Make sure his/her equipment doesn't further contaminate after cleaning. The HCH2 uses proprietary compressor oil. If you use equipment with PAG oil residue (every semi-modern non-hybrid A/C uses this), he/she will contaminate the system upon refill.

 

What do they have to do to make sure there is no residue?

The battery was at 186V before I went to bed, and this morning at 11 hours is at 190V. Everything from here on out is just balancing the sticks, correct? I am tempted to pause charging to put the pack in the car to see if I still have the same codes or if any new ones pop up.

 

Step 1 is to insure that they don't introduce new contaminants from contaminated equipment.

11h * 350 = 3850mAh. Capacity is 5500 and efficiency is progressively lower as SoC increases.

 

I've been sitting here watching it all day. I saw it go up slowly to 190.5V, then drop slowly to 189.7/.8. It stayed between those two readings for several hours and then started to slowly go up again to 190.9V. I then witnessed the first rapid drop to 189V, and then I think I even saw it go to 188V. The temp remained stable at 84° from the probe, however I realized that the sun had lowered and was shining on one corner of the pack for a few minutes. Nothing felt hot, but I lowered the garage door to make sure the pack wasn't in the light, and within minutes it was up to 191V. It's currently going between 191.2/.3V.

Is the pack done technically done balancing when the voltage no longer adjusts at all? It only has 2 hours left to hit 25 hours. Would it be good/bad/safe to let it go longer?

 

Well, just in case it might be harmful in any way, I did unplug the charger. The pack was between 192.0/.1V. I will let it sit for at least half an hour before I try to put it in the car and see what happens.

 

Assuming you hit 25 hours. How did the install go?

 

I decided to wait until this morning. HV battery voltage was over 183V after sitting all night. The car still starts with the conventional starter, and CEL, IMA, and flashing D all remain. The p code is gone, but both U codes remain. Scan tool live data shows ECU volts going up to 14V when the car is revved over 1500 rpms, but 12V battery light never goes off.

Stick voltages on the scan tool are 16.7 or 16.8, except #8, which is 16.6.

I guess it's time to order an MCM. Does it seem at all odd that both my BCM and MCM would be bad? I am operating on the assumption that there was a problem with my BCM since the car didn't seem to recognize the low HV battery until swapping it.

 

0.2V variation on a freshly grid charged pack is not a good sign. I rarely see more than .05V on known good subpacks. Given the terrible 0.1V precision, a 0.1V variation after a grid charge is common. Due to rounding it could be as little as 16.64 to 16.76, which isn't so horrible. However, with #8 being the outlier, it's the one to watch.

Surprised to see the "U" codes back.

I indicated surprise at the BCM solving the "U" codes. I'm in uncharted waters.

 

I'm wondering if my battery was really done charging/balancing at 25 hours because I was still seeing the meter fluctuating. Given the deep discharge state after over 2 years, might it take a little longer than 25 hours? I ordered my mcm so that could potentially take a week to get here. What do you think about me doing some discharge and charge cycles during that time?

I've also been wondering about when I got to step #19 in the diagnostic process, where the voltage needs to be tested within 1 second of turning the key to the ON position at pin 18 in the MCM 20p connector. The test is already fairly difficult, but I can't help but wonder if my auto ranging meter made this more difficult, or obscured my results, especially with me being new at this. This step says if there is 12V, the next step is to replace the MCM. Given the appearance of circuit board where the terminal is soldered in, I really can't help but wonder if that has actually been the problem all along and I just couldn't get an accurate reading at that step. I think I'm going to try it again today with the cheap meter to see if I get a different measurement.

 

25 hours puts in 160% of the battery's capacity and is usually enough to top everything off.

If you have the time on your hands, additional charges and discharges won't hurt - just don't overdo it.

Discharge to 132V
Charge for 25hr (longer is fine if you want. Would never exceed 48 hours).
Discharge to 106V
Charge for 25hr
Discharge to 79V

Always use two same-watt bulbs in series. Above 145V, use as high a wattage as you like. Below 145V, make sure the bulbs are 60W or less. Bulbs need to be incandescent or halogen.

Series means: Battery (+) ---------------- bulb 1 --------------------- bulb 2 ---------------- battery (-), i.e. if either bulb is removed or blows, current stops. If you remove one bulb and current still passes through the other bulbs, you have them wired in parallel, and you don't want this.