Old BMS Hardware Thread

Threads relating to the BMS system begun by Peter Perkins

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Old BMS Hardware Thread

Postby retepsnikrep » Mon Jun 15, 2009 9:38 am

Edit by Peter 10/08/09

Welcome to my opensource free BMS thread.
I have added some basic at a glance specs for the working BMS now. And a few basic pics of the setup. I strongly recommend you read all of this first post and wade through as much of the three threads as you can to understand how it all works, was developed and fits together :wink:

Specs for Modules are as follows.

*********** Slave Module Specification **********

Approx Parts Cost inc pcb $5.00 each.
One slave module per Lithium Cell.
Supply/Cell Voltage 1.75 - 5.00V DC.
Average Supply Current at 3.35v <1ma.
Voltage Ref LM 385 1.235V accuracy 1% Supply/Cell.
Voltage sensing maximum accuracy +/- 20mv.
Maximum balancing/bypass current with 15R resistor 333ma at 5.00V. Maximum Serial Master Bus data rate 4800 baud.
Maximum cell Capacity 65ah. Can be increased to 650ah.
Maximum 128 Slave Modules per Master Module.
Can be increased to 255 Modules using 28X2 Picaxe.
Slave CPU Speed 8mhz with internal resonator.
Permitted Working Cell Voltage Range 1.75 - 4.30V.


************ Master Module Specification *************

Approx Parts Cost inc pcb $100.00 each.
One Master module per complete system.
Supply Voltage 8.00-30.00V DC or as limited by 5.00V 78L05 regulator.
CPU Supply Voltage 5.00V.
CPU Speed 8mhz with internal resonator.
Average Board Supply Current at 12.00v <100ma.
Maximum Serial Master Bus data rate 4800 baud.
Maximum Cell Capacity 65ah. Can be increased to 650ah.
Maximum Pack Voltage 650v.
Maximum Charge/Discharge rate depends on current sensor used.
Maximum 128 Slave Modules per Master Module.
Can be increased to 255 Modules using 28X2 Picaxe.
Battery Pack Temp Sensor Range (-25 to +100C).
Composite Video Display data rate 9600 baud (SV2000 Video Chip).
Composite RCA Video Monitor Output 1V 75ohm PAL/NTSC.
Charger relay output is board supply voltage max 30v at 500ma.
Opto Isolated Charger/Controller Cutback outputs max 50ma 50v.
The Video display is limited to 16x9 characters in a 0-15 & 0-8 matrix.

Pictures & Videos

Digital Slave Schematic.

www.solarvan.co.uk/bms/DigitalSlave080908.jpg

Early test run of Slaves & Master with display from 2008.

www.solarvan.co.uk/bms/MasterTest01.jpg

Latest software display showing various info.

www.solarvan.co.uk/bms/BMS050809001.jpg

www.solarvan.co.uk/bms/BMS050809004.jpg

Youtube BMS Tour Videos. Note there are several available from 2008.

http://www.youtube.com/watch?v=gAaSTQ2cWrk

http://www.youtube.com/watch?v=Wgyg41GIGxU

Hope that helps.

Peter


Dear All

This BMS thread had grown a bit too large, so I'm am starting two additional threads to run alongside the original one.

This BMS General thread contains all the work/discussion upto 15/06/09.

http://www.batteryvehiclesociety.org.uk ... php?t=1245

The BMS Hardware thread will contain any new work/discussion related to the hardware.

http://www.batteryvehiclesociety.org.uk ... php?t=2059

The BMS Software thread will contain any new work/discussion related to the software.

http://www.batteryvehiclesociety.org.uk ... php?t=2060

I hope this makes it a bit more manageable.

New readers should work through the General thread first until they reach 15/06/09, they should then look at specific hardware/software/general threads for further info.

Thanks Peter
Last edited by retepsnikrep on Wed Jun 23, 2010 5:50 pm, edited 2 times in total.
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.

steiner
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Postby steiner » Mon Jun 22, 2009 4:12 am

Peter,

I have been looking at some displays similar to the one that you are using. I noticed that yours seems to have a resolution of 640x480 (standard RGB). The more common displays I have found here in have a resolution of 480 x 234. Do you think this will make much of a difference or should I keep shopping for the higher resolution display?

Rick

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Postby retepsnikrep » Mon Jun 22, 2009 5:29 am

I went for the little 640x480 rca video colour dashboard stick on display as it looks neat and matched very well with the SV2000 video chip driving it.

http://www.speechchips.com/shop/item.aspx?itemid=5

This was the item I bought

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0100862640

This search terms brings up a few variations "Car 3.5" LCD TFT Monitor"

The 640 x 480 4:3 format gives good resolution without distorting the characters on screen.

Couple of photos of my own unit in situ. It looks just like a GPS unit.

Image

Image

Please ignore the Google Attack site warning message. I have sorted that issue!!!

It also has two video inputs so can be driven with a reversing camera if you wanted as well.
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.

MindMil2
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Location: Lithuania

Postby MindMil2 » Tue Jun 23, 2009 9:09 pm

Looks very nice Peter. It was long time since I last checked your thread. I have finished my battery modules design, produced them and have them working now on my cells however I moved from PIC12F683s to ATtiny25Vs. My progress is not as quick as yours though as I have a bigger scope of work to be done which consumed lots of time. I hope I'll be putting my batteries, BMS and charger into the car soon.
My recent progress is on my blog http://hr-ev.blogspot.com/2009/06/bms-c ... works.html

Regards,
Mindaugas

steiner
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Postby steiner » Thu Jun 25, 2009 2:36 am

Peter,

I am going to show my ignorance here..... The chips that you sent are Microchip PIC chips. I was under the assumption that Picaxe chips were different from Micrchip chips.

Are they the same chips but just use different software? The reason this doesn't make any sense to me is the Micochip PIC's use different pins for in circuit serial programming (ICSP).

Rick

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Postby retepsnikrep » Thu Jun 25, 2009 4:44 am

Nice to here about your good progress MindMil, well done.

Rick the chips are Picaxe chips.

Picaxe chips are baiscally pics chips with a special proprietory bootloader/interpreter already loaded into them so they perform like Picaxe chips.

They should be fine.

If you try to use them as pics and overwrite the bootloader software using a hardware programmer etc they revert to being standard pics.

Don't do that though, just use them as planned on the pcbs etc.

http://www.picaxeforum.co.uk/faq.php?fa ... aq#faq_1_1
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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Current sensor

Postby GregsGarage » Mon Jun 29, 2009 11:50 am

Been looking for current sensors in the 500 amp range and found this.

What do you think Peter, would it work o.k.?
Greg Fordyce

Daewoo Matiz
http://www.evalbum.com/4191

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Postby retepsnikrep » Mon Jun 29, 2009 2:39 pm

Looks good should give a resolution of about 1amp in either direction.

-500 - 0 - 500+ 2.5v being 0 Amp if I read the data sheet right.

Have to reconfig the master software to suit but easy enough.
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.

steiner
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Location: Florida

Postby steiner » Mon Jun 29, 2009 11:57 pm

Greg,

I would recommend getting the HAAS 300 instead of the 500. Both the 300 and the 500 can measure up to a peak of +/-900 amps. However, the 300 gives better resolution (300 amps = .625 volts vs 500 amps = .625 volts). When I spoke with the tech rep he said the only real reason to use the 500 is if your continuous current would be above 300 amps. I orginally purchased the 500 and it works fine but will be using the 300 next time.

Rick

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Postby GregsGarage » Tue Jun 30, 2009 7:57 am

Rick,

I was thinking of using a smaller sensor like the 300 amp anyway. The hi power cells have a current limit of 300 amps, so that would be fine. Also may look at using the low voltage cutback to also limit amp draw as well. Shouldn't be too difficult to add to the software.
Greg Fordyce

Daewoo Matiz
http://www.evalbum.com/4191


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