OTC Tools 3182 - Charging Test

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3.HaveanassistantturntheignitionswitchtotheStartPositionandcrankengine
for15seconds.Ifworkingalone,usearemotestarterswitch.Do not press the
Load Switch.Observethebatteryvoltageindicatedonthedisplay.
4.Ahealthystartingsystem,with a good, fully charged battery,shouldreadabove
9.0Vduringthistest.
5.Readingsbelow9.0Vmayindicateaprobleminthestartingsystem.Recharge
batteryandrepeatthistest.Ifvoltagereadingsstillremainbelow9.0V,then
probablyeitherthebatteryisbad(performtheLoadTest),thestarterisdefective
or the cables are loose or corroded.
Charging Test
Thistestmeasuresthebatteryvoltagewhiletheengineisrunningtodetermine
ifthechargingsystemisoperatingproperly.
1.Startthevehicleandallowittowarm-up.Thismaytake10to15minutes.
2.TurnengineOFF.
3.WhenperformingtheChargingTest,thebatteryshouldbepartiallydischarged.
TurntheignitionswitchtotheACCESSORIESpositionandturnheadlightsON
andfantoHIGHfor1minute.
4.Whendone,turnheadlightsandfanOFFandthenturnignitionswitchtothe
OFFposition.
5.Whileobservingpolarity,connectthetesteracrossthebatteryposts:Redto
positive(+),Blacktonegative(-).RefertoFigure 6.
6.Start engine andrunatfast-idle(1200-1500 RPM).Ahealthy12Vcharging
systemshouldmaintainreadingsbetween13.5V and 15.5V.
Proper Charging System Operation
Within several minutes, the voltage will gradually increase to the regulated
voltagerangeof13.5Vto15.5V.Ina6Vsystem,thevoltageshouldgradually
risetotheregulatedvoltagerangeof6.7Vto7.4V.
Incorrect Charging System Operation
Low Regulated Voltage: Ifafterseveralminutes,thevoltageisbelow13.5V
fora12Vsystem(6.7Vfora6Vsystem),thanaproblemexistswitheitherthe
charging system orbattery. Performthe Load Test on thebattery and then
repeattheChargingTest.
High Regulated Voltage: Ifthevoltageisabovetheregulatedvoltagelimit
(15.5Vfora12Vsystem,7.4Vfora6Vsystem),thenaproblemexistsinthe
chargingsystem.Damagetothevehicleelectricalsystemmayresultfromthe
excessivelyhighvoltage.
AdecisiontoREPLACEthealternatororotherelectricalsystemcomponents
shouldnotbebasedsolelyonthesetestresults.Refertotheapplicablevehicle
servicemanualforadditionaltestandtroubleshootingprocedures.