JK 4S 200A BMS 4.5" LCD display

[Hans Kroeger]

https://www.aliexpress.com/item/1005004027834830.html?spm=a2g0o.cart.0.0.292c38dawf1biM&mp=1

I bought 2 displays to be used with my JK-B2A8S20P modules...... and I am not happy with their performance.
1. The display shows the Balancer to be on at all times, independent of its actual status.
2. The BMS has 2 external Temperature Sensors. The display shows only one Temperature. Could not find out what is displayed. It is not one of the two Sensors, and it is not the average temperature of the two sensors.
3. The power consumption of the display is some 100 mA but the current is not included in the actual module current value. As a consequence the SOC value will be wrong over Time and the cells are discharged.
4. Could not find out how to turn of the display.
5. As mentioned above the cable is too short.
6. The On button is separate rather than being part of the Display.

 

[OzSolar]

I bought 2 displays to be used with my JK-B2A8S20P modules...... and I am not happy with their performance.
1. The display shows the Balancer to be on at all times, independent of its actual status.
2. The BMS has 2 external Temperature Sensors. The display shows only one Temperature. Could not find out what is displayed. It is not one of the two Sensors, and it is not the average temperature of the two sensors.
3. The power consumption of the display is some 100 mA but the current is not included in the actual module current value. As a consequence the SOC value will be wrong over Time and the cells are discharged.
4. Could not find out how to turn of the display.
5. As mentioned above the cable is too short.
6. The On button is separate rather than being part of the Display.

Thank you for the report.

 

[yourunclefats]

Any update @dtidmore ?

 

[dtidmore]

sorry for the delay in getting back. The project got sidelined for awhile. I have returned to building it out and I can report that extending the 4.5" LCD display cable is completely feasible. Turns out the display gets all its data via RS485. The wires in the display cable consist of +/-12V, pair of RS485 and a pair for the boot/shutdown pushbutton. I extended the cable using a premade 25ft Cat 6 straight thru cable (my choice over a custom cable). I cut the display cable with just sufficient room on the display end to allow me to attach a RJ45 connector, leaving the majority of the cable to the BMS side with another RJ45 connector. I mounted a RJ45 pass thru in my battery box allowing me to connect/disconnect the BMS side easily. On the other side of the battery box, the Cat 6 extension cable connects and runs to where I have located the actual display. I superglued the female side of the extension cable to the back of the display to remove ALL stress on the thin wires of the original display connector.

Everything works perfectly. I added a latching pushbutton to interrupt the +12V wire to the display to provide a way to turn on/off the display (tested and display boots up just fine after being reconnected to power and the bluetooth app shows the BMS is unaffected by the action). I wired the pushbutton LED pilot lite across the 12v display power wires to provide visual feedback as to the BMS operational status.

david

 

[tim0shel]

sorry for the delay in getting back. The project got sidelined for awhile. I have returned to building it out and I can report that extending the 4.5" LCD display cable is completely feasible. Turns out the display gets all its data via RS485. The wires in the display cable consist of +/-12V, pair of RS485 and a pair for the boot/shutdown pushbutton. I extended the cable using a premade 25ft Cat 6 straight thru cable (my choice over a custom cable). I cut the display cable with just sufficient room on the display end to allow me to attach a RJ45 connector, leaving the majority of the cable to the BMS side with another RJ45 connector. I mounted a RJ45 pass thru in my battery box allowing me to connect/disconnect the BMS side easily. On the other side of the battery box, the Cat 6 extension cable connects and runs to where I have located the actual display. I superglued the female side of the extension cable to the back of the display to remove ALL stress on the thin wires of the original display connector.

Everything works perfectly. I added a latching pushbutton to interrupt the +12V wire to the display to provide a way to turn on/off the display (tested and display boots up just fine after being reconnected to power and the bluetooth app shows the BMS is unaffected by the action). I wired the pushbutton LED pilot lite across the 12v display power wires to provide visual feedback as to the BMS operational status.

david

What color wire on there is the 12v +. Currently going to be extending mine and running through box but mostly I am just trying to put the display on the outside to see it.

 

[yourunclefats]

What color wire on there is the 12v +. Currently going to be extending mine and running through box but mostly I am just trying to put the display on the outside to see it.

 

[dtidmore]

If you look carefully to the right side of the display connector on the circuit board, the pins are clearly labeled. Starting at top is VSS (top 2 pins but only one of them is used) which is the +12V wire (red). The bottom 2 pins are ground, but like the VSS pin, only 1 of them is used. The red wire IS the one you want to switch to effect a display on/off separate from the BMS state (+12V will only be present on the red wire IF the BMS is powered up).

 

[yourunclefats]

If you look carefully to the right side of the display connector on the circuit board, the pins are clearly labeled. Starting at top is VSS (top 2 pins but only one of them is used) which is the +12V wire (red). The bottom 2 pins are ground, but like the VSS pin, only 1 of them is used. The red wire IS the one you want to switch to effect a display on/off separate from the BMS state (+12V will only be present on the red wire IF the BMS is powered up).

You ran your 12v through the cat6? Is it a hard 12 or a 12-14 "12v" like a battery?

 

[dtidmore]

The ONLY current that is being delivered via the CAT6 is for the display, which amounts to 250ma at the most and the voltage, be it 12v or 24v is inconsequential. Remember we are talking about extending the cable between the BMS and the display and NOTHING more. It is my understanding that the display operates at 12V regardless of whether the battery pack is a 4S or and 8S variety, but I am only dealing with 12V so no way of verifying.

 

[tim0shel]

If you look carefully to the right side of the display connector on the circuit board, the pins are clearly labeled. Starting at top is VSS (top 2 pins but only one of them is used) which is the +12V wire (red). The bottom 2 pins are ground, but like the VSS pin, only 1 of them is used. The red wire IS the one you want to switch to effect a display on/off separate from the BMS state (+12V will only be present on the red wire IF the BMS is powered up).

Awesome I'll need to get my magnifying glass out!