Patent Publication Number: US-2023163382-A1

Title: Portable power supply

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application No. 63/282,477 filed on Nov. 23, 2021, U.S. Provisional Patent Application No. 63/304,336 filed on Jan. 28, 2022, and U.S. Provisional Patent Application No. 63/407,921 filed on Sep. 19, 2022, the entire contents of which are incorporated by reference herein. 
    
    
     FIELD 
     The present disclosure relates to structures having a housing, and more particularly to structures such as a storage container, a battery storage container, a battery, a battery charger, and a power tool. 
     BACKGROUND 
     The internal temperature of a power supply can increase over time due to extended periods of use, extended exposure to solar irradiation, and other reasons. When a first entity is relatively colder than a second entity, bringing the first entity and the second entity together will yield a resultant temperature for both entities that is somewhere between the relatively lower temperature of the first entity and the relatively higher temperature of the second entity. 
     SUMMARY 
     The disclosure provides, in one aspect, a portable power supply including a housing, at least one battery cell, a charger, and an attachment. The housing defines a cavity. The housing includes an upper portion, a lower portion, a plurality of air inlets defined in the lower portion, and a plurality of air outlets defined in the upper portion. The plurality of air inlets is in fluid communication with the cavity. The plurality of air outlets is in fluid communication with the cavity. The at least one battery cell is disposed in the cavity. The charger is electrically coupled with the battery cell. The attachment is coupled to the upper portion. The attachment is configured to at least partially cover each of the air outlets such that airflow exiting the air outlets travels a circuitous path. 
     In some aspects of the portable power supply, the at least one of the plurality of air inlets is additionally configured as a liquid drain opening. 
     In some aspects of the portable power supply, the attachment includes at least one coupling interface provided on a surface of the attachment that is opposite the upper portion. 
     In some aspects of the portable power supply, the air outlets are upwardly facing. 
     In some aspects, the attachment includes a wall angled relative to an axis that is defined by and extends through the air outlets such that the wall redirects airflow. 
     In some aspects, the attachment includes a downwardly depending sidewall. The downwardly depending sidewall defines a plurality of attachment outlet apertures such that airflow redirected by the wall is configured to exit through the attachment outlet apertures. 
     In some aspects, the upper portion includes an upwardly extending ridge disposed adjacent the air outlets. 
     In some aspects, the upper portion further includes a drainage trough, the ridge disposed between the drainage trough and the air outlet. 
     In some aspects, the attachment includes a gap between the downwardly depending sidewall and the wall, the gap in fluid communication with the drainage trough. 
     In some aspects, the drainage trough extends along at least a portion of the perimeter of the upper portion. 
     In some aspects, the upper portion further includes a plurality of drainage openings, and the drainage trough is in fluid communication with the drainage opening. 
     In some aspects, the charger is disposed in the cavity. 
     The disclosure provides, in another aspect, a portable power supply including a housing, a fan, at least one battery cell, and a charger. The housing includes an outer wall, an inner wall, and an airflow passage. The inner wall defines a cavity in the housing. The airflow passage is disposed between the outer wall and the inner wall. The fan is coupled to the housing. The fan is configured to force airflow through the airflow passage. The at least one battery cell is disposed in the cavity. The charger is electrically coupled with the battery cell. 
     In some aspects, the outer wall is coupled to the inner wall by a plurality of fasteners. 
     In some aspects, the fan is disposed between the inner and the outer wall. 
     In some aspects, an inlet of the airflow passage is formed in the portable power supply at a location opposite from an outlet of the airflow passage such that airflow entering the inlet travels in a direction that is parallel to a direction of airflow exiting the outlet. 
     In some aspects, the airflow passage is disposed within a majority of a perimeter of a cross-section of the portable power supply. 
     In some aspects, the charger is disposed within the cavity. 
     The disclosure provides, in another aspect, a portable power supply including a housing, at least one battery cell, and a charger. The housing defines a cavity. The housing includes an upper portion, a lower portion, a plurality of air inlets defined in the lower portion, and a plurality of air outlets defined in the upper portion. The plurality of air inlets is in fluid communication with the cavity. The plurality of air outlets is in fluid communication with the cavity. The plurality of air outlets open laterally. The at least one battery cell is disposed in cavity. The charger is electrically coupled with the battery cell. 
     In some aspects, a deflector is disposed in the cavity. The deflector is disposed in the cavity. The deflector and the upper portion cooperating to define a duct including a downwardly opening portion. At least on of the plurality of air inlets is aligned vertically with the downwardly opening portion. 
     In some aspects, the upper portion includes an interface configured to receive a lower portion of a stacking interface. 
     In some aspects, the upper portion includes one or more raised upper surfaces. The plurality of air outlets is opened laterally between a top surface of the upper portion and the one or more raised upper surfaces. 
     In some aspects, the cavity is one of a plurality of cavities. 
     In some aspects, the portable power supply further includes an attachment coupled to the upper portion. The attachment is configured to at least partially cover each of the air outlets such that airflow exiting the air outlets travels a circuitous path. 
     The disclosure provides, in another aspect, a portable power supply including a housing, at least one battery cell, a charger, and a frame. The housing defines a cavity. The housing includes an upper portion, a lower portion, and a plurality of vents. The plurality of vents is defined in the housing. The plurality of vents is configured to release heated air from within the cavity. The at least one battery cell is disposed in the cavity. The charger is electrically coupled with the battery cell. The frame extends around the housing. A portion of the frame at least partially covers the plurality of vents. 
     In some aspects, the frame is positioned at a distance from the plurality of vents. 
     In some aspects, the housing comprises a polymer. The housing includes one or more weld lines. At least one of the weld lines extends in a direction transverse to at least one of the plurality of vents. 
     In some aspects, the housing further includes a plurality of louvers that define the plurality of vents. At least one louver is intersected by a respective weld line. 
     The disclosure provides, in another aspect, a portable power supply including a housing, a first subsystem, a first fan, a second subsystem, a second fan, and an airflow duct. The housing defines a cavity therein. The first subsystem is disposed within the cavity. The first subsystem emits heat. The first fan is configured to induce a first exhaust airflow in a first direction, thereby transferring heat away from the first subsystem in the first direction. The second subsystem is disposed within the cavity. The second subsystem emits heat. The second fan is configured to induce a second exhaust airflow in a second direction, thereby transferring heat away from the second subsystem. The airflow duct receives the first exhaust airflow and the second exhaust airflow. The airflow duct redirects the first exhaust airflow and the second exhaust airflow out of the housing. 
     In some aspects, the airflow duct includes a baffle that defines a first subchannel and a second subchannel within the airflow duct. The first subchannel receives the first exhaust airflow, and the second subchannel receives the second exhaust airflow. 
     In some aspects, one of the first fan and the second fan is integrally formed with the airflow duct. 
     In some aspects, the airflow duct is a first airflow duct, and the portable power supply further includes a second airflow duct. 
     In some aspects, the first airflow duct receives a portion of the first exhaust airflow and a portion of the second exhaust airflow. The second airflow duct receives another portion of the first exhaust airflow and another portion of the second exhaust airflow. 
     In some aspects, the airflow duct includes a plurality of drain holes for directing flow of environmental ingress out of the housing. 
     In some aspects, the first subsystem is a battery subsystem, and the second subsystem is a charger subsystem. 
     In some aspects, the housing includes a mounting port for coupling the second subsystem to the housing. The airflow duct is couplable to the same mounting port as the second subsystem. 
     In some aspects, the air duct redirects the first exhaust airflow out of the housing along a third direction, and the air duct redirects the second exhaust airflow out of the housing along the third direction, and the third direction extends transverse to the first direction and the second direction. 
     In some aspects, the first direction is orthogonal to the second direction. 
     The disclosure provides, in another aspect, a portable power supply including a housing, a first subsystem, a second subsystem, and an airflow duct. The housing defines a cavity therein. The first subsystem is disposed within the cavity. The first subsystem emits heat. The second subsystem is disposed within the cavity. The second subsystem emits heat. The airflow duct includes a channel defined therein and a baffle. The baffle extends through the channel such that the channel is divided into a first subchannel and a second subchannel. The first subchannel receives a first exhaust airflow transferring heat from the first subsystem. The second subchannel receives a second exhaust airflow transferring heat from the second subsystem. 
     In some aspects, the portable power supply further includes a fan that is in fluid communication with the first subchannel. 
     In some aspects, the first subchannel is larger than the second subchannel. 
     In some aspects, the air duct further includes a seal provided on a periphery of the air duct at an outlet opening of the channel. The seal is formed with a thermoplastic elastomer overmold that creates an interference between a housing of the portable power supply and the outer housing of the air duct. 
     The disclosure provides, in another aspect, a portable power supply including a housing, a control system, a subsystem, and an airflow duct. The housing defines as cavity therein. The control system is disposed in the cavity and is configured to control operation of the portable power supply. The subsystem is sealed within the cavity. The subsystem emits heat. The airflow duct includes a fan for directing heat out of the housing and a thermistor for monitoring a temperature within the cavity and the airflow duct. The thermistor is configured to convey a temperature signal to the control system. 
     In some aspects, the thermistor is positioned downstream of the fan. 
     In some aspects, the control system inhibits operation of the portable power supply when the control system receives a temperature signal from the thermistor indicating that an ambient system temperature is outside of an operating temperature range for the portable power supply. 
     In some aspects, the airflow duct is a first airflow duct including a first fan and a first thermistor. The portable power supply further includes a second airflow duct having a second fan and a second thermistor. The control system inhibits operation of the portable power supply when the control system receives a temperature signal from at least one of the first thermistor and the second thermistor indicating that an ambient system temperature is outside of an operating temperature range for the portable power supply. 
     Other features and aspects of the invention will become apparent by consideration of the following detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a cross-sectional side view of a portable power supply. 
         FIG.  2    perspective view of the portable power supply of  FIG.  1    with an attachment missing. 
         FIG.  3    is a top view of the portable power supply of  FIG.  2   . 
         FIG.  4    is a perspective view of a section “A” of the portable power supply of  FIG.  1    with the attachment missing. 
         FIG.  5    is an exploded perspective view of the portable power supply of  FIG.  1   . 
         FIG.  6    is an enhanced side view of the portable power supply of  FIG.  5     
         FIG.  7    is a top view of the portable power supply of  FIG.  1   . 
         FIG.  8    is a side view of the section “A” of the portable power supply of  FIG.  1   . 
         FIG.  9    is a perspective view of the section “A” of the portable power supply of  FIG.  1   . 
         FIG.  10    is a cross sectional view of a portable power supply. 
         FIG.  11    is a section view of the cross-sectional view of the portable power supply of  FIG.  10   . 
         FIG.  12    is a top view of a portable power supply. 
         FIG.  13    is a section view of the portable power supply of  FIG.  12   . 
         FIG.  14    is a top view of the portable power supply of  FIG.  12   . 
         FIG.  15    is a perspective view of an attachment and a stackable interface of the portable power supply of  FIG.  12   . 
         FIG.  16   . is a perspective view of the attachment and the stackable interface of  FIG.  15    and the portable power supply of  FIG.  12   . 
         FIG.  17    is a section view of the portable power supply of  FIG.  12   . 
         FIG.  18    is a cross-sectional side view of the portable power supply of any of  FIG.  1   ,  FIG.  10   , and  FIG.  12   . 
         FIG.  19    is a perspective view of the portable power supply of  FIG.  1   . 
         FIG.  20    is a side section view of the portable power supply of  FIG.  1   . 
         FIG.  21    is a schematic view of the portable power supply according to any of the embodiments of  FIG.  1   ,  FIG.  10   , and  FIG.  12   . 
         FIG.  22    is another schematic view of the portable power supply according to any of the embodiments of  FIG.  1   ,  FIG.  10   , and  FIG.  12   . 
         FIG.  23    is a schematic view of a portable power supply according to another embodiment of the disclosure. 
         FIG.  24    is a perspective view of a combination air duct for the portable power supply of  FIG.  23   . 
         FIG.  25    is another schematic view of the portable power supply of  FIG.  23   . 
         FIG.  26    is another perspective view of the combination air duct for the portable power supply of  FIG.  24   . 
         FIG.  27    is a schematic view illustrating installation of a combination air duct for the portable power supply of  FIG.  23   . 
         FIG.  28    is a schematic view illustrating installation of the combination air duct and a subsystem for the portable power supply of  FIG.  23   . 
         FIG.  29    is a perspective view of a portion of the portable power supply of  FIG.  23   . 
         FIG.  30    is a perspective view of a subsystem for the portable power supply of  FIG.  23    according to an embodiment of the disclosure. 
         FIG.  31    is a graphical illustration of performance of the portable power supply. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS.  1 - 2    illustrate a portable power supply  5  having a battery  10 , a charger  15 , an inverter  20 , a housing  25  that defines a cavity  28  in the interior of the housing  25  such that the battery  10 , the charger  15 , and the inverter  20  are disposed within the cavity  28 . The housing  25  further includes a lower portion  35 , an upper portion  40 , a plurality of air inlets  45  defined in the lower portion  35 , and a plurality of air outlets  50  defined in the upper portion. The plurality of air inlets  45  is in fluid communication with the cavity  28 . The plurality of air outlets  50  is in fluid communication with the cavity  28  such that the plurality of air inlets  45  and the plurality of air outlets are in fluid communication with each other. The portable power supply  5  further includes a user interface  55  and an attachment  60 . In the illustrated embodiment, the attachment  60  is a charging plate that is configured to electrically engage chargeable objects (e.g., batteries), as will be described in more detail below. The attachment  60  is coupled to the upper portion  40  and configured to at least partially cover each of the plurality of air outlets  50  such that airflow exiting the plurality of air outlets  50  travels a circuitous path. In other embodiments, any one of the battery  10 , the charger  15  and the inverter  20  may be positioned outside of the cavity  28 . In further embodiments, the portable power supply  5  may just have one or any combination of the battery  10 , the charger  15 , and the inverter  20 . 
     In the present embodiment, the battery  10  may have any suitable chemistry for storing and providing electricity, or energy. For example, the battery  10  may be formed of Lithium-ion (Li-ion), Nickel-Cadmium (Ni—Cad), or other suitable chemistry. The charger  15  is positioned adjacent the battery  10  within the cavity  28  such that the battery  10  may be electrically connected to the charger  15 . The charger  15 , cooperating with an external powering means, is configured to charge the battery  10 . In some embodiments, the charger  15  may be positioned outside of the cavity  28 . The battery  10  may output electricity via a direct current (i.e., DC) to the inverter  20 . The inverter  20  transforms the direct current provided by the battery  10  into an alternating current (i.e., AC), and thus, the portable power supply  5  is configured to provide, or output, an alternating current. As such, the portable power supply  5  may function, in a non-limiting manner, substantially similarly to an electric wall outlet. In some embodiments, the portable power supply  5  may not include the inverter  20 . In such embodiments, the battery  10  is a battery pack including one or more battery cells configured to provide electricity to, for example, a power tool. 
     The housing  25  is surrounded by a frame  65  that includes a plurality of bar members  70 . In the illustrated embodiment, the frame  65  is provided such that the frame  65  envelops the outer periphery of the portable power supply  5 . That is, the frame  65  is provided on each side of the portable power supply  5 . As such, the frame  65  provides support for the portable power supply  5  when the portable power supply  5  is in an upright position as illustrated in  FIG.  2   . The frame is also configured to support the portable power supply  5  if the portable power supply  5  is tipped over from the upright position illustrated in  FIG.  2   . The frame  65  further includes a handle portion  75 . The handle portion  75  is configured to be gripped by a user for the purpose of transporting the portable power supply  5 . In some embodiments, the frame  65  may be metal. In other embodiments, the frame  65  may not be formed as a unitary body such that the frame  65  includes separate individual components positioned in any orientation around the housing  25 . In further embodiments, the portable power supply  5  may not have a frame  65 . 
     As illustrated in  FIGS.  19 - 20   , the portion of the frame  65  covering the bottom of the portable power supply  5  is advantageously positioned adjacent vents  80  that are defined in the housing  25  of the portable power supply  5 . In the illustrated embodiment, the housing  25  includes louvers  81  provided at corners of the lower portion  35  of the housing  25 . The louvers  81  define the vents  80 . The louvers  81  may be structurally weaker, and therefore, more prone to fracture, than the rest of the housing  25 . The vents  80  are configured to release warm, or heated, air from within the cavity  28  of  FIG.  1   . The frame  65  is positioned such that the frame  65  at least partially blocks external objects (e.g., a ball  82  as shown in  FIG.  19 - 20   ) from directly hitting the louvers  81 . In some embodiments, the frame  65  may be positioned at a distance from the louvers  81 . That is, the frame  65  may be positioned such that the frame  65  does not directly touch the louvers  81 . In absence of the frame  65 , the ball  82 , or another similar object, may directly hit the louvers  81 , thereby fracturing the louvers  81 . Therefore, the bottom portion of the frame  65  increases protection and durability of the louvers  81 , and thus, the vents  80 . 
     Additionally, with reference to  FIG.  20   , weld lines (e.g., knit lines)  84  for the housing  25  are advantageously positioned adjacent to and under cover of the bottom portion of the frame  65 . The weld lines  84  extend in a direction transverse to the opening of at least one corresponding vent  80 . As such, each weld line  84  may intersect at least one corresponding louver  81 . The weld lines  84  have relatively lower material strength in a plastic mold than other areas of the plastic mold such that the weld lines  84  have a higher risk of fracture. By placing the weld lines  84  under cover of the frame  65 , the risk of fracture is reduced, thereby increasing durability and longevity of the portable power supply  5 . While the frame  65  covers the vents  80  and the weld lines  84  on the lower portion  35  of the portable power supply  5  in  FIGS.  19 - 20   , the frame  65  may additionally cover vents  80  and weld lines  84  positioned elsewhere on the portable power supply  5 . 
     With reference to  FIG.  2   , the lower portion  35  of the housing  25  in the present embodiment is formed of a solid material such as, but not limited to, a plastic (e.g., a polymer). In some embodiments, the lower portion  35  may be formed of a different material. The lower portion  35  includes a plurality of exterior channels  85  positioned between a plurality of exterior ridges  90 . At least one of the plurality of bars  70  (e.g. a portion of the frame  65 ) is positioned within a corresponding one of the plurality of exterior channels  85 . The handle portion  75  is positioned adjacent the lower portion  35  in the illustrated embodiment. In other embodiments, the lower portion  35  may not include the plurality of exterior channels  85  and/or the plurality of exterior ridges  90 . In further embodiments, the frame  65  may not include a portion that is positioned within a corresponding one of the plurality of exterior channels  85 . In yet further embodiments, the handle portion  75  may be positioned elsewhere on the portable power supply  5 . 
     With reference to  FIGS.  2 - 4   , in the illustrated embodiment, the upper portion  40  of the housing  25  is formed of a solid material such as, but not limited to, a plastic. The upper portion  40  is configured to couple with and lie upon the lower portion  35 . The user interface  55  is provided on the upper portion  40 . In some embodiments, the user interface  55  may be positioned elsewhere on the portable power supply  5 . A surface  95  (i.e., a top surface) of the upper portion  40  includes an attachment receiving portion  100 . The attachment receiving portion  100  has a generally square shape and includes a first set of walls  105  and a second set of walls  110  that define a plurality of drainage openings  115 . Each of the first set of walls  105  includes a first vertical portion  120 , a sloped portion  125  and a second vertical portion  130 . Each of the first set of walls  105  is positioned opposite the other of the first set of walls  105 . Each of the second set of walls  110  is positioned opposite the other of the second set of walls  110 . In the illustrated embodiment, the first set of walls  105  includes two walls, and the second set of walls  110  includes two walls such that the attachment receiving portion  100  is formed in the shape of a square. As such, each of the first set of walls  105  is adjacent to the two walls of second set of walls  110 , and each of the second set of walls  110  is adjacent to the two walls of the first set of walls  105 . In other embodiments, the attachment receiving portion  100  may be positioned elsewhere on the portable power supply  5 . In further embodiments, the attachment receiving portion  100  may be formed in a generally different shape than a square such that the attachment receiving portion  100  includes more, fewer, or the same number of walls. In still further embodiments, the attachment receiving portion  100  may not have any walls. In any of the embodiments disclosed above, the lower portion  35  and the upper portion  40  may form one continuous structure. 
     Returning reference to  FIGS.  1 - 2   , in the illustrated embodiment, the plurality of air inlets  45  is positioned at and defined in a bottom of the lower portion  35  and is in fluid communication with the cavity  28 . In other embodiments, the plurality of air inlets  45  may be positioned elsewhere on the portable power supply  5  such as on a side of the portable power supply  5 . The plurality of air inlets  45  is configured to permit airflow to enter the cavity  28 . The airflow entering the plurality of air inlets  45  is relatively cooler in temperature than the air throughout the cavity  28 . The entering airflow may then interact with the battery  10 , the charger  15 , and the inverter  20  to cool the battery  10 , the charger  15 , and the inverter  20 . In the illustrated embodiment, at least one of the plurality of air inlets  45  may also be configured as a liquid drain opening of the portable power supply  5 . That is, the air inlets  45  may be configured to receive condensation produced within the cavity  28  of the portable power supply  5  and further configured to provide an outlet for said condensation to exit the cavity  28  of the portable power supply  5 . 
     With reference to  FIGS.  3 - 4   , the plurality of air outlets  50  is positioned at and defined in the upper portion  40  of the portable power supply  5 . The plurality of air outlets  50  is in fluid communication with the cavity  28  ( FIG.  1   ) and the plurality of air inlets  45 . In the illustrated embodiment, the plurality of air outlets  50  is positioned adjacent to and is partially formed in the first set of walls  105 . The plurality of air outlets  50  defines an outlet axis A 1  that extends through the plurality of air outlets  50 . An opening to each of the plurality of air outlets  50  faces upwardly. That is, the opening to each of the plurality of air outlets  50  is defined in the top surface  95  of the upper portion  40  and faces away from the upper portion  40 . The upper portion  40  further includes a drainage trough  135  that is formed in the upper portion  40  of the housing  25  such that the first set of walls  105  is positioned between the drainage trough  135  and the plurality of air outlets  50 . The drainage trough  135  extends along at least a portion of the perimeter of the upper portion  40  of the housing. The drainage trough  135  is in fluid communication with the second set of walls  110 . More specifically, the drainage trough  135  is in fluid communication with the plurality of drainage openings  115 . The drainage trough  135  is sloped such that portions of the drainage trough  135  closer to the second set of walls  110 , and thus closer to the plurality of drainage openings  115 , are relatively lower than portions of the drainage trough  135  that are located further from the second set of walls  110 , and thus further from the plurality of drainage openings  115 . 
     In some embodiments, the plurality of air outlets  50  may be positioned elsewhere in the upper portion  40 . In other embodiments, the upper portion  40  may not include a drainage trough  135  or the drainage trough  135  may have other configurations than the sloped configuration of the illustrated embodiment. In even further embodiments. The drainage trough  135  may extend in different orientations and directions than those of the illustrated embodiment. 
     With reference to  FIG.  2   , in the illustrated embodiment, the user interface  55  includes a plurality of user operation screens  140 . The user operation screens  140  may supply information to a user such as, but not limited to, battery life of the portable power supply  5 , internal temperature of the portable power supply  5 , and/or power output of the portable power supply  5 . The user interface  55  may further be configured to allow a user to switch the portable power supply  5  on and off. The user interface  55  may further be configured to allow an external powering means to engage with the charger  15 . That is, the user interface  55  may include a port that is configured to receive an external powering means. In the illustrated embodiment, the user interface  55  is positioned on a surface of the upper portion  40  that is directly above the handle portion  75 . 
     In reference to  FIGS.  5 - 8   , the attachment  60  is configured to couple to the portable power supply  5  at the attachment receiving portion  100 . A plurality of fasteners  145  are configured to secure the attachment  60  to the portable power supply  5 . In the illustrated embodiment, the fasteners  145  extend from a position within the upper portion  40  of the housing  25 , through the attachment receiving portion  100 , and into a plurality of fastener receiving holes  150  formed in the attachment  60 . Stated another way, the plurality of fasteners  145  extend upwardly through the attachment receiving portion  100  and into the plurality of fasteners receiving holes  150  in the attachment  60 . As such, the attachment  60  is coupled to the portable power supply  5  such that the plurality of fasteners  145  is not accessible to a user from an exterior location of the portable power supply  5 . When coupled, the attachment  60  substantially covers the attachment receiving portion  100 . In the present embodiment, the fasteners  145  are screws. In other embodiments, the attachment  60  may be coupled to the attachment receiving portion  100  by a different fastening means such that the fasteners  145  are accessible to a user. 
     With reference to  FIGS.  5  and  7   , the attachment  60  includes at least one coupling interface  155  formed on a surface of the attachment  60  that is opposite the upper portion  40 . In the illustrated embodiment, the attachment  60  includes ten coupling interfaces  155 . More specifically, the attachment  60  includes eight roughly square shaped coupling interfaces  155   a  and two roughly rectangular coupling interfaces  155   b . In other embodiments, the attachment  60  may include more or fewer coupling interfaces  155  of differing shapes and sizes. The inverter  20  ( FIG.  1   ) is configured to transmit an alternating current to the attachment  60  such that the attachment  60  is configured to supply power at the coupling interfaces  155 . The attachment  60  may be configured to supply power to one or multiple of the coupling interfaces  155  at a time. 
     Referring to  FIGS.  8 - 9   , the attachment  60  of the illustrated embodiment further includes a wall  160  that is provided around the outer periphery of the attachment  60 . The wall  160  extends transversely to the outlet axis A 1  such that the wall  160  is configured to redirect airflow flowing through the plurality of air outlets  50 . The attachment  60  further includes a downwardly depending sidewall  165  that extends from the wall  160 . The downwardly depending sidewall  165  defines a plurality of attachment air outlets  170 . When the attachment  60  is coupled to the upper portion  40  of the housing  25 , the downwardly depending sidewall  165  is positioned above the first vertical portion  120  of the first set of walls  105  of the upper portion  40 . As such, a gap  175  is defined between an inside surface of each of the downwardly depending sidewalls  165 , the wall  160 , the first vertical portion  120  of the first set of walls  105 , the sloped portion  125  of the first set of walls  105 , and the second vertical portion  130  of the first set of walls  105  such that the gap  175  is in fluid communication with the drainage trough  135 . In other embodiments, the attachment  60  may include components with different shapes, structures, and sizes oriented at different angles than that of the illustrated embodiment. 
     Returning reference to  FIG.  1   , in operation of the portable power supply  5 , the portable power supply  5  may be cooled when relatively cooler ambient air enters the portable power supply  5  through the plurality of air inlets  45 . The relatively cool air rises through the cavity  28 , cooling the battery  10 , the charger  15  and the inverter  20 . Warm air exhausted, or released, by any one of the battery  10 , the charger  15 , and the inverter  20  may rise to the plurality of air outlets  50 . With reference to  FIGS.  8 - 9   , the wall  160  on the attachment  60  redirects the flow of warm air to the downwardly depending sidewall  165 . The flow of warm air may then exit the portable power supply  5  via the plurality of attachment outlets  170 , thereby lowering the internal temperature of, or cooling, the portable power supply  5 . Any moisture (e.g. condensed water) formed within the cavity  28  ( FIG.  1   ) may exit the cavity  28  ( FIG.  1   ) through the at least one of the plurality of air inlets (e.g. liquid drain openings)  45 . Further, any moisture (e.g. condensed water) formed in the plurality of air outlets  50  from the flow of warm air as the flow of warm air is exhausted from the portable power supply  5  is directed to the drainage trough  135  by the downwardly depending sidewall  165 , the second vertical portion  130 , the sloped portion  125 , and the first vertical portion  120 . The moisture may then travel along the drainage trough  135  until the moisture reaches the second set of walls  110 , and more specifically, the plurality of drainage openings  115 , to exit the portable power supply  5 . Airflow and moisture may enter, pass through, and/or exit from the portable power supply  5  with respect to any alternative features of the previously disclosed embodiments. In further embodiments, the portable power supply  5  may include fans (not shown) for active airflow cooling through vents (not shown). In such embodiments, the portable power supply  5  may be cooled entirely by passive airflow as described above, entirely by active airflow brought about by the fans, or any combination of passive airflow and active airflow. 
       FIGS.  10 - 11    illustrate a portable power supply  205  according to another embodiment of the disclosure. The portable power supply  205  of  FIGS.  10 - 11    may be substantially similar to the portable power supply  5  of  FIGS.  1 - 9    except for the differences described below. As illustrated in  FIG.  10   , the portable power supply  205  includes a housing  225  having an outer wall  230 , an inner wall  235 , and an airflow passage  240  defined between the outer wall  230  and the inner wall  235  such that a fan  242  is coupled to the housing  225 . The fan  242  is configured to induce airflow through the airflow passage  240 . In the illustrated embodiment, the fan  242  is positioned outside of and is coupled to the housing  225 . In other embodiments, the fan  242  may be disposed between the outer wall  230  and the inner wall  235 . 
       FIG.  10    displays a cross-section of the portable power supply  205 . In the illustrated embodiment, a plurality of fasteners  245  couples the outer wall  230  to the inner wall  235  such that the outer wall  230  is adjacent to but does not touch the inner wall  235 . Each of the plurality of fasteners  245  extends through a corresponding one of a plurality of buffers  250  that extend between the outer wall  230  and the inner wall  235 . The portable power supply  205  includes an inlet  255  to the airflow passage  240  on a first side  260  of the portable power supply  205 , and an outlet  270  of the airflow passage  240  positioned on a second side  265  that is opposite the first side  260 . In other words, the inlet  255  of the airflow passage  240  is opposite the outlet  270  of the airflow passage  240  such that the direction of airflow flowing into the portable power supply  205  is parallel to the direction of airflow flowing out of the portable power supply  205 . The airflow passage  240  is disposed in a majority of a perimeter of the cross-section of the portable power supply  205 . In other words, the airflow passage  240  travels through at least half, or 50%, of the perimeter of the cross-section of the portable power supply  205 . Airflow enters through the inlet  255  of the airflow passage  240  positioned on the first side  260  of the portable power supply  205  and travels up to a top side  275  of the portable power supply  205 . The airflow then travels across the top side  275  from the first side  260  to the second side  265  of the portable power supply  205  and down to the outlet  270  of the airflow passage  240  such that the airflow passage  240  covers roughly 75% of the perimeter of the cross-section of the portable power supply  205 . 
     In some embodiments, the outer wall  230  may couple to the inner wall  235  by another coupling means such as, but not limited to, welding. In other embodiments, the outer wall  230  and the inner wall  235  may be one singular entity such that a second cavity is defined within, the airflow passage  240  travelling through the second cavity. In further embodiments, the inlet  255  of the airflow passage  240  may be positioned elsewhere on the portable power supply  205  such as, but not limited to, a top or bottom in which airflow entering the inlet  255  of the airflow passage  240  may or may not be parallel to airflow exiting the outlet  270  of the airflow passage  240 . In even further embodiments, a fan  242  ( FIG.  11   ) may be inside or outside of the portable power supply  205  and configured to induce airflow through an airflow passage  240 . 
     With reference to  FIG.  11   , the outer wall  230  has an outer surface  230   a  that faces away from the portable power supply  205  and an inner surface  230   b  that faces inwards towards the portable power supply  205 . The outer wall  230  is made of a plastic material having a low thermal conductivity and a low thermal diffusivity. The outer surface  230   a  has a high total solar reflectance. A high total solar reflectance results in the outer surface  230   a  having a low absorptivity to emissivity ratio. Alternatively, the outer surface  230   a  may be opaque in some embodiments. In such embodiments, a high total reflectance results in the outer surface  230   a  having a low ratio of the difference between one and reflectivity (i.e., one minus reflectivity) to emissivity. The inner surface  230   b  has a low emissivity. 
     The inner wall  235  has an outer surface  235   a  that faces away from the portable power supply  205  and towards the outer wall  230 . The inner wall  235  is made of a plastic material having a low thermal conductivity and a low thermal diffusivity. In some embodiments, the outer surface  235   a  has a high total solar reflectance. A high total solar reflectance results in the outer surface  235   a  having a low absorptivity to emissivity ratio. In other embodiments, the outer surface  235   a  is not directly exposed to solar irradiation, and therefore may not require a high total solar reflectance. Alternatively, the outer surface  235   a  may be opaque in some embodiments. In such embodiments, a high total reflectance results in the outer surface  235   a  having a low ratio of the difference between one and reflectivity (i.e., one minus reflectivity) to emissivity. In some embodiments, the outer wall  230  and the inner wall  235  may be made of the same plastic material such that the outer wall  230  and the inner wall  235  have the same relatively low thermal conductivity and thermal diffusivity. Further, the outer surface  230   a  of the outer wall  230  and the outer surface  235   a  of the inner wall  235  may have the same surface properties such that the two outer surfaces  230   a ,  235   a  have the same relatively high total reflectance. In other embodiments, the outer wall  230  and the inner wall  235  may be formed of different plastic materials such that one of the outer wall  230  and the inner wall  235  has a relatively higher one or both of thermal conductivity and thermal diffusivity than the other of the outer wall  230  and the inner wall  235 . In such embodiments, one of the outer surfaces  230   a ,  235   a  may have a relatively lower total solar reflectance than the other of the outer surfaces  230   a ,  235   a.    
       FIGS.  12 - 17    illustrate a portable power supply  405  according to another embodiment of the disclosure. The portable power supply  405  may be substantially similar to the portable power supply  5  of  FIGS.  1 - 9    and the portable power supply  205  of  FIGS.  10 - 11    except for the differences described below. As illustrated in  FIGS.  12  and  13   , the portable power supply  405  includes a housing  425  having a plurality of air inlets, such as the air inlets  45  of  FIG.  1   , that are in fluid communication with a cavity, such as the cavity  28  of  FIG.  1   , although the air inlets and the cavity are not illustrated in  FIG.  12   . The housing  425  further includes a plurality of air outlets  450  in fluid communication with the cavity. The plurality of air outlets  450  is opened laterally between an upper surface  455  and a raised upper surface  460 , both of which are positioned on an upper portion  440  of the housing  425 . The raised upper surface  460  may be one of a multiple of raised upper surfaces  460 . In the illustrated embodiment, there are two raised upper surfaces  460   a ,  460   b . Some of the plurality of air outlets  450  may face outwardly from the center of the portable power supply  405 . Another some of the plurality of air outlets  450  may face inwardly toward the center of the portable power supply  405 . 
     With reference to  FIGS.  12  and  15   , the upper portion  440  includes an interface  465  configured to receive an attachment stacking interface  470 . In the illustrated embodiment, the stacking interface  470  is a toolbox having charging inlets. In other embodiments, the stacking interface  470  may be another chargeable structure. In the illustrated embodiment, the interface  465  includes the upper surface  455 , the raised upper surfaces  460   a ,  460   b , and a plurality of latches  475 . The stacking interface  470  may fit on top of one or both of the upper surface  455  and the raised upper surfaces  460   a ,  460   b  and is secured in place by the plurality of latches  475 . A handle  480  is disposed within the upper surface  455  between the two raised upper surfaces  460   a ,  460   b . The stacking interface  470  covers the handle  480  when the stacking interface  470  is coupled to the portable power supply  405 . The portable power supply  45  further includes supplementary handles  485   a ,  485   b  that are disposed on a corresponding side of the portable power supply  405  for use when the handle  480  is covered by the stacking interface  470 . 
     With additional reference to  FIG.  13   , the stacking interface  470  lies on top of the raised upper surface  460  such that a space  490  exists between the stacking interface  470  and the upper surface  455  in the illustrated embodiment. The space  490  defines a height H which is equal to distance between the raised upper surfaces  460   a ,  460   b  and the upper surface  455 . The plurality of air outlets  450  opens laterally such that airflow is redirected as the airflow flows through the portable power supply  405  similarly to the portable power supply  5  of  FIGS.  1 - 9   . More specifically, airflow is configured to enter the portable power supply  405  substantially similarly to the portable power supply  5  of  FIGS.  1 - 9    and is configured to cool inner components of the portable power supply  405  (e.g., the battery  10 , the charger  15 , and the inverter  20  of  FIG.  1   ). Warm air released by the inner components of the portable power supply  405  rises to the laterally opened plurality of air outlets  450  such that air rising vertically is redirected horizontally by the raised upper surface  460  and the stacking interface  470  to exit the plurality of air outlets  450  and cool the portable power supply  405 . 
     In some embodiments, as illustrated in  FIGS.  14  and  15   , the portable power supply  405  is configured to receive an attachment  500  that is substantially similar to the attachment  60  of  FIG.  5   . The is attachment  500  is mountable to the raised upper surfaces  460   a ,  460   b  such that the plurality of air outlets  450  is opened laterally between the upper surface  455  and the attachment  500 . As illustrated in  FIGS.  15  and  16   , the attachment  500  includes the plurality of latches  502  for coupling and securing the stacking interface  470 . Although not shown in  FIGS.  15  and  16   , the attachment  500  of the illustrated embodiment includes a plurality of coupling interfaces that is substantially similar to the plurality of coupling interfaces  155  of  FIG.  7   . The plurality of coupling interfaces is positioned on a surface of the attachment  500  that is opposite, or faces away, from the upper portion  440 . The plurality of coupling interfaces is configured to engage the stacking interface  470 , or another similar structure, to provide electricity thereto. 
       FIG.  17    displays a section view of one of the plurality of air outlets  450 . The upper surface  455  includes a first set of walls, or upwardly extending ridges,  505  positioned adjacent to the corresponding one of the plurality of air outlets  450 . The upwardly extending ridges  505  include a first vertical portion  520 , a sloped portion  525 , and a second vertical portion  530 . The attachment  500  includes an upper wall  560  angled relative to an axis, b, defined by and extending through the plurality air outlets  450  such that the upper wall  560  redirects airflow. A downwardly depending sidewall  565  extends from the upper wall  560  and includes a plurality of attachment outlets  570  through which airflow is configured to exit the portable power supply  405 . 
     With reference to  FIG.  18   , any of the previously disclosed embodiments of the portable power supply  5 ,  205 ,  405  ( FIGS.  1 ,  10 , and  12   ) may include a deflector  600 . Although each portable power supply  5 ,  205 ,  405  ( FIGS.  1 ,  10 , and  12   ) may include the deflector  600 , for the sake of brevity, the deflector  600  is described just with respect to the portable power supply  5  of  FIG.  1   . The description of the deflector applies equally to the portable power supply  205 ,  405  of  FIGS.  10  and  12   . As illustrated in  FIG.  18   , the portable power supply  5  is disposed in the cavity  28  such that the deflector  600  and the upper portion  40  ( FIG.  2   ) cooperate to define a duct  605 . The duct  605  includes a downwardly opening portion  610  positioned over at least one of the plurality of air inlets  45 . The duct  605  is configured to receive liquids from an exterior of the portable power supply  5  and direct the liquids along the deflector  600  to the downwardly opening portion  610 . The liquid then travels downwardly, under the force of gravity, to at least one of the plurality of air inlets  45  aligned vertically with the downwardly opening portion  610 . The at least one of the plurality of air inlets  45  then provides a drain opening for the liquid such that the liquid exits the portable power supply  5  through the at least one of the plurality of air inlets  45 . 
     Each embodiment of the portable power supply  5 ,  205 ,  405  may be exposed to outdoor conditions such as, but not limited to, rain, dust, mud, and sun exposure. Therefore, the portable power supply  5 ,  205 ,  405  may be advantageously provided with features for protecting against said outdoor conditions. 
     In each embodiment of the portable power supply  5 ,  205 ,  405 , the portable power supply  5 ,  205 ,  405  may include sealed subsystems  615 ,  620 . For example, in the illustrated embodiment of  FIGS.  21  and  22   , the portable power supply  5 ,  205 ,  405  may include a battery subsystem  615  and a charger subsystem  620  that are provided with sealant to substantially seal the subsystems  615 ,  620  from the rest of the portable power supply  5 ,  205 ,  405 . Sealing the subsystems  615 ,  620  may inhibit outdoor elements from entering and moving between subsystems  615 ,  620  of the portable power supply  5 ,  205 ,  405 . The subsystems  615 ,  620  of the portable power supply  5 ,  205 ,  405  may be provided with any common form of sealant such as, but not limited to, water based latex sealant, acrylic sealant, and silicone sealant. As such, the sealant improves ingress protection without taking up excess space and may therefore inhibit environmental ingress without substantially increasing the size of the portable power supply  5 ,  205 ,  405 . Additionally, providing sealant between subsystems  615 ,  620  of the portable power supply  5 ,  205 ,  405  may advantageously increase the thermal resistance for the portable power supply  5 ,  205 ,  405 . 
     In another embodiment of the portable power supply  5 ,  205 ,  405 , each subsystem  615 ,  620  of the portable power supply  5 ,  205 ,  405  (e.g., the battery, the charger, the inverter) may be fully rated according to a system-level Ingress Protection Code (i.e., IP Code) and/or Underwriter&#39;s Laboratories Rating. For example, the subsystems  615 ,  620  of the portable power supply  5 ,  205 ,  405  may be manufactured to have a solid IP Code of 6 and a liquid IP Code of 9k. At a solid IP Code of 6, the subsystems  615 ,  620  of the portable power supply  5 ,  205 ,  405  inhibit dust ingress for at least eight hours while in close contact with dust and other debris. At a liquid IP Code of 9k, the subsystems  615 ,  620  of the portable power supply  5 ,  205 ,  405  are able to withstand high pressure and high temperature water jets/sprays at a close range. By fully rating each of the subsystems  615 ,  620  of the portable power supply  5 ,  205 ,  405 , the ingress protection is specifically defined for smaller systems which may improve ease of manufacturing. Fully rating each of the subsystems  615 ,  620  may also provide ingress protection that is better protected from external harm than when the subsystems  615 ,  620  are just sealed and not fully rated. That is, the housing  25  and the frame  65  may protect the subsystems  615 ,  620  against external harm. Therefore, said ingress protection may be less likely to be damaged or comprised than in embodiments of the portable power supply  5 ,  205 ,  405  than embodiments of the portable power supply  5 ,  205 ,  405  in which subsystems are just sealed. 
     One issue that may arise from fully rating each subsystem  615 ,  620  individually is that managing airflow and thermal performance may become more difficult when each subsystem  615 ,  620  is fully rated. For example, as illustrated in  FIGS.  21  and  22   , the battery subsystem  615  may utilize airflow A 1  over end faces  625  of the battery subsystem  615  to accelerate the removal of heat while the charger subsystem  620  may utilize a dedicated impinging jet airflow A 2  from a fan  630  through the center of the charger subsystem  620 . As a result, the ideal air outflow path for the battery subsystem  615  and the charger subsystem  620  may be provided orthogonal to each other which may reduce the overall efficiency of the portable power supply  5 ,  205 ,  405  to remove heat. 
       FIG.  23    illustrates another embodiment of a portable power supply  805 . The portable power supply  805  may include all features described herein with respect to the previous embodiment of the portable power supply  5 ,  205 ,  405  as well as the additional features described below. To mitigate thermal management and performance issues without unnecessarily increasing the size of the portable power supply  805 , the portable power supply  805  may be provided with a combination air duct  810  that is configured to transfer heat from a battery subsystem  812 , a first subsystem, and a charger subsystem  815 , a second subsystem, out of a housing  820  of the portable power supply  805  in the same direction as each other. In the illustrated embodiment, the portable power supply  805  includes two combination air ducts  810 . The battery subsystem  812  and the charger subsystem  815  are both disposed within a cavity defined by the housing  820 . The portable power supply  805  may additionally be provided with a control system  822 , such as a processor, a control board, or another similar control unit, that is disposed within the cavity defined by the housing  820  and configured to control operation of the portable power supply  805 . 
     With reference to  FIG.  24   , the combination air duct  810  includes an outer housing  825 , a baffle  830 , an outlet opening  835 , a fan  838 , and a seal  840 . The outer housing  825  defines an interior channel. The baffle  830  extends through the interior channel to divide the interior channel into a first subchannel  845   a  and a second subchannel  845   b . The first subchannel  845   a  is larger in area and volume than the second subchannel  845   b . The outlet opening  835  overlaps the first subchannel  845   a  and the second subchannel  845   b  such that the outlet opening  835  provides an opening for both the first subchannel  845   a  and the second subchannel  845   b . The fan  838  is positioned opposite the outlet opening  835  in fluid communication with the first subchannel  845   a . The seal  840  is provided on the outer housing  825  around an outer periphery of the outlet opening  835  and mates with the housing  820  of the portable power supply  805 . 
     The seal  840  may be formed of any common sealant such as, but not limited to, water based latex sealant, acrylic sealant, and silicone sealant. The seal  840  is bendable and compressible such that the seal  840  may mate with irregularities in the housing  820 . The seal  840  reduces airflow leakage at an interface between the outlet opening  835  of the combination air duct  810  and the housing  820 . The seal  840  also inhibits debris (e.g., dust, water, aerosols, and other particulates) leakage, recirculation, and buildup within the overall system of the portable power supply  805 . The seal  840  may additionally increase the required tolerance between the outlet opening  835  of the combination air duct  810  and the housing  820 , thereby improving ease of manufacturing for the combination air duct  810 . In some embodiments, the seal  840  may be formed with a thermoplastic elastomer overmold. As such, with additional reference to  FIG.  25   , the seal  840  may be intentionally formed to have an interference  848  with the housing  820  around a periphery of the outlet opening  835 . The interference  848  between the periphery of the outlet opening  835  and the portable power supply  805  may further improve the strength of the seal  840 , thereby improving ingress protection of the portable power supply  805 . 
     In some embodiments, with continued reference to  FIG.  25   , the combination air duct  810  may additionally include ingress drain holes  850  that are in fluid communication with ingress outlet holes  855  provided in the housing  820  of the portable power supply  805 . The ingress drain holes  850  and the ingress outlet holes  855  enable any ingress, such as water, that has entered the combination air duct  810  during operation of the portable power supply  805  to effectively drain out of the combination air duct  810  and the portable power supply  805 . Therefore, the ingress drain holes  850  may improve the ability of the portable power supply  805  to remove ingress from housing  820  of the portable power supply  805 . 
     In further embodiments, as illustrated in  FIGS.  23  and  26   , the combination air duct  810  may additionally include a thermistor  860  provided adjacent to the fan  838 . Specifically, the thermistor  860  is provided at a position downstream of the fan  838 . The thermistor  860  enables a user to monitor system ambient temperatures of the portable power supply  805 . Specifically, the thermistor  860  may determine the system ambient temperature at the location downstream of the fan  838  and provide, or convey, a temperature signal to the control system  822 . In the illustrated embodiment, the system ambient temperature is the temperature of ambient air within the housing  820  of the portable power supply  805 . In other embodiments, the system ambient temperature may be the temperature of ambient air surrounding the housing  820  of the portable power supply  805 . As such, the portable power supply  805  includes an operating temperature range. Performance of the portable power supply  805  may worsen if the system ambient temperature is outside of the operating temperature range. 
     The control system  822  inhibits operation of the portable power supply  805  when the control system  822  receives a temperature signal from the thermistor  860  indicating that the ambient system temperature is outside of the operating temperature range for the portable power supply  805 . Additionally, the fan  838  includes an operating temperature range. The control system  822  inhibits operation of the fan  838  when the control system  822  receives a temperature signal from the thermistor  860  indicating that the ambient system temperature is outside of the operating temperature range for the fan  838 . The operating temperature range of the portable power supply  805  and the operating range of the fan  838  may be different such that the thermistor  860  may provide a temperature signal to the control system  822  to inhibit operation of just one of the portable power supply  805  and the fan  838  or both of the portable power supply  805  and the fan  838 . As stated above, the portable power supply  805  includes two combination air ducts  810 . Each duct  810  includes a fan  838  and a thermistor  860 . As such, the control system  822  may inhibit operation of the portable power supply  805  when the control system  822  receives a temperatures signal from the thermistor  860  of at least one of the combination air ducts  810  that ambient system temperature is outside of the operating temperature range for the portable power supply  805 . 
     As illustrated in  FIGS.  27  and  28   , the portable power  805  includes a mounting port  865  for the charger subsystem  815  having mounting features such as fastener receiving apertures. The combination air duct  810  may be installed on the same mounting port  865  as the charger subsystem  815 . By utilizing the same mounting port  865  as the charger subsystem  815 , system integration and overall size of the portable power supply  805  is not substantially affected by the introduction of the combination air duct  810  to the portable power supply  805 . As such, various components of the portable power supply  805  may be easily interchanged without altering the overall size of the portable power supply  805 . 
     Returning reference to  FIG.  23   , during operation of the portable power supply  805 , each of the battery subsystem  812  and the charger subsystem  815  emit heat. The battery subsystem  812  emits heat over end faces  870  of the battery subsystem  812 . The fans  838  may then induce a first exhaust airflow  875  in a first direction A 3 , thereby transferring heat away from the battery subsystem  812 . More specifically, the fans  838  may induce the first exhaust airflow  875  along conduits  880  that extend along the right side and the left side of the portable power supply  805 , respectively. The first exhaust airflow  875  flows along the conduits  880  in the first direction A 3  to reach the combination air duct  810 . In the illustrated embodiment, the portable power supply  805  includes at least two combination air ducts  810  such that one combination air duct  810  is positioned on the right side and another combination air duct  810  is positioned on the left side of the portable power supply  805 . As such, the right-side combination air duct  810  receives a portion of the first exhaust airflow  875 , and the left-side combination air duct  810  receives another portion of the first exhaust airflow  875 . 
     The fans  838  of each combination air duct  810  then direct the first exhaust airflow  875  to the first subchannel  845   a  so that the first exhaust airflow  875  may exit the portable power supply  805  via vents  885  in the housing  820  of the portable power supply  805 , as illustrated in  FIG.  29   . With reference to  FIGS.  23  and  29   , the vents  885  are provided at the intersection between the left side and the front side of the portable power supply  805  as well as at the intersection between the right side and the front side of the portable power supply  805 . As such, the first subchannel  845   a  in the left-side combination air duct  810  directs the first exhaust airflow  875  out of the housing  820  along a third direction A 5 , and the first subchannel  845   a  in the right-side combination air duct  810  directs the first exhaust airflow  875  out of the housing  820  along a fourth direction A 6 . Each of the third direction A 5  and the fourth direction A 6  extend diagonally, or transverse, to the first direction A 3  and a second direction A 4 , which is described in more detail below. 
     In the illustrated embodiment, the charger subsystem  815  includes a charger fan  890 . The charger fan  890  may induce a second exhaust airflow  895  in the second direction A 4  towards the right side or the left side of the portable power supply  805 . In the illustrated embodiment, the first direction A 3  and the second direction A 4  are orthogonal. In some embodiments, as illustrated in  FIG.  30   , the charger subsystem  815  may be provided with a cover  897 . The cover  897  may be positioned over fins in the housing  820  to improve flow of the second exhaust airflow  895  away from the charger subsystem  815 . 
     Returning reference to  FIG.  23   , as the second exhaust airflow  895  exits the charger subsystem  815 , the second exhaust airflow  895  is directed into one of the right-side combination air duct  810  and the left-side combination air duct  810 . As such, the right-side combination air duct  810  receives a portion of the second exhaust airflow  895 , and the left-side combination air duct  810  receives another portion of the second exhaust airflow  895 . The second exhaust airflow  895  is directed into the second subchannel  845   b  of each of the combination air ducts  810 . The second subchannel  845   b  in the left-side combination air duct  810  directs the second exhaust airflow  895  out of the housing  820  along the third direction A 5 , and the second subchannel  845   b  in the right-side combination air duct  810  directs the second exhaust airflow  895  out of the housing  820  along the fourth direction A 6 . As such, the combination air duct  810  advantageously enables the first exhaust airflow  875  and the second exhaust airflow  895  to exit the portable power supply  805  along the same direction by redirected the first exhaust airflow  875  and the second exhaust airflow  895  such that inefficiencies from heat removal are reduced and heat may be quickly removed from the portable power supply  805  to inhibit the portable power supply  805  from overheating. 
       FIG.  31    illustrates performance variance of the portable power supply  805 . Specifically,  FIG.  31    provides a graph of mass flow rate according to the various embodiments of the portable power supply. Under normal discharge conditions, illustrated by bar  899   a , the portable power supply  805  may exchange air at a mass flow rate of less than 20 g/s. More specifically, the portable power supply  805  may exchange air at a mass flow rate of roughly 19 g/s. Under conditions in which the charger fan  890  is provided, illustrated by bar  899   b , the portable power supply  805  may exchange air at a mass flow rate between 20 and 25 g/s. More specifically, the portable power supply  805  may exchange air at a mass flow rate of roughly 23 g/s. Under conditions in which the charger fan  890  and the cover  897  is provided with the charger subsystem  815 , illustrated by bar  899   c , the portable power supply  805  may exchange air at a mass flow rate between 25 and 30 g/s. More specifically, the portable power supply  805  may exchange air at a mass flow rate of roughly 27.5 g/s. 
     Returning reference to  FIGS.  21  and  22   , in another embodiment of the portable power supply  5 ,  205 ,  405 , each subsystem of the portable power supply  5 ,  205 ,  405  may be designed to an Ingress Protection Code or Underwriter&#39;s Laboratories Rating that is lower than the desired rating. For example, each subsystem may be designed and manufactured to have a solid IP Code of 3 and a liquid IP Code of 5. At a solid IP Code of 3, each subsystem is protected against solid objects over 2.5 mm, such as a screwdriver. At a liquid IP Code of 5, each subsystem is protected against harmful effects from water jets in all direction. Once each of the subsystems  615 ,  620  are integrated within the housing  25  and the frame  65  of the portable power supply  5 ,  205 ,  405 , each of the subsystems  615 ,  620 , and the overall system of the portable power supply  5 ,  205 ,  405  achieve the desired fully rated IP Code or UL Rating. By partially rating each subsystem  615 ,  620  such that the portable power supply  5 ,  205 ,  405  achieves the desired fully rated IP Code or UL Rating when fully assembled, the portable power supply  5 ,  205 ,  405  may advantageously have improved system thermal management and performance. The partial rating of each subsystem  615 ,  620  may also reduce manufacturing costs and improve manufacturing ease. 
     As described above, some or all illustrated features may be omitted in a particular implementation within the scope of the present disclosure, and some illustrated features may not be required for implementation of all embodiments. The features described above may be implemented in an order different from the order described above and does not prohibit implementation in another order or combination. While not explained in detail for each embodiment and/or construction, the features of the disclosure described herein may be included on a tape dispenser independent of other features and are not limited to the illustrated disclosure. Embodiments and limitations disclosed herein are not dedicated to the public under the doctrine of dedication if the embodiments and/or limitations: (1) are not expressly claimed in the claims; and (2) are or are potentially equivalents of express elements and/or limitations in the claims under the doctrine of equivalents. 
     Although the invention has been described with reference to certain embodiments, variations and modifications exist within the scope and spirit of one or more independent aspects of the invention as described. Various features of the invention are set forth in the following claims.