Old BMS Hardware Thread

Threads relating to the BMS system begun by Peter Perkins

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Postby GregsGarage » Fri Aug 07, 2009 10:38 am

retepsnikrep wrote:Forgot to scope the Slave bus which runs from Master down to first Slave near all the nasty noise to initiate data transfer :oops:

Just looked at it and pretty noisy so bunged an 0.1uf poly cap across it and that's sorted. 8)

Off for another test shortly.


Peter, did you fit that cap at the master or the first slave?
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Postby retepsnikrep » Fri Aug 07, 2009 11:58 am

Cap fitted at Master. Slaves are all installed and covered up.

Just got back from 29 mile test no errors at all. 8)

Going to remove the Alarm count thing i added yesterday to see if it works OK this afternoon. Pretty hot here today!!
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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BMS Remote Display & PC Data Logger

Postby retepsnikrep » Mon Aug 10, 2009 9:40 am

Here is a first schematic for the remote BMS display/alarm and data logger receiver interface.

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

It's very simple and will use some cheapo 433mhz AM/FM data transmitters. I've got some of these max claimed range 70M to play with.

http://www.rfsolutions.co.uk/acatalog/D ... AM-RTx.pdf

http://www.rfsolutions.co.uk/acatalog/D ... AM-HRR.pdf

The unit will have a basic two line lcd display, audible alarm and logging to PC/Excel output via the Picaxe programming lead and software such as.

http://www.eltima.com/products/rs232-data-logger/

or

http://www.windmill.co.uk/rs232.html

Might get it working later this week.
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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You will love this!!!

Postby retepsnikrep » Tue Aug 11, 2009 10:56 am

Remote Master display 1200 baud wireless data link working 8)

I'm using a cheapo AM 433mhz tx/rx pair to do the remote data link.

Some pics of the veroboard Tx & Rx units.

www.solarvan.co.uk/bms/RemoteDisplay001.jpg
www.solarvan.co.uk/bms/RemoteDisplay002.jpg
www.solarvan.co.uk/bms/RemoteDisplay003.jpg
www.solarvan.co.uk/bms/RemoteDisplay004.jpg

The mandatory Picaxe 08M on the Rx unit decodes the signals and drives the 16x2 lcd display / Alarms / PC Logger. The in car Master simply uses the unused "Drive Inhibit" output on my Master board to drive the Tx unit. I fitted both units with simple aerials made from inner core of a coax cable cut to 173mm 1/4 wave for 433mhz.

I have been wandering around my garden and down the road holding the receiver, peple giving me very strange looks! Works well over 50M so far :shock: not even line of sight! Works all over my house with car in garage. Greg should work with your car down end of you garden I think! :D

Only used most basic software to try this sending "Pack Voltage" to remote. Now need to work on software to get Remote to sound alarm etc when things go wrong! Need to put remote display into nice neat box Mrs Perkins won't mind having in the Kitchen :roll:

www.solarvan.co.uk/bms/MASTER_SERIAL_10 ... 00BAUD.txt
www.solarvan.co.uk/bms/RemoteDisplay100809_v01.txt

YouTube Video of first test of remote display. :lol:

http://www.youtube.com/watch?v=wb4qedZ_RbI

As far as Install in car goes might try finding some black cable outer covering to put on aerial and then mount it near to stock car aerial. Might try feeding signal into stock car roof aerial as I don't need massive range. TX unit is so small can mount directly under roof Aerial beneath headlining.

Next question. what data available from the Master should I/we log to a PC spreadsheet/data file via the wireless link? I'm assuming here the wireless link is only going to be used when the car is parked up and charging as a safety feature.

Pack Voltage?
Soc?
Charge Current?
Battery Temp?
Charging finished?
Any Alarms?
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 » Wed Aug 12, 2009 9:07 pm

Peter, One place you could try hiding the aerial is underneath a door/boot aperture seal on the outside edge. Many cars you can lift the rubber seal and feed the aerial wire underneath the rubber seal. Makes for a nice and concealed aerial, particularly when you want to keep it hidden.
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Postby retepsnikrep » Thu Aug 13, 2009 5:19 am

Could do Greg but aerial and TX board need to be directly connected for best results so TX board must fit underneath as well. No wire from tx board to aerial if possible. I think some heat shrink on the aerial to make it black and then a minute hole in the roof to poke it through with TX board directly underneath. Hot glue/silicone etc and it's done. 3 core screen cable from tx board to master and sorted. The tx board is tiny when veroboard mount cut down to match it. 30x20mm or something.

This looks like quite a neat roof mount solution

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0459058084
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 » Thu Aug 13, 2009 10:28 am

retepsnikrep wrote:Could do Greg but aerial and TX board need to be directly connected for best results so TX board must fit underneath as well. No wire from tx board to aerial if possible.


O.K. But you don't necessarily need "best" results, you only need "good enough for your application". Personally I would try solutions that don't involve drilling holes in the roof first as they can lead to water leaks, even the car manufactures struggle with this on roof aerials. Try and keep any connecting wires even multiples of the length of the aerial.
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Postby retepsnikrep » Thu Aug 13, 2009 10:58 am

I agree but I'm just trying to start with max possible range. Been testing today with my improved setup. Data rate now doubled to 2400 baud 8)

Range is very good and works at 75M+ I've been walking round village again looking like the mad professor holding the receiver.

Added a signal fail alarm as well using a few sneaky discrete components to my single 08M receiver circuit. It now sounds the alarm if signal dispapears for more than 2.5 seconds. :wink:

That means we have most options covered.

1) BMS detects an error and sends alarm signal. We can react to and display that! Covers standard things like Over V / Over Temp etc.

2) BMS fails and stop transmitting or sends garbage or inteference present meaning signal can't get through. Alarm now sounds after 0-5 seconds (adjustable) without valid incomming signal :D

I'm almost ready to get a pcb made up for the remote receiver.

Edit

I have a spare input/output pin on the 08M receiver chip any ideas?

How about a text message sent to your phone when an alarm occurs?

http://www.riccibitti.com/tinyplanet/tiny_article.htm

http://www.steliosm.net/picaxetwitter.html
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 steiner » Fri Aug 14, 2009 3:35 am

Peter,

I had to laugh when you mentioned people in the village looking at you like you were a mad professor. About a year ago I built a very tiny transmitter that just sent a pulse signal. I used a very similar transmitter and receiver like you are using. I built a yagi antenna to provide direction to the transmitter. I remember several of my neighbors calling my wife asking her what I was doing outside with a funny looking stick and a set of head phones on wandering about.

I'm still waiting on my replacement display. I am growing very tired of their excusses. I doubt I will be doing business with them again.

Good job on the wireless link. I know for me it will give me some piece of mind during the balancing phase of the charging.

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Postby retepsnikrep » Fri Aug 14, 2009 4:56 am

Rick I have a spare bare BMS screen if you want it, just paypal me postage costs later. It has no bezel. Just bare circuit board but does work and I had it hot glued into that little cubby hole from my early versions. i suggest you open the dead display up then if you have lost hope in them and fingers crossed it is something obvious.

The remote display requires a 16x2 serial lcd axe033 from the picaxe website or similar.
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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