kiev
Posts: 1070
Joined: Sun May 03, 2015 7:15 am
Location: The Heart o' Dixie
Contact: Website

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

Sun Dec 15, 2019 6:53 pm

Howdy Ziad and welcome to the forum,

Yes that is a large voltage difference, it should normally be much less for example 40mV, i.e. 0.040 V. There is a low cell that is causing the turtle under acceleration.

A cell swap is possible, see this thread: viewtopic.php?p=23601#p23605
kiev = kenny's innovative electric vehicle

DBMandrake
Posts: 264
Joined: Mon Mar 20, 2017 4:57 am
Location: Scotland

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

Tue Dec 17, 2019 2:19 am

0.6 volt difference at 50% SoC is huge, and will definitely trigger the turtle mode.

Either you have a faulty cell, or a faulty LTC voltage monitoring chip on one of the CMU boards in the battery pack that is causing an intermittent faulty voltage reading for a cell. Both issues have been documented and diagnosed both on here and over in a couple of threads on speakev.com.

It will take some careful diagnosis to reliably confirm which you have, if you are prepared to go to the trouble and have good DIY skills. Both are repairable however they are both big jobs as it means dropping the battery pack out of the car and (carefully) disassembling it.

I have done cell swaps on my own car and also assisted another owner with diagnosing a faulty LTC chip so I know what's involved, and they're not jobs to be taken on lightly unless you're reasonably well equipped and determined and understand safety procedures for working on high voltage equipment. (The battery pack can give you a lethal shock if not treated with respect, even with the safety link plug removed) Access to a 2 post lift would help immensely - I did mine without a lift by standing the car up high on stands and lowering the battery down on threaded rods and it worked but it was a very time consuming and intricate job compared to using a proper lift.
- Simon

EV: 2011 Peugeot Ion
ICE: 1997 Citroen Xantia V6

Graveaxis
Posts: 8
Joined: Fri May 27, 2016 12:58 am

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

Wed Jan 15, 2020 1:37 pm

Ended up replacing the 12 volt battery at the dealer and the dc-to-dc converter code never came back. After gaining some rapport with the dealer I've scheduled a test and talked to the technician. The dealership is fairly confident a replacement battery is in order. I'm still under warranty, so should be some what less painful. I am excited about getting a few more years out of the car. The dealership has a hill right next door, so it should be very easy to reproduce if they can't determine it with a scan. I ended up buying a scan tool and the cells that are lower are 10 and 11. About .4v to .6v at 50% load range has definitely took a hit also.

DBMandrake
Posts: 264
Joined: Mon Mar 20, 2017 4:57 am
Location: Scotland

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

Thu Jan 16, 2020 2:24 am

Graveaxis wrote:I ended up buying a scan tool and the cells that are lower are 10 and 11. About .4v to .6v at 50% load range has definitely took a hit also.

So two cells are 400-600mV lower than the rest ? At 50% SoC ? That's massive - I'm surprised the car would drive at all. :shock:

Careful diagnosis would be necessary to confirm whether it's two faulty cells (a little bit suspicious that they're side by side) or whether its a faulty LTC chip on a CMU board (since the same LTC chip will be monitoring cells 9-15) but if they are just going to swap the entire traction battery under warranty then that will of course swap all the cells and all the CMU monitoring boards which are bolted directly to the top of the cells, so will definitely fix the problem regardless of whether it's cells or LTC chip.

For a DIY out of warranty repair you'd want to figure out whether it was cells or chip of course.

What does it report for the Ah capacity on the first trip screen in Canion ?
- Simon

EV: 2011 Peugeot Ion
ICE: 1997 Citroen Xantia V6

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