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think 2009

Startet av jonandse, søndag 18. april 2021, klokken 21:32

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jonandse


jonandse

Tonight I spent some time reading the electrical schematic. The AC heater for the Zebra battery is connected to the charge port through the PCU so I figured it would be interesting to find out if the AC voltage was present at the A4.X1 connector.

The A4.X1 connector can be accessed through the lid below the passenger seat.

I unplugged the EVSE from the car, unplugged the A4.X1 and reconnected the EVSE. Now the relay on/off sound could no longer be heard and "Orla-diag" showed AC present as 0 all the time.

I measured the voltage in the connector. As expected it showed mains voltage (241V tonight!) between L1 and N but 127V towards GND?! This is very strange (Sweden has TN electricity, 230V from phase to neutral and ground).

The typical reason for seeing mains voltage /2 towards ground is that the ground cable is broken and that there is a mains filter (typically X1 capacitors) to both L and N, effectively creating a voltage divider when GND is broken.

As you remember my EVSE had a bad cable. Could a broken protective earth cable in the EVSE be the reason for the heater not engaging? Sounds weird. I am more leaning towards that the EVSE bad mains cable has caused the AC heater relay contact surfaces to weld so connection is intermittent / poor, but still weird that the GND seems broken.

To my understanding the AC heater relay is located inside the Zebra battery?


jonandse

The AC heater connector is somewhat difficult to unplug. I used a Biltema interior removal hook tool to reach the connector hatch.


Orla Pedersen

There is a huge insolation transformer in the circuit, that explains the ac/2
The mains go through the transformer. It's located under the floor behind the seats.
Mvh
Orla Pedersen

jonandse

Ah, interesting! I can hear it somewhere in the back of the car!
Is the isolation transformer located inside the PCU?

And the relay controlling the AC heater is inside the battery?

Sounds like I need to drop the battery out of the car to find out why the AC heater doesn't heat?

Or is it the BMI for some reason thinking the battery shouldn't be heated?

Orla Pedersen

There is a relay, and a solid state switch in series. The relay is a kind of extra safety.
As shown in the diagnose, both relay and switch is not aktive. That indicates that the BMI has stopped heating for some reason.  :(

The transformer is not in the PCU.
Mvh
Orla Pedersen

jonandse

Thanks Orla! On the MY2011 electric schematic there is no transformer was this later removed or am I missing it?

According to the same schematic there should be a BMI reset button Q4 separate from the Q32 TPMS reset button in the fuse "box". Does this reset button exist? If so, where is it located?


jonandse

Blir ikke klok på dette jeg.

Battery temp is now down to 49 deg so despite being plugged in the AC heater is not on. I can hear the relay toggle on and off. If I pull the AC cable to the Zebra box the relay I can't hear the relay anymore. Tried pulling the multipin connector to the battery box and that ofcourse stopped the communication. Reconnecting it did not heal the heating behaviour.

Does anyone has experience using a PCAN clone with Zebra monitor? I might be able to borrow a clone from a person across town, please let me know if that is a dead end.

Any other idea before dropping the Zebra battery out of the car - which I obviously want to avoid if I can?  :-\


BauDemo

Think of the BMI as a computer with a hard disk, operating system, and sensors.
Unplugging and plugging back in the computer would normally not do much.
If there is an error of certain level/class stored in the BMI the BMI will not permit heating. I am not sure of what kind of errors are considered "General error" but this would indicate to me that there is something fishy.
Dropping the battery will actually make it harder to diagnose since then you would need to have a different cable to connect to the AC.
I have not seen any clones of p-can - do you have a link for such a clone?
laddplats? -www.uppladdning.nu
nikometer? - www.evmonitor.info

jonandse

Thanks Bauhaus. "Svenskereset" have solved many electronics problems so it is definitely worth trying. Then I'll keep the battery in the car for now and aim my efforts at getting hold of a PCAN adapter.

There seem to be some different clones on ebay, aliexpress etc.

Expensive clone: $125 https://www.aliexpress.com/item/1005001909644558.html
Cheaper clone: $45 https://www.aliexpress.com/item/1005002186465775.html

I don't know which one (if any!) of these it is I might be able to borrow, but I'm told it is not an original unit. By experience I also know that electronics live a tough life at that workshop - it is more than once I have borrowed equipment that I was told it "should" work and it turned out to be completely broken so before looking into that (read "spending time pulling my hair"!), what are the odds of getting Zebra monitor software to get along with a clone at all?

If anyone has been successful (or the opposite!!), please chime in here.

Also, if anyone has a PCAN adapter up for sale, don't hesitate to PM me!

Orla Pedersen

Maybe my tread: https://elbilforum.no/index.php?topic=27036.0 would help understanding the BMI's "working in mysteries ways"   :o
Mvh
Orla Pedersen

jonandse

Interesting read, thanks for documenting Orla!

I noticed the cooling fan running in periodic cycles (like 5 seconds on, 8 seconds off) after the charging stopped at roughly 30% SOC.

Seems the BMI isn't that reliable in all (fault) conditions.

I also sometimes see the "zebra temp error 3", but it is not permanent so maybe this is a sign of BMI glitching.

BauDemo

Sitat fra: jonandse på torsdag 06. mai 2021, klokken 15:46
Expensive clone: $125 https://www.aliexpress.com/item/1005001909644558.html
Cheaper clone: $45 https://www.aliexpress.com/item/1005002186465775.html
I have only used the original p-can - there is a swedish distributor for it here:
https://lawicel-shop.se/elektronik/kommunikation/can/pcan-usb/

Both links you provided seem to be compatible - there are screenshots, etc.
With faster shipping and VAT the final price in Sweden would be about 1000kr.
laddplats? -www.uppladdning.nu
nikometer? - www.evmonitor.info

jonandse

I haven't seen PCAN at Lawicel, nice surprice! Very tempted to order one - that would for sure help to know it would be working rather than messing around with clones in unknown condition.

I have now installed the Zebra monitor software and its helpfile was an interesting read. Recommended for anyone who want to learn more on the Zebra battery. Also seems the

Using Nikometer and diagvga from Orla it is obvious that this car has had AC heating problems some time in history - the AC heater relay error flag is lit. This flag is described as category "Notice" but needs to be reset with Zebra monitor (which I don't have hardware for just yet).

The helpfile elaborates: AC heater heats the battery using power from the main line. A relay and a
semiconductor switch are used to control the heating.  AC heater relay error happens
when close relay or open relay commands don't  have a successful conclusion
DPH_NTB_AC_HEATER_RELAY_ERROR

As I posted earlier in this thread, this car has been operated with a glitchy EVSE so I wouldn't be surprised if the AC heater relay has been taking some damage due to that spark fest. Next step is to examine the AC heater relay and possibly the AC heater loop to see if it is an open circuit.

Not sure if this will happen first or if I will order the PCAN first but this is the plan for now. Also weather is improving so that motivates me to be outdoors working on the Think!

I would love to get it to a driving condition first to be able to decide on its destiny but can't deny I'm starting to fall in love with this very special little vehicle!


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