LCD Instrumentation for Cougar Controller

[mora]

MPLAB 8.60 seems to build fine. Weird stuff. I'm using another program to program the chip and have to swap chip between LCD board and programmer. That's why I export file as .hex. It would be good idea to get a cheap clone-programmer from ebay. But now I get proper functioning of LCD board and 124% SOC reading, heheh. LCD has also LED backlight pins reversed but I think I can come up a solution with that.

[ianbartie]

The LCD panels that I could get also had the reversed pin problem. Simple solution is to remove the last 2 pins so it is a 14 pin strip then solder a couple of crossover wires from the board to the led. Leave a bit of slack so you can get them apart.
I actually connected the LCD backlight to my instrument light circuit. From memory I stuck a 750 ohm resistor in series. Works fine.
I can see the display just fine during the day & the backlight comes on when I turn the lights onto the first position.

[ianbartie]

I did a couple of tests on the fuel gauge. It can take about 1/2 - 3/4 second for the needle to to go from empty to full from the time it is given the full 1.7V when it is on empty. Same going the other way. There is a short lag time before the needle starts to move & it will always move at the same constant speed going from empty straight to full or vise versa.
The temp gauge test is tomorrow morning.

[mora]

Hurray, it works. Fuel gauge reads about 70% full when LCD reads 50% SOC when using default value for max PWM. Pack voltage shows 7V less than actual, but I remember this being adjustable too. Thermal sensor inside 9" Kostov must not be compatible with this board as it gives 120C reading and lowers to 100C when in use. Good thing I bought two sensors mentioned in BOM. Some fine tuning and more permanent mounting of LCD and that's it.

124% SOC was something that went away when switching between 100% and 20% SOC. One minute at 100% SOC and proper value was saved.

[harlequin2]

I compiled the thing with MPLAB V8.66 but had to change some configuration bits - this version uses somewhat different ones and if you look in the include file for the chip you can see what they are.

[Freyguy]

Originally Posted by mora

Hurray, it works. Fuel gauge reads about 70% full when LCD reads 50% SOC when using default value for max PWM.

Mora,
Use value of R20 or PWM_Max to set fuel gauge needle to full when SOC=100%. For SOC values under 100%, the position of VR2 comes into play. At 20%VR2 has most significant impact and is used to set empty. Think of PWM_MAX as your offset and VR2 as setting the range of duty cycle values required from full to empty.

124% SOC was something that went away when switching between 100% and 20% SOC. One minute at 100% SOC and proper value was saved.

The capacity value in EEPROM by default after programming is 115Ahrs(my batteries). If your capacity is larger then this, then yes it will initially show >100%. After programming, you should do an SOC reset. This will reset to 100% and use your capacity values to overwrite mine in EEPROM

[ianbartie]

I did a couple of tests this morning on the temp gauge. I think the response time will be OK for the most part.
The voltage to drive it is really small. It needs 15 millivolts for a max scale reading & 65 millivolts for a minimum scale reading.

[mora]

Originally Posted by Freyguy

The capacity value in EEPROM by default after programming is 115Ahrs(my batteries). If your capacity is larger then this, then yes it will initially show >100%. After programming, you should do an SOC reset. This will reset to 100% and use your capacity values to overwrite mine in EEPROM

Yes, I did a SOC reset. I have 90Ah cells and I set capacity parameters to 04 (high) and F1 (mid). (3 bytes/24 bits: 00000100 11110001 00000000). If I understood right this should be 89.95Ah (or 323 840 As). I set pmile to 17 and at 124% SOC I got 49 KTE, which is 80% of 61km. When SOC is "reduced" to 100% KTE also lowers.

I must have missed cougarLCD_Config_Rev_1_3.pdf when browsing wiki as it has lots of useful info regarding setup.

[Freyguy]

Originally Posted by ianbartie

I did a couple of tests this morning on the temp gauge. I think the response time will be OK for the most part.
The voltage to drive it is really small. It needs 15 millivolts for a max scale reading & 65 millivolts for a minimum scale reading.

Ian,
Was that determined with the adjustable voltage source with 68 Ohm series resistor? Was this measured with a DMM? Be curious if this is pulsed like the fuel gauge was. You could probably get a much larger voltage swing using a larger value series resistor. First need to know if those voltages are based on DC state or average of pulses.

-Chris

[Freyguy]

Originally Posted by mora

Yes, I did a SOC reset. I have 90Ah cells and I set capacity parameters to 04 (high) and F1 (mid). (3 bytes/24 bits: 00000100 11110001 00000000). If I understood right this should be 89.95Ah (or 323 840 As). I set pmile to 17 and at 124% SOC I got 49 KTE, which is 80% of 61km. When SOC is "reduced" to 100% KTE also lowers.

I must have missed cougarLCD_Config_Rev_1_3.pdf when browsing wiki as it has lots of useful info regarding setup.

Oh yeah, It's the other way. If your capacity value is LESS than my default in EEPROM, the SOC will come up >100%. Bcapacity constant is used for determining divisor used in SOC percentage calculation as well as value written to EEPROM during SOC reset.

Yes, that document is specific to determining your custom constants and how to compile&program the PIC.