14 Cell 12F1822 Slave Board for A123 28S3P Packs
Posted: Fri Sep 14, 2012 5:15 am
Just a heads up.
I have just finished a schematic for a special slave board to fit onto four OEM A123 28S3P pouch cell packs I bought recently. These fine 60Ah packs are about 100V each fully charged and comprise 20Ah A123 pouch cells in 3 parallel 28 series groups.
http://endless-sphere.com/forums/downlo ... a17fe71ff3
They have a nice JST part number S22B-AIT2G-2FS connector and OEM BMS board on the end.
Unfortunately using the OEM BMS was impossible as nothing is known about it.
However is has two nice connectors on the packs which are split into two 14 cell halves. It seemed a shame and risky to hack that off so I have sourced the sockets from JST based on the pcb info and designed a 14 cell 12F1822 schematic to suit it.
The schematic is currently being laid out for pcb production to be the exact size and shape as OEM pcb, same mounting points and socket positions etc. It will be a drop in replacement for the OEM BMS board.
The Slave's themselves are similiar to all our previous designs but feature a much reduced component count and are based on the 12F1822 pic which has an internal voltage reference.
The OEM A123 Packs have four NTC thermistors mounted on them so each BMS board has the first slave also looking after the output from two of these sensors. Each pack has two 14 cell slave boards so the first slave on each board looks after the two sensors at it's end of the pack.
The Master will be similiar to earlier designs and use the same comms with three additional commands.
1) Report NTC 1 Reading.
2) Report NTC 2 Reading.
3) Report 12F1822 Internal Temp reading
These temp commands only need to be sent every 10-30 seconds or so, so won't have much impact on the scanning.
All slaves will run the same code, the slaves that arent connected to NTC's will report garbage but that doesnt matter as we know which slaves are monitoring the NTC's.
Some info for you
1) Discussion about the A123 OEM packs.
http://endless-sphere.com/forums/viewto ... a17fe71ff3
2) A123 BMS Connector Pinout
https://docs.google.com/spreadsheet/ccc ... mk2aXBaWnc
3) Connector PDF
https://www.jst.co.uk/productSeries.php?pid=15175
4) Picture of three of my packs.
http://endless-sphere.com/forums/downlo ... a17fe71ff3
5) OEM BMS Board
http://endless-sphere.com/forums/downlo ... a17fe71ff3
6) New 14 Cell Slave Schematic.
http://www.solarvan.co.uk/A123/12F1822_ ... 130912.jpg
I have just finished a schematic for a special slave board to fit onto four OEM A123 28S3P pouch cell packs I bought recently. These fine 60Ah packs are about 100V each fully charged and comprise 20Ah A123 pouch cells in 3 parallel 28 series groups.
http://endless-sphere.com/forums/downlo ... a17fe71ff3
They have a nice JST part number S22B-AIT2G-2FS connector and OEM BMS board on the end.
Unfortunately using the OEM BMS was impossible as nothing is known about it.
However is has two nice connectors on the packs which are split into two 14 cell halves. It seemed a shame and risky to hack that off so I have sourced the sockets from JST based on the pcb info and designed a 14 cell 12F1822 schematic to suit it.
The schematic is currently being laid out for pcb production to be the exact size and shape as OEM pcb, same mounting points and socket positions etc. It will be a drop in replacement for the OEM BMS board.
The Slave's themselves are similiar to all our previous designs but feature a much reduced component count and are based on the 12F1822 pic which has an internal voltage reference.
The OEM A123 Packs have four NTC thermistors mounted on them so each BMS board has the first slave also looking after the output from two of these sensors. Each pack has two 14 cell slave boards so the first slave on each board looks after the two sensors at it's end of the pack.
The Master will be similiar to earlier designs and use the same comms with three additional commands.
1) Report NTC 1 Reading.
2) Report NTC 2 Reading.
3) Report 12F1822 Internal Temp reading
These temp commands only need to be sent every 10-30 seconds or so, so won't have much impact on the scanning.
All slaves will run the same code, the slaves that arent connected to NTC's will report garbage but that doesnt matter as we know which slaves are monitoring the NTC's.
Some info for you
1) Discussion about the A123 OEM packs.
http://endless-sphere.com/forums/viewto ... a17fe71ff3
2) A123 BMS Connector Pinout
https://docs.google.com/spreadsheet/ccc ... mk2aXBaWnc
3) Connector PDF
https://www.jst.co.uk/productSeries.php?pid=15175
4) Picture of three of my packs.
http://endless-sphere.com/forums/downlo ... a17fe71ff3
5) OEM BMS Board
http://endless-sphere.com/forums/downlo ... a17fe71ff3
6) New 14 Cell Slave Schematic.
http://www.solarvan.co.uk/A123/12F1822_ ... 130912.jpg