Battery pack change plans

[MickeyS70]

Charge put on granny charge last night and got over 50 miles showing on the range - first time it has done that for years.

Every time you fully AC charge the car from a low SoC (<3.85V/cell) the BMU re-calculates the battery capacity. It compares this new value with the stored one and if there is a difference makes adjustments but very, very slowly.

Somebody did an experiment and iirc the capacity will go up/down about 2Ah per month.

So keep at it but if you need fast results swap back the red CMU09 and use HobDrive to do this in one go…

 

[jray3]

I’m swapping a couple of packs this long weekend, and am thinking to try something new, as the incoming pack was a recent warranty replacement, courtesy of Donny’s bad luck. The idea is to also move the BMU over from the donor car to avoid any recalibration issues via this “brain transplant”. Anyone tried that?

 

[MickeyS70]

I’m swapping a couple of packs this long weekend, and am thinking to try something new, as the incoming pack was a recent warranty replacement, courtesy of Donny’s bad luck. The idea is to also move the BMU over from the donor car to avoid any recalibration issues. Anyone tried that?

Yes, a chap recently put a 80 cell Ion pack into an IMiev, wouldn’t work correctly until he also changed the BMU.
Can’t find the thread presently, but iirc some mod needed to be done to get the battery cooling fan running, as the cars where of different build year.

 

[jray3]

Thx @MickeyS70. Next variable is those pesky plastic-head bolts securing the splash tray at some points. I haven’t figured the reason for their precise placement, and they rarely survive removal and reinstallation (if the 10mm socket rounds off the plastic bolt head, a 10mm nut extractor sometimes works, and if the plastic twists off and leaves the round wavy head behind, an 8mm nut extractor has yet to fail me).

Soo, am considering all steel bolts for reinstalling the splash tray, perhaps with Nylon washers though since the mesh grid on 2012 models and the grounding straps on 2014 models are grounded to the battery case at multiple points, what’s the worry?

Lastly, the warranty replacement pack has heavy steel covers over the cable lugs and fuses rather than aluminum as original. I’ve seen no galvanic corrosion issues on the originals so plan to save some weight and reuse aluminum plates (same size, mounting holes and gasket pattern).

 

[jray3]

Well, the swap from @DonW ‘s wreck went flawlessly, and since I also swapped over the BMU this time, MR BEAN awoke with 47.5 Ah capacity and 71 miles RR from an incomplete charge! This is pack #4 that has resided in MR BEAN’s belly due to his quest for eternal youth. The prEVious packs didn’t die, they just declined to serve in the matter to which he had been accustomed….

To answer my own silly question about the plastic-headed bolts: their shafts are shorter so as to not bottom out against or penetrate pack internals! A hand wrench on the standard steel bolts confirmed that resistance, but a fast impact driver stands the best chance of removing a plastic-headed bolt intact. In hindsight, some penetrating oil the day before might have saved a few from beheading!

Another bit of learning is that unlike a LEAF, the auxiliary HVDC connectors at the front of the pack do not include high voltage interlock pins, so no errors are shown if you forget to plug ‘em in! I didn’t take the test further by turning on the heating or aircon, but it could be interesting to re-task those outputs, such as for a 5 kw power export inverter without hacking CHAdeMO.

Next, the hand-me-down pack from MR BEAN will go into the BAJA MiEV, which has a sick cell that rests 0.07 V below the rest and causes a max charge of 11 bars and turtles popping up below 50%SOC. This pack from MR BEAN came from a crashed 2014 and left all of its improved capacity hidden in reserve, as the 2012 BMS nEVer re-learned the capacity. We’ll see about transplanting the BMU from storage to wake up that 2014 pack for adventures in off-roading, as the BMU brain transplant that rEVived MR BEAN has left him feeling so much better so much faster! Cheers, Jay

 

[MickeyS70]

This pack from MR BEAN came from a crashed 2014 and left all of its improved capacity hidden in reserve, as the 2012 BMS nEVer re-learned the capacity.

Interesting, could it be that the 2012 BMS was programmed for LEV50 while the 2014 pack cells are LEV50N?

 

[alviseven]

Feel much happier with the car now after several weeks continuous use to work and back. I still get very occasional ECU faults but they are getting fewer and farther apart i think. Yesterday I managed to get a much longer run covered 42 miles and still had 8 miles on the guess o meter at the end of the run - car had just got to flash two bars but was going fine. I was also amazed to find that the car charged straight away on the granny charger and charged non stop to full without dropping out and had a 55 reading this morning and the charge does seem to have all gone into the car as well as its been very good again today. Previously the CMU09 fault would raise its head when this low down the charge meter and I have to restart the charge several times or even go and chademo it to get it to half way then it would charge fine. I think the battery is enjoying regular use again and the voltages are more stable not is has several cycles and use.
Had consistent good days past couple of weeks with the battery only using about 2 bars to cover 10 miles in the morning to work which it never used to do and the guess o meter matches the miles travelled always nearly adds up to the original suggestion which is unheard of for my car - yesterday 53 at start and covered 42 miles with 8 miles estimated when stopped so 50 miles compared to 53.

Used to be suggesting about 46 before and covering sometime less than 25 but even when first bought at 70K miles would register about 52 and only cover about 43 to flat or needing charge.

Is it too early to start feeling smug?

 

[MickeyS70]

Is it too early to start feeling smug?

Looking good, if you feel lucky, you could give the battery calibration function in HobDrive another go

 

[alviseven]

Now passed over 1400 miles since the battery change and regularly getting 40 plus out of the new batteries but the CMU09 is becoming increasing problematic and throwing issues which is stopping the slow charge and have to pop up to the chademo- Rather worried today since it refused to chademo too so makes me think the CMU09 may have failed permanently - might be time to replace it with the red one I have as I know this will work for now. Have placed a wanted Ad but the green CMU 09 board I think would solve all the issues...

 

[MickeyS70]

it refused to chademo too so makes me think the CMU09 may have failed permanently

Car won’t drive, if a CMU has failed completely

might be time to replace it with the red one I have as I know this will work for now.

Good idea

Have placed a wanted Ad but the green CMU 09 board I think would solve all the issues..

If you can’t get a CMU09, you might consider sourcing any 8-cell CMU and change the ID with proven methods (clone ID information, swap ID chip or use MUT3 to re-number CMUs)