Search found 9 matches

by MindMil2
Wed Jun 24, 2009 7:05 am
Forum: All things battery related
Topic: Lifepo4 cells catch fire!
Replies: 82
Views: 245624

I have bought an Elcon charger recently. I must say I like it. I only used it on bench test charging environment but it looks promising and still waits to be put into the car together with my BMS. I like it that it is sealed and quality construction. My 144V 16A model is able to put out 20Amps. When...
by MindMil2
Tue Jun 23, 2009 9:09 pm
Forum: BMS thread
Topic: Old BMS Hardware Thread
Replies: 613
Views: 1033434

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 d...
by MindMil2
Fri Dec 26, 2008 1:15 pm
Forum: BMS thread
Topic: Old BMS General Thread
Replies: 658
Views: 1251319

If you take 1k resistor as a R then you should try capacitor of something like 10-22nF. I've done some simulation VSM circuit for you so you can experiment with values: http://www.sklandymas.lt/EV/RC_noise_filter.DSN The simulated scope shows how your filtered output should look like if you put a 22...
by MindMil2
Sat Dec 20, 2008 9:30 am
Forum: BMS thread
Topic: Old BMS General Thread
Replies: 658
Views: 1251319

Well :shock: So problem is as Mike surmised horrible noise on Master Bus. This noise is on the paralleled opto isolated side of the digital slaves Master Bus which weaves it's way round the packs before exiting to the Master board input. I need some sort of filtering now to sort this, any ideas mor...
by MindMil2
Tue Dec 09, 2008 9:50 pm
Forum: BMS thread
Topic: Old BMS General Thread
Replies: 658
Views: 1251319

I'm also looking at the remote programming of the digital slaves on the fly as well. I did do a fair bit of work on this months ago and I would like to get it going before I install my batteries so I can adjust load balancing and other parameters on the fly without having to re-program each slave i...
by MindMil2
Thu Dec 04, 2008 11:07 pm
Forum: BMS thread
Topic: Old BMS General Thread
Replies: 658
Views: 1251319

As the variable charger and controller optos are driven by a pwm output from the Master pic I need to hack a capacitor onto the drive side pins 1 & 2 of the opto's U4 & U5 to smooth out the pulses, so it is a smoothly changing analogue output rather then the pwm at the moment. Once I have g...
by MindMil2
Fri Oct 31, 2008 2:29 pm
Forum: BMS thread
Topic: Old BMS General Thread
Replies: 658
Views: 1251319

I'm using 9600bps speed which I might decide to reduce to lower values if stability would suffer. I was thinking to make chips initialize at much lower speed like 1200 by master reset ( holding Tx low for long period) and then create a new command by which master could reconfigure slaves to higher s...
by MindMil2
Thu Oct 30, 2008 6:25 pm
Forum: BMS thread
Topic: Old BMS General Thread
Replies: 658
Views: 1251319

Re: Oh Lot's of questions

Mindaugas. Nice to see your input on the thread thanks. I'll have a look at your formula and see how it works out... Peter, I'll go through your questions one by one. I'm not using floating point maths. The best estimated resolution is 20mV. This is just because my formula looses just one bit durin...
by MindMil2
Wed Oct 29, 2008 6:27 pm
Forum: BMS thread
Topic: Old BMS General Thread
Replies: 658
Views: 1251319

...No unforseen errors and cells are all within 40mv of each other according to the bms, which is about the limit of it's resolution. Spot checks with dmm put them bit closer than that but BMS can't resolve it. ... Peter, I've been watching your progress and was impressed what results can be achiev...

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