into the threaded insert; and then advancing the mounting hardware into the threaded inserts until a back panel of the housing is flush with a surface of the wall. 
     In additional aspects of the method, the cable-harness hole is located a distance from a closest edge of the wall. The distance is equal to at least one times the diameter of the cable-harness hole. In another aspect, the threaded insert is formed of a rigid metal configured to provide structural support to the wall in an area of the plurality of mounting holes. In yet another aspect, the housing includes a grommet that projects outward from the back panel. The grommet has a maximum cross sectional dimension that enables placement of the grommet into the cable-harness hole through the wall. The cable-harness hole has a corresponding maximum cross sectional dimension that preserves the structural integrity of the wall and the aircraft monument. 
     Disclosed herein is a modular power charging unit for mounting to a wall of an aircraft monument that is certified to withstand a load in a range of 1 g and 9 g. The modular power charging unit includes an electrical port component having a power input terminal and a ground terminal, a cable harness having a power input pin and a ground pin configured to couple to an external power supply, a manually operable switch electrically interposed between the power input terminal of the electrical port component and the power input pin of the cable harness, and a housing containing at least a portion of the electrical port component, the cable harness, and the manually operable switch. The manually operable switch is configured to toggle the modular power charging unit between a power on state where the power input pin is electrically coupled to the power input terminal, and an off state where the power input pin is electrically decoupled from the power input terminal. The housing is configured to be secured to a first side of the wall so that the entirety of the housing projects outward from the first side. 
     In additional aspects, the modular power charging unit also includes an indicator light electrically associated with the electrical port component and configured to illuminate only when the modular power charging unit is in the power on state. In other aspects of the modular power charging unit, the electrical port component may be a charging interface and/or an electrical power outlet. 
     In additional aspects of the modular power unit, the housing includes a back panel with an opening through which the cable harness extends to place the power input pin and the ground pin outside of the housing. The housing is secured to the wall by mounting hardware, e.g., screws, that extends into mounting holes formed in the wall so that the back panel is flush with a surface of the wall. The mounting holes may extend only partially into the wall to further preserve the structural integrity of the wall. The housing includes a grommet surrounding the opening of the back panel, and the grommet has a maximum cross sectional dimension that enables placement of the grommet into a cable-harness hole through the wall, where the cable-harness hole has a maximum cross sectional dimension that preserves the structural integrity of the wall and the aircraft monument. 
     Thus disclosed herein is a modular power charging unit that expands the capability of existing aircraft monuments. The module power charging unit (MPCU) provides a convenient add-on system that efficiently adds additional, scalable, power interfaces to existing aircraft monuments. The MPCU is configured to require minimal modification of aircraft monument structures, e.g., walls, so that aircraft structural load certifications are not compromised. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various aspects of apparatuses and methods will now be presented in the detailed description by way of example, and not by way of limitation, with reference to the accompanying drawings, wherein: 
         FIG.  1 A  is illustration of an aircraft monument in the form of a galley having a vertical wall that is retrofitted to include a modular power charging unit. 
         FIG.  1 B  is illustration of an aircraft monument in the form of a storage closet having a vertical wall that is available for retrofitting with a modular power charging unit. 
         FIG.  2    is an illustration of one configuration of a modular power charging unit that includes a dual USB port with power indicators and a power switch for turning the dual USB port on and off. 
         FIG.  3 A  is an illustration of the modular power charging unit of  FIG.  2    from the front. 
         FIG.  3 B  is an illustration of the modular power charging unit of  FIG.  2    from the rear, showing an electrical cable harness extending through the back panel of the modular power charging unit. 
         FIG.  4    is a cross-sectional side view of the modular power charging unit of  FIG.  2   . 
         FIG.  5 A  is a plan view of a section of a monument wall having a cable-harness hole formed therethrough and four mounting holes formed therein for purposes of electrically coupling the modular power charging unit to a power unit and for securing the modular power charging unit to the wall. 
         FIG.  5 B  is a cross-sectional, side view of the section of the monument wall of  FIG.  5 A  along line A-A. 
         FIG.  6    is a side view of the modular power charging unit of  FIG.  4    secured to the monument wall of  FIGS.  5 A and  5 B . 
         FIG.  7    is a functional block diagram of a modular power charging unit coupled to a power source of the aircraft. 
         FIG.  8    is an electrical diagram of a modular power charging unit coupled to a power source of the aircraft. 
     
    
    
     DETAILED DESCRIPTION 
     A typical aircraft includes a fuselage, which generally corresponds to the main body of the aircraft for holding passengers, crew, cargo, and/or equipment. Typically, the fuselage of an aircraft is elongate and somewhat cylindrical or tubular. The fuselage may include one or more personal spaces, such as one or more crew rests, lavatories, private suites, galley areas, and/or a cockpit. One or more aircraft monuments, e.g., galleys, closets, etc., may be located within such personal spaces. 
     Aircraft monuments are structurally certified pursuant to one or more of the airworthiness standards with respect to static loads, as specified in 14 CFR Part 25, which is hereby incorporated by reference. For example, an aircraft monument in the form of a galley must be certified to withstand specified load requirements. An aircraft monument is generally considered to withstand load requirements when no component part of the monument, such as a monument wall, detaches from the overall monument while being subjected to a test load. Bending, cracking and deforming of component parts are generally acceptable and the occurrence of one or more of these does not negatively affect the certification of a monument. 
     Subsequent modification of a component part of an aircraft monument may structurally compromise the entire aircraft monument. For example, a large hole formed through a monument wall of the aircraft monument may cause that wall to become detached if the monument were to be subjected to the test load it was originally certified under. Accordingly, when retrofitting an aircraft monument it is desirable to minimize the amount and types of modifications made to the component parts of the monument; otherwise the structural integrity of the aircraft monument may be affected to a degree that renders the monument no longer structurally certified pursuant to one or more of the airworthiness standards with respect to static loads, as specified in 14 CFR Part 25. 
     Modular power charging units for retrofitting existing aircraft monuments and related methods of retrofitting monuments in a way that preserves certification of the monument are disclosed herein. A modular power charging unit includes at least one electrical port component, which may be, for example, a power outlet or a charging interface. A charging interface may comprise, for example, one or more of a USB port, a micro-USB port, a Lightening port, and any other type of power/charging port. These modular power charging units allow for retrofitting of existing aircraft monuments to provide power outlets and charging interfaces in locations where they are not currently located and in a way that does not reduce the integrity of the monuments to a degree that would require recertification of the monument. 
     With reference to  FIG.  1 A , an aircraft monument  100  in the form of a galley has a monument wall  102  that is retrofitted to include a modular power charging unit (MPCU)  104 . The MPCU  104  electrically couples to an AC-to-DC converter (not shown) located near the galley. Prior to being retrofitted with the MPCU  104 , the galley  100  was structurally certified pursuant to one or more of the airworthiness standards with respect to static loads, as specified in 14 CFR Part 25. With reference to  FIG.  1 B , another aircraft monument  110  in the form of a storage closet has a door wall  112  that is available for retrofitting with a MPCU (not shown). The MPCU unit may be installed on the exterior side of the door wall  112  or the interior side. The aircraft monument  110  includes a false wall  114  behind which is located an AC-to-DC converter  116  that is available to supply power to the MPCU. 
     The MPCUs disclosed herein are designed to allow for integration into existing aircraft monuments in a manner that does not affect the structural integrity of the component part, e.g., monument wall, to which it is mounted, and thus does not affect the structural integrity of the monument. To this end, the MPCUs are configured to be secured to a wall of an aircraft monument in a manner that requires the formation of a single, small hole through the thickness of the wall. Requiring only a single, small hole through the wall preserves the structural integrity of the wall and the entire aircraft monument. The back panel of the MPCU is secured flush against a surface of the monument wall so that the entirety of the MPCU housing is on the front or exterior side of the wall and projects outward from the wall, and the only part of the MPCU that extends through the back or interior side of the wall is a cable harness. 
     With reference to  FIGS.  2 ,  3 A,  3 B and  4   , one configuration of a MPCU  200  includes electrical components comprising an electrical port component  202 , e.g., a dual USB port with power indicators, a power switch  204 , and an electrical cable harness  205 . The MPCU  200  is configured for mounting to a wall of an aircraft monument that is configured and certified to withstand static loads pursuant to 14 CRF Part 25 requirements. For example, a galley monument such as shown in  FIG.  1 A  may be required to withstand a static load in the range of 1 g-force (g) to 9 g. 
     The MPCU  200  includes a housing  206  having a container portion  208  that contains all or at least a portion of the electrical components of the MPCU, and a cover portion  210  that couples to the container portion to enclose parts of the electrical components inside the housing. The container portion  208  and the cover portion  201  may be formed of plastic. The container portion  208  has a top panel  212 , a bottom panel  214 , two side panels  216 ,  218 , and a front panel  220  through which the electrical port component  202  and power switch  204  are exposed. A pair of screws  222  secure the electrical port component  202  to the front panel  220  of the housing  206 . A flange  224  extends around the perimeter of the container portion  208 . The flange  224  has four screw holes  226  for receiving mounting hardware, e.g., screws, that are used to secure the MPCU  200  to a monument wall. 
     The cover portion  210  includes a top panel  228 , a bottom panel  230  and a back panel  232 . The back panel  232  includes a hole or opening  207  through which the electrical cable harness  205  extends. As shown in  FIG.  4   , a pair of grommets  234   a ,  234   b  surrounds the portion of the electrical cable harness  205  near the back panel  232 . The grommets  234   a ,  234   b  are flush with opposite sides of the back panel  232  and secure the electrical cable harness  205  in place relative to the opening  207  and the back panel  232 . 
     The cover portion  210  is sized to fit into the container portion  208  such that the top panel  228  and bottom panel  230  are respectively in abutting contact with the top panel  212  and bottom panel  214  of the container portion, and the back panel  232  is generally flush with the back side of the flange  224 . As shown in  FIG.  4   , the cover portion  210  is secured to the container portion  208  by two screws extending through the respective top panels  212 ,  228  and two screws extending through the respective bottom panels  214 ,  230 . 
     With reference to  FIGS.  5 A,  5 B and  6   , an existing monument wall  500  is retrofitted with an MPCU  200  as follows: 
     1) A cable-harness hole  502  is formed through an entire thickness of the monument wall  500 . The cable-harness hole  502  is sized such that it does not affect the structural integrity of the monument wall  500  to a degree that negatively affects the certification of the wall and the aircraft monument of which the wall is a part. The cable-harness hole  502  is also located a distance from the edges of the monument wall  500  such that it does not affect the structural integrity of the wall. The cable-harness hole  502  is preferably no more than 3 inches in diameter, and in one configuration is 1 inch in diameter; and is preferably located a distance from the closest edge of the wall that is equal to 1 times the diameter of the cable-harness hole  502 . The cable-harness hole  502  is also preferably sized to match the outer diameter d of the grommet  234   a . As shown in  FIG.  6   , this sizing of the cable-harness hole  502  allows for the grommet  234   a  to extend into the hole, which in turn allows for the back panel  232  of the MPCU  200  to be flush with a first surface  504  of the monument wall  500 . 
     With reference to  FIG.  3 B , in one embodiment, the MPCU  200  is configured so that the minimum distance x between the outer edge of the grommet  234   a  and the outer edge of the flange  224  of the housing  206  is at least 1 times greater than the diameter d of the grommet  234   a . This ensures that the cable-harness hole  502  sized to receive the grommet  234   a  will be formed a sufficient distance from the edge of a monument wall  500  to preserve the certification of the wall and the aircraft monument of which the wall is a part, even if an outer edge of the housing  206  is positioned at the edge of the wall. 
     2) Four mounting holes  506   a - d  are drilled into the monument wall  500 . The mounting holes  506   a - d  may extend partially through the wall. For example, as a general rule, the depth of the mounting holes  506   a - d  are no more than one times the diameter of the mounting holes. Alternatively, the mounting holes  506   a - d  may extend completely through the monument wall  500 . In either case (partial or complete extension through the monument wall  500 ), a rigid metal threaded insert  507   a - d  is inserted into the mounting holes  506   a - d  and secured therein by adhesive. These threaded inserts  507   a - d  are sized to receive the mounting screws of the MPCU  200 , and serve to strengthen the monument wall  500  in the regions of the mounting holes  506   a - d , thus negating any degradation of the wall strength that would otherwise result from the mounting holes themselves. 
     3) Once the cable-harness hole  502  and the mounting holes  506   a - d  are formed and threaded inserts  507   a - d  are inserted in the mounting holes, the MPCU  200  is held in the area of the mounting holes and the portion of the electrical cable harness  205  extending from the back of the MPCU is fed through the cable-harness hole. As shown in  FIG.  6   , the MPCU  200  is then secured to the monument wall  500  using four screws  602  sized to engage the threaded inserts  507   a - d  in the wall. As the screws  602  are tightened and the back of the MPCU  200  becomes positioned parallel with the monument wall  500 , the grommet  234   a  becomes aligned with the cable-harness hole  502 . As the screws are further tightened, the grommet  234   a  extends into the cable-harness hole  502  and the back of the MPCU  200  becomes flush mounted to the monument wall  500 . The threaded inserts  507   a - d  are of a length/depth that prevents the mounting hardware (screws) from extending through the entire thickness of the monument wall  500 . 
     4) The exposed end of the electrical cable harness  205  is then electrically coupled to an appropriate power supply located in the aircraft near the MPCU  200 . With reference to  FIG.  7   , in the case of an MPCU  200  that includes a USB charging port, the electrical cable harness  205  is coupled to an AC to DC converter  702 , which in turn, is coupled to a 115 volt AC power source  704 . In cases where the MPCU  200  includes an electrical outlet, the cable harness  205  may be directly coupled to the 115 volt AC power source  704 . 
     With reference to  FIG.  5 B , the monument wall  500  may include a first skin layer  510  having a first surface  504 , a second skin layer  512  having a second surface  514 , and a core  516  extending between the first surface and second surface, such that first skin layer and second skin layer are positioned on opposites sides of the core. The first skin layer  510  may be arranged such that first surface  504  faces outwardly and away from the core  516 . Similarly, the second skin layer  512  may be arranged such that second surface  514  faces outwardly and away from the core  516 . The thickness of the monument wall  500  may be, for example, in the range of 1 to 3 inches. 
     The monument wall  500  may be formed of any suitable materials, having a flexible, rigid, or semi-rigid first skin layer  510 , and a flexible, rigid, or semi-rigid second skin layer  512 , and core  516  therebetween. Generally, the first skin layer  510  and the second skin layer  512  may be relatively thin sheets or plates, while core  516  may have a thickness that is significantly greater than the respective thicknesses of first skin layer and second skin layer. In some examples, the density of core  516  may be less than that of first skin layer  510  and second skin layer  512 . 
     The monument wall  500  may be, for example, a honeycomb core sandwich panel, but other constructions are contemplated within the scope of the present disclosure. The first skin layer  510  and the second skin layer  512  may be, for example, aluminum sheets, or may be formed of one or more layers or plys of composite materials (e.g., fiber-reinforced polymers). In some examples, the core  516  may be formed of a plurality of longitudinally-extending open cells of any shape, and formed of any material, such as aluminum, Nomex®, or other lightweight material. In some examples, the core  516  may be formed of foamed material, or low-density materials, such as balsa wood or polystyrene. 
     With reference to  FIG.  8   , in one configuration the MPCU  200  includes a USB charging port  802  that is electrically coupled to a 28 VDC output line, a DC return line and a remote on-off line of an AC to DC converter  804 . While the USB charging port  802  is directly coupled to the DC return line and a remote on-off line, the port is also coupled to the 28 VDC output through a manual switch  806  to allow for local turning on an off of the USB charging function. An indicator light associated with the USB charging port  802  illuminates when power is being supplied to the port. While conventional USB charging ports do not include on/off switches and indicator lights, these components are necessary in order to satisfy FAA safety standards that require the ability to manually shut off power to electrical outlets and ports and the ability to visually confirm via an indicator light that power is off. 
     Disclosed herein is a system for retrofitting a wall  500  of an aircraft monument  100 ,  110  that is certified to withstand a load in a range of 1 g-force (g) and 9 g. The system includes a modular power charging unit  200  and mounting hardware. The modular power charging unit  200  includes a housing  206  containing at least a portion of an electrical port component  202 , an electrical cable harness  205 , and a power switch  204 . The housing  206  has a plurality of screw holes  226  and a back panel  232  having an opening  207  through which the electrical cable harness  205  extends. The mounting hardware includes a plurality of threaded inserts  507   a - d , each configured to be inserted into one of a plurality of mounting holes  506   a - d  formed in the wall  500 , and a plurality of screws  602 , each configured to extend through a screw hole  226  of the housing  206  and into a threaded insert  507   a - d . The housing  206  is configured to be secured to a first side of the wall  500  so that the entirety of the housing projects outward from the first side and only the electrical cable harness  205  extends through a cable-harness hole  502  formed through a thickness of the wall. Because the housing  206  is configured to be secured in place on one side of the wall  500  and only the cable harness extends through the wall, structural modification of the wall during retrofitting is limited to a single, small cable-harness hole  502  through the wall and a plurality of even smaller mounting holes  506   a - d  into, but not necessarily through, the wall. As such, the structural integrity of the wall  500  and the aircraft monument is preserved. 
     In additional aspects of the system, the housing  206  includes a grommet  234   a  surrounding the opening  207  of the back panel  232  through which the cable harness  205  extends. The grommet  234   a  has a maximum cross sectional dimension that enables placement of the grommet into a cable-harness hole  502  through the wall. The cable-harness hole  502  has a maximum cross sectional dimension that is small enough to preserve the structural integrity of the wall  500  and the aircraft monument. In another aspect, each of the plurality of threaded inserts  507   a - d  has a length less than the thickness of the wall  500 . 
     In other aspects related to the modular power charging unit  200 , the electrical port component  202  may be a charging interface, or a power and electrical power outlet. The modular power charging unit  200  may further include an indicator light electrically associated with the electrical port component  202  and configured to illuminate only when the modular power charging unit  200  is in a power on state. 
     Disclosed herein is a method of mounting a modular power charging unit  200  to an aircraft monument  100 ,  110  that is certified to withstand a load in a range of 1 g and 9 g. The method includes forming a cable-harness hole  502  through an entire thickness of a wall  500  of the aircraft monument  100 ,  110 . The size of the cable-harness hole  502  is large enough to allow for a portion of an electrical cable harness  205  of the modular power charging unit  200  to pass through, and the size and location of the cable-harness hole preserves the structural integrity of the wall  500  and the aircraft monument  100 ,  110 . The method further includes forming a plurality of mounting holes  506   a - d  only partially into the wall  500 , wherein the size and location of each of the plurality of mounting holes preserves the structural integrity of the wall and the aircraft monument  100 ,  110 ; and inserting a threaded insert  507   a - d  in each of the plurality of mounting holes. The method also includes feeding the portion of the electrical cable harness  205  of the modular power charging unit  200  through the cable-harness hole  502 . Next, the method includes, for each of a plurality of screw holes  226  of a housing  206  of the modular power charging unit  200 , aligning a screw hole with a corresponding one of the plurality of threaded inserts  507   a - d  and inserting a mounting hardware, e.g., screw, through the screw hole and into the threaded insert; and then advancing the mounting hardware into the threaded inserts until a back panel  232  of the housing  206  is flush with a surface of the wall  500 . 
     In additional aspects of the method, the cable-harness hole  502  is located a distance from a closest edge of the wall  500 . The distance is equal to at least one times the diameter of the cable-harness hole  502 . In another aspect, the threaded inserts  507   a - d  are formed of a rigid metal configured to provide structural support to the wall  500  in an area of the plurality of mounting holes  506   a - d . In yet another aspect, the housing  206  includes a grommet  234   a  that projects outward from the back panel  232 . The grommet  234   a  has a maximum cross sectional dimension d that enables placement of the grommet into the cable-harness hole  502  through the wall  500 . The cable-harness hole  502  has a maximum cross sectional dimension that preserves the structural integrity of the wall  500  and the aircraft monument  100 ,  110 . 
     Disclosed herein is a modular power charging unit  200  for mounting to a wall  500  of an aircraft monument  100 ,  110  that is certified to withstand a load in a range of 1 g and 9 g. The modular power charging unit  200  includes an electrical port component  202  having a power input terminal and a ground terminal, an electrical cable harness  205  having a power input pin and a ground pin configured to couple to an external power supply, a manually operable power switch  204  electrically interposed between the power input terminal of the electrical port component and the power input pin of the cable harness, and a housing  206  containing at least a portion of the electrical port component, the cable harness, and the manually operable switch. The manually operable power switch  204  is configured to toggle the modular power charging unit  200  between a power on state where the power input pin is electrically coupled to the power input terminal, and an off state where the power input pin is electrically decoupled from the power input terminal. The housing  206  is configured to be secured to a first side, e.g., exterior side, of the wall  500  so that the entirety of the housing projects outward from the first side. 
     In additional aspects, the modular power charging unit  200  also includes an indicator light electrically associated with the electrical port component  202  and configured to illuminate only when the modular power charging unit is in the power on state. In other aspects of the modular power charging unit  200 , the electrical port component  202  may be a charging interface and/or an electrical power outlet. 
     In additional aspects of the modular power unit, the housing  206  includes a back panel  232  with an opening  207  through which the electrical cable harness  205  extends to place the power input pin and the ground pin outside of the housing. The housing  206  is secured to the wall  500  by mounting hardware, e.g., screws, that extends into mounting holes  506   a - d  formed in the wall so that the back panel  232  of the housing is flush with a surface of the wall. The mounting holes  506   a - d  may extend only partially into the wall  500 . The housing  206  includes a grommet  234   a  surrounding the opening  207  of the back panel  232 , and the grommet has a maximum cross sectional dimension d that enables placement of the grommet into a cable-harness hole  502  through the wall  500 . The cable-harness hole  502  has a maximum cross sectional dimension that preserves the structural integrity of the wall  500  and the aircraft monument. 
     The various aspects of this disclosure are provided to enable one of ordinary skill in the art to practice the present invention. Various modifications to exemplary embodiments presented throughout this disclosure will be readily apparent to those skilled in the art. Thus, the claims are not intended to be limited to the various aspects of this disclosure, but are to be accorded the full scope consistent with the language of the claims. All structural and functional equivalents to the various components of the exemplary embodiments described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims.