JP2013077466A - Power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device which, when a solar cell breaks down or a power conversion device goes wrong, for example, can be detached from the solar cell easily by manipulating a switch opening or closing a circuit.SOLUTION: A power storage device 1A is connected to the power line of a power supply system which feeds DC power from a solar cell to a load after converting it to AC power, in which line the DC power flows, thereby making it possible to charge and discharge DC power to and from the battery. In the power storage device, a battery module configured to obtain a desired rated voltage and charging capacity is fixed to the internal lower side of a body part 10A of a casing 10 detachably via fixing means, a switch box is installed on a top board 11, and a control unit which controls charging and discharging to and from the battery module is installed on the internal top side of the body part 10A. Furthermore, a cover 10B having a waterproof function is fitted detachably to a switch box, and a manual switch SW is provided, protruding from the top plate 11 of the body part 10A, which opens or closes a circuit which guides DC power to the control unit.

Description

  The present invention relates to a power storage device that is used together with a power conversion device that links power generated by a solar battery to a system.

  In recent years, power converters that convert DC power generated by solar cells into AC power and superimpose it on the system have been used. With this power converter alone, AC power cannot be output and superimposed on the grid at night when the solar cell is not generating power, especially when a power outage occurs at night, no power can be supplied It is.

  Therefore, as a device that copes with such a problem, for example, a device provided with a power storage device as described in Patent Document 1 is known. Such a power storage device is provided with a storage battery, and in the daytime, the power generated by the solar battery is supplied to the storage battery for charging, and at night, the storage battery is charged with the power from the system. Yes, it was compatible with AC power output regardless of day or night.

Japanese Patent No. 3181423

  By the way, in the power conversion device provided with such a power storage device, for example, when the solar cell is damaged, the power conversion device fails, or maintenance is performed, it is necessary to disconnect the power storage device from the solar cell for safety. There is. In that case, the troublesome work of opening the inside of the housing of the power storage device and manually operating, for example, a predetermined switch provided in the housing is necessary.

  However, when the above-described operation is performed by opening the housing and exposing the internal substrate or circuit in this way, a specialist person such as a service person normally performs this operation. In many cases, it takes time to arrive at the installation location. In an emergency such as damage to the solar cell due to a disaster such as an earthquake or typhoon, the user of the power storage device, not a service person, manually operates the switch. There are cases where it must be done. It is difficult for the user who is unfamiliar with the operation to operate the switch as described above. Also, when performing such circuit opening operation, capacitors, transformers, resistors, transistors, and other electronic components are installed on the circuit near this switch. If touched, some parts may cause burns due to heat generation or dangerous electric shocks.

  Therefore, the object of the present invention is to ensure that anyone can easily operate the switch for opening and closing the electric circuit when work such as damage to the solar cell, failure of the power conversion device, or maintenance is necessary. It is another object to provide a power storage device that can be separated from the solar battery.

(1) A power storage device according to claim 1 of the present invention includes:
A DC power obtained from a renewable energy source via a solar cell is converted into AC power and supplied to a load. The power supply system is connected to the power line through which the DC power flows and is configured to allow charging and discharging of the DC power. In the power storage device
A battery module configured to connect a plurality of cells to obtain a desired rated voltage and charging capacity is fixed in a detachable manner via a fixing means on the lower side inside the housing having a predetermined waterproof performance,
A control unit for controlling charging and discharging of the battery module is provided fixed to the upper side inside the housing,
Providing a switch box protruding or recessed in a part of the housing,
A cover having a waterproof function is detachably attached to the switch box,
A manual switch that projects from the bottom surface of the switch box of the housing and opens and closes an electric circuit that guides the DC power to the control unit is provided.
(2) Moreover, the power storage device according to claim 2 of the present invention is the power storage device according to claim 1,
The switch is only provided in a dedicated switch box formed on at least a part of the top plate or side plate of the housing and covered with the cover,
The switch box and the cover have a waterproof structure that prevents rainwater from entering.
(3) Moreover, the power storage device according to claim 3 of the present invention is the power storage device according to claim 1 or 2,
The fixing means for fixing the battery module is characterized in that the battery module can be attached in accordance with the shape of the battery module to be mounted.
(4) Moreover, the power storage device according to claim 4 of the present invention provides:
A DC power obtained from a renewable energy source via a solar cell is converted into AC power and supplied to a load. The power supply system is connected to the power line through which the DC power flows and is configured to allow charging and discharging of the DC power. In the power storage device
A battery module configured to connect a plurality of cells to obtain a desired rated voltage and charging capacity is fixed in a detachable manner via a fixing means on the lower side inside the housing having a predetermined waterproof performance,
A control unit for controlling charging and discharging of the battery module is provided fixed to the upper side inside the housing,
Removably attach a cover that covers the top plate of the enclosure with a waterproof function,
An operation unit projects from the top plate into the cover, and includes a manual switch that opens and closes an electric circuit that guides the DC power to the control unit.

(1) According to the power storage device according to claim 1 of the present invention, for example, when work such as damage to the solar cell, failure of the power conversion device, or maintenance is required, anyone can easily It is possible to stop the operation by reliably operating the switch for opening and closing the electric circuit.
(2) According to the power storage device of the second aspect of the present invention, since only the manual switch is installed in the dedicated switch box, there is no risk of touching another switch or another component accidentally, A reliable manual switch operation can be performed. Moreover, it is possible to prevent burns and electric shocks from touching other parts.
(3) According to the power storage device according to claim 3 of the present invention, it is possible to replace various types of battery modules with different shapes, in other words, using a power storage device having a common configuration. Since a storage battery with a shape can be mounted, the versatility increases and the manufacturing cost decreases accordingly.
(4) According to the power storage device according to claim 4 of the present invention, for example, when work such as damage to the solar cell, failure of the power conversion device, or maintenance is required, anyone can easily It is possible to stop the operation by reliably operating the switch for opening and closing the electric circuit.

1 is a perspective view illustrating an appearance of a power storage device according to a first embodiment of the present invention. It is explanatory drawing which shows the whole power supply system structure containing the electrical storage apparatus. It is a disassembled perspective view which shows the installation position of the manual switch in the housing of the electrical storage apparatus. It is explanatory drawing which shows the internal structure in the main-body part of the housing of the electrical storage apparatus. It is a circuit diagram which shows the electrical whole structure of the power supply system containing the electrical storage apparatus. It is a principal part perspective view which shows the state which mounted the lithium battery as a battery module in the electrical storage apparatus. It is a principal part perspective view which shows the state which mounted another large sized lithium battery as a battery module in the electrical storage apparatus. (A) is a perspective view which shows the external appearance of the electrical storage apparatus which concerns on the 2nd Embodiment of this invention, (B) is a disassembled perspective view which shows the principal part. (A) is a perspective view which shows the external appearance of the housing upper part side of the electrical storage apparatus which concerns on the 3rd Embodiment of this invention, (B) is a disassembled perspective view which shows the principal part. (A) is the perspective view which shows the whole housing of the electrical storage apparatus which concerns on the 4th Embodiment of this invention, (B) is an exploded perspective view which shows the principal part, (C) is principal part sectional drawing of (B). is there.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings.
[First Embodiment]
FIG. 1 shows a power storage device 1 according to a first embodiment of the present invention. As shown in FIG. 2, the power storage device 1 has an input connected to a connection box 3 connected to a solar cell 2, and an output connected to an input of a power conversion device (hereinafter referred to as “power converter”) 4. As shown in FIG. 3, the switch box provided at the top of the housing 10 includes a manual switch SW. In FIG. 2, reference numeral 5 indicates a remote controller for operating the power storage device 1, and reference numeral 6 indicates a distribution board.

  The solar battery 2 is formed by connecting a plurality of solar battery cells in series and in parallel to have a predetermined rated voltage and / or parallel connection, and has a rated voltage of 300 V, an output of 2.4 kW, an output of 4.8 kW, and the like.

  The connection box 3 is for connecting the string of photovoltaic modules and the power conditioner 4.

  The power conditioner 4 converts DC power obtained from sunlight, which is a renewable energy source, through the solar cell 2 into AC power and superimposes it on the AC power from the system in the house. On the other hand, the power storage device 1 charges and discharges direct-current power with respect to an on-board storage battery. This power storage device 1 is connected to a power line through which direct-current power supplied from the solar cell 2 through the current collection box 3 flows, and direct current power obtained through the solar cell 2 is supplied to the battery module B (FIGS. 4 and 5). The battery module B is appropriately charged and the battery module B is discharged.

The battery module B is configured to connect a plurality of cells so as to obtain a desired rated voltage and charging capacity. The battery module B can be replaced in a battery chamber below the casing 10 described later. It is firmly fixed and mounted. In the case of the present embodiment, as shown in FIG. 4, as a battery for power storage, a lead type storage battery (for example, four 12V and 20Ah batteries are connected in series to have a rated voltage of DC48V). is used to B _1, the present invention is not limited to this, the rated voltage can be any voltage. Moreover, the output per hour is only required to change the number of storage batteries connected in parallel according to demand, and a lithium ion battery or the like may be used and the type of storage battery is not limited. Absent.

  The power storage device 1 according to the present embodiment has a cover that the casing 10 is covered with the main body 10A and the top plate 11 of the main body 10A so as to be screwed and fixed to the upper portion of the main body 10A. 10B.

  The main body 10A is configured such that the front panel 12 is detachably screwed into an opening 13 (see FIG. 4) having a large opening on the front surface (front) so that the storage battery B can be replaced easily and reliably. Yes. In addition, the internal space of the main body 10A has a partition plate S (can be omitted as long as the strength of the housing can be secured) as a boundary, a battery chamber that houses a storage battery B that is a battery module in the lower part thereof, and a controller 20 in the upper part thereof And a substrate chamber for accommodating a circuit board P on which various electronic components and the like are mounted. When the main body 10A is attached to the top plate 11 above the substrate chamber by screwing it through a waterproof packing (not shown) so as to cover the cover 10B from above, the top plate 11 and the cover 10B are attached. A certain large space serving as a switch box is formed between the two. This space is configured as a dedicated space in which only the operation part of the manual switch SW is installed.

  Further, the main body 10A is closed in a watertight state by attaching the above-mentioned front panel 12 to the opening 13 that opens largely to the front side through a seal member such as a rubber packing (not shown). When the substrate P is exchanged or maintenance work, it can be removed to perform necessary work. In addition, the main body portion 10A is provided with an operation portion of the manual switch SW protruding from the top plate 11 in order to open the electric path between the power storage device 1 and the DC power from the solar battery by manual operation when necessary. . The power storage device 1 is installed outdoors where there is a risk of being exposed to rainwater. Even if the cover 10B is removed from the housing 10 and the switch SW is opened / closed outdoors, the rainwater is placed inside the main body 10A. In order to prevent intrusion etc., the main body 10B itself including the top plate 12 has a structure having a waterproof function.

  The cover 10B is removed from the main body 10A only when the manual switch SW is operated, and the operation part of the manual switch SW is exposed. Usually, the cover 10B is fixed so as to be integrated with the main body 10A. is there. That is, the cover 10B is usually fixed in a watertight manner to the main body 10A so that the main body 10A of the housing 10 is covered from above via a seal member such as a rubber packing (not shown).

  The circuit board P is integrally assembled with the chassis 30 and is fixed to the upper surface of the partition plate S that partitions the battery chamber and the board chamber via the chassis 30. The component is mounted.

The control unit 20 controls the operation of the power storage device 1. In the present embodiment, the control unit 20 has a circuit configuration as shown in FIG. 5, for example. That is, the control unit 20 constitutes a charge / discharge circuit by two sets of single-layer inverter circuits 21 and 22 in which four switching elements are connected in a bridge shape and the transformer 23. The capacitors 24 and 25 and the resistor 26 are
Each is a capacitor for smoothing at the time of boosting, and a resistance for protection. The current detectors 27 and 28 are for detecting the power generation current of the solar cell 2 and the current supplied to the power conditioner 4. The current detectors 27 and 28 detect the potential at the connection point V to detect the detected current value. Each power value can be specifically obtained from the product of the voltage value.

  The manual switch SW constitutes a manual switch unit that opens and closes an electric circuit connected to a direct power line connecting the solar cell 2 and the power conditioner 4. For example, damage to the solar cell 2, failure of the power conditioner 4, necessary maintenance, etc. In this case, the power storage device 1 is separated from the solar cell 2. As described above, the operation part of the manual switch SW according to the present embodiment protrudes toward the end of the battery box, which is a space extending over the entire surface between the top plate 11 and the cover 10B, so that reliable operation is possible. In order to perform the stop operation, the rotary switch is used. However, the switch is not particularly limited as long as the same effect can be obtained.

Next, the structure of the battery chamber inside the housing 10 according to the present embodiment will be described with reference to FIGS.
The battery chamber that occupies the lower part inside the housing 10 is provided with a spacer 40 and a rack 50 that constitute fixing means for the battery module so that the battery chamber can be replaced with a member corresponding to the battery module to be mounted.

  Among them, the spacer 40 extends over the entire space between the left and right side wall surfaces of the floor surface of the battery chamber, and in a state of being parallel to each other along the depth direction, a strong member 41 (hereinafter referred to as a rectangular member) 41 is equally spaced. Each battery constituting the battery module, in particular, a lead type storage battery (four stations) is fixed in a gap between the rectangular members 41.

  Further, in the rectangular member 41 constituting the spacer 40, in order to mount a single lithium ion battery on the upper surface of the rectangular member 41 in a non-moving state, a round hole on the bottom surface side of the L-shaped metal fitting 43 shown in FIG. Screw holes 42 are provided to be screwed together through (not necessarily all installed, but may be opened to all five in order to be able to select any one). .

  On the other hand, the rack 50 has round holes 52 that are opened at equal intervals in the vertical direction, and are arranged as tension bars at the four front and rear, right and left corners between the floor surface of the battery chamber and the ceiling surface (the lower surface of the partition plate S). The four pillars 51 and the round holes 52 of these pillars 51 are fixed at a plurality of heights with fixing members such as screws or the like at the same height, and fixed to each other at equal intervals. And a support shelf 53 provided in a solid state so as to withstand.

  The support shelf 53 is provided with a screw hole 54 for fixing each battery constituting the battery module on a wall portion standing upward. Further, the support shelf 53 is screwed to the column 51 by a screw hole provided exclusively for fixing the column 51 separately from the screw hole 54 provided on the side surface 53A on the front side. And the installation height and the number of installation in the pillar 51 can be changed suitably according to the number of installation.

In the present embodiment, as shown in FIG. 4, four lead-type batteries B ₁ having a predetermined standard size are used as the batteries used in the battery module B. For this reason, it is possible to install the battery B ₁ without a gap between the spacers 40 by using the space between the spacers 40 that are positioned and fixed in advance according to the battery size.
Thus, the lead-type battery B ₁ has a certain weight, and has a low center of gravity by being installed on the floor of the battery chamber provided on the lower side inside the main body 10A of the housing 10. Therefore, it is possible to store in a stable state.

In the present embodiment, although a battery-B ₁ Lead type as described above, the type of the battery module B to be mounted is not particularly limited thereto. As described above, in order to enable mounting of a battery corresponding to various types of batteries to be mounted, not only the spacer 40 but also a rack 50 is provided.

For example, when a lithium ion type battery B ₂ having a relatively flat shape as shown in FIG. 6 is mounted, it is supported on a pair of left and right support shelves 53 that are installed on the pillar 51 at a required equal interval. together to a screw hole 54 provided on the front side of the side surface 53A of the support shelf 53, a screw hole 55 provided in the housing of the battery B ₂ in a state of being aligned with the screw hole 54, between the screw To fix it together.

Further, as shown in FIG. 7, for example, another large lithium ion type battery B _{3 that} can be completed with a predetermined capacity can be mounted. In the battery B _3, it is the screw holes 56 provided at a predetermined position of the front.

Accordingly, those of the battery B _3, (if not particularly disturbing, may be previously course leaving.) Remove the support shelf 53 from column 51, it is mounted thereon by utilizing the upper surface of the spacer 40. Moreover, the battery B ₃ obtained by this mounting, between using special fasteners 43 or the like, the screw hole 42 provided in the spacer 40 upper surface, a screw hole 56 is provided in front of the battery B ₃ Is inserted into the hole of the L-shaped metal fitting 43, which is a fastener (the inner peripheral surface of this hole may not be cut by an internal thread), and a screw is inserted into the screw hole between them. .

  By the way, as an alternative means of the commercial power source, by converting the direct current power obtained from the sunlight that is a renewable energy source through the solar cell 2 into the alternating current power and superimposing it on the indoor wiring connected to the system, In a power storage device configured to be incidental to a power supply system that supplies power to various loads, the power storage device 1 is connected to the power supply system in the case of, for example, damage to a solar cell, failure of a power conversion device, or maintenance. It was necessary to separate from. However, conventionally, for example, an operation in which the inside of the housing of the power storage device is opened and the electric circuit is opened with an internal switch is required.

  On the other hand, according to the present embodiment, in order to turn off the desired switch and disconnect the power storage device from the solar cell, the expertise of the service person, such as opening the inside of the housing 10 and exposing the circuit board P, is often used. There is no need to carry out the work. That is, when the screw 10 is removed from the housing 10 in the state shown in FIG. 1 and the cover 10B is removed from the main body 10A of the housing 10, the switch SW protruding from the top plate 11 of the main body 10A is exposed as shown in FIG. Therefore, in this state, the operation of opening the electric circuit manually by the switch SW can be easily performed. In this way, the possibility of touching high-voltage components on the circuit board P, elements that generate a large amount of heat, and the like is eliminated, and a general user of the power storage device can safely turn on / off the switch SW.

  Further, since it is not necessary to expose the circuit board P, a dangerous electric shock accident is not caused. Furthermore, according to this embodiment, even if there is no electrical knowledge, the switch operation can be performed in a relatively short time by simply removing the cover 10B. Therefore, an emergency due to damage to the solar cell due to a disaster such as an earthquake or a typhoon is possible. In some cases, it is possible to respond quickly and reliably to shutdown operations.

[Second Embodiment]
FIG. 8 shows a power storage device 1B according to the second embodiment of the present invention. In the power storage device 1B according to the second embodiment, the switch box 61 covered with the switch cover 62 is provided integrally with a part of the top surface 60A (a portion near one end) of the casing 60 so as to protrude, This switch box 61 is different from the power storage device 1A of the first embodiment in that the same manual switch SW as that of the first embodiment is provided in the switch box 61.

  A switch cover 62 is attached to the switch box 61 so as to be removable with screws. Further, since the power storage device 1B of the present embodiment is also installed outdoors that may be exposed to rainwater, the switch cover 62 is provided with a seal member such as a rubber packing on the inner peripheral surface (not shown), Waterproof structure is secured. Also in this power storage device 1B, the switch cover 62 is not removed except when the switch SW in the switch box 61, which is a dedicated space for the manual switch SW, is operated.

  Therefore, according to the present embodiment, since the switch SW protrudes in the switch box 61 provided on the top surface 60A of the housing 60, the manual operation of the switch SW can be easily performed without requiring an unreasonable posture.

[Third Embodiment]
FIG. 9 shows a power storage device 1C according to the third embodiment of the present invention. In the power storage device 1C of the third embodiment, the switch box 71 is integrally provided in a part of the side surface 70A side of the housing 70 in a depressed state, and the switch box 71 is the same as that of the first embodiment described above. Is different from the power storage devices 1A and 1B of the first and second embodiments in that the same manual switch SW is provided. Further, in this power storage device 1C, both upper sides of the casing 70 are formed in a bowl shape projecting outward, and the switch box 71 is protected from rain water at the section of the bowl 70B in case of some rain. It is also possible to do.

  Since this power storage device 1C is also installed outdoors that may be exposed to rainwater, a switch cover 72 having a seal member such as rubber packing attached to the inner peripheral surface (not shown) is screwed to the switch box 71. It is removably attached and is waterproof. In this power storage device 1C, the switch cover 72 is not removed except when the switch SW in the switch box 71, which is a dedicated space for the manual switch SW, is operated.

  The switch cover 72 is formed in a substantially rectangular shape with each side larger than the switch box 71, and is screwed into a screw hole provided in the peripheral side surface 70 </ b> A so as to surround the switch box 71. Yes. The switch cover 72 is provided with a rubber packing 72 </ b> A around a seal wall that protrudes in a substantially square shape on the inner surface facing the switch box 71.

  Therefore, according to the present embodiment, the switch SW protrudes in the switch box 72 provided inwardly from the side surface 70A of the housing 70 and covered with the switch cover 72. The insertion of rainwater into the interior can be avoided to some extent by the kite 70B, which is convenient.

[Fourth Embodiment]
FIG. 10 shows a power storage device 1D according to the fourth embodiment of the present invention. In the power storage device 1D of the fourth embodiment, one step along the entire peripheral portion of the switch box 81 so as to surround the switch box 81 that is integrally provided in a state of being recessed in a part of the side surface 80A of the housing 80. A raised step portion 81A is provided, and the switch cover 82 is screwed into a screw hole provided in the step portion 81A in a state of being embedded in the step portion 81A.

  Also in this power storage device 1D, as in the third embodiment, both upper sides of the casing 80 are formed in a bowl shape that protrudes outward. Thus, it is possible to protect the switch box 81 from rainwater.

  Also in this power storage device 1D, the switch cover 82 is formed in a substantially rectangular shape with each side having the same size as the depression of the switch box 81, and fits in the depression of the switch box 81, which is a dedicated space for the manual switch SW, without a gap. As a result, the outer surface of the switch cover 82 is flush with the side surface 80A. The switch cover 82 is also provided with a rubber packing 82 </ b> A on a seal wall that protrudes in a substantially square shape on the inner surface facing the switch box 81.

  Therefore, according to this embodiment, since the switch cover 82 is attached to the side surface 80A of the housing 80 in a flush state, it is not only convenient in appearance but also can effectively prevent intrusion of rainwater. .

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible in the range which does not deviate from the summary as described in a claim.

1A to 1D Power storage device 2 Solar cell 3 Junction box 4 Power conversion device (Powercon)
REFERENCE SIGNS LIST 5 Remote controller for power storage device operation 6 Distribution board 10, 60, 70, 80 Housing 10A Body 10B Cover 11 Top plate 12 Front panel 13 Opening 20 Control unit 30 Chassis 40 Spacer
41 Rectangular member 42 Screw hole 43 L-shaped bracket 50 Rack (fixing means)
51 Pillar 52 Round hole 53 Support shelf 53A, 70A, 80A Side surface 54, 55, 56 Screw hole 60A Top surface 61, 71, 81 Switch box 62, 72, 82 Switch cover 70B ７２ 72A, 82A Rubber packing 80B ８１ 81A Step B Battery module (storage battery)
B ₁ Lead type storage battery B ₂ Lithium ion type battery B ₃ Large lithium ion type battery P Circuit board S Partition plate SW Manual switch

Claims (4)

A DC power obtained from a renewable energy source via a solar cell is converted into AC power and supplied to a load. The power supply system is connected to the power line through which the DC power flows and is configured to allow charging and discharging of the DC power. In the power storage device
A battery module configured to connect a plurality of cells to obtain a desired rated voltage and charging capacity is fixed in a detachable manner via a fixing means on the lower side inside the housing having a predetermined waterproof performance,
A control unit for controlling charging and discharging of the battery module is provided fixed to the upper side inside the housing,
Providing a switch box protruding or recessed in a part of the housing,
A cover having a waterproof function is detachably attached to the switch box,
A power storage device comprising: a manual switch that projects from a bottom surface of the switch box of the housing and opens and closes an electric circuit that guides the DC power to the control unit. The switch is only provided in a dedicated switch box formed on at least a part of the top plate or side plate of the housing and covered with the cover,
The power storage device according to claim 1, wherein a waterproof structure is provided between the switch box and the cover so that rainwater does not enter. The power storage device according to claim 1 or 2, wherein the fixing means for fixing the battery module is configured to allow the battery module to be attached in accordance with the shape of the battery module to be mounted. A DC power obtained from a renewable energy source via a solar cell is converted into AC power and supplied to a load. The power supply system is connected to the power line through which the DC power flows and is configured to allow charging and discharging of the DC power. In the power storage device
A battery module configured to connect a plurality of cells to obtain a desired rated voltage and charging capacity is fixed in a detachable manner via a fixing means on the lower side inside the housing having a predetermined waterproof performance,
A control unit for controlling charging and discharging of the battery module is provided fixed to the upper side inside the housing,
Removably attach a cover that covers the top plate of the enclosure with a waterproof function,
A power storage device comprising: a manual switch that opens and closes an electric circuit that projects an operation unit from the top plate into the cover and guides the DC power to the control unit.

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