Coastal areas can have some crazy buss bar corrosion. AZ dry weather yields amazingly clean bus bars - just a small ring of corrosion around the perimeter of the (-) terminal contact area. One could easily just scuff them up and re-install - without even removing the bus bars from the harnesses/straps.

If you want easy-mode, you can just buy some nickel plated bus bars off ebay.

If you insist on DIY, soak them in white vinegar for as long as needed to dissolve the patina (1 hour +). Rinse thoroughly. Use steel bristle brush to scuff module terminal side of bus bar only. The nut side doesn't matter.

If you want to expedite, use muriatic acid. Typical swimming pool additive muriatic acid is about 30% concentration and costs about $8-10/gallon. You can cut the concentration in half (equal parts acid and water), and it only takes about 30-60 seconds in the muriatic acid to completely dissolve the patina.

 

I just stitched the data in each table together along a continuous timeline (added time of previous group(s) to current group to make it continuous). Charted SoC, current and 17 block voltages.

Note that for quick charting purposes, the min and max can be charted if you're just looking for total deltaV... or you can subtract min from max and just plot the difference. I stuck with all 17 because I was looking to see if they were moving mostly as a group (they were) or if there's an outlier.

 

So basically my battery seem to be fine (considering the age), so cleaning terminals should do the trick, at least for now and I don't need to buy any modules yet, am I correct?
I could probably gain some capacity by using prolong conditioner, which I may try now, or maybe wait for cooler weather (we got over 90F for next few days, more inside unconditioned garage, not the best time to do full charge/discharge cycles, I think).
I probably take it apart and see how bad things are. I think I saw advertisement for nickel plated bus bars and voltage sensor harness, if they're reasonably priced and I can find them again, I order them.
Too bad you're so far away.
Thank you.

 

(1) No, it is significantly deteriorated and is at risk for cell failure in the lagging blocks.
(2) likely, if they are the source of the code.
(3) likely correct
(4) 70% likely per my previous speculation
(5) Daily highs don't mean much, but 90 is about the upper limit of when you want to do charging. If you timed your 24 hour charges to terminate first thing in the morning when it's coolest, that would likely be fine. Discharging temperature doesn't matter.
(6) not sure if I've ever seen a Camry harness, but they're probably out there. Not sure if it's worth purchasing, but the bus bars are probably worth it if reasonably priced.

 

Just to give quick update, I took hybrid battery out, cleaned bus bars and voltage sensor terminals, broke 2 of them in the process (they are very flimsy, toothpick would be much harder to break than those), so had to solder them. I wish I could purchase whole new voltage sensing harness (if anybody knows the source, let me know), but all I could find so far are used ones, probably not much better than what I have now. After putting battery back inside the car and driving 100 miles, so far all is good, but will see if anything shows up later. it was very intermittent to begin with (about once a week), so not sure if problem was fixed or not. Now, going forward I'm debating, if I should get prolong system and try recondition the battery myself, get Greenbean battery ($1900 installed with 5yr/ unlimited mileage warranty) or should I try to get new battery from the dealer and be done with it. BTW all that fear about expensive battery replacement propagated by many, when talking about hybrid cars, little bit exaggerated, even dealer price is not much more than auto transmission repair etc.and with over 200k miles on my car I would be on second or third transmission by now if I had non hybrid car.

 

Glad to hear the car is working well.

Back to the original question about coasting - I can't imagine how coasting in neutral could be bad for the car other than losing some potential energy.

 

Well, I calculated the chances of this error showing up randomly withing 5 sec of me putting the car into neutral at more than 100000 to one 1, lol, maybe I should play lottery? I read somewhere a while ago about back EMF, but I do not remember the details, but keep thinking this may have been the reason, something similar to towing the car in neutral which supposed to be bad and can damage hybrid system, anyway car runs good and still no new errors yet. Am I reading correctly your car has 400k on it? That is amazing, in comparison my car is barely broken in, lol.I know in the past Toyota gave new Prius in exchange for some high mileage taxi car, for research purposes. Maybe you should call Toyota and let them know, they could probably use it for advertising or something.

 

Another update (BTW I wish people would update status on issues they had, more often, for future references and as help to others):
I went to dealer and ordered new voltage sensing harness for $88 (I've seen listings for used one on ebay for $150 BTW!!!), also ordered Prolong charger/light bulb discharger and installed it all few days ago.
Did not have much time to play around with it yet, due to holiday weekend and associated engagements, but few things already came up:
1. The instructions are not very clear (at least to me) as to when to terminate the charge. I terminated the charge after voltage came up to over 292v and then dropped to 289v first time around. However second time around the voltage never went up above 286v, it was going up until it hit 286 and stay there for hours, so I terminated the charge anyway, but not sure if I should keep it going or not.
2. whoever came up with the connector used by the charger, probably never used it, it takes me few minutes to align it properly inside dark trunk and the thing is spinning on it's own, very frustrating, will need to put some marks on it, or maybe rewire with better connector.
3. On/Off switch on the charger worked first couple times, but now no longer works. Thankfully got stuck in the on position, so I can live with it.
4. Got really confusing result I can't figure out: Charge the battery with charger to full (290v), but then didn't have time to discharge it. So left the car sitting for few hours, came back and started it, the battery was showing only 3 blue lines, so I hooked up meter and was showing 270V and about 50% SOC, so what happened to 290v and full charge? Normally when I park my car with full green bars at night, I get full green bars on the start up next morning, but when using the charger it seems the battery was never fully charged, even when it showed it was, what am I missing? I will be testing this much more, when I get more time, but wasn't expecting this. BTW car runs fine and I did some rough calculations on the discharge data, it seems my battery still holds about 3.5A (factory listing is 6.5A), I hope to increase it after more conditioning cycles.

 

Sensing harness P/N?

#1:

• https://hybridautomotive.com/pages/pc
• https://hybridautomotive.com/pages/pc#peak
• It's slightly general because there are no hard rules as each battery is different, and folks are using the equipment in different environments, but there's more than enough to go on if you read it and understand. If you want 3 lines of instructions, you're outta luck.
• One thing they don't mention is that you can always calculate the input. 10 hours at 350mA = 3500mAh input. If you've emptied a battery and only input 3500mAh, then you probably need to charge longer.
• 24 hours is generally a "safe" and effective charge period if you want to pick something arbitrary.

#2 & #3: Connector has been used for the better part of 6-7 years. It works very well. I use one nearly daily. You often need to tighten the housing on a new harness as the plastic relaxes a little after the initial tightening. I would immediately contact HA and inform them of the power switch issue.

#4:

• Ever charged a 12V battery? You typically charge it to 14.4-14.8V, and it quickly falls off. After 24 hours of sitting, they're around 12.6-12.8V fully charged. Same concept with any battery.
• With current flow, there is an increase in voltage in line with the internal resistance of the pack. Once the charge is removed, the voltage drops.
• Once you started the car, you hit the battery with a 30-50A load, so you pulled the voltage down rapidly.
• You can't correlate the car indicated SoC with anything. The SoC computation is very sluggish, and it gets particularly worthless when the battery is outside the normal 40-80% operating range.
• What you describe is completely consistent with expectations.
• How did you calculate capacity?

 

" How did you calculate capacity? "
Little over 7 hours of discharge time at .5 A. Actual measured amperage was between 0.611 and 0.526 A, but I'm not sure how accurate my amp meter is with DC and I had no time to calibrate it, so rounded down to 0.5 A. I also don't remember what's the cutoff voltage should be for NIMH discharge capacity, my cutoff was at 0.8 V per cell. This is more for my future comparisons than anything else. I couldn't find any 100W bulbs around the house, so used 65w or 75W, can't read the number and also not sure how the wattage is affected by DC, instead of AC, heat etc so used meter readings every half an hour or so and it was pretty consistent 0.6 -0.5, I guess lower voltage = less heat so lower resistance = rather flat amperage. When I get more time I'll calibrate my meter on some exact voltage/ resistor load and make it very accurate, but I'm pretty sure it was in a ballpark of 3.5 A first time I tested.

the 350 mA steady input is only present at higher voltage, somewhere between 244 and 260v, bellow that my charger was showing pulsing charge between 0 and 0.6 A. I kept it on the charger for more than 10 hours and mostly charging from 40%-50% SOC. I only managed one full charge/full discharge cycle.