How to fix error “Voltage collect cable dropped” of DALY BMS APP

Error Description:

The app displays the status message: ‘Voltage collect cable dropped’, and one or more battery cells show 0V. See Figure 1.

For the battery:
– When measuring voltage with a voltmeter, the reading differs from the voltage shown in the SMART BMS App, and the actual battery voltage drops rapidly. See Figure 2.
– Plugging the battery pack into a charger may damage the charger.
– When connected to a load, the battery operates for about 0.1 seconds and then stops. At that point, a voltmeter’s reading will show 0V at the output terminals of the entire pack. See Video 03.

Image 1: Illustration of  ‘Voltage collect cable dropped’ error on the Daly BMS app.

Image 2: Voltmeter shows 23V recorded a sharp drop, while the app reading is 46.4V.

Video 03: The battery’s abnormal behavior under load (it shuts itself after 0.1 second)

 

Step by step guide to fix the error “Voltage Collect Cable Dropped”

Step 1: Update Firmware

You should visit the manufacturer’s website to download the latest version of the app:
https://www.dalybms.com/download-bluetooth-app/

Currently, in July 2025, there are two common apps: DALLY BMS and SMART BMS, but the manufacturer is gradually consolidating everything into DALLY BMS.

Go to: Preferences > BMS Software Update > Enter Code: ‘SXYCOG’
(You can request this code from the BMS seller.)

 

Then, navigate to ‘MOS Temp Protect’ and set the value to 60.

If the update fails, it usually indicates a faulty BMS, and you should request a warranty replacement.

Step 2: Check for loose cable connections or broken/rusted welder points.

You need to open the battery  case  and inspect cable/welding tabs/ connectors that may have come loose or rusted

– Disconnect the welding sampling cable from the BMS.
– Use a voltmeter to measure the voltage of each cell group (example shown for a 13S battery pack). Or, you can use a battery balancer to check each group’s voltage.

Measure voltage of each battery string using a voltmeter

Using battery balancer machine to check string voltage. 

 

If any group shows abnormal voltage, consider replacing that cell group.

In our case, the readings were normal and the battery/cables were fine, so the issue was with the BMS.

Final Step:

If the above two steps do not resolve the issue, request for a replacement.
Daly offers replacement policy, and replacing the BMS typically resolves the error completely. Once done, the app will send status information to 0. See below photo.