Battery Vehicle Society

I did some bench testing of the master and had a problem with picture quality, lots of interference and unstable picture. The tellymate on a arduino works fine with this monitor, so that would appear to be o.k. I did make a couple of substitutions of some caps and resistors as I had run out of the exact values, so I have ordered the correct bits. Should get them tomorrow, hopefully that will cure it.

My battery boxes are coming along quite nicely, the center box which runs under the car in the exhaust tunnel was giving me some grief but I have cracked it now. Just have to work on the front boxes.

My main reason for posting was an interesting product I came across from an Australian company 4D Systems. They have a large product range but one caught my eye in particular. It is a 3.2 inch 240x320 touch screen colour display with a micro SD card slot and speaker as well as 16 GPIO pins. It is a serial device that only requires 5 wires, +5v, GND, RX, TX and RESET. And the price, around £63. Could be a candidate for V3 of the master

Oh, and the link, http://www.4dsystems.com.au/prod.php?id=113

Hi Folks,

I know the latest bms stuff is using plain PICs but I thought you might be interested to see the latest picaxe 18 pin jobbie. I am using an 18X for my lights/wipers ECU but was missing the 28X1s hardware timers for background counting (settimer) so I'm going to use the 18M2 now. Details here http://www.rev-ed.co.uk/docs/picaxe18m2.pdf looks like a really good chip

Derek

I just recently ran across a possible replacement PIC chip for the slaves. It is the 12F1822. What is nice is that it has an onboard fixed voltage reference which should simplify the circuit a little. I also heard that you only need two wires for ICSP but I haven't verified that yet. Here is the link http://ww1.microchip.com/downloads/en/D ... 41413A.pdf

Derek

The 18M2 is interesting but i've moved away from picaxe now to plain pics to get the price down a bit more. Nothing to stop others using or porting the code though.

Rick

Agree that looks interesting especially the enhanced EUSART and the internal Vref. Save a couple of components.

The 12F683 still has more to offer in that we can do away with the vref pull up resisitor by using internal pullups, put it to sleep with a pin swap and probably set it up for ICSP.

Of course others can have a tinker i might get some samples but a lot will depend on wether the pbpro compiler supports it.

Peter,

I agree, the 12F683 has plenty of capability. It looks like ver 2.60A covers the 12F1822.

steiner wrote:I just recently ran across a possible replacement PIC chip for the slaves. It is the 12F1822. What is nice is that it has an onboard fixed voltage reference which should simplify the circuit a little. I also heard that you only need two wires for ICSP but I haven't verified that yet. Here is the link http://ww1.microchip.com/downloads/en/D ... 41413A.pdf

I've ordered half a dozen of the above to play with but they don't seem to be available until december.

I also ordered some 5k digital pot chips to properly control the output voltage of my cheapo chargers. They have 256 steps so should given reasonable resolution. spi interface. Def something for master v3?

retepsnikrep wrote:I've ordered half a dozen of the above to play with but they don't seem to be available until december.

I didn't know Santa's elves made microcontrollers!

The digital pots etc have arrived but I haven't even opened the box!! I need to pull my A123 20ah battery now and update my 50 slaves and master to the new serial software.

I think I will soon start on laying out the master v3 board so keep an eye on that thread.

Hi all.

In last days I've been seeing your topic to see how works your BMS. I have some doubts:

1 - What exactly do the varistors? There are no other alternatives?

2 - In my application, I have a touch pad lcd screen, can I turn the screen to the video output or do I have to make an additional circuit?

Thank you.

Best Regards,

Francisco Mendes.

Franciso

The varistors suppress voltage spikes on the data lines. They may not be necessary depending on your instalation and how much EMI RFI your vehicle generates.

The video is an RCS 1.00V Standard composite output i have no idea if it will interface with your device. probably not without some sort of converter. The touch screen certainly won't.

Peter
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