LTC6802 based 12 cell slave.

Threads relating to the BMS system begun by Peter Perkins

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danmachen
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Re: LTC6802 based 12 cell slave.

Postby danmachen » Mon Jul 30, 2012 7:33 am

Thanks alot Greg,

Do you know what sort of accuracy iteadstudio can make the boards to? Have you ever had any trouble with the tracks being too close?

Dan

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Re: LTC6802 based 12 cell slave.

Postby GregsGarage » Mon Jul 30, 2012 8:09 pm

I've not had a problem, but if your layout is very tight you might want to have a look at this goof from itead, but it was over a year ago, it may be better now. http://www.eevblog.com/2011/03/11/eevblog-155-itead-studio-pcb-prototype-goof/

Or you could send a test board and see how it goes. It's around £10 for 10 5x5cm boards. Mine have been dispatched, so I might see them this week, hopefully no later than next week. I'll post pictures.
Greg Fordyce

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http://www.evalbum.com/4191

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Boards have arrived!

Postby GregsGarage » Fri Aug 03, 2012 9:40 pm

Postman Pat delivered my boards today! :D
DSC_0011.JPG
USB connectors at top for daisy chaining from master to slaves. At the bottom, DB15 for cell voltages and RCA connectors for temperature sensors.
DSC_0011.JPG (186.16 KiB) Viewed 10009 times

I've ordered the rest of the components for Monday.
Greg Fordyce

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http://www.evalbum.com/4191

mikethebike3
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Re: LTC6802 based 12 cell slave.

Postby mikethebike3 » Fri Aug 03, 2012 9:55 pm

Excellent work Greg, that looks like a nicely laid out board.
Fingers crossed with the 6802 though, 0.5mm pin separation ain't gonna be easy!
Mike

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Re: LTC6802 based 12 cell slave.

Postby GregsGarage » Fri Aug 03, 2012 10:34 pm

I'm saving the 6802 for last. :shock: First thing will be to get the pic on and test master and slave busses with simulated cell readings in software.
Greg Fordyce

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retepsnikrep
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Re: LTC6802 based 12 cell slave.

Postby retepsnikrep » Sat Aug 04, 2012 5:15 am

You are really getting the hang of that pcb layout program now!! 8)
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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dillond666
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Re: LTC6802 based 12 cell slave.

Postby dillond666 » Sat Aug 04, 2012 3:24 pm

Nice and tidy work Greg, I'm salivating :lol: . What width did you make the traces going to the LTC6802?
I'm using 0.2mm but I've never done them as narrow before and I'm flapping a little about it.
Are you hand soldering? Are your caps and resistors etc 0805 packages? Hope you've bought a flux pen!

Derek

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Re: LTC6802 based 12 cell slave.

Postby GregsGarage » Sat Aug 04, 2012 5:14 pm

They are 0.2mm. I will be hand soldering, but I've made the pads on the 6802 longer than normal which should help make things a bit easier. The resistors are 0603. For the caps I am using 0603 for 100nf and 0805 for 1uf.
Greg Fordyce

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Re: LTC6802 based 12 cell slave.

Postby GregsGarage » Sat Aug 04, 2012 10:19 pm

retepsnikrep wrote:You are really getting the hang of that pcb layout program now!! 8)
I'm pleased with it, and as long as I am trying new things heres a small program to flash the leds on the board. Just a quick test program to check ICSP and basic operation.

Code: Select all

-- ------------------------------------------------------
-- Title: Blink-a-led of the Microchip pic16f886
--
-- Author: Rob Hamerling, Copyright (c) 2008..2010, all rights reserved.
--
-- Adapted-by: Greg Fordyce on 4 Aug 2012
--
-- Compiler: 2.4o
-- Revision: $Revision: 2760 $
--
-- Original file is part of jallib  (http://jallib.googlecode.com)
-- Released under the BSD license (http://www.opensource.org/licenses/bsd-license.php)
--
-- Description:
-- Sample blink-a-led program for Microchip PIC16f690.
--
-- Sources:
--
-- Notes:
--  - Original File creation date/time: 14 Mar 2010 14:33:00.
--
--  A small program to quickly test the 6802 slave board.
--  Red and Green leds should flash alternatly.
-- ------------------------------------------------------
--
-- ******************** Compiler Results *********************************
-- Errors :0       Warnings :0
-- Code   :76/8192    Data:4/352  Hardware Stack : 0/8  Software Stack :96
-- ***********************************************************************

include 16f886                      -- target PICmicro
--
-- This program uses the internal oscillator at 8 MHz
pragma target clock 8_000_000       -- oscillator frequency
-- configuration memory settings (fuses)
pragma target OSC  INTOSC_NOCLKOUT  -- internal oscillator
pragma target WDT  disabled         -- no watchdog
pragma target MCLR external         -- reset externally
--
enable_digital_io()                 -- make all pins digital I/O
--
OSCCON_IRCF = 0b111                 -- set internal oscillator for 8 MHz
--
-- Specify the pin to which the LED (with serial resistor!) is connected:
alias   red_led      is pin_A0
pin_A0_direction =  output

alias   green_led      is pin_A1
pin_A1_direction =  output
--
forever loop
   red_led = on
   green_led = off
   _usec_delay(250_000)
   red_led = off
   green_led = on
   _usec_delay(250_000)
end loop
--


You may have noticed this isn't pbp. :shock: JAL is open source and free. We'll see how it goes. Program complies with no errors, but is untested.

EDIT: Jal home page is at http://www.casadeyork.com/jalv2/
Greg Fordyce

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ICSP problem

Postby GregsGarage » Mon Aug 06, 2012 11:52 pm

Just tried soldering a couple of boards and have a problem with the ICSP. When I plug it in the pic overheats and won't program. Anyone see a problem with the schematic? http://www.batteryvehiclesociety.org.uk/forums/download/file.php?id=336

EDIT: Found the problem got pins 1, 2 and 3 in the wrong place. :? I'll make an adapter and start on a list of corrections for the next board. :shock:
Greg Fordyce

Daewoo Matiz
http://www.evalbum.com/4191


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