LCD Instrumentation for Cougar Controller

[adamj12b]

Originally Posted by 1-ev.com

Hey Chris,

It looks like LEM Hass 300-S going up to 300A.

Can we use something larger then 300A?

Let say LEM Hass 500-S or LEM Hass 600-S

Current | Digi-Key

Thank you.
-Y.

The LEM Hass 300-s goes all the way up to 900A. 300A is just the nominal current.

-Adam

[mora]

I was able to program PIC using MBHP and P18. I still had to download MPLAB for exporting .asm to .hex. Of course I need to set all the required parameters too.

I ordered all the parts from Mouser and thought that I could throw in a LCD display too. Now this random 16x2 character display isn't using HD44780 controller and whole circuit draws 700mA when powered. Backlight is lit but nothing shows up on the screen. Without screen attached circuit draws something like 30mA. Maybe I should have read more carefully, hehe. Time to order correct LCD.

[Freyguy]

Originally Posted by adamj12b

The LEM Hass 300-s goes all the way up to 900A. 300A is just the nominal current.

-Adam

Yes, from the datasheet you can see the LEM Hass 300 up through 600 have a measurement range to 900A. Each model differs only in their sensitivity.
The 300= 2.08mV/A, 400=1.56mV/A, etc. The Tamura is 3.75mV/A which is why when you use the 300, you need to apply 1.8x gain in the code.

The LEM Hass 200-S is actually the closest fit to the Tamura. It's sensitivity is 3.125mV/A and would require a gain of 1.2 (multiplier value in code =19 vs 29 used for LEM 300). It's range is a bit smaller at 600A, but still higher than the 500A limit of the Tamura.

-Chris

[jackbauer]

Little update on the bmw fuel gauge. I had some play time today so i hooked up a 500r pot and made some measurements. At 500r the wiper of the pot read 3.75v and the gauge read just over full. Reduced the pot to 3v then 2.5v. Gauge stayed the same. Recycled the ignition switch and at 2.5v gauge read just over half full. Reduved to 1v. Still no movement then recycled ignition and gauge reads about 1/8th.

So it looks like i can "fill" the tank as quickly as i like but it won't "empty" very fast. So it looks as if the stock gauge is useless for soc as its the opposite for an ev. Fast drain and slow fill. I'll be getting rid of the bmv600hs battery monitor soon now that the lcd module can measure charge and will just fit a normal resistive fuel gauge in the pod.

[harlequin2]

Originally Posted by Freyguy

Yes, from the datasheet you can see the LEM Hass 300 up through 600 have a measurement range to 900A. Each model differs only in their sensitivity.
The 300= 2.08mV/A, 400=1.56mV/A, etc. The Tamura is 3.75mV/A which is why when you use the 300, you need to apply 1.8x gain in the code.

The LEM Hass 200-S is actually the closest fit to the Tamura. It's sensitivity is 3.125mV/A and would require a gain of 1.2 (multiplier value in code =19 vs 29 used for LEM 300). It's range is a bit smaller at 600A, but still higher than the 500A limit of the Tamura.

-Chris

The Melexis sensor (or the CSA-1V) that Paul used in the 1000A controller could be pressed into service. Its much cheaper, but might need a bit of fiddling to get the current range right. Also, I am using a Tamura 500A one in mine, with a suitable multiplier as per Jackbauer's code snippet.

[Freyguy]

Originally Posted by mora

I was able to program PIC using MBHP and P18. Now this random 16x2 character display isn't using HD44780 controller and whole circuit draws 700mA when powered. Backlight is lit but nothing shows up on the screen. Without screen attached circuit draws something like 30mA.

Hi Mora,
At 700mA I have to think something was miswired (different pinout for LCD).
An LED backlight draws 60~100mA and LCD controller logic is typically less than 7mA. I'm thinking Vcc and Gnd swapped on J3 or maybe this required a much larger LED ballast resistor for R19? With all control pins being digital inputs, I'm thinking the PIC should be OK.
Just curious, do you have a datasheet for this LCD?

[Freyguy]

Originally Posted by jackbauer

...So it looks as if the stock gauge is useless for soc as its the opposite for an ev. Fast drain and slow fill. I'll be getting rid of the bmv600hs battery monitor soon now that the lcd module can measure charge and will just fit a normal resistive fuel gauge in the pod.

Man, that's too bad Out of curiosity though I did a quick search for those simple resistive input fuel gauges. Not that expensive and empty/full polarity is correct for us (follows the industry standard shown in my chart in manual)

Sunpro CP8219 - Sunpro Analog StyleLine Gauges - Overview - SummitRacing.com

I've been using the "automode" display option. Fine for me and my stop & go local driving. Every time I take my foot off the throttle the SOC screen will pop up (after a few seconds of course).

-Chris

[mora]

Originally Posted by Freyguy

Hi Mora,
At 700mA I have to think something was miswired (different pinout for LCD).
An LED backlight draws 60~100mA and LCD controller logic is typically less than 7mA. I'm thinking Vcc and Gnd swapped on J3 or maybe this required a much larger LED ballast resistor for R19? With all control pins being digital inputs, I'm thinking the PIC should be OK.
Just curious, do you have a datasheet for this LCD?

Yes, it is way too much. At least I was able to read contents of PIC after noticing current being too high so I suppose PIC is (somewhat) ok. I didn't solder any wires between board and lcd yet but used those spikes fitted in a plastic bar (or whatever it is called, heheh) for testing. Like the original design. I can't fit big LCD in my car easily. This display also doesn't mount correctly over the PCB.

Datasheet for the display is here:
http://www.newhavendisplay.com/specs...XZ-FSW-GBW.pdf

I remember checking it was pin compatible. I might have failed though. Datasheet tells that backlight should draw 20mA. Hmm.

[Freyguy]

Originally Posted by mora

I remember checking it was pin compatible. I might have failed though. Datasheet tells that backlight should draw 20mA. Hmm.

Sorry to say the pinout is different. While the pin assignments are the same, the physical location of those pins on the board are in a different order.
(see attached)

The eio display goes pin 14 down to 1, then 15, 16. Yours is 1 straight through 16. Basically 1 thru 14 swapped. 15&16 same so LED works.
Backlight looks like a single white LED to only draw 20mA. Assuming there no on board series limiting resistor, the 15 ohm would cause it to draw a lot of current, but not 700mA! If white LED dropped 3.5V then 15ohm would limit to 100mA. Swapping among the other lines must be the culprit.
I'd be prepared to have a backup PIC just in case

[mora]

It was easy to try reversing pins 1-14. Didn't work, upper row was only filled with blocks. I guess I need new display with proper controller (HD44780).

Whole assembly drew 35mA from 12V supply with display connected (pins 1-14 reversed). Same without display. Display had 130 ohm onboard resistor for backlight and it drew only 13mA when 5V was applied (+15 ohm from PCB, total 145 ohm). So reversing pins 1-14 (unintended) made current go up.

I don't have those two leds or anything else connected to TB1 and TB2 yet. Does this matter?