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Probably isn't needed at this point. Resetting the ECM will clear learned values like fuel trims and idle and also the readiness monitors, so it's best not done unless there is a good reason. Since you've got the USOC set there's nothing more to be gained by an ECM reset.
 

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2011 Horizon Turquoise Pearl CR-Z GT-Nav Dynamic+, Glow Pack and Electra 17" Alloys
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Just to add my own experience to this long thread - in my opinion, if you have the ability (and the time/space to allow a mains cable to run to your car safely) then I would advise you to absolutely BALANCE CHARGE YOUR IMA PACKS!

I've carried out my own balance charge using a single LED driver that broadly matches the requirements laid out by PeterPerkins - 260ma constant current at up to 130v DC, which i attached to a pair of insulated croc clip cables and housed in a little project box.

I monitored the battery voltage before, during and after charging, and using a Delphi software setup on a laptop, I was able to read the 'usable' percentage of the two cars i've carried this process out on.

'Resetting' to 75% wasn't available in Delphi, but I can reset the adaptions on the ECU with this software, not sure if this is the same thing. In the absence of a software reset, I disconnected the 12v battery for 30 seconds instead as recommended by peterperkins.

Car 1 - 2011, 92k miles, 29% usable battery capacity in diagnostic software. Symptoms: Short IMA assist, reduced assist after a few seconds, and Assist unavailable at 3 bars or lower.

Charged overnight - starting at just over 100v, stopped gaining voltage at 117.5v after 12+ hours.

Result: 75% usable capacity reported, assist is stronger and longer lasting. On board battery charge meter spends more time in the upper third than before. SUCCESS

Car 2 - 2011, 70k miles, 37% usable battery capacity in diagnostic software. No symptoms as such, but the owner wanted to see if it would help as she'd seen me do mine. (Apparently a new pack was fitted a while ago to this car)

Charged during a working day, 8am-5pm - started at 116v, stopped gaining voltage after reaching 121.7v.

Result: 75% usable capacity reported. Owner says driving home was 'like silk' and she's noticed more stop starts. Happy! I think the higher voltage at the end of charge is down to the replacement battery pack compared to mine.

In my two strip downs so far, it's a straightforward process to gain access to the battery pack, just lift out the boot floor, the polystyrene tray, and pull upwards sharply on the rear boot floor support to disengage the plastic clips holding it down (one on each side) Once you've done that, remove the screws/bolts in the IMA Pack cover (10mm, 12mm, torx screws) and don't forget the bolt located in the well where the isolation switch is.

Finally, 2x trim clips (a trim clip remover is your friend here) and you're in.

I will do a lamp based discharge/charge cycle on mine to hopefully reawaken some more material in the cells when I have access to the space to charge and don't need the car for a couple of days, but so far, i'm very happy. (My 75% usable hasn't changed, but my Assist still stops when the guage still shows 3 bars of capacity left - which then drops to zero after the assist has already stopped (voltage sag from the old cells under load maybe?) and I'd like to see if that would improve with an empty/full charge. (My Braun Electric toothbrush uses the same NiMh cells, and performs significantly better if I run it until it stops working, then charge again to full, vs popping it back on the charger every time I use it. (Memory effect?) - I think the car has the same issue?



As everyone else has said though, be mindful of the dangers of messing with DC and AC currents, and if you feel like any of this is out of your skill level, STOP and get help with it.
 

· IMA Enthusiast
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Discussion Starter · #343 ·
Just to add my own experience to this long thread.
Thanks for the feedback.

I would say you should have charged longer in each case. 24hrs really is an optimum minimum in my experience.
If one or more cells was very low then with only 12hrs they won't all reach full.

Simple charging as you know is only half the battle, a long period of slow discharging and then charging again is also needed for best long term results.

End of charge voltage is dependent on lots of factors including battery temperature.
 

· IMA Enthusiast
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Discussion Starter · #344 ·
(My 75% usable hasn't changed, but my Assist still stops when the guage still shows 3 bars of capacity left - which then drops to zero after the assist has already stopped (voltage sag from the old cells under load maybe?) and I'd like to see if that would improve with an empty/full charge.
That sounds like negative recalibrations so possibly still some imbalance left and as you say a proper charge/discharge/charge cycle should help to wake it up.
 
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