Service Manual

Inspecting,Maintaining,andTestingtheBattery(continued)
IMPORTANT
Ensurethattheareaaroundthecellsiscleanbeforeopeningthe
batterycaps.
A.Useahydrometertomeasurethespecicgravityofeachcell.Pullthe
electrolyteinandoutofthehydrometerbarrelbeforetakingareading
towarm-upthehydrometer.Atthesametime,takethetemperatureof
thecell.
B.T emperaturecorrecteachcellreading.Foreach5.5°C(10°F)above
27°C(80°F)add0.004tothespecicgravityreading.Foreach5.5°C
(10°F)below27°C(80°F)subtract0.004fromthespecicgravityreading;
refertotheCellSpecicGravityExample(page5–97).
CellSpecicGravityExample
CellTemperature100°F
CellSpecicGravity
1.245
38°Cminus27°Cequals11°C
(100°Fminus80°Fequals20°F)
11°Cmultiplyby0.004/5.5°Cequals0.008
(20°Fmultiplyby0.004/10°Fequals0.008)
ADD(conversionabove)
0.008
Correctionto27°C(80°F)
1.253
C.Ifthedifferencebetweenthehighestandlowestcellspecicgravityis
0.050ormoreorthelowestcellspecicgravityislessthan1.225,charge
thebattery.
D.ChargeattherateandtimegiveninChargingtheBattery(page5–98)
oruntilallcellsspecicgravityis1.225orgreaterwiththedifferencein
specicgravitybetweenthehighestandlowestcellislessthan0.050.If
youcannotmeetthesechargingconditions,replacethebattery.
3.Doahigh-dischargetestwithanadjustableloadtester.Thisis1ofthemost
reliablemeansoftestingabatteryasitsimulatesthecold-crankingtest.A
commercialbatteryloadtesterisrequiredtodothistest.
CAUTION
Followthemanufacturer'sinstructionswhenusingabatteryload
tester.
A.Checkthevoltageacrossthebatteryterminalsbeforetestingthebattery.
Ifthevoltageislessthan12.4VDC,chargethebatterybeforecontinuing
thetest;refertoChargingtheBattery(page5–98).
B.Ensurethatthebatteryterminalsarefreeofcorrosion.
C.Measuretheelectrolytetemperatureofthecenterbatterycell.
D.Connectabatteryloadtestertothebatteryterminalsfollowingthe
manufacturer'sinstructions.Connectadigitalmultimetertothebattery
terminals.
Groundsmaster
®
4300-D
Page5–97
ElectricalSystem:ServiceandRepairs
16226SLRevD