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Re: Battery Replacement - Lessons Learned

Posted: Sun Jun 16, 2019 12:50 pm
by Aerowhatt
Don wrote:Tesla packs are arranged in replaceable modules, either 13 or 15 of them in the complete pack IIRC. I would bet if they have a failure, it's as simple as changing out the defective module. In addition, they use thousands of small cells, each fused separately so that if a single cell shorts out, the fuse blows and you've lost maybe 1/10th of 1% of the total capacity of the pack which would not even be noticed. One bad cell means the end of the entire pack on our cars


Tesla packs are made of bricks of smaller cells. We can think of a brick of paralleled Tesla cells as a single cell when comparing to our iMiev battery packs. Indeed a single small cell failing does not render a Tesla pack unusable at all. However the capacity impact is much larger than you stated. The standard range model 3 pack is made of bricks of 31 cells each and the long range pack is made of bricks of 46 cells. Since the range loss or usable capacity of any high voltage battery is limited by it's lowest capacity cell (or tesla brick) then a single cell failure in a standard range pack would reduce the usable capacity of the battery pack by just over 3% { 30 / 31 = 0.96774 or 96.774% capacity remaining }.
On the long range pack the single small cell failure would reduce the the usable capacity of the battery pack by just over 2% { 45 /46 = 0.97826 or 97.826% usable capacity remaining}

Absolutely Teslas battery architecture is superior to any other on the market for reliability. It is however complex to manufacture and the way they immobilize the entire modules of bricks with blue goo, they don't look very serviceable. The point is that they are engineered to not need serviced. Time will tell how well this works out in the long run, including recycle-ability. I think it might make more sense to use large prismatic cells and make it very easy to replace any individual cell if need be.


Re: Battery Replacement - Lessons Learned

Posted: Mon Jun 17, 2019 11:16 pm
by jray3
Sorry to be the bearer of bad news Suzanne, but I’m in the same boat as you and have seen my range declining rapidly since the RR stopped showing 60 on a regular basis as we reached 100k miles. Now at 103k miles, 40 is a more typical starting range, though a 29 mile highway run at 60 mph pushed me down to 2 bars yesterday.

Re: Battery Replacement - Lessons Learned

Posted: Sun Sep 29, 2019 9:07 am
by DocJr

Still waiting to hear where in SD you got a battery replacement as none of the dealers here claim to be able to do a battery swap. Also, two days ago, I noticed that the display is showing two bars shy of a full charge after the car quits charging. Is a failure to show all of the bars an indication that one or more cells has failed.


Re: Battery Replacement - Lessons Learned

Posted: Mon Sep 30, 2019 6:54 pm
by kiev
DocJr wrote:...
showing two bars shy of a full charge after the car quits charging. Is a failure to show all of the bars an indication that one or more cells has failed.

Yes it can be an indicator of that, especially if it happens several times.

Check to be sure that your 12V aux battery is fresh and full charged, charge it separately if necessary to ensure it is good and rule that out as a cause.

The dealer will ask you to fill out a form to describe your symptoms, and failure to fully charge is covered by warranty.

Re: Battery Replacement - Lessons Learned

Posted: Mon Sep 30, 2019 8:39 pm
by DocJr
Thanks Kiev,

Ya, 4 days in a row it charges to the same indicated point, 3-bars less than full (it wasn't 2-bars as I originally thought). I just tried using my back-up car charger and it charged the battery to the same point. I will check my 12V battery tomorrow and if needed, throw it on a trickle charger. Not sure how that affects the charging for the drive battery, but, it is 7 years old (although I have been religious about maintaining cell water level).

I could find no one in SD that has worked on the batteries on these. But the Mossy Mitsu in Escondido says he has a trained tech and his shop is authorized. Let's hope he wants to figure this out. 37 miles is the indicated range if I stick to mostly city streets. Weird, it was fine one day, and, the next this happened. You think it would just drop one or two bars.

Re: Battery Replacement - Lessons Learned

Posted: Tue Oct 01, 2019 5:12 am
by kiev
Howdy Docjr,

Here is picture showing the voltage of each cell in a fully charged but defective pack. This was generated by using a ScanTool LX OBDII dongle with an android device app called canion. It is discussed on this forum and is a handy tool for about $50 to get an independent look at the condition of your pack.

Notice that all the cells are fully charged up to about 4.1V except the one cell #87 is lagging at 3.9--it is a defective cell and is causing the State of Charge to show only 8 or 9 bars and RR of 31, even though the average pack voltage is 360VDC.

The dealer will do some discharge and chargging tests as part of troubleshooting to verify that is the issue, but it is always fun to be able to tell them "cell #__ is bad" and let them wonder how you knew.

If you keep the water level properly maintained and fully charge and de-sulfate periodically, then it is possible to get a good long service life out of a lead-acid battery. Most folks don't do anything but drive and let the car (EV or ICE) recharge the starter battery, and the service life will be less. Load test your 12V aux battery and check the electrolyte specific gravity to know how good it is.


Re: Battery Replacement - Lessons Learned

Posted: Thu Oct 03, 2019 7:05 pm
by DocJr
Dropping car off Saturday at Mossy Mitsu. Measured the accessories battery and it was 13.1 volts so we will see. Wish there was a dealership in San Diego that had experience with this car. I know the big one in Orange County does, but, it would take three charges to get there and (assuming they fix the issue), two charges to get back. Not sure the early adopter thing was a good idea in hind-sight. I guess I thought more people would buy these. Maybe if they don't fix it, I can see if the San Diego auto museum will take a rare car donation! 'Still have my other gas Mitsus that have never let me down (and they are even older than my 2012!)

Re: Battery Replacement - Lessons Learned

Posted: Sat Oct 05, 2019 10:33 pm
by DocJr
So from fully charged (charging stops at 12 of 16 bars), I am able to make it the 15 miles to the dealership with 3 bars left. 3-weeks ago, I was able to make it to the dealership AND BACK on a single charge (went there to look at the Eclipse Cross). The battery pack just doesn't seem to want to take the charge. Maybe a failure of the charging circuit. I looked at my hour-by-hour energy use and where the car used to charge (at 12A) for 6 hours and then quit charging, the battery now charges for 5 hours and then sort of keeps charging but at say 4A and then at hour 6, stops charging.

The Tech at the dealership who can work on these only works 3 days a week, so, I will know on Thursday where I am at.

Re: Battery Replacement - Lessons Learned

Posted: Wed Oct 09, 2019 12:16 pm
by Dailydriver
Hello, I own Mitsubishi I-Miev 2012 16 KW.

I live in North County near San Diego. My vehicle stills shows 16-bars, but I'm noticing less distance for same charge. I have to make a decision soon as to replacing the battery or selling it now while I can still get something for it. So my question is after looking online for some time, does Mitsubishi offer battery replacement/upgrade and if they do is there one in San Diego/North County area? I'm hoping your reply will be quicker than spending time at Mitsubishi, they seem to know little about the electric cars they sell. The Auto-parkway dealer in Escondido had a charger put in for customers, but it has never worked as the charging company does not recognize it. Things like that make you wonder.

Re: Battery Replacement - Lessons Learned

Posted: Wed Oct 09, 2019 2:09 pm
by JoeS
Hi Dailydriver and welcome to the forum. I haven't checked lately, but in the past it was cost-prohibitive to have a new traction pack installed by Mitsubishi. Almost all of their installs have been under warranty for failures of one or more cells within the pack. Although you might be noticing 'range loss' by having a gradually-declining RR (Range Remaining) readout for your 'standard' trip, the degradation is gradual and you need to judge for yourself whether its tolerable for your driving needs. You can get a bluetooth OBD adapter and one of a number of i-MiEV apps (e.g., free CaniOn for Android) which will tell you what your battery pack capacity is.

My car's utility is undiminished at close to 70K miles. At half-charge I still routinely show a RR of 32 which has changed little over the life of the car even though my capacity is now at 38.2Ah compared to about 45Ah when new.