Service Manual

Inspecting,Maintaining,andTestingtheBattery(continued)
C.Ifthedifferencebetweenthehighestandlowestcellspecicgravityis
0.050ormoreorthelowestcellspecicgravityislessthan1.225,charge
thebattery.
D.ChargeattherateandtimegiveninChargingtheBattery(page5–106)
oruntilallcellsspecicgravityis1.225orgreaterwiththedifferencein
specicgravitybetweenthehighestandlowestcellislessthan0.050.If
youcannotmeetthesechargingconditions,replacethebattery.
CellSpecicGravityExample
CellTemperature100°F
CellSpecicGravity
1.245
37.7°Cminus26.7°Cequals11.0°C
(100°Fminus80°Fequals20°F)
11°Cmultiplyby0.004/5.5°Cequals0.008
(20°Fmultiplyby0.004/10°Fequals0.008)
ADD(conversionabove)
0.008
Correctionto26.7°C(80°F)
1.253
3.Doahigh-dischargetestwithanadjustableloadtester.Thisis1ofthemost
reliablemeansoftestingabatteryasitsimulatesthecold-crankingtest.A
commercialbatteryloadtesterisrequiredtodothistest.
CAUTION
Followtheloadtestermanufacturer’sinstructionswhenusinga
batteryloadtester.
A.Checkthevoltageacrossthebatteryterminalsbeforeloadtestingthe
battery.Ifthevoltageislessthan12.4VDC,chargethebattery.
B.Ifyouchargethebattery,applya150Aloadfor15secondstoremove
thesurfacecharge.Useabatteryloadtesterfollowingthemanufacturer’s
instructions.
C.Ensurethatthebatteryterminalsarefreeofcorrosion.
D.Measuretheelectrolytetemperatureofthecenterbatterycell.
E.Connectabatteryloadtestertothebatteryterminalsfollowingtheload
testermanufacturer’sinstructions.Connectadigitalmultimetertothe
batteryterminals.
F.Applyatestloadof345A(1–1/2thecrankingperformanceratingof
thebattery)for15seconds.
G.Takeabatteryvoltagereadingat15seconds,thenremovethetestload.
Thisreadingisthetestvoltage.
H.UsetheMinimumVoltageT able(page5–106),determinetheminimum
voltagefortheelectrolytetemperatureofthecenterbatterycell.
Groundsmaster5900TractionUnit
Page5–105
ElectricalSystem:ServiceandRepairs
08159SLRevC