Hi Guys
we have installed a system in a vessel and have had a Issue where the Shore power was kicked out and battery left to drain to around 9V, we have installed 20-30 systems so think we know he gear fairly well,
System
2 x 200AH 12.8 V Smart Batteries
ve.bus BMS
multiplus 12/2000/ Compact running latest 497 Firmware
BP200 for Loads
BP65 For DCDC chargers
- went to boat to find system at 9V or slightly less,
- Alarm not running As i assume to Low voltage for BMS
- Plugged in shore power nothing Came to Life
- Checked Charge current no Current
Question 1
By the Manual if the Mulitplus cannot see the VE.Bus BMS it should charge at 5a until it reaches it nominal Voltage (12v) , it suggests this can be tested by removing the VE.bus BMS cable from the Compact and this should happen
this in our case did not happen.
we also tried to re run the test with the batteries at 10V (less then the 12v) by pulling the BMS cable out of the Multi ( tired before or after the AC-Detector) never did we see any current Come out of the Multiplus Compact to attempt to recover the batteries,
Is this because its a Compact not a standard Multi??
Question 2
I think our buzzer helped drain the batteries to this level the Pre alarm does not seem to work as per manual, the alarm would sound 100% of the time while the loads have been switched off, meaning it will just keep draining untill the BMS switches off at max of 1A
See manual
In case of an imminent under voltage shutdown, the pre-alarm output of the BMS will switch on. In case the voltage continues to decrease, the loads are switched off (load disconnect) and at the same time the pre-alarm output will switch off again. In case the voltage rises again (operator has enabled a charger or has reduced the load) the pre-alarm output will switch off, once the lowest cell voltage has risen above 3.2V.
can someone explain why this is the case, and i have also seen this on another vessel also where loads are disconnected but Prealarm keeps going, ?