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COPYRIGHT 2002 OUTBACK MARINE AUSTRALIA PTY LTD
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Vessel Electrical Systems
Functional OverviewThe vessel has a DC (direct current),
battery-based power system to supplyall major vessel loads, which may in-clude engine starting, anchor windlass,pumps, lighting, electronics, communi-cations, navigation equipment, refrigera-tion, desalination and entertainmentsystems. Energy to power these systemsis stored in a battery bank, which meansthat the DC system is capable of provid-ing power at any time without the needto run an engine. With the right designand product selection, an engine-drivenpower source might only need to run forone hour each day - or significantly lessif sufficient solar and/or wind power isavailable.
Battery System
The battery capacity is generally sizedso that on a 24-hour basis, the typicaldischarge from the battery bank will notcause the batteries to be less than a 50%charge level. Deeper discharges are pos-sible, however the battery life span will
be shortened. It is interesting to notethat battery life span may also be short-ened by too-frequent shallow dischargecycles. Optimum performance isreached when the batteries are rechargedafter taking 40% of their capacity.
Charging System
The energy that devices take from abattery system can be replaced by:
an engine driven alternator
AC battery charging
solar panels
wind generation
water generationAlternators mounted on a propulsion
engines converts engine power to DCenergy. A battery charger converts AC
(alternating current) electrical power toDC energy. Solar panels convert solarpower to DC energy. Wind generatorsconvert wind power to DC energy.Water generators convert flowing-water energy to DC energy.Steps that can be taken for a reduction
in engine run time include:
reducing power consumption by
selecting energy efficient appli-ances
employing renewable energy
charging devices - solar panels andwind generation
having faster charging from the
engine - large alternator, smartalternator regulation and batterieswith a high charge acceptance rate
AC Power System
Certain appliances are not capable ofbeing powering directly from the DCbattery based system and require ACpower. AC power can be derived fromthree sources:
Shore Power Outlet
On-board Generator Inverter
The shore power outlet at the marinaprovides utility power when the vesselis docked. An on-board generator setprovides AC power when the vessel isaway from dock. The inverter convertsDC energy to AC power.The inverter is a preferred choice for
AC power because it does not requireconnection to shore power or the needto immediately run a generator set.Appliances connected to the inverter
will consume battery energy as re-quired. This energy can be replacedlater, either by running an enginedriven power source or by connecting
to shore power at a more convenienttime. Solar and/or wind power may besufficient on certain days to maintainan energy system balance.Practical considerations restrict the
type of appliances that are suitable forinverter power. Provided that batteryenergy levels are maintained and thatthe sum of loads is kept within inverterspecifications, the inverter is suitablefor powering plug-in appliances suchas microwave ovens, electric kettles,computer equipment, TVs, powertools, clothes washer etc.Although some of these appliances
may require a moderate power level tooperate, we refer to them as light loadsbecause their duration of operation isrelatively short and the correspondingenergy consumed is easily replaced.AC power for air conditioning, hotwater heating and clothes drying willrequire a shore power connection orgenerator set to be run. These appli-ances fall within the heavy load group.
Design and ImplementationA healthy respect of AC power sys-tems from a lethal voltage point ofview is almost general knowledge - yetthe risks associated with DC powersystems are not so evident.A professional design and implemen-
tation will consider all factors includ-ing AC grounding, earth bonding,earth leakage, over-current, lighting,corrosion, wire size, environmentstress, RF interference and so on.Always consult a suitably qualified
marine electrical professional for de-sign and maintenance of the system.
A primary objective for a vessel electrical system is to allowoperation of the vessel within the parameters of safety, reliabil-
ity, performance and long term total cost of ownership.At the same time, we wish to provide support for a healthy and
comfortable living environment that is akin to a modern home.The demand on, and the dependence placed on the electrical
system of a modern vessel has never been higher. The systemneeds to satisfy a number of driving factors:
Operation of the system should be simple, functional, con-
venient and enjoyable
The safety of the vessel and its occupants should never be
compromised
The system needs to be reliable
Engine run time should be kept to a minimum
DC PowerDistribution
Batteries
Engine(s)
Solar
DC Loads
Wind
ELECTRICAL SYSTEM
Shore PowerAC Power
Distribution
InverterCharger
Heavy AC Loads
Light AC Loads
AC POWER
DC POWER
AC Generator
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The AC power system providespower to AC appliances and the in-verter/battery charger via the AC dis-tribution panel. AC power is availablefrom either shore power, the generatorset or an inverter. In this discussioncertain values are vessel specific.
Shore Power Inlet
The Shore Power Inlet is used to con-nect the vessel to dockside power andis rated at 15-amps (3600 VA). Thesum of AC loads on the system shouldnot exceed this rating when connectedto shore power.
Isolation Transformer
The isolation transformer circumventsthe need to connect the shore powerground to the vessel ground, whichavoids the possibility of dockside re-lated electrolysis.
Generator Set
The Generator Set is rated at 32-amps(7600 VA). Care must be taken not toexceed generator set capacity whenconnecting additional loads in paralleland load start-up restrictions may alsoapply. An AC Multi-meter is fitted tothe main AC panel to monitor genera-tor and shore power sourced loads.
AC Source Select Panel
The AC Source Select panel incorpo-rates an interlocking double pole cir-cuit breaker to select either the genera-tor or shore power for connection to
the electrical system. The shore-powerselect circuit breaker must be in the offposition before connecting the shorepower cord to the dockside power out-let. A reverse polarity indicator is pro-
AC Source Select Panel
SHOREPOWER
GENERATORSET
REVERSEPOLARITY
AC Distribution Panel
INVERTERCHARGER
POWEROUTLETS
HOT WATERSYSTEM
AIRCONDITIONER
WASHERDRYER
AC Power System
vided shore power must not beswitched on if a reverse polarity condi-tion is present.The AC Source select panel:
provides reverse polarity indica-
tion to guard against an incorrectlywired shore power system
ensures that only the generator or
shore power source can be selectedat any one time
switches both line and neutral to
ensure that MEN integrity is main-tained
provides separate circuit-overload
protection
Residual Current Device (RCD)
A safety RCD provides a level ofprotection against electrical shockwhen the vessel is powered from eithershore power or generator set.
AC Distribution Panel
The AC Distribution Panel has sepa-rate circuit breakers for the supply ofpower to the Hot Water System, theAir Conditioners and the Inverter/Battery Charger. Note that these cir-cuits are powered when the generatorset or shore power source is available
the system is not configured to run anyof these loads from the inverter. AnAC Multi-Meter is provided to showthe exact load parameters to avoid un-wanted circuit breaker trips at the ma-rina or overload conditions on the gen-erator set. It can indicate AC volts,amps, frequency and watts.The output from the inverter charger
returns to the AC Distribution Panelthrough an isolation breaker to feed thepower outlets to service appliances thatcan be powered from the inverter,shore power or generator. An auto-matic transfer function of the inverter/charger will source shore power orgenerator power if available, otherwisethe inverter will take energy from thebattery system to deliver AC power.
Inverter / Battery ChargerThe battery charger output of 100-
amps allows around 90 amp-hours ofbattery capacity to be replaced for eachhour of operation. The inverter has acontinuous rating of 2500 watts. Thisis sufficient power for a 2000-wattelectric kettle it characteristicallytakes only 4.5 amp-hours of energy tobring 1 litre of water from room tem-perature to the boil in less than 3 min-utes. Later on, only 4 minutes of incre-mental generator run-time would berequired to replace the energy used on your time table.
A remote panel provides full controlover inverter/charger functions includ-ing variable battery charger load ratingand remote on/off control.
AC Outlets
The AC outlets (GPOs) feed all de-vices that can be powered from theinverter. When generator or shorepower is available, the inverter systemtransfers this power direct to the out-lets; otherwise the inverter generatesthe power from the DC system. Thefirst GPO in the outlet chain is fitted
with an RCD safety device which pro-tects all outlets in the chain irrespec-tive of power source.
AC POWER SYSTEM
Shore PowerInlet
AC Generator
AC Dist.Panel
ACSourceSelectPanel
ACMultiMeter
IsolationTransformer
RCD
Hot Water
Air Conditioner
Inverter Charger
AC Outlets
Washer - Dryer
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DC Distribution Board
At the core of the DC power systemis a DC Distribution Board; a specialty
design that ties together all of theheavy power devices on the vessel. Itincludes:
A simple change-over/isolation
switch to select either house bat-tery, reserve battery or full isola-tion
A single positive and negative
distribution bus point for the ves-sel
Individually fused terminals for all
heavy power devices including theengines, generator set, windlass,
inverter/charger and electrical pan-els
DC Power System
Automatic cross-charging of the
reserve battery from any source controlled by the Smart Alternator
Regulator Direct fused connections and ter-
minals for the Energy Monitor andAlternator Regulator
Field switching to enable one al-
ternator regulator to drive multiplealternators
An alternator field disconnect to
protect the alternators when thebattery switch is operated whilethe engines are running
Auxiliary fused outputs from the
house battery for security and car
radio memory; which remain pow-ered when the battery selector
switch is off
A solar panel relay that is con-
trolled by the Energy Monitor for
solar panel regulation A stop relay facility for remote on/
off control of a wind generatorTo minimise voltage drop and cable
weight, the major power devices; DCDistribution Board, batteries and in-verter/charger; are physically groupedin one local area. For hierarchical pro-tection, individual fuses and powerfeeds to each power device ensuresthat an overload condition on one cir-cuit does not disable other circuits; andthat interactive voltage drops are mini-
mized.BatteriesDC power for the entire vessel
(including engine cranking and wind-lass operation) is sourced from a single
House Battery Bank. The consolidationof all vessel loads and the chargingsystem to a single house battery bankgives the best utilization of batterycapacity; increases the effective life ofthe batteries; simplifies energy moni-toring and management; and results inthe fastest possible charge.
In case the house battery becomes
HouseBattery
DCDistribution
Board
DC POWER SYSTEM
ReserveBattery
EnergyMonitor
AlternatorRegulator
InverterCharger
SolarPanels
Engine(Alternator/Starter)
Windlass
WindGenerator
EngineeringPanel
REFRIGERATORFREEZER
WATER PUMP
F'RD BILGE PUMPAFT BILGE PUMP
TOILET SYSTEM
BLACK WATER PUMPSHOWER SUMP PUMP
NavigationPanel
ANCHOR LIGHTSTEAMING LIGHTRUNNING LIGHTSTRICOLOR LIGHT
INSTRUMENTSVHF RADIOHF RADIO
CABIN LIGHTS/FANS
DECK WASH PUMP
GAS DETECTOR
HELM PANEL
STEREO
DESALINATOR
HelmPanel
SPREADER LIGHTSHORN
COCKPIT LIGHTSINSTRUMENT LIGHTSWINDLASS UP/DOWN
AC PowerSystem
BATTERIESDC DISTRIBUTION BOARD
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totally discharged, a Reserve Batteryprovides power for priority vesselfunctions including engine cranking,windlass, communications and bilgepumps. Before switching to the reservebattery, switch off all nonessentialloads. Once the engine is started andthe alternator is charging, the batteryselect switch can be restored to the
house battery bank position.Operationally, the battery switch is
simply left on Position 1. No poweris drawn from the reserve battery and itis always kept topped-up. Position 2is available for reserve. Off is usedfor service or emergency disconnect.As a last resort, the Both positionwill join the house and reserve batter-ies.
Energy Monitor
The Energy Monitor provides com-plete management of battery state-of-
charge; accurately indicates batteryvoltage and current; controls batterycharging from solar panels and otherunregulated sources; and keeps awatchful eye on vital battery parame-ters including over voltage and tem-perature. An alarm is generated if anyparameter is outside of specification -
an indication to fix-it before seriousdamage results.The energy monitor gives a direct
indication of energy consumed andenergy remaining from the house bat-tery this is an essential tool for bat-tery management and is especially
useful to indicate when to start andstop battery charging from the mainengine or generator set.
Inverter/Battery ChargerThe Inverter/Battery Charger builds
two functions into the same package.The battery charger has three-stage
regulation to ensure a fast and fullcharge. Charging voltage is variedaccording to battery temperature; es-sential to prevent thermal runaway andconsequent explosive risk.
Engine AlternatorsThe Engine Alternators charge the
house battery and are controlled by aSmart Alternator Regulator. They eachhave an isolated ground with a dedi-cated ground return to the DC distribu-tion board. The engine blocks have aseparate ground return to ensure thatboth are at a common potential par-
ticularly important when only one en-gine is being run; this arrangement isnecessary to avoid electrolysis.
Smart Alternator Regulator
The Smart Alternator Regulator(SAR) utilizes 3-step regulation withbattery temperature compensation toensure safe, accurate and fast charging.The SAR also monitors the voltage on
the positive distribution bus to detectany active charging source; if present,it drives a cross-charge relay to keepthe reserve battery in a fully chargedcondition. The cross-charge relay iso-lates the reserve battery when nocharging source is present. A singleSAR is used to drive multiple alterna-tors
Solar PanelsThe Solar Panels charge the batteries
during the day. The amount of energyreplaced by the solar panels depends
on the capacity of panels fitted andsolar conditions. A greater investmentin solar energy will result in less en-gine run time. The Energy Monitorcontrols solar panel regulation bymeans of a relay fitted to the DC Dis-tribution Board. Solar charging pa-rameters are fully programmable.
Wind GeneratorThe DC Distribution Board is pre-
wired with terminations and a relaythat can be controlled by an externalswitch to turn a suitable wind genera-tor on and off. A wind generator canbe most effective to replace additionalenergy consumed by the vessel instru-ments and autopilot when the vessel issailing.
SMART ALTERNATOR REGULATOR
ENERGY MONITOR
Engineering Panel
REFRIGERATOR
FREEZER
WATER PUMP
FORWARD BILGEPUMP
TOILET SYSTEM
BLACK WATERPUMP
SHOWER SUMPPUMP
AFT BILGE PUMP
Navigation Station Panel
ANCHORLIGHT
STEAMINGLIGHT
RUNNINGLIGHTS
TRICOLORLIGHT
CABIN LIGHTS/FANS
DESALINATOR
DECK WASHPUMP
INSTRUMENTS
VHF RADIO
HF RADIO
STEREO
GASDETECTOR
HELM PANEL
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DC Electrical PanelsThe purpose of the electrical panels is
to allow switching of vessel devicesand to provide overload protection ofwires leading to devices. They are nor-mally fitted with circuit breakers,which switch power to devices andwill trip if the current in the circuitexceeds the circuit breaker rating. In
the case of a single circuit breakerfeeding multiple branch circuits, sub-fuses are used to provide over-currentprotection for each branch circuit. Ourfuse holders incorporate an LED toindicate a blown fuse condition.The wire connecting the circuit
breaker or fuse to the load is sized ac-cording to the current required for thedevice and the distance to the device.The wire will have a maximum currentcarrying capacity referred to as am-pacity. The wire may be sized higher
than the required ampacity to compen-sate for the voltage drop due to wirelength.The circuit breaker or fuse is always
sized to be less than the cable ampacityand greater than the device load. Underno circumstances should the sum ofdevice current in a circuit result in thecircuit carrying current greater than thecable ampacity rating. Further, a cir-cuit breaker or fuse fitted to a circuitshould never have a rating which ex-ceeds cable ampacity. Failure to ob-
serve these rules may result in fire and/or serious damage.
Navigation Station PanelThe Navigation Station Panel powers
devices that are commonly switchedon and off throughout the day. It isreadily accessible at the navigationstation fascia with functionality kept toa minimum for ease of operation. Carehas been taken to avoid poweringpumps and other high power devicesthat might subject sensitive navigationdevices to voltage excursions from this
panel. A dedicated circuit breakerfeeds power to the Helm Panel wherewaterproof switches control functionsapplicable to the helm station.
Engineering Panel
The Engineering Panel uses circuitbreakers to power devices that are lesslikely to be switched during the routineoperation of the vessel.
To avoid inadvertent switching ofvessel services (for example refrigera-tion) it may be advisable to recess thispanel behind a door.
Vessel Wiring and SafetyAll vessel wiring and power distribu-
tion components must connect powerto devices in a safe and efficient man-ner.
The vessel environment is prone tovibration and corrosion so all wiring ismulti-strand tinned copper and is regu-larly held in place with the use of cabletray and saddles. Heat-shrink moisturebarriers further protect wiring termina-tions that are subject to excessivemoisture ingress. Cables are selectedaccording to loads, ampacity rules andlength. Each electrical circuit isequipped with either a fuse or circuitbreaker of the correct rating to protectagainst fire.
DC Battery systems require specialcare to avoid risk of fire and/or per-sonal injury.
The battery isolation switch should
be turned to the OFF positionwhenever work is carried out onany part of the DC system.
Special care is required when
working in close proximity to thebatteries and battery switch be-cause these are not isolated whenthe switch is OFF.
AC voltages are lethal. Safety proce-dures must be followed for work onthe AC system:
Only a qualified electrical trade
person should perform work onthis system
All AC circuit breakers must be in
the off position
Inverter DC input must be discon-
nected
The shore power cord must be
removed
The generator must be disabled
from starting Any changes of wiring or design
must be documented
Your Vessel System?All vessel electrical systems follow
the same principals as discussed here.This document is an example of anelectrical system specification derivedfor an Australian 15-metre sailing ves-
More than a product
vendor!At Outback Marine, we look beyond
the product to a complete engineeredsolution. We need to meet your per-formance and budget expectations.We understand the importance ofsafety and reliability. We relate toquality products and services.As a primary importer and distribu-
tor, our pricing is fair and reflectsservice support with in-depth productand application knowledge. Our sys-tem designs are fully documented tomeet Australian and/or Internationalstandards. Outback Marine can helpyou in a number of ways:
Design - Supply - Install -
Commission: The design is fullydocumented including CADschematics. In addition to theproduct manufacturer warranty,we offer a 2-year warranty on ourwork.
Design - Supply: We can
support your installation team
and provide drawings for surveyapproval if required.
Supply only: Our technical
support people are ready to assistyou throughout the design andinstall process.
Authorised dealer opportunities areavailable throughout Australia.
Outback Marine Australia Pty Ltd
3/5 Ereton Drive
Labrador QLD 4215
Ph: (07) 5563-9088
Fax: (02) 9475-0486
System solutions for mobile:
Air Conditioning
Desalination Electrical
Electronics
Refrigeration
sel. A few changes are necessary forvessels requiring survey approval orvessels destined for foreign countries.Whether your vessel is power or sail;
mono-hull, catamaran or trimaran; forleisure or commercial use; OutbackMarine has the design and productsolution to meet your needs.For vessel designers and manufactur-
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