Multi-Cell Slave-Version 2

Threads relating to the BMS system begun by Peter Perkins

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Re: Multi-Cell Slave-Version 2

Postby retepsnikrep » Tue Apr 03, 2012 2:06 pm

V10 good spot :oops:

Not sure about CellS

CellS is used to store the unloaded cell voltage from a known acquisition with the loads off.

The sequence goes

1) Turn off loads.
2) Measure cell voltages and store CellV in CellS. Report V to master
3) Turn on loads according to CellS

I'll look at it. Suggest try is as is first to get it working.

If we have thickish short wires to the cells we may be able to revert to the older software where we did not have to turn off the loads to take the cell V
Regards Peter

Two MK1 Honda Insight's. One running 20ah A123 Lithium pack. One 8ah BetterBattery Nimh pack.
One HCH1 Civic Hybrid running 60ah A123 Lithium pack.

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Re: Multi-Cell Slave-Version 2

Postby GregsGarage » Tue Apr 03, 2012 2:41 pm

VData was/is the low byte of the CellV word variable. But if you define VData as a separate byte variable, unrelated to CellV, then you can use the statement VData = CellV - DLow. CellV stays unchanged so you can still use it later instead of CellS. CellS becomes redundant, so we can get rid of it, freeing up a whole 2 bytes of memory. :lol:

EDIT: Actually it only saves 1 byte, I forgot that VData needs a byte. :roll:
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Re: Multi-Cell Slave-Version 2

Postby GregsGarage » Wed Apr 04, 2012 8:40 am

retepsnikrep wrote:If we have thickish short wires to the cells we may be able to revert to the older software where we did not have to turn off the loads to take the cell V

We could have both options in the software. Add another command like this

Code: Select all

   if Command = 14 then       'If command = 14 then send voltage data on Master Bus and turn on loads as required
   if CellV >DHigh or CellV <DLow then   'If V >4.30V or V <1.75V set out of range    
   VData = 0         'Set VData = 0 Cell error out of Voltage range condition
   low Load         'Turn off bypass resistor and bypass led in case of cell error
   else
   VData = CellV - DLow      'Convert Word (CellV) data into Byte (VData) for output
      if CellV > CutInV then   'If stored cell voltage CellV > CutInV then
      high Load      'Turn on bypass resistor and bypass led
      endif
      if CellV < CutInV then   'If stored cell voltage CellV < CutInV then
      low Load      'Turn off bypass resistor and bypass led
      endif

   endif     
   endif

By adding a new command we keep compatibility with the existing master software. The new functionality will require changes in the master software, but the new slave software will still work with the older master software, you just don’t get the new features. 8) It also means you have more flexibilty in wiring. You are not required to use thicker, shorter wires if you don't want to by using the command 2, 1, 3 combination. Note, I haven't yet upgraded my pbp to the latest version so I can't test these changes. Also, this example uses my idea of ditching the CellS variable, but it would be simple to change this.
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Re: Multi-Cell Slave-Version 2

Postby GregsGarage » Wed Apr 04, 2012 9:47 pm

retepsnikrep wrote:Looks nice but for auto assembly in china can the machines cope with parts at an angle I've only ever seen pcb's with stuff at 90 degrees or aligned vertically or horizontally?
I just saw this video on pick and place process, note the battery holders are at a 45 degree angle. :)

http://www.eevblog.com/2012/04/04/eevblog-264-pcb-pick-place-assembly/

EDIT: pcbs have been shipped! :) I'm away next week, hopefully they will be waiting for me when I get back.
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Boards have arrived!

Postby GregsGarage » Mon Apr 16, 2012 9:42 am

Got the pcbs today. :D :D
IMAG0165.jpg
Nicely packaged
IMAG0165.jpg (99.13 KiB) Viewed 13564 times

IMAG0170.jpg
Through hole side
IMAG0170.jpg (175.5 KiB) Viewed 13564 times

IMAG0171.jpg
Surface mount side
IMAG0171.jpg (196.07 KiB) Viewed 13564 times


I've been away over the Easter holidays and haven't had time to order the components yet. Hopefully will be able to order the bits later this week.
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Re: Multi-Cell Slave-Version 2

Postby retepsnikrep » Mon Apr 16, 2012 1:38 pm

Looks good www.pcbcart?
Regards Peter

Two MK1 Honda Insight's. One running 20ah A123 Lithium pack. One 8ah BetterBattery Nimh pack.
One HCH1 Civic Hybrid running 60ah A123 Lithium pack.

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Re: Multi-Cell Slave-Version 2

Postby GregsGarage » Mon Apr 16, 2012 2:01 pm

These came from itead.
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Re: Bill of Materials

Postby GregsGarage » Tue Apr 17, 2012 9:56 am

I've ordered enough parts for all 10 pcbs. I'll build a few of them to start with and some more when we know it works. :wink:

I found a mistake in the BOM, the Farnell part no for the opto was incorrect, I've fixed it below.

Code: Select all

4 Cell Slave Version 2 Rev A
part #   price   qty   value      ref
1833888   0.082   4   100n         C10x     
1738662   0.220   4   10R 3W       R10x     
9332650   0.011   4   160R         R20x       
9332804   0.025   4   220R         R30x       
9332383   0.025   4   1K           R40x         
9846662   0.074   4   BC818-40     Q10x           
2001671   0.160   4   LED          D10x         
1971857   0.530   4   PIC12F1822   U10x         
8310750   0.240   8   TCLT1009     U20x/U30x
Greg Fordyce

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Re: Multi-Cell Slave-Version 2

Postby retepsnikrep » Tue Apr 17, 2012 10:42 am

I'll have to start on the 12F683 Master now!!

Good effort Greg :)
Regards Peter

Two MK1 Honda Insight's. One running 20ah A123 Lithium pack. One 8ah BetterBattery Nimh pack.
One HCH1 Civic Hybrid running 60ah A123 Lithium pack.

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Re: Multi-Cell Slave-Version 2

Postby GregsGarage » Fri Apr 20, 2012 10:10 pm

I had a go at building a couple of boards. I still need to work on getting the correct amount of solder paste on the pads and also the right amount of heat, U301 got a bit too much! :(
IMAG0189.jpg
IMAG0189.jpg (186.52 KiB) Viewed 13543 times

It's not good enough to go in something at the moment but I could try and program it for starters. Peter do you have a hex file I could try? I haven't updated my pbp yet.
Greg Fordyce

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