Volvo Bus CorporationGothenburg, SwedenBodybuilding InstructionBuses and coachesSect.GroupNoDate3019060518Electrical power consumptionApplies to all modelsGeneralCurrent drain must be limited during idling and when the engine is switched off,to increase the service life of the batteries. For this reason, the body builder must dimension the body electrical system using the tables below for guidance.ActionIdlingChassis current drain is shown in the table below 1. The values apply to idling at 600rpm unless otherwise specified. If the outdoor temperature is greater than -5°C, it is possible to ignore the current needed to heat the AdBlue hoses.Chassis current requirements3-0-19 R01Max current consumption at idle •At idle, the total current consumption for the body and chassis together must not be greater than the charge received by the batteries, please refer to the table 2. NOTE! The charge values in the table must therefore be reduced by the current requirement in table 1. In exceptional cases, short term loading on the batteries can be permitted, however.NOTE! At low idling speed, the charging capacity falls dramatically.Bus modelCurrent required for heating the AdBlue hoses at temperatures below -5°C (Euro 4 engines)Current required for pump sensors etc. when the SCR system is used (Euro 4 engines)Current required for batterycharging, control units, instrument lighting etc.B7R B7LE 10A 10A 20A B9L B9TL B9S 20A 10A 20A B12B 6x228A 10A 20A B12B 4x225A 10A 20A B12M B12MA19A10A20ATable 1. Chassis current requirementsModelAlternator aRatioCharge current at idle(600rpm)Total charge current at idle Charge current at ambient temperature B7R/B7RLE MkII80 A 1:4.560 A 90ºC Engine mounted2x80A 1:4.5120 A 25ºC 2x110A1:4.5160 A 25ºC B7R/RLE MkIII 2x100 A1:3.392 A90ºCB7L115 A 1:2.8105 A ---25ºCIdle speed for B7L and B7TL is 700rpm140 A 1:2.8100 A 180 A 1:2.8135 A 140+80 A1:2.8 and1:3.7150 A B7TL 115 A 1:2.9105 A 140 A 1:2.9100 A 180 A1:2.9135 A B9L 2x80 A 1:5.2108 A 90ºC2x80 engine mounted 2x110 A 1:5.2156 A 234 A90ºC110 engine mounted 110 A1:5.1178 AMounted on ACcompressorB9TL 2x80 A 1:5.2108 A 90ºC 2x80 engine mounted 2x110 A1:5.2156 A219 A90ºC2x110 engine mounted 110 A 1:463 A110 on auxiliary bridge2x180 A 1:2,9230 A ---25ºCTable 2. Max current consumption at idleB9R 2x80 A 1:5.2108 A 90ºC 2x80 engine mounted 2x110 A1:5.2156 A90ºC2x110 engine mounted B9S 2x80 A 1:3.988 A 90ºC2x80 auxiliary bridge 2x110 A 1:3.9110 A 90ºC2x110 auxiliary bridge 3x110 A 1:3.9165 A 90ºC3x110 auxiliary bridge B12B 2x80 A 1:4.44100 A 90ºC 2x80 engine mounted 3x80 A 1:4.44150 A 90ºC 3x80 engine mounted 2x110 A4.44140 A90ºC2x110 engine mounted 3x110 A 4.44209 A 90ºC3x110 engine mounted B12M 3x80 A 4.48150 A 90ºC3x80 auxiliary bridge 3x110 A 4.48209 A 90ºC3x110 auxiliary bridgepact alternators: 80A, 110AModelAlternator aRatioCharge current at idle(600rpm)Total charge current at idleCharge current at ambient temperature Table 2. Max current consumption at idleEngine stoppedThe table below shows examples of how various current drains affect the batteries when the engine is shut off, such as at a terminus. The tables also show how long the bus needs to be driven before the batteries are fully charged again.The values in the table are specified for about 20°C. NOTE! In cold climates,there must be much longer recovery time.DefinitionsElectric balance is defined as the relationship between current produced and current consumed per minute.This relationship can also be expressed by specifying a margin between current produced and current consumed per minute. See figure (1).Producer:I p Load:I c Margin:I mFigure 1I p Current, produced Current drain fromthe batteriesTime in minDriving time in min to recharge the batteries to full charge10A 101610A 203210A304830A104830A 209630A 3014450A 108050A 2016050A30240Electric balanceThe purpose of electric balance is:-Avoid consumption from the starter battery when the engine is running and electrical loads are activated.-Ensure that the required current for starting the engine is available.-Avoid too low voltage level when the engine is turned off and electrical loads are activated.Starter batteries - service lifeLife span for starter batteries is directly dependant on the current consumption level they are exposed to.Starter batteries - rechargingWhen a starter battery supplies a load, the recharging capacity depends on:-Current, consumption level -Consumption time -Outdoor temperatureCurrent, consumption levelRecharging upper level is about 10 Ampere.Consumption timeRecharging time is 1.6 times the consumption time for outdoor temperatures of 20º C.Outdoor temperatureLow outdoor temperatures, -20 ºC , gives recharging time 3 x 1.6= 4.8 times consumption time .Estimated recharging time Consumption:X Ampere Time, recharging: t re Minutes Time, consumption: t co Minutes Temperature factor:f 1.6 ≤ f ≤ 4.8Minutest re X10-----f t co ××=Generation / loadThe relationship I p ≥I c + I m shall be performed for all engine speeds.I p is determined at the engine idling speed, 550rpm for Euro3 engines and600rpm for Euro4 engines, if no other idling speed is specified.I c is determined in the check list below.The margin, I m is determined at the engine idling speed and concerns loadingcapacity for starter batteries as well as instrument lighting.I m, city buses I m = 20 A.I m, long distance buses I m = 0 A.Figure 2Connection3-0-19 R02Connection of electrical loads•Connection of electrical loads shall be performed so that:•Current supply for safety related functions shall have priority to other loads.•Too low voltage level in starter battery is avoided, when the engine is turnedoff and electrical loads are activated. Safety related functions are notaffected by this requirement.Check list for electric balance analysisNo Load Number NominallyAmpere Degree ofutilisation%EstimatedconsumptionAmpereA External lighting1Headlamp, low beam2Headlamp, high beam3Headlamp, spot lamp4Headlamp, curvature5Headlamp, front fog lamp 6Headlamp, passing light 7Headlamp, reverse light8Headlamp, operating light 9Headlamp, rear door light 10Headlamp, miscellaneous 11Lamp, tail light12Lamp, position light13Lamp, parking light14Lamp, width marking light 15Lamp, identifying light 16Lamp, day running light 17Lamp, side marking light 18Lamp, stop light19Lamp, number plate light 20Lamp, rear fog light21Lamp, direction indicator 22Lamp, miscellaneousB Lighting, interior1Roof light, 1/12Roof light, 1/23Roof light, driver4Roof light, night5Roof light, reading lamps6Lighting, floor 7Lighting, instrument 8Lighting, guide 9Lighting, lavatory 10Lighting, pantry equipment 11Lighting. destination plate front 12Lighting. destination plate side 13Lighting, number plate 14Lighting, stop plate 15Lighting, drivers cabin 16Lighting, luggage compartm.17Lighting, engine room 18Lighting, miscellaneous C Sight facility 1Windscreen wiper 2Windscreen washer 3Headlamp, wiper and washer 4Electrical heating, window 5Electrical heating, mirror 6Electrical window lift 7Sight facility, miscellaneous D Communication 1Horn 2Radio 3Video 4TV-monitor 5Mobile telephone 6Radio communications 7Telefax 8Computer 9Advertising plates10Communication, miscellaneousNo Load NumberNominally AmpereDegree of utilisation %Estimated consumption AmpereE Fans 1Fan, air floor 2Fan, air driver 3Fan, air doors 4Fan, defroster5Fan, ventilation 1/3-speed 6Fan, ventilation 1/2-speed 7Fan, ventilation 1/1-speed 8Fan, air condition 9Fan, air condition, driver 10Fan, pantry 11Fan, lavatory 12Fan, miscellaneousF Pumps 1Heat water 2Auxiliary heater 3Air condition 4Lavatory5Pump, miscellaneousG Service 1Refrigerator2Coffee making machine 3Water heater 4Stove 5Furnace6Service, miscellaneousNo Load NumberNominally AmpereDegree of utilisation %Estimated consumption AmpereSummaryCurrent, total produced I p Ampere ______ Current, total consumed I c Ampere - _______Margin I mAmpere= _______If I m < 0:______Estimated recharging timet re Minutes ______ Requirement listRequirementnumber Requirement headingPage 3-0-19 R01Max current consumption at idle 13-0-19 R02Connection of electrical loads6H Other systems1Electrical system, components 2El.- air pre-heater or glow plug 3Electrical diesel control, EDC 4Easy gear shift, EGS 5Anti lock brakes, ABS6Electronic control air suspension, ECS 7Air dryer 8Retarder, hydraulic 9Retarder, electromagnetic 10Ticket vending machine 11Electrically operated doors 12Hoist for disabled 13Electrically operated ramps 14AdBlue-pump 15AdBlue hoses, heatingNo Load NumberNominally AmpereDegree ofutilisation %Estimated consumption Amperet re X10-----f t co ××=。