Samlexpower PST-1000-12 Owner's manual - Section 7 |
20 | SAMLEX AMERICA INC.
Table7.3(page19)willshowthata100Ahcapacitybatterywilldeliver100%(i.e.full
100Ah)capacityifitisslowlydischargedover20hoursattherateof5Amperes(50W
outputfora12Vinverterand100Woutputfora24Vinverter).However,ifitisdis-
chargedatarateof50Amperes(500Woutputfora12Vinverterand1000Woutputfor
a24Vinverter)thentheoretically,itshouldprovide100AH÷50=2hours.However,the
Tableaboveshowsthatfor2hoursdischargerate,thecapacityisreducedto50%i.e.50
Ah.Therefore,at50Amperedischargerate(500Woutputfora12Vinverterand1000W
outputfora24Vinverter)thebatterywillactuallylastfor50Ah÷50Amperes=1Hour.
State of charge (Soc) of a Battery – Based on “Standing Voltage”
The“StandingVoltage”ofabatteryunderopencircuitconditions(noloadconnected
toit)canapproximatelyindicatetheStateofCharge(SoC)ofthebattery.The“Standing
Voltage”ismeasuredafterdisconnectinganychargingdevice(s)andthebatteryload(s)
andlettingthebattery“stand”idlefor3to8hoursbeforethevoltagemeasurement
istaken.Table7.4belowshowstheStateofChargeversusStandingVoltagefora12V
batterysystemat80°f(26.7ºC).for24-voltsystems,multiplyby2;for48-voltsystems,
multiply by 4.
tABLe 7.4: StAte oF cHARGe VeRSUS StAnDinG VoLtAGe – 12V BAtteRY
Percentage of
Full charge
Standing Voltage of 6 cell,
12V nominal Battery
Standing Voltage
of individual cells
100%
12.63V
2.105V
90%
12.6V
2.10V
80%
12.5V
2.08V
70%
12.3V
2.05V
60%
12.2V
2.03V
50%
12.1V
2.02V
40%
12.0V
2.00V
30%
11.8V
1.97V
20%
11.7V
1.95V
10%
11.6V
1.93V
0%
=/<11.6V
=/<1.93V
Checktheindividualcellvoltages/specificgravity.Iftheintercellvoltagedifference
ismorethana0.2V,orthespecificgravitydifferenceis0.015ormore,thecellswill
require equalization. Please note that only the non-sealed / vented / flooded / wet cell
batteries are equalized. Do not equalize sealed / VRLA type of AGM or Gel Cell Batteries.
State of Discharge of a loaded battery – Low Battery /
Dc input Voltage Alarm and Shutdown in inverters
MostinverterhardwareestimatetheStateofDischargeoftheloadedbatterybymeas-
uringthevoltageattheinverter’sDCinputterminals(consideringthattheDCinput
seCtIOn 7 |
General Information on Batteries for