CANOpen has the concept of NMT node control and NMT node monitoring frames, both of which are present in the CAN logs provided earlier in this thread.
NMT node monitoring indicate that two different nodes are sending their “heartbeat” using identifiers: 0x700 + NodeID
node 1 (0x701)
node A (0x70A)
Both CAN logs start with node A sending the 7F = pre-operational state. In the “good batt” logs we can later see node A transitioning to the 05 = operational state. node 1 is only seen sending 05 = operational state in the logs.
In the provided logs these CAN frames appear as:
70A 1 7F
701 1 5
70A 1 5
The first value represents the CAN frame standard (11-bit) identifier (as hexadecimal)
The second value represents the CAN frame DLC (how many data bytes are in the frame)
The remaining values are the data bytes (0-8 bytes, each as a hexadecimal value)
The NMT node control frame (0x000), seen in the logs as 0 2 1 A, only appears in the “good batt” log with two bytes of data:
1 = command: start device
A = node A
So potentially node 1 is the eBox and node A is the BMS?
CANOpen also has the concept of Emergency frames (EMCY) utilizing the identifier: 0x080 + NodeID.
They are only to be transmitted once per error event with frame data as per:
1 byte: Error register
2 bytes: Emergency error code
Up-to 5 bytes: Manufacturer-specific error information
The logs contain such EMCY frames with id 0x08A from node A, presumably the BMS, but they appear in both “Good batt” and “Bad batt” logs so they are probably not the main cause for one battery to be considered as working and the other one not.
The emergency error code is in the manufacturer specific range? (if so, probably makes it hard to decipher more)
I’m guessing that the remaining frames in the logs are PDO:s according to a predefined mapping scheme, potentially without any convention between CAN frame identifier and the sending node id. The interesting battery data is likely hiding within these frames.
If we could get CAN logs from only the battery or the eBox on the CAN bus we could maybe figure out more details.
Wow, you guys have come a long way since I last posted anything. Anyhow. A friend of mine purchased a Lift e-foil within the last year. After riding he went to charge it. It would not charge. The only indication of life was one little green LED, would flash ON every several seconds. After a few calls and several attempts to revive the battery with tech support, Lift sent him a new battery and said get rid of the old one there is nothing more we can do. So he gave it to me because I had built e-foils. And I don’t think he wanted the hazard around his house. So I got it open. Here are some photos.
I tried to do kind of a master reset by removing the leads at the main relay to drop power to the whole thing. That did not get it working.
My observations. No water inside. all cells measure 3.37. total = 47.24 this was 3 months after the battery stopped working .
Today at least 6 months later all cells measure 3.29. Total 46.10. the green led has stopped flashing.
I’m wondering if its normal for cells to discharge so perfectly over 6 months time. I suspect the BMS is still working???
I currently don’t have a voltage source high enough to attempt to charge the battery. Parts on order.
My plan is to try to use the battery in a new foil build, but first i need to know how to disable all the smart features???
Try first to replace only the master relay, often they Lose contact inside. If you get original charger try it first. maybe all work is done after that. Otherwise use only the cells and put a new bms from daly to it. The Lift bms got its own software that can be crashed totally. If lift support and resetting did fail, rip every cables and electronics of and weld the new bms on to the cells. thats easy and fast to do.