If your BCDC Alpha charger (25A, 50A, or 50R) shows a flashing Boost, Absorption, or Float LED, it means the battery temperature sensor is disconnected or faulty.
This is a soft fault, so charging continues, but the sensor should be checked.
This article explains causes such as poor connections, cable damage, or a faulty sensor, and provides steps to fix the issue.
REDARC recommends seeking the support of a qualified auto electrician or technician.
Important
In this article we explain the need for testing to determine the cause of the issue. Testing may involve changes to the installation or wiring. For your safety and accuracy, REDARC recommends engaging a REDNetwork member or a suitably qualified auto electrician - Find Your Local Installer
This information is applicable to the following BCDC Alpha Chargers:
- BCDC Alpha 25A DC Battery Charger (BCDC12024B)
- BCDC Alpha 50A DC Battery Charger (BCDC12050B)
- BCDC Alpha50 R DC Battery Charger (BCDC12050R)
What does this look like?
The BCDC Alpha flashes one of the Battery profile (Boost, Absorption or Float) status LEDs.
This fault condition is a soft fault and therefore only one of the Boost, Absorption or Float status LEDs will flash corresponding to the current charging stage the BCDC Alpha is in.
Note: Only one of the LED’s will flash depending on what stage the charger is in.
What does one of the flashing boost, absorption or float LEDs mean?
This fault indicates that the BCDC Alpha has detected that the battery temperature sensor has been disconnected.
Will the BCDC Alpha still charge my battery in this condition?
In this fault condition, being a soft fault, the BCDC Alpha will continue to charge the auxiliary battery.
What is the purpose of the battery temperature sensor?
The battery temperature sensor cable allows the BCDC Alpha to monitor the temperature of the auxiliary battery during the charging process. The BCDC Alpha will then adjust the charging rate automatically to protect against overheating for faster and safer charging.
What are the torque specifications for the battery sensor bolts?
Torque to 1 N∙m (0.74 ft∙lbf).
Note: Ensure accurate torquing of the terminal screws. Over-torquing can cause damage to the terminal threads. Under-torquing leads to loose screws which can create a high-resistance connection that could overheat, damaging the main unit and wiring.
What can cause this fault mode?
- Disconnected battery temperature sensor
- Damaged battery temperature sensor cable
- Faulty battery temperature sensor
How to determine the cause of this fault?
Below is a list of the common causes and repairs.
A) POOR CONNECTION AT THE BCDC ALPHA OR AUXILIARY BATTERY
Things to check:
- Check the connection points of the battery temperature sensor.
- If loose, remove, clean surface and re-connect.
- Re-check operation.
- If fault persists, refer to step B.
B) DAMAGED CABLE
Things to check:
- Review battery temperature sensor installation.
- Look for over tightened cable ties, squashed cable or any visible damage.
- If damage is found, refer to step C.
OVERTIGHTENED CABLE TIES
SQUASHED CABLE
VISIBLE DAMAGE
C) FAULTY BATTERY TEMPERATURE SENSOR
If all the steps in A and B have been completed the outcome is due to a damaged battery temperature sensor.
Things to check:
- Remove damaged battery temperature sensor.
- Replace with a new battery temperature sensor.
- Re-check operation.