25.6 lithium battery only showing 4.7 across main terminals. Batteries stored fully disconnected for 3 months. Are they in a sleep mode
asked
25.6 lithium smart only 4.7 volts across main terminals fully disconnected is this normal, is the battery in sleep mode please help
Please help only a small time window
That is definitely not normal, there is not "sleep mode", the battery is dangerously ultra deeply discharged. 4.7V across 8 cells is less then 0.6V per cell and the cells are permanently damaged now.
Was it fully charged 3 months ago?
With "fully disconnected" you mean everything was disconnected from the terminals?
This should not happen with nothing connected to the terminals. Victron says after a full charge and with nothing connected you can store the batteries for at last 1 year.
You can try to slowly charge the battery (with 5A or less) without a BMS under permanent supervision until it is shown in VictronConnect. Then connect the BMS and continue the slow charging until the battery is full.
This will take many hours or days.
Battery very low terminal voltage:
https://www.victronenergy.com/media/pg/Lithium_Battery_Smart/en/troubleshooting-support-and-warranty.html#UUID-fa74555d-8d49-087a-cdab-6168799f1eec
