12v charging when plugged in but not in “ready”

[tewharaunz]

pbui19,

Excellent point. I've been measuring it at the battery terminals but that will be influenced by the 12v battery charge level.

Also for Kiev,
There is power to the OBD port, but it stopped connecting. I've been successfully using a wifi dongle and hob drive on an iOS device and it connects with the dongle, but cannot "see" the car. On the weekend, I tried a bluetooth dongle and an Android device with Torque app (just to see whether it would connect). and it was able to connect to the dongle but also couldn't "see" the car. I wish I had a cabled OBD so I could rule out wireless connectivity issues...

Still chasing....

David

[tewharaunz]

OK, I've done some more diagnostics, and it definitely charges when plugged in but not when it is running.

I haven't been able to connect with Hobdrive but there is power on pin 16 and less than 2 ohms between pins 4 and 5 so not sure what's going on...but I don't know of whether clearing any codes would help things...

Not sure what to do next. It's summer now, so I can easily drive in "low 12v usage mode": no radio, no fan, not sure if I can disconnect electric power steering. However, when it rains I get nervous using the wipers, and have the leave the windows open to avoid turning on fan.

Does anyone know whether the key and the charging port use different circuits to activate the DC/DC converter?

FYI, I followed the service manual diagnostic procedure for OBC/DC-DC unit and didn't find any glaring problems...
I-miev Inspection Procedure 9: Power supply system of on board charger (with some added tests from later bulletins)

Step 1: yes, battery voltage OK
Step 2: yes, looks undamaged
Step 3: yes, A-06x and A-08x relays bench tested and both function properly
Step 4: yes, voltage from A-06x terminal 4 to earth is 13v
Step 5: yes, with motor switch ON, voltage from A-06x (terminal No. 3) to earth is 13v
Step 6: yes, continuity between A-08X (terminal No. 1) and A-06X (terminal No. 3)
Step 7: yes, C-108 looks undamaged
Step 8: yes, with motor switch ON, voltage from C-108 (terminal No. 66) to earth is 13v
Step 9: yes, A-06x terminal 4 to earth is 13v (Same as step 4?)
Step 10: yes, continuity between A-08X (terminal No. 1) and A-06X (terminal No. 3) (same as step 6?)
Step 11: yes, continuity between A-06X (terminal No. 2) and C-108 (terminal No. 66) EV-ECU
Step 12: yes, connector E-03 looks undamaged
Step 13: yes, continuity between A-06X (terminal No. 1) and E-03 (terminal No. 2)
Step 14: yes, resistance from E-03 (terminal No. 10) to earth is 2 ohms or less
Step 15: yes, earth cable looks undamaged (removed and cleaned)
Step 16: yes, earth cable less than 2 ohms
Step 17: yes, voltage between E-03 (terminal No. 7) to earth is 13v
Step 18: yes, continuity between auxiliary battery and E-03 (terminal No. 7)
Step 18a: yes, with motor switch on, voltage between E-03 (terminal 8) and earth is 13v
Step 18b: yes continuity between A-08x (terminal 1) and E-03 (terminal 8) [edited typo and removed reference to terminal 2]
Step 19: yes, C-106 seems undamaged
Step 20: yes, continuity between C-106 (terminal No. 11) EV-ECU and E-03 (terminal No. 12)
Step 20a: yes, continuity between C-111 (terminal No. 116) and E-03 (terminal No. 4)
Step 20b: yes, continuity between auxiliary battery and E-01 (terminal No. 1)


Cheers, David

[PV1]

I've been successfully using a wifi dongle and hob drive on an iOS device and it connects with the dongle, but cannot "see" the car. On the weekend, I tried a bluetooth dongle and an Android device with Torque app (just to see whether it would connect). and it was able to connect to the dongle but also couldn't "see" the car.

CANbus not working properly and the car's falling back to a secondary communication circuit? Surely that should throw a warning light of some kind. Also, the red battery light should be lit indicating a problem with the 12 volt side.

On the driver's side of your car, the main wiring harness runs under the trim at the bottom of the doors. Have you inspected the harness for signs of rodent damage? Maybe even check the backside of the OBD port. Might even be as simple as the pins got pushed out and are shorting against something.

Kind of interesting to have range anxiety because of the 12 volt battery. That doesn't happen all that often.

[JoeS]

tewharaunz, sorry you're still dealing with this, and some of us need to go back to poring through the workshop manual in an attempt to unravel this mystery with you.

In the meantime, in order to delay your 12v battery range anxiety with a quick and dirty fix, I'd be inclined to grab any old 12v battery (the bigger, the better) and strap it down in the passenger footwell and feed the car's auxiliary outlet ("cigarette lighter") through a 0.1Ω resistor, figuring at worst there will be a 1v∆ which would max out at ten amps. Might monitor it with a voltmeter as you drive. I have an EV converted old-school pickup that I drove for years for short hops to town (~30km round trip max) that I never bothered putting in a dc-dc but just ran with a large AGM which I manually recharged at home.

[kiev]

OK, I've done some more diagnostics, and it definitely charges when plugged in but not when it is running.

Does anyone know whether the key and the charging port use different circuits to activate the DC/DC converter?

Step 17: yes, voltage between E-03 (terminal No. 7) to earth is 13v
Step 18: yes, continuity between auxiliary battery and E-03 (terminal No. 7)

Step 18a: yes, with motor switch on, voltage between E-03 (terminal 8) and earth is 12v

Step 18b: yes continuity between A-08x (terminal 1) and E-03 (terminal 8) [Also on terminal 2 on A-08x]

Step 20: yes, continuity between C-106 (terminal No. 11) EV-ECU and E-03 (terminal No. 12)
Step 20a: yes, continuity between C-111 (terminal No. 116) and E-03 (terminal No. 4)


Cheers, David

Steps 17 and 18 check that the 12V Hot All The Time supply to the OBC and DC Converter (DCC) is present and okay.

18a: checks that the key-switched 12V supply to the DCC is working, okay.

18b: checks the wire over which the supply of 18a is carried, okay.

18b: [Also on terminal 2 on A-08X] ??? what does this mean? That there was continuity to chassis?

20: checks wire that carries the enable signal for the OBC, okay

20a: checks the wire that carries the enable signal for the DCC, okay

So it seems that the wiring is intact.

My guess is toward something different in how the EV-ECU receives its power supply when charging and when going to READY.

The EV-ECU has a Hot All The Time 12V supply in addition to Switched 12V supplies. And it operates in different Modes to control functions of the car.

The DCC is a dumb box with no CAN control; it just needs the enable signal from the EV-ECU, called "DCSW" on the schematics.

i can imagine there is a diode-OR circuit in the EV-ECU such as shown here for the OBC block diagram [ 3 diodes can supply the 12V drive for the EV Control Relay]


that is also used for the DCC, although not shown in this diagram


If one of these diodes were blown open, then that could explain how the DCC works when charging but not when in READY.

[tewharaunz]

Thanks to everyone for their help.

I'm now convinced that the 12v aux battery is not being charged at all (it never shows over 14v, whether plugged in (EVSE) or in ready.

I've managed to keep commuting through a sunny Dec/Jan with a 20w solar panel on the dash, so I only had to put the 12v on the charger every 5th day. Unfortunately, we've had some cloudy days recently and I'm back to 12v top up every day or every other day if I won't need to use the wiper.

I've followed the service manual and traced all the connections all the way to the E01 and E03, but the next step in the manual is to replace the DC/DC converter. Is there any (easy) way to test the operation of the DC/DC converter?

Kiev, I assume since I'm getting signal to E03 the diodes you mentioned in your message are inside the DC/DC converter?

Also, does anyone know where the DCSW wire goes into the DC/DC converter?

Thanks again for everyone's patience and generous help.

Cheers, David

[kiev]

i'm inclined to think that maybe your lithium 12V is not suitable to the task. The DCC will not activate if the 12V buss voltage is not within expected range. Maybe the BMS of that lithium battery is defective or limiting current somehow. It might be worth putting in a fresh fully charged lead acid.

What is the open circuit voltage of the 12V?

What is the voltage with the car in READY?

Did you read thru the other thread at the posted link? The DCSW is a 12V signal to cause the DCC to start and goes to the DC/DC board in the bottom plenum of the OBC. What is the voltage of DCSW that you are reading?

The three "OR-ed" diodes are shown in the the EV-ECU in the diagram of my previous post. Those are shown to provide the supply voltage for the EV Control Relay.

You could put a clamp-on current probe on the big white wire out the DCC or at the input to the 12V battery to see if any current is flowing, meaning the DCC was working when charging or in READY. It sounds like you don't really know if or when it is working. There are fuses on the DCC, both input and output. If it is not working at all, then that would be the first thing i would check.