The installation of the PCU is mechanically straightforward - a rectangular cutout, four cables, done. The mistakes happen beforehand: when choosing the installation location and when deciding where the sensor cables converge. This article goes through the order in which the installation is actually done.
Cutout and Space Requirements
The PCU has a 144 x 90 mm display and requires a 120 x 70 mm mounting cutout. The visible frame thus covers about twelve millimeters all around - enough to forgive minor inaccuracies when sawing, but not enough to conceal a cutout that has shifted by a centimeter.
Before the first cut, it's worth making a life-size paper template, sticking it to the intended spot, and leaving it for a day. Two things almost always only become apparent during operation: whether you can view the display without straining from your usual sitting or standing position, and whether the sun or a light source shines directly on it. A touch display that can only be read in backlight will not be used.
Behind the cutout, there must be space for the housing and for the connectors. If you place the display in a thin furniture front, plan for the space behind it - cables that bend sharply at the housing are the most common cause of loose contacts that appear months later.
Choosing the Installation Location
The PCU is both a display and a control unit. It therefore does not belong where there is space, but where you are already standing: at the entrance, at the galley, at the helm. Three criteria are decisive:
- Viewing angle. As frontal as possible, not from below. A display at knee height is difficult to read and even more difficult to operate.
- Accessibility when passing by. If you switch on lights or heating via the display, you want to do it standing up, not squatting.
- Dryness. The device is built for continuous use on board, but the area behind the panel should not be where condensation collects.
A second display location is often a topic in planning. With the PCU, this leads to a fundamental question: it is the central unit, not one of several. If you want to operate it from two places, plan this before sawing and not afterwards.
Wiring: one cable instead of many
All interfaces are located in the display itself - the PCU does not require additional modules. However, this does not mean that every sensor cable has to be routed to the panel. The intended path leads via the Connect Hub: tank sensors, shunt, and battery cables are connected there without tools, and exactly one cable runs from the Hub to the display. Ten meters of length are available for this.
The practical gain is greater than it sounds. The Hub is located where the technology is - in the cabinet next to the battery and distribution. The paths to it are short. Only a single line then goes to the display, which is located elsewhere for operational reasons. Without a Hub, you would instead pull each sensor wire individually across the vehicle or ship, and each of these wires is a potential point of failure.
NoteDetermine cable routes before sawing, not afterwards. The cutout cannot be moved, but the conduit can.
Power Supply
The PCU operates at 12 V and 24 V. The power supply should be on its own, small fused circuit - not on the same one as the lighting, and not behind a switch that is turned off when leaving. An on-board monitor that turns off with the light loses exactly the operating hours from the count that are later missed.
The same applies to the connection as to any electronics on board: the supply line is fused close to the source, not at the device. The fuse protects the line, not the device - and the line is at risk along its entire length.
Initial Commissioning
After switching on, the sensible order is:
- Set onboard voltage. 12 V or 24 V - all subsequent thresholds depend on this.
- Set up battery. Enter type and nominal capacity of the consumer bank, then the starter battery, if it is also monitored.
- Create tanks. For each tank, sensor type and volume. The subtleties - characteristic curve, compensation for irregularly shaped tanks - come later, once the real fill level is known.
- Assign consumers, if devices are connected via CI or CAN bus.
- Check energy flow. Only when sources and consumers are correct does the flow diagram show anything useful.
Tank calibration is not done on the day of installation. It requires at least one full and one empty state as reference points - so realistically, the first trip.
What needs to be checked after installation
- Sign of battery current. When charging, the current must be positive. If it is negative, the battery and load sides at the shunt are reversed.
- Quiescent current. Everything off: The displayed current should be small, but not exactly zero. Exactly zero usually means that the measurement is not being received.
- Tank values in known state. A tank that is known to be full must be displayed as full - otherwise the sensor type or tank height is incorrect.
- Display brightness day and night. Consciously check both before the cover goes back on.
Typical Installation Errors
- Cutout made to display dimensions instead of cutout dimensions. 144 x 90 mm is the display, 120 x 70 mm is the cutout. If you cut the first number, you'll have a hole.
- Each sensor cable run individually to the display. Works, but costs many times more time and introduces more sources of error. The hub is designed precisely for this.
- Power supply behind the main light switch. The monitor only counts as long as it has power.
- No space behind the panel. Connectors need space, cables need bend radius.
- Forcing calibration on the day of installation. Without known full and empty states, any entered characteristic curve is guesswork.
