Old BMS Hardware Thread

Threads relating to the BMS system begun by Peter Perkins

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retepsnikrep
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Re: BMS Hardware

Postby retepsnikrep » Sat May 08, 2010 4:25 am

Hi

I know very little about I2C and suggest you try google or a dedicated I2c forum there must be one about.

When you have a long string of series connected cells then the potential difference as you progress along the chain is always an issue, you need some form of isolation between cells that will suit the I2C bus or your choosen bus. I selected a very simple serial system because i was familiar with that.

Peter
Regards Peter

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Re: BMS Hardware

Postby martinwinlow » Sun May 16, 2010 4:38 pm

Peter,

I had a night duty at one of the station offices at work the other night and managed to get the about 60% of the master and 2-and-a-bit x 16-slave boards populated. A couple of things came up...

Any chance you could put a really high res image of http://www.solarvan.co.uk/Life/LifebattahCells025.jpg ? Just for comparison...

I see that you may have used tantalum caps for C2 on the slaves...?

What about doing a master board with the addition of a USB I/O socket?

I wondered is it might be an idea to put a little soldered-on fuse in the cell wires? If so what value would you suggest?

I see from LifebattahCells025.jpg that the cell wires to the slave boards are not shielded. Would using Cat5 cable and keeping the screen intact be an improvement? The sheath would have to be cut, one pair extracted, separated and the shield continuity re-made but I'd have thought it would do well (and I've got oodles of the stuff).

Why has the speed sensor on the Master only got 2 connections? Is it not designed for use with a hall effect-type sensor - which has 3 connections:- +ve, -ve and signal? I have the NetGain sensor designed for their motors.

I found a current sensor at RS which is a very reasonable £10 (+- 600A) and appears compatible if you would be kind enough to confirm it is...
http://uk.rs-online.com/web/search/sear ... R=532-9249

Lastly, is there an easy way to download the entire contents of this (or any other) thread without copy and pasting each page?

I've attached a spreadsheet of the parts for the Master and 16x Slave boards - needs a bit of tidyig up and a few planks still...

Regards, Martin.
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BVS BMMS Component Lists.xls
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Re: BMS Hardware

Postby retepsnikrep » Sun May 16, 2010 5:00 pm

martinwinlow wrote:Any chance you could put a really high res image of http://www.solarvan.co.uk/Life/LifebattahCells025.jpg ? Just for comparison...


I can't at the moment I don't have one and the slave boards are installed in the car in a very inacessible position. Sorry.

martinwinlow wrote:I see that you may have used tantalum caps for C2 on the slaves...?
Yes better for noise I understand.

martinwinlow wrote:What about doing a master board with the addition of a USB I/O socket?
Why? Be my guest if you want to have a go.

martinwinlow wrote:I wondered is it might be an idea to put a little soldered-on fuse in the cell wires? If so what value would you suggest?
1amp is not a bad idea.

martinwinlow wrote:I see from LifebattahCells025.jpg that the cell wires to the slave boards are not shielded. Would using Cat5 cable and keeping the screen intact be an improvement? The sheath would have to be cut, one pair extracted, separated and the shield continuity re-made but I'd have thought it would do well (and I've got oodles of the stuff).
For the multi slave board screened wire is not required to the cells IMO.

martinwinlow wrote:Why has the speed sensor on the Master only got 2 connections? Is it not designed for use with a hall effect-type sensor - which has 3 connections:- +ve, -ve and signal? I have the NetGain sensor designed for their motors.
I designed it to work with my car and it uses the cars own sensor, so i piggy back onto it's output and only need ground and signal connections. You will have to supply your sensor with the required power and then feed the reqd common ground and signal (max 5v peak) into the master board.

martinwinlow wrote:I found a current sensor at RS which is a very reasonable £10 (+- 600A) and appears compatible if you would be kind enough to confirm it is...
http://uk.rs-online.com/web/search/sear ... R=532-9249
That looks ok although it says it's out of stock and you are probably better on getting one that screws to the chassis etc. That is a pcb mount device. You will need to fiddle with master software and calibrate it to your requirements.

martinwinlow wrote:Lastly, is there an easy way to download the entire contents of this (or any other) thread without copy and pasting each page?
Not that i know of.

martinwinlow wrote:I've attached a spreadsheet of the parts for the Master and 16x Slave boards - needs a bit of tidyig up and a few planks still...
Can you ammend or add this info to our project spreadsheets https://spreadsheets.google.com/ccc?key ... yeHc&hl=en
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: BMS Hardware

Postby retepsnikrep » Mon May 17, 2010 4:21 am

Regards Peter

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One HCH1 Civic Hybrid running 60ah A123 Lithium pack.

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Re: BMS Hardware

Postby martinwinlow » Mon May 17, 2010 7:54 am

Thanks Peter... and USB so I can connect it to my ap easily! M
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Re: BMS Hardware

Postby GregsGarage » Mon May 17, 2010 11:16 am

retepsnikrep wrote:
martinwinlow wrote:I wondered is it might be an idea to put a little soldered-on fuse in the cell wires? If so what value would you suggest?
1amp is not a bad idea.


Also make sure the fuses are rated for full pack voltage. Might even be an idea to make a simple test rig so that you can test the fuse can safely interrupt the pack voltage.

Greg
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Re: BMS Hardware

Postby retepsnikrep » Tue May 18, 2010 7:35 am

For those that may be interested we now have a 26cell slave board laid out ready for PCB production.

This board has a slightly reduced component count and is for non picaxe slaves only.

Schematic and pdf etc here.

http://www.solarvan.co.uk/bms/26cell100510.png

http://www.solarvan.co.uk/bms/26CSB-COLOUR.pdf

I will be placing an order within next seven days for ten boards, if anyone wants some let me know asap.

Price yet to be determined but won't be excessive.

PS I also have some V2 Master boards for a tenner each + postage ;) + free remote board.
Regards Peter

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One HCH1 Civic Hybrid running 60ah A123 Lithium pack.

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Re: BMS Hardware

Postby steiner » Wed May 19, 2010 2:24 am

Peter,

What software did you use for the schematic?

Rick

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Re: BMS Hardware

Postby retepsnikrep » Wed May 19, 2010 7:29 am

Greg did the schematic for this board and the 16 cell slave board he will be along shortly to update us i'm sure.
Regards Peter

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One HCH1 Civic Hybrid running 60ah A123 Lithium pack.

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Re: BMS Hardware

Postby GregsGarage » Wed May 19, 2010 6:37 pm

Schematic was done with the open source gEDA suite. http://www.gpleda.org/ Links to the files are in this thread, back a few pages or so.

Greg
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