Turtle at Half Charge Under Load?!?!?!

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Graveaxis

Member
Joined
May 27, 2016
Messages
11
Location
Portland, OR
The turtle light is coming on, on my way home going up hill. I took the car into the dealer and they seem to think its a DC/DC convertor. I was under the impression the light was related to the traction pack. The car has had no problems charging to all 16 bars. We have seen a range drop, but I don't have any hard numbers. The dealer wants ALOT for the DC/DC convertor. You Guys have any Ideas! This is the video of the problem https://youtu.be/EQWfFRi5zgA
 
Please add "under load" to your subject line.

Usually if turtle mode is triggered, it doesn't turn off until the pack is re-chargged. But in your case the light comes on under high load with a full throttle and with the Heater ON, then turns off when you release the throttle.

Try again with the heater OFF just to see if that affects the response.

But it is likely that one cell is lower than the rest and hitting the low voltage limit during the high load periods, then recovering up above the limit when the throttle is released.

You would need to use one of the cell voltage reading apps for android or iphone to watch the cell voltages and determine if you have a weak or worn out cell, or the entire pack is out of calibration.
Maybe try a calibration charge session to see if that affects it also.

[EDIT]
p.s. ask the dealer what diagnostic trouble codes were showing up when they connected the MUT tool--we can look up the meaning and the troubleshooting sequence.
 
Graveaxis, sorry to hear and thank you for posting your video.

Yes, "under load" is important information and I modified the title to reflect that.

What year and how many miles does your car have?

I note that the outside temperature was 32°F at the time you took the video.

Totally agree with kiev's assessment and simple first step to address the issue.

An app which shows cell voltage is the primary tool you need to diagnose this problem.

As a side note, it is disturbing that the dealer's first (kneejerk) reaction was to want to change the OBC/dc-dc ... this perhaps becoming the most common i-MiEV failure? :roll:
 
The light will come on with less load and no heat at a lower state of charge. I don't understand how the dc-to-dc converter has anything to do with battery voltage drops under load. I'm going to the dealer today to get the powertrain codes. The car is mostly charged on level one overnight. About two days a week it is drawn down to two bars. Temperature obviously assertives the situation.
 
Graveaxis said:
I don't understand how the dc-to-dc converter has anything to do with battery voltage drops under load.
The OBC/dc-dc doesn't. Edit: this could be wrong - see kiev's comments two posts down.
Graveaxis said:
The car is mostly charged on level one overnight. About two days a week it is drawn down to two bars.
I'd be inclined not to take her down that much if you can help it. Do get an app and bluetooth OBDII adapter asap and measure those cells so you can better assess the situation yourself and see if repeated full-charge balancing is helping any. How many miles on the car?
 
The code is obd dtc 39 PFC output voltage fail
Or obc dtc 39 PFC output votltage fail. Kind of hard to understand him over the phone. I'm going to order a scan tool are you guys mentioned before. My current OBD 2 reader doesn't seem to work on the car. The technician was under the impression the turtle light could come on because of low voltage on the 12 volt battery. I asked them if they could draw the battery down and then do some real time capture on the battery cells. They recharged the car to full...
 
What is the age and condition of the 12V aux battery--is it the original OEM or has it been changed, etc.? We have a separate thread devoted to troubleshooting the OBC/DCDC Converter with lots of detailed information in post #2 about testing the 12V aux battery.

i would have expected to hear that they found a P-code DTC, such as P0A09 or P0A10, which are codes for something wrong in the DCDC converter.

The OBC code 39 is a very specific sub-code related to the Power Factor Control circuit located in the upper plenum of the On Board Chargger which creates the high voltage necessary to recharge the pack. It has nothing to do with the operation of the DCDC.

The DCDC converter is located in the bottom plenum of the OBC box and it uses HV from the pack to create the 12V needed to recharge the aux battery and supply the 12V loads while in READY.

But here is one idea, if the DCDC is pulling a high current from the pack in order to try to charge a weak, worn or failed aux battery, then it may be that the pack is getting pulled down to "turtle" voltage level whenever the throttle is pressed, which sends HV current thru the Motor Control Unit. The combined current load may be pulling the pack voltage down. The voltage rises when the load is released so the turtle doesn't stay set.
 
The car has about 54,000 miles. It still got the original battery. I'll see what the replacement cost is maybe throwing a battery at the problem wouldn't be a bad idea. I ordered the Bluetooth scan tool recommended on here. We've had the car for about 40,000 miles and it has been a rockstar! Only thing I wish I could change is the color. The used car factory seems to only produce purple 2012 I-miev's.
 
Graveaxis said:
The car has about 54,000 miles. It still got the original battery.

i would bet that your problems will go away when you replace the OEM aux battery. Put the money for the obdii tool toward a new battery. i hardly ever use my scantool, but i use that battery every day...
 
Style said:
Having same issue. OP-What was the resolution to the issue ?

This is generally caused by a battery cell going bad. Turtle is triggered by low voltage on a battery so even though the car has plenty of charge, one cell's voltage drops when it is used.

What country are you located?

Thanks.
 
RTFM - "turtle light" means "Power down warning light". Illumination of the power down warning light does not
indicate a malfunction.

This warning light will illuminate;
*When the energy level in the main drive lithium-
ion battery is near empty.
*When temperature of the electric motor unit
or the main drive lithium-ion battery is too
high or too low.
*When voltage of the main drive lithium-ion
battery becomes low.

According to HobDrive app and my expirience - internal resistance of cells are between 0,0015 when normal temperature and 0,0028 Ohms @ 41F. so this means colder battery / higher internal resistance. (see LEV50 datasheet Voltage vs Discharge capacity / Ah @ -25 -10 0 25 Celsius)

So do the math - 0.0028 x 185 Amps (full acceleration) -> 0.518 V voltage drop on cell. At ~50% SoC this means 3,8V maybe. So to protect cells, car limits amps. And older battery, lower temperatures, full acceleration - whay do You expect? Voltage becomes low -> power down light "on".

Days ago tested I-miev with 34Ah capacity with Canion app - this voltage drop (on all cells) can be observed directly.


So, I don't bet on DC-DC converter fail or replacing 12V battery or one cell in the pack gone bad. It is normal case - cold weather, high load.
 
A bit late to this thread, but.....There are two triggers for the turtle mode light.

The normal one seen is that if the estimated state of charge goes below about 10-12% (as reported by Canion) the turtle light will come on and not go out again until the car is charged back up above the SoC threshold. The load on the battery doesn't matter for this trigger it's purely SoC.

The second trigger is the turtle light will come on if any individual cell goes below 3.0 volts, even momentarily. Normally this will never be hit in practice because even under full load at 10% SoC the cell voltage will not drop as low as 3.0 volts, as the open circuit voltage will still be about 3.6 volts.

However if you have a faulty cell that has high internal resistance the voltage of the cell may drop below 3.0 volts under full load even at a relatively high SoC. In this case the turtle light will come on when accelerating and then go out as soon as you ease off the accelerator.

So if this is happening with a reported 50% SoC the issue is almost certainly a faulty cell or cells with high internal resistance, and this would be easily confirmed by monitoring the individual cell voltages with Canion while the car is driven under load, as one or more cells will drop well below the voltage of other cells, and below 3.0 volts if the turtle light is coming on, something that should never normally happen.

One other thing that could cause it is if the BMS's estimation of Ah capacity of the battery is grossly out - for example if the battery is really 32Ah but it thinks it is 45Ah it will keep driving the car well past the point where the SoC turtle threshold would normally kick in, as a result you will eventually get to the point where cells start droping below 3.0 volts under load as the cells are OK but just over discharged.

This happened to me when I did a BMS reset causing the BMS to go back to the default 45.8Ah while my pack was really around 33Ah - it kept driving the car well past where it normally should until the low voltage shutdown started triggering under load.

Unless someone has accidentally done a BMS reset, it seems unlikely that this is the cause, more likely there is an individual high resistance cell.

Diagnosing this problem should be relatively easy with Canion - first check the reported Ah capacity to make sure it is not unusually high for a car of the age/milage (to rule out the erroneous BMS reset scenario above) and assuming not, monitor cell voltages under load when the turtle light is flashing on to identify the faulty cell(s).

I have three high resistance cells in my car at 56k miles that I will be replacing soon - they're not yet bad enough to cause the symptoms described in this thread, however they are already affecting rapid charging speeds and regenerative braking.

As far as I can see DC/DC inverter is a red herring - if that wasn't working the 12v battery wouldn't charge and before long the car would stop working altogether.

The DC/DC inverter is easy to test - measure the 12v battery at the battery terminals while the car has been turned off and unplugged for an hour, it should be between about 12.2 and 12.6 volts. Then turn the car on to ready mode - if the voltage immediately goes up to 14.2 - 14.4 volts and stays there, the DC/DC inverter is working normally. You can turn high beams on for extra load and it should still stay in that range.
 
Graveaxis said:
The code is obd dtc 39 PFC output voltage fail
Or obc dtc 39 PFC output votltage fail.

kiev said:
i would have expected to hear that they found a P-code DTC, such as P0A09 or P0A10, which are codes for something wrong in the DCDC converter.

The OBC code 39 is a very specific sub-code related to the Power Factor Control circuit located in the upper plenum of the On Board Chargger which creates the high voltage necessary to recharge the pack. It has nothing to do with the operation of the DCDC.
Error code 39 in the OBC is caused by excessively high AC mains voltage, as measured after the power factor correction circuit in the OBC. Diagbox reports error code 39 as "Fault on the power factor correction module output voltage". Please see my experience with this last year from the following thread:

https://www.speakev.com/threads/peugeot-ion-not-charging-with-high-mains-voltage.104001/

In short, when the AC voltage goes above 247v the car will refuse to charge and sets temporary error code 39 in the OBC. The code is informational and the car will charge normally as soon as the AC voltage is back in range.

Although I don't know for sure low AC voltage might also set the same code, however if it can I have no idea what the low threshold might be. In the UK AC voltage is allowed to be as high as 252 volts, so this 247v limitation can be an issue for us.

So it's probably nothing to worry about and unrelated to the fault at hand - just the AC voltage being too high or too low during an attempted charging session.
 
thanks for the information. I think its a cell going bad. I borrowed a OBDzero previously from my Brother. I may have to borrow it again and check it. I've made an appointment at the local Mitsubishi dealership to get it checked. my warranty on the battery goes until November 2022, so I'm covered for about 3 more years. It would be nice to get my range back to what it was like a couple of years ago.

The other thing that happens is when charging here on a chargepoint system (Chargepoint is a pay-to-use system in the US) the app will report that the battery has stopped charging. after maybe 10 minutes to a half-hour it will start charging again. see attached graph from the chargepoint app. not sure how to attach photos, so here's a link to a screenshot:

https://drive.google.com/open?id=0B0oh0aQQWjUEV05xZXBtRHo1dDM4TjZ5RU5VRWVJLUhPY1dV

I think it happens at home when charging too, but that's usually overnight so I don't care. When I'm sitting in a parking lot waiting and every minute matters, having it stop charging for a few minutes is annoying. I also had it charging one time at 3kW, stop for 5 minutes and then continue to charge again but at 1kW, so only added like 3.3kW in 2 hours of charging. charging for 2 hours and only being able to drive 13 miles is really annoying.
Is that due to battery temperature or something?
 
A pause in charging current of up to 30 minutes at a low SoC is actually a characteristic of these cars - they all do it, so it’s normal and unrelated to your problem.

Note: only the current draw drops to near zero - the pilot signals that keep the EVSE operating remain active.
 
Greetings to all, I suffer a similar case, turtle shows up when battery is almost 50% charge under load, car is almost 60,000 miles did electric monitor and inverter temp. 25-45 C (77-110 F) cell temp was 25-35 C (77-95 F) but I did notice a Voltage variation of up to 0.6 of a Volt between the cells, could it be that the issue? are you aware of a way to replace just the weak cells?

All the best for such a great team

Ziad from Amman , Jordan.
 
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