Quick and dirty rebalance...

Still haven't started rebalance, waiting for some parts to arrive to connect to the meanwell power supply...

Spent yesterday using a orbital and meguires ultimate cutting compound cleaning off all the nasty paint oxidization, should have taken a before/after photo, it literally looked like someone had plastidip'd the thing matte white. There was also algae and moss growing in every crack and crevice so that was fun cleaning. Going to polish and apply ceramic sealant so I won't have to mess with it for another year, besides the front left fender and bumper will need replacing anyway with an eventual junkyard find.

Also did a top end cleaning on the motor with CRC GDI intake valve cleaner...I have to do it for the wife's 1.6L turbo gdi engine in her hyundai every 10k miles, so I have a 6 pack of them and figured why not? Wow. After letting the stuff heat soak for 45min I took it on some full throttle runs to 60mph and it made quite the smoke show for a few minutes. Engine idle is now buttery smooth, and feels like I gained a bit more power again based on the pedal angle I'm holding around 35-40mph. Worth doing imo based on the results if the top end has never been cleaned.

They had a fleet of 70, and apparently over the course of a weekend someone broke into their yard and stole ALL the cats...given that they have policy to replace with OEM parts only, administration decided it wasn't worth spending 2-3k per car on something 15-17yrs old so they auctioned them.

 

Here's some pictures of the outside post detail, you can see the fender that will need replacing eventually, some pretty decent chunks out of the paint on the driver's side front door as well.

Something I didn't notice previously is it looks like there's a crack in the lower hatch glass, tiny chip with a crack about 4" in length...not sure what to do about it, have read about that glass exploding on people with even the slightest damage, or sometimes no damage at all! Suggestions if anyone has them would be appreciated...

 

The reason I wanted to open the pack was because of the measured internal resistance being out of spec, the fact that there was algae and moss growing on the car including inside the windows leads me to believe that there has been adequate condensation due to the lack of use that could definitely have caused corrosion on the copper. If I discovered corrosion on the bus bars, the plan was going to be spending $60 on a new bus bar wire loom combo, and $40 on nickel plated bus bars to replace out on everything.

I'm not an electrical engineer, but I do have a quality voltmeter and a soldering gun. One of my hobbies is building ebikes, and while I don't build battery packs myself for them I have had to do repairs in the past like replacing cells a bad BMS. I do realize though that I am working with 240v not 52, so safety is the highest priority.

The meanwell power supply is the 257v 350ma.. The plan will be to set up a permanent cable using ring terminals, an inline fuse, and a female xt60 (with rubber end cap) to the battery terminal side that I can keep in the car, and then trickle charge once a month to keep the cells balanced monitoring with the voltmeter. If I do this right I should only have to pull the pack once, at least that's how it works in my head.

I appreciate the suggestion, I might get that a try with some permatex...I'm worried about this one though. Normally any rock chip repair I've done before is with a circular type chip that hasn't spidered out more than an inch diameter. The chip in this seems to be aligned with the crack itself, and I'm not sure if the resin will completely fill or not. Only one way to find out I guess! I will start getting quotes now just in case as the odds of it getting worse are high now that winter is upon us and it will likely be stressed from freezing temperatures and defrost

 

I appreciate the advice, and based on the suggestions by folks with what seems like a lot of experience I will take my time researching a bit more to prepare before I dive in. Part of the impetus to remove the pack is preventative maintenance to keep maximum conductivity hopefully for the next 30-50k miles, the other part is my sheer curiosity...I'm that kid that had fun at 6yrs old taking a telephone apart and putting it back together again much to my parent's dismay lol. I fully understand that if I short something it would cause a lot more trouble than the intent.

Regarding the rebalance, for now I was just planning on topping off the pack to leak voltage to the slightly weaker cells, not going through multiple discharge cycles to wipe any memory. After more testing, the largest voltage variance regardless of idle or driving condition is 0.25v between the strongest (#1) and weakest (#7) block. Dr. Prius app shows poor balance in blocks 7, 8, 11, 12 in its battery test most consistently, though if you run it multiple times it will show different blocks occasionally (5, 6, 13, 14) so im skeptical of the accuracy/validity of it's test.

Also let me say, I'm excited to join this community! There appears to be a host of active, like-minded, technically inclined folks willing to provide input. I'll do my best to filter the bonehead questions out of posts with the search function.

 

The idea for me is to get as close to factory new spec as possible so a. It is as efficient as Toyota engineered it and b. The engine, cooling system, BMS have less work to do for longevity's sake...an ounce of prevention worth a pound of cure and all that.

The meanwell power supply, tune up parts, cat, pack sensor loom, etc by the end of this means roughly a $500 investment on a vehicle I purchased at a significant discount via auction...I can very likely drive this thing for 10ys and STILL sell it for more than I paid for it which is a pretty amazing feat...but thats only likely to happen if I apply the utmost care from day one of ownership. Reliable, overbuilt used cars tend to have a market forever in my experience