Re the dash buttons/LEDs - I've had a look thru the threads and can't find any info on what they all do exactly.
I found the schematic for them ... BMSKeyMatrixLeds.jpg (?) So...
J1/Pin 1 - +5V
J1/Pin 2 - D4 - Watchdog LED - Tells you watchdog is working by flashing (at what rate?) This only illuminates if the watchdog chip signals a timeout error
J1/Pin 3 - D3 - Pulse LED - Tells you Master is working? How? This flashes once a second with picaxe master, more frequently with a pic master
J1/Pin 4 - D2 - Dash LED - Doesn't do anything yet?Works when master in place under specific conditions
J1/Pin 5 - D1 - Dash LED - Ditto Works when master in place under specific conditions
J1/Pin 6 - Switch Common rail(?) What do all these switches do?Control the command system and can reset soc, trip meter etc
J1/Pin 7 - Master Reset Switch(?) Resets whole caboodle? Resets Master chip
J1/Pin 8 - Gnd
JP1 - Master Reset Enable on the Master PCB - is this supposed to be shorted for normal operation or open? Shorted when in use but open when downloading software to master and during testing etc. It allows the watchdog chip to reset the master chip if a timeout occurs
WRT... 'because without an active master chip plugged in, the input to the watchdog pin floats and detects static and stray emi as pulses reseting the watchdog timer'... can I confirm that the input pin is 4? And that it needs to be 'pulled down' to gnd with a 1k resistor?Pin 4 is correct on the watchdog IC however connect the 1-10k resistor to pin 3 of the switch and led connector (pulse led) and then to pin 1 or pin 8 of the same connector
I take it that the dash buttons and leds do not need to be installed to test the Watchdog on its own? And the temp sensors? Both of them?Correct.
For bench testing the system, I thought about using 3 x AA rechargeable cells (in series, obviously) to simulate one lithium cell and then rig 2 or more of these to the same number of slaves. Can you see any issues with this? No issues good idea, but make sure combined cell voltage is within BMS working range 1.75-4.30V
Will I have to remove the PICs from the unused slaves to avoid errors etc? No but you will probably have to reprogram them when i get the software working correctly!!
Connecting the 16 slaves PCBs to the master... I assume Master PCB 'Master Bus', J11 connects to Slave PCB 'Master Data Bus', Conn3 and the other end of the SlavePCB 'Master Data Bus', Conn 4, connects to the Conn3 of the next slave board and so on? Correct, you can stack the boards with PCB standoffs if you wish, but when stacked stand them on there sides in use so heat can rise between the boards and escape
Further, the Master PCB 'Slave Bus', J8 connects to the Slave PCB 'Slave Data Bus In', Conn1 and the Slave PCB 'Slave Data Bus Out', Conn2 daisy chains to the next Slave PCB 'Slave Data Bus In', Conn1 etc...? Will a simple twisted pair of 1/4 of a bit of Cat5 cable do for these connections?yes twisted pair is fine for all this, try and keep things as short as possible of courtse. polarity of the connections is important, so pin 1 of any connector goes to pin 1 of any other
Lastly, the Slave to cell connections... We already discussed fusing these with a 1A, suitably rated, in-line fuse and I gather each slave connects across the cell it is monitoring with adjacent cells sharing the connection thus saving a wired connection per cell?Correct you need a good size wire for the cell connections and keep them as short as practicable, voltage drop in these leads gave us the problem which required the fancy new software as slaves interfere with each other when switching the loads when only one wire is used due to voltage drops in wires. The single cell boards do not suffer from this issue. Remember your high current cell interconnects will also factor into the equation so be methodical and clean every connection so it is spotless and tight
How are your cell blocks being assembled? can you post a photo? are there any long high current connections between seperate cell blocks?