Old BMS General Thread

Threads relating to the BMS system begun by Peter Perkins

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mikep_95133
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Postby mikep_95133 » Mon Nov 10, 2008 7:26 am

I didn't see anywhere how I can check for the version.

Mike

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retepsnikrep
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Postby retepsnikrep » Mon Nov 10, 2008 7:44 am

When you program it, it displays the version at the end of the completed download, also there is a 'FirmWare' button under the Option tab in the editor.
Last edited by retepsnikrep on Mon Nov 10, 2008 8:17 am, edited 1 time 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.

mikep_95133
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Postby mikep_95133 » Mon Nov 10, 2008 7:52 am

A.3 here. I will get in contact with the vendor I bought them from and see what they will do.

Mike

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Postby retepsnikrep » Mon Nov 10, 2008 8:16 am

Mike refer them to that Picaxe thread.

I'm sure they should change them, they still work fine for basic testing so long as relevant HPWM/PWM code is REM'd out.

I shall probably upload a newer Master today with that code REM'd out for the time being and some other revisons :wink:
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.

mikep_95133
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Postby mikep_95133 » Mon Nov 10, 2008 8:20 am

I did include the thread link you posted Peter. I'll call them tomorrow if there is any delay.

Mike

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retepsnikrep
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Losing will to live

Postby retepsnikrep » Mon Nov 10, 2008 10:44 am

I'm losing the will to live with the big display. It works, slowly, but causes a lot of problems for me with the critical alarms and warnings display etc. I'm not happy with that, so I'm going to remove it from future Master versions at the moment. Trying to be flexible makes it very hard :(

Greg you can use the code from the last version below that includes it if you want. I might re-visit it much later with Master MK2. Any updates/code changes from now on you will have to copy into this older version. Sorry Mate :roll:

Old version, last to include Big Display at this time, has issues with big display after an alarm occurs. :cry:

www.solarvan.co.uk/bms/MASTER101108_V77_2400BAUD.TXT

Note pressing button 5 on the menu simulates an Alarm condition for testing purposes.

***********************************

The version below has the Big Display removed and updated button config.

The buttons work as follows in the version below.

1) Toggle charge on/off
2) Show individual cell voltages
3) Enter security code

4) Set Alarm conditon for testing purposes Pack>AbsMaxTemp (While held down)

5) Set Warning condition for testing purposes Soc<10% Remaining (While held down)

Warnings now appear on the bottom line of the main screen.

Alarms cause display to change to negative, and display until condition which caused it has cleared.

www.solarvan.co.uk/bms/MASTER101108_V78_2400BAUD.TXT
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.

mikep_95133
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Postby mikep_95133 » Mon Nov 10, 2008 4:08 pm

Peter,

I purchased my 28X1 through Advanced Micro Circuits Corp here in the US. I called him this morning. He says that his 4 years experience with Picaxe yields slow results. So I will hang on to my 28X1 so my system development does not stop. This fellow also has a source in Canada that could very well have the A.4 versions already.

It would help my project to have a second 28X1 at this point that will be exchanged eventually.

Thanks for the offer to correct this issue.

Mike

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retepsnikrep
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Improved voltage resolution & <0C temp sensing

Postby retepsnikrep » Tue Nov 11, 2008 10:06 am

Thanks to 'Mindaugas' for pointing out an improvement to the Slave voltage sensing calculation.

I've now implemented that in the DigitalSlave code and updated my 50 cells with it.

It seems to be working fine, and is providing a narrower spread of voltages with resolution to about 20mv,
a decent improvement over the previous 40mv deviation 8) Spot checks with my DVM confirm seems OK.

So the current Digital Slave and Master code is here.

www.solarvan.co.uk/bms/SLAVESIMPLEDIGIT ... 00BAUD.TXT

www.solarvan.co.uk/bms/MASTER111108_V81_2400BAUD.TXT

I'm going to implement voltage sensor temperature compensation into the Master code as well at some point. It measures the pack temperatures, so I can use this to implement a correction factor when I have gathered some variable temperature voltage data over the next few months.

Greg & Roger chips received :wink:

Edit

Improved temperature routine so it now handles values <0C, Greg you might need this up there in't North :wink: Range is now -55C to +125C
Last edited by retepsnikrep on Tue Nov 11, 2008 12:37 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.

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Postby GregsGarage » Tue Nov 11, 2008 11:29 am

Peter,

I can live without the big numbers for now, makes sense to concentrate on the basic features and then worry about the extras later, after it all works! :wink:

I still haven't had the time to try the new slave software. :( Will try and have a go tonight. My suspicions are that it may improve the accuracy between the programmed value and actual value, but probably won't improve the difference between each cell as all the boards are performing the same calculation and so any errors in the calculation will be the same for each board. I don't expect to see an improvement in balancing with the new equation for this reason, but will have to test it to see. :shock:

I have had a good result with the new values that I loaded into the slave boards the other week. The cells are much better balanced now (and still improving), finishing to within 200mv per 4 cells, so around 50mv per cell. The lowest group is the first 4 cells, my Paktrakr draws 12 volts for its supply here and the next lowest is the next 4 cells, which is where my e-meter draws its 24 volt supply from. So while these have provided some useful information, I am still going to replace them with the digital solution, probably in the new year at the rate I am going. :shock:
Greg Fordyce

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http://www.evalbum.com/4191

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retepsnikrep
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Postby retepsnikrep » Tue Nov 11, 2008 12:30 pm

GregsGarage wrote:I don't expect to see an improvement in balancing with the new equation for this reason, but will have to test it to see. :shock:


Assuming the result it returns is accurate/consistent, then the improved resolution must make it more accurate :? I think it will help a bit with your balancing.

Just to clarify, I havent gone as far as Greg with his Analogue boards and the pre-calculation used in the Analogue software.

The Digital Slaves just use the formula

CellV = RefVADC / CellA * 2 (RefVADC = 63200)

instead of the old way

CellV = RefVADC *25 / CellA * 100 / 25 (RefVADC = 1263)
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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