SOC Meter stopped working

I've had an SOC meter (purchased it fully assembled) for over a month now, and it has worked beautifully. While I haven't gotten around to logging data, I particularly appreciate the SOC and pack voltage information. I leave it electrical-taped to the dashboard, above the touchscreen.

Unfortunately, last night while driving up our mountain, the SOC meter spontaneously stopped working. The display went dark, no matter the switch positions. I slightly jostled around the meter and the OBD connection, power cycled the car, and the meter started working again. Then the same thing happened today while driving, except that the meter still isn't working.

My guess is that there might be a loose connection somewhere. Before I open it up and start tinkering, can anyone suggest where I might want to start? Has anyone had issues with the OBD port itself? My OBD port (on the car) does feel just a little loose.

Edit (new info just below):
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The most likely cause of Nothing on the Display is an overheated
(and blown, open-circuited) Zener Diode. The overheating seems
to be caused by the shrink tubing touching the Zener's glass body,
instead of being about 1/4 inch away. A Zener Diode Upgrade
is now available (see post #30, at the bottom of Page 3).

-------
Try these checks and tests:

1. Switch the SOC-Meter OFF (Power switch toggle straight out).

2. Make sure the OBD cable is securely plugged into the LEAF's OBD
connector, which is usually a little wobbly by itself. However. the
connection to the OBD cable should be nicely firm.
A loose connection is the most likely problem.

3. Switch the SOC-Meter Always-ON (Up), and the display should show "0000"
immediately. If it does not, there is something wrong.

4. With the LEAF turned ON (ACC2 or Ready), try the Down-ON (Auto-ON position).
Again, the display should show "0000" immediately.
If it does not, there is something wrong.

Download the circuit diagram from my web site:
http://www.wwwsite.com/puzzles/socmeter/" onclick="window.open(this.href);return false;

If that does not work, PM a phone number and a time to call,
and I will try to help.

Thank you, Gary, for your support. Knowing that you stand behind your work, I was able to approach this without undue worry.

I followed the above steps, but the display still did not light up. I opened the unit and discovered a crimped wire, the gray one in the upper left of this photo:


Presumably, the wire accidentally got smashed when screwing the unit together. My theory is that this was the cause of the malfunction. I squeezed the wire in an attempt to ensure conductivity, then retried the unit. It is now working fine. Hopefully this holds!

Also, know that I am praying for your upcoming surgery and recovery.

Note: It appears in your picture that the DB9 connector (where the grey wire connects to pin 2) MIGHT not be pushed in quite far enough for the Power-in (on pin 9) to make contact. Try seating the connector better. No-power is basically the cause of No-Display.

------
The grey wire carries the "low" side of the CAN-buss
from the Selector switch to the Board.

Even with it cut, the Display would still light up and display "F1.08"
and then "----". Then, it would "stick" there and not show proper data.

Is that your failure "symptom"?

I thought you were describing NO visible light from the display at all ... a much different symptom.

If No-Light is really your symptom, the cause is unlikely this grey wire, but rather the red wire that comes from the center pin on the Power Switch and attaches to the Zener Diode that is soldered onto pin 9 of the DB9 connector.

If the Board gets sufficient power, its red Power LED will be ON, and the other on-board LED will flash during the power-up sequence. Or, it might be a bad power switch.

Please clarify for me.

If the grey wire is "broken" inside, then cutting out the small bad section, soldering the wire ends back together, and covering the "joint" with insulation (tape or shrink tubing) would be the thing to do.

If you cannot get it to work properly, I should be able to fix it if you send it to me.

Thanks for the kind thoughts, and prayers!!!

Thanks for helping me find the problem.

When found, the knowledge will help me improve future builds.

Cheers, Gary

Thank you. Yes, the display was not lighting up at all, so it appears that the gray wire was not actually the culprit. At the moment, the unit is working and is taped in place on my dashboard. If it goes on the fritz again, I will check that red wire.

Thanks.

To defuse the bomb:
1. Cut the Red wire.
2. But first, cut the Blue wire.
3. ... boom ... :lol:

I seem to have a temperature sensitive SOC meter.

The first trials of the unit went without a hitch. Then, as the weather got colder,
the meter would either start up showing random patterns on the display or fail
shortly after power up with the same symptoms. I suspected a flakey PB switch,
as I have had problems with them before, but couldn't isolate the problem. Then
I noticed that the meter started to work normally (after a power cycle) once the
cabin warmed up. As a trial, I started to take the meter inside at night. Sure enough,
if I keep it warm it works. Now that the overnight temps are in the lower 40's the
meter takes 15-20 minutes to start working if I leave it in the car. Works right off
if I keep it in the house overnight.

I don't know what the operating temperature range is for the AVR-CAN board, but
I suspect that is what is failing.

Anyone else having cold problems?

highcountryrider said:

I seem to have a temperature sensitive SOC meter.


-snip-
Anyone else having cold problems?

Click to expand...

No problems with mine, but the coldest it's gotten here overnight has been the high 40s, and it's usually in the 50s. Checking Accuweather for your area, it looks like it's getting into the 30s overnight.

Abasile lives in the mountains, where it gets colder than where you are. Any temp related problems, Abasile?

LEAF is kept in an unheated garage and our night time temperatures are similar to yours.
No malfunction of the SOC meter.

Thanks. I'm thinking I have a bad AVR-CAN board.

You sure it's not dampness getting inside the box? My experience with malfunctioning boards is generally the opposite - that a malfunction will make them run hot, and cooling them down (typically done in the troubleshooting mode by sticking them in a freezer for a few minutes) will make them function properly again.

Pretty sure. Although I live in a soggy climate, the inside of the LEAF is pretty dry.

I have seen electronics go both ways, they can fail at high or low temps. Usually
if something fails when cold, we don't wait for it to warm up, just consider it
broken.

Possibly just the display losing its Baud Rate setting, to reset:
1. SOC off
2. hold both buttons down
3. SOC on
4. after 3 seconds, release both buttons.
Cheers ...

Boomer23 said:

Any temp related problems, Abasile?

Click to expand...

Unfortunately, the day after I last posted to this thread, the SOC meter stopped working, and I haven't gotten it working again. (I only made matters worse by breaking a solder joint to that crimped gray wire in an attempt to splice it; maybe it would help if I actually owned a soldering iron.) It'll probably be best if I simply let Gary take care of it when he's feeling better.

It seems possible that our temperature swings further weakened a solder joint or two that might have been weak to begin with. Vibration from our less than perfectly smooth roads, including a few miles of dirt road driving, could have also been a factor. EDIT: Our nighttime lows have been in the 20s and 30s, and the LEAF is not garaged.

In any case, I appreciate Gary's groundbreaking work, and accept that "beta testers" such as myself have to be prepared for a few glitches.

That would not explain the temperature thing. But, like abasile says, this can wait until you
are fully recovered.

garygid said:

Possibly just the display losing its Baud Rate setting, to reset:
1. SOC off
2. hold both buttons down
3. SOC on
4. after 3 seconds, release both buttons.
Cheers ...

Click to expand...

highcountryrider said:

I seem to have a temperature sensitive SOC meter.

The first trials of the unit went without a hitch. Then, as the weather got colder,
the meter would either start up showing random patterns on the display or fail
shortly after power up with the same symptoms.

Click to expand...

My meter is somewhat flaky, but not related to temperature that I can tell. It will be fine for a few days, then have one or two times with seemingly random numbers. Power cycling always fixes it, so I have been too lazy to do anything more about it.

Mine is very consistent. When it's cold, nothing you do will make it work. It does power
up in an odd state sometimes when it's not cold, but a power cycle always fixes that.

For now, just keeping it inside at night works.

This post may be a little pre-mature, but I might have solved the temperature? sensitivity issue. Mine, too, recently would come up in a strange state with garbage on the display about half the time. Toggling power multiple times would usually get it going eventually. While investigating, I noticed that the output of the 5V regulator was only 4.5V and the input was only 6.5V. The datasheet says the input must be 7-12 so first I replaced the zener with a 3.3V zener which raised the input to >8V. However, this didn't solve the problem. I still was seeing 4.5V on the output and encountering the malfunction. So next, I soldered a 1.5K surface mount resistor on top of the 220 Ohm R49 to bring it's effective resistance to 192 which, by my math should raise the output 500mV. That seems to have worked. It's only been installed 24 hours but so far no sign of the funky poweron state and the output voltage is 5.0V. I am not sure the zener replacement was necessary but I mention it in case it was. I recommend anyone experiencing this issue measure the output of VR1 on the back of the AVR-CAN board and see if they are getting 5V. Datasheet says it should work at 4.5V, but my guess is some may be marginal there.

I didn't have the right size SM resistor but the capacitor next to it shares a connection so I was able to solder from the cap to the far 220 Ohm R49 terminal. If you are handy with a soldering iron and long nose pliers, you may even manage to make an axial resistor work. Disclaimer: Proceed at own risk. If you screw it up and short something that shouldn't be you could destroy your AVRCAN. Measure the output of the Vreg even if it looks like it is working to make sure you are not over-stressing the chip.

That sounds very likely - will investigate. Thanks.