Why won't my Victron SmartShunt let me set the state of charge manually?
Fresh out of the box, or after the shunt has lost power, the state of charge reads "---" and the State of charge setting in VictronConnect does nothing. That is by design. Victron's manual states that the field is only active once the battery monitor has been synchronised at least once, either automatically or manually. Until the shunt has a known 100 percent reference, it refuses a guess.
Unlock it in two steps
- Charge the bank to full, with whatever charger you have, until the current has tapered.
- In VictronConnect open Settings, then Battery, and press Synchronise. The reading jumps to 100.0 percent and the State of charge field becomes editable, in 0.1 percent steps from 0 to 100.
The same manual synchronisation is the fix whenever the shunt was unpowered, for example after a battery disconnect switch was opened for storage, because the monitor comes back unsynchronised.
If you want the shunt to assume a full battery every time it powers up, the setting is Battery starts synchronised (older firmware calls it "Start synchronized"). Leave it off if the bank is often disconnected part-full, or the reading will be wrong from the first minute.
Why it may never sync on its own
Automatic synchronisation needs three conditions to hold at the same time, and the defaults are written for lead-acid:
| Setting | Default | Victron's guidance |
|---|---|---|
| Charged voltage | 13.2 V on a 12 V bank (26.4 V at 24 V, 52.8 V at 48 V) | 0.2 to 0.3 V below the charger's float voltage |
| Tail current | 4 percent of capacity | Must be above the current at which your charger stops |
| Charged detection time | 3 minutes | Range 0 to 100 minutes |
Example from the manual: a 200 Ah bank syncs when voltage is above 13.2 V and charge current is under 8 A for three minutes. If your lithium charger shuts off at 10 A, the shunt never sees 8 A and never syncs; raise the tail current. If your charger floats at 13.5 V, set charged voltage to about 13.2 or 13.3 V. Set these wrong and a shunt that reads "---" for weeks is the result.
Lithium settings while you are in there
Victron's lithium section says the factory defaults are fine for LiFePO4 except four settings: tail current (higher, for the reason above), Peukert exponent 1.05 instead of 1.25, charge efficiency, and the discharge floor, which should be lower than the 50 percent lead-acid default because lithium can be used deeper. Battery capacity must also be entered; the default is 200 Ah.
If syncing does not fix it
The State of charge setting is only offered inside the VictronConnect app, whether you connect over Bluetooth, over a VE.Direct to USB interface, or remotely through a GX device with VictronConnect Remote. It is not in the GX menus. Accept the firmware update prompt too; Victron recommends updating on a new install. Shop the SmartShunt in 500, 1000 and 2000 A, or the BMV Smart if you want a panel display as well. Both ship from Upland, California.
What you need
Want the full walkthrough? Read the complete guide.