Electrical - Battery Current Consumption And RDAR
Title Battery current consumption and RDARRef No: US25590.1.1 en-US
Issuer -
Partner 3 US 7510 Volvo Cars North America
Func Group: 3117
Func Desc: Battery, general
Status Released
Status Date 12-09-2011
Issue Date 12-02-2011
Reference
Attachment
Vehicle Type
CSC = Customer Symptom Codes
DTC = Diagnostic Trouble Codes
Text
CSC = Customer Symptom Code
CCA = Cold Cranking Amps
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DESCRIPTION:
It has come to our attention that there is an increasing replacement rate of Sirius control units (RDAR) due to high quiescent current. Reports have been submitted stating that a value of 30 to 70 milliamperes is causing a flat battery within a time frame anywhere from overnight to several days.
Although the value above could be a contributor in a drained battery over extended periods, it is important to understand how a small current drain of for example, 50 milliamperes (0.050 amperes), will affect a healthy automotive battery.
Volvo original equipment batteries are rated at a capacity of 60 ampere hours for the 600CCA battery and 80 ampere hours for the 700CCA battery. In the simplest of terms, a 1.0 ampere drain would take 50 hours to drain a 50 amp hour battery. Therefore, if we use a 50 milliamp (0.050 amp) drain as an example for a 80 amp hour capacity battery, it would take 1600 hours (66.6 days) to completely drain the battery.
80 amp hour batt capacity divided by 0.050 amp drain = 1600 hours
The above example is given the battery has not had any charge applied to it and has remained static for 66 days.
SERVICE:
Although 70 mA is out of specification for the complete vehicle current consumption, it is not enough to drain the battery in a few days.
Do NOT replace the RDAR as a repair for battery drainage if the RDAR current consumption is less than 100 milliamp unless the customer reports that the vehicle is not used for extended periods.