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

[DBMandrake]

I have the same issue (turtle light comes on under load) with our 2012 SE. The car has about 36k miles and has been absolutely trouble free for the seven years that we have owned it. Until now, that is.

The dealer read the trouble codes and there were several : B1477, B1476, B210D and P1A2F. Since the first three of those codes appear to relate to the 12v battery, I will replace that tomorrow even though it tests good. If that resolves the issue, wonderful. If not, I am guessing that the P1A2F code indicates one or more bad cells.

P1A2F is a "secondary" code which is set by other codes:

http://mmc-manuals.ru/manuals/i-miev/on ... 100ENG.HTM

However none of the codes which can cause P1A2F (shown in that article) are listed above, so I must conclude that whatever diagnostic tool the dealer used did not read all the codes or the codes were reset before reading, so some information you need is missing.

I have already tried the battery rebalance procedure (i.e. drain it almost to zero, wait two hours, recharge with slow charger).

Am I missing anything with this?

It's hard to know for sure when one of the codes (which triggered P1A2F) is missing, but in general turtle light coming on under load at a high SoC means you have one or more faulty (high resistance) cells in the traction battery.

Your dealer should have been able to diagnose this, but apparently they have not. If you want to have a go at confirming this yourself you can use an android tablet with Canion and Hobdrive using a suitable bluetooth OBD-II adaptor.

Hobdrive works with most adaptors but Canion only works with a limited selection of adaptors. I used Canion with an OBDLink LX successfully for years and it also worked with Hobdrive. (I no longer have one of these cars - I have a Leaf now and use the same adaptor with the Leaf)

Canion can show a realtime graph of all the cell voltages - if you have someone drive the car for you you can watch the cell voltages in real time, watch for any particular cells that drop much lower than others during acceleration and you will find your culprit(s).

If any cell drops below exactly 3.0 volts during driving the turtle mode will instantly come on. Normal no-load voltage of a nearly discharged traction battery is around 3.6 volts per cell.

Hobdrive is a bit more tricky to use (see other threads here for help) but is able to do limited fault code reading and may be able to provide the missing fault codes.

[DBMandrake]

Duplicate post.

[Gearhead1961]

DBMandrake -

I do appreciate the information. Replacement of the 12v battery has been delayed a day due to some other obligations but i have taken the opportunity to download Canion and order an OBDLink LX. I am a little out of my depth with all of this but I am sure that I can muddle through and eventually get to an accurate diagnosis.

The problem is, of course, that if all of this leads to confirmation of one or more bad cells, I am dead in the water as I do not have the facilities or skill set necessary to drop the battery assembly and swap out cells. I guess I'll cross that bridge when I get there.

[Gearhead1961]

Well, I replaced the 12 volt battery today and ---- as expected --- it had no effect on the turtle coming on under load. OBDLink will be here in a day or two so I will see what the Canion app can tell me then.

[Gearhead1961]

Looks like cell 85 is the culprit, drawing down to 2.790 volts under load.

[JoeS]

Looks like cell 85 is the culprit, drawing down to 2.790 volts under load.

Commiserations, but at least you identified a bad cell. How do the others look under load?

[Gearhead1961]

There are a half dozen other cells that fall into that 3.2 - 3.1 range under load but #85 really stands out as the bad guy.

[MickeyS70]

There are a half dozen other cells that fall into that 3.2 - 3.1 range under load but #85 really stands out as the bad guy.

Sorry to hear about your troubles, it really looks like these early LEV50 cells degrade a lot faster in high ambient temperatures as the car has only done moderate mileage overall.

Even if you had the means to replace the bad cell, improvements will most likely only be short lived, therefore the only permanent solution is to change the complete pack. If I remember correctly the 10 year battery warranty expired last month but even if still in place a claim was unlikely to be successful as it charged up fully…

You could pay for a replacement yourself but dealer prices are astronomical and therefore I’m afraid it’s time to look for a successor…

[vh2q]

I replaced a cell last year that was lagging at rest after a full charge. That cell is a trooper, the strongest cell in my pack. And my pack now gets up to 16 bars when charged (vs 3 before).

Now a new problem unfortunately. All my cells are strong at rest after a charge however 13, 87, 38 now sag below 3V under mild load at 8 bars and below. They get as low as 2.8 which triggers the turtle, and will bounce back to 3.4 after a rest. The cell I replaced is still at 3.8 under this scenario. I had to crawl home today, with a push assist to get up the driveway.

Looks like 3 more have to come out. Car has 25k miles.

I hate electric cars!

[vh2q]

And now something new. Car is dropping bars while parked overnight. Cells still level but down fractionally. It got unusually cold here, down to 60 vs the normal 75 to 80.