Old BMS General Thread

[timpootle]

Great work, Peter! Good luck with the gods...

[retepsnikrep]

1) PCB's are enroute from China

2) Got another cheap small display to try and this is the dogs Boll**ks. RCA Video input.

Native 640*480 resolution to match Video Chip on Master, very sweet and crisp display just like a tom tom type thing. Sticky pad or velcro to dash.

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

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

Banding is a photo artefact. No distortion on this, it looks great.

Has a spare video input so may put a small nightvision/infrared/camera into battery compartment to watch data leds flashing or hot spots etc etc.

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0078827165

Back to connecting/laying out batteries now.

In my quest to achieve the lowest interconnect resistance I've been looking closely at my new cells. The terminals are held in place by a large nut and the centre conductor of the terminal is either level, proud or recessed depending on how tight it has been fitted or individual variations among cells. (One of my cells had a cross threaded nut but I can't take it off as I have no way of holding the other side of the terminal) This causes an issue straight away, and means there are gaps on the intercell bus bars contact point with the cell terminals. Anyway i've used a power file to level all the terminals so they are perfectly flat and clean giving maximum contact area. I'm also using 6mm studding inserted into the cell terminals to the maximum depth to give more available torque for the terminal nuts. More pressure less resistance

Quick diagram of Insight cell installation plan. Cells go in the spare wheel well. I've included an insulating divider to split the pack into two slightly less dangerous halves

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

[dillond666]

Just ordered 30 slave boards from China and now i'm absolutely bricking it!

Assuming they actually work, I should have 17 spares available for cost price should anyone be bonkers enough to be interested. Maybe best to wait and see though

[retepsnikrep]

Good effort and good luck with them, I'm in the same position as you, my boards should arrive today though

Building them up and making it work on the bench is one thing, making it work reliably in the EV/HYbrid is another fingers crossed.

[retepsnikrep]

Well they look nice! Hope they work!!

Now got to make up 50 for my own pack in the Digital configuration with one Master as well.

Fingers crossed.

www.solarvan.co.uk/bms/MasterPCB1.jpg

www.solarvan.co.uk/bms/SlavePCB1.jpg

Been working hard on the actual integration of my new pack into the Insight oem system. So re plumbing temp sensors and battery voltage sensors from oem Battery and Computer to the new pack.

[retepsnikrep]

Well some good and some bad news.

Built up one Slave and one Master.

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

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

Slave responded correctly when attached to a cell and turned on load when V increased etc. Also reponded correctly when test signal applied in analogue mode and running at 31khz minimum speed, current drain was 200ua. Took about 30 minutes to make one Slave, only another 49 to go

Master a bit more problematic, Video chip running OK and Watchdog chip running OK accepted program etc, But main Pic does not apper to be running correctly at present and won't accept program download hmm

I'm knackerd now as been working hard all day. Took about 2 hours to build the Master. I'll check it carefully later and perhaps change the main pic tomorrow, never know might have a duff one. Have a go at it when fresh something obvious hopefully.

[qdos]

Well they look pretty if nothing else !

Hope you get that Eureka moment. Waiting with baited breath here

[retepsnikrep]

It's Alive

I built up a second Master board at 04:00hrs this morning after laying awake fidgeting in bed with it all going round in my mind, it worked straight away, indicating a duff main pic on the first one which is damn annoying. Might be able to unsolder that and replace it.

Spent the next few hours getting it to talk to the single slave built so far and just got succesful comms. Failure to talk straight away was due to my bad choice of resistor value, I went for a 100k pull down and it was too feeble, changed to a more normal TTL 4k7 and works fine As usual, spent a lot of time arseing about with the scope looking at serial signals and scratching head Think that's sorted now. Must remember to tweak the schematics to reflect new values.

Current consumption of digital mode Slave running at 8mhz with no speed/current reduction implemented is 800ua. Should be able to slash that when proper software back up and running. That's not bad though and could run slave for 1000hrs for 1Ah drain. Digital Slave current drain with beta power reducing slow speed software is 200ua, 5000hrs for 1Ah.

The slow speed cpu setting is fine for the Analogue Slave versions as it doesn't have the comms issues.

I shall build up another 3 slaves, wire them up and start working on building up functioning subpacks. All the little glitches in the software are comming out now of course Display alignment is all over the place. Hope to have a pic/vid of 5 slaves and master working together by tuesday

Just a teaser here are two Slaves (cut down pcbs) and the Master connected and running, ran out of 3mm led's whilst building good job I opened an account with Farnell

www.solarvan.co.uk/bms/Master&Slaves.jpg

[qdos]

Whey hey success Well done Peter !!!!!

[ChrisB]

Oh its so good when it all comes togther and works eh Loving the TTL moment

ChrisB