Hi Keith,

Attached is the Hybrid Assistant report based on the test they specified at: http://hybridassistant.blogspot.com/...ery-check.html

Would be grateful for your comments.

Thanks in advance.

 

PDF page 13 shows the 17 block voltages. There's an outlier and likely has a failed cell. Each horizonal line is 0.8V difference, so the spread doesn't look as bad as the techstream report suggests.

Each vertical mark is 13 seconds, so the discharge ran from 15:01:57 to 15:05:21 + 39 seconds or 243 seconds or 243/3600 hours. The report on PDF page 17 shows 659mAh consumed. This comes out an average current of 9.76A (let's say 10A) - well under the high 20s (let's say 30A) of the Techstream report. The techstream report is also a snapshot at lower State of charge. The higher current and lower SoC amplify the deviation; however, a healthy battery will show fairly tights voltage deviations even at these levels.

The response above 40% SoC makes me lean toward the likelihood that it's more capacity loss from voltage depression vs. permanent damage; however, the SoC curve (yellow shaded region, p13) does not show the characteristic drop-off. there is a kick down shortly after 15:05:21, but that may be more due to the weak block than anything else. OR, the capacity loss is permanent, but it's not as severe as I've seen, i.e., instead of many blocks in the low 1-2Ah range, it's in the 3-4Ah range, which is still usable.

Page 15 shows the high/low/avg block voltage and the total deviation (shaded grey). The first part of the discharge looks pretty close at 0.2V based on the 0.8V scale, but it quickly hits 0.4V and continues to climb. The charge phase also shows about 0.4V the whole range - at 20A charge.

Lastly, PDF page 17 shows an estimated capacity of 3.11Ah. that's an extrapolation of the 659mAh used over the 22.4% SoC range of the test.

It will be very interesting to see these results AFTER the reconditioning.

 

Many thanks for the analysis, Keith. I should be receiving the Prolong kit next week. Will post the reconditioning results. Thanks again.

 

Hi Keith,

Just received the Prolong kit this afternoon. I see the instructions in the below call for using "8 ft lb" torque for the end terminals of the HV battery. There are several general posts on PriusChat that specify HV battery terminal torque to be "48 in lb" which I figure is "4 ft lb". I am wondering which would you recommend I follow.

Thanks in advance.

 

WAIT... I forgot you have a Camry... let me look that up. Bigger nuts... but only on the relay terminals. 80 in-lb if you end up disconnecting the frame wires from the main relay.

The grid charger attach points should be 48 in-lb.

 

FWIW, I've spoken to the owner. He is going to correct their instructions ASAP.

 

Thanks for the corrections and for alerting the owner, Keith. I see Jeff has updated the website. I actually learned about it from a thread I am interacting with at Priuschat; somehow I didn't get emails on your posts to this thread, like I normally do.

I had to return the charger I got last week because of the fan on the charger not working. I received the replacement charger this afternoon and started the charging step. I am thinking about seeing how the battery behaves for a few days right after the initial balancing. Do you see any downsides to it? I am planning to run a load test after using the car for a few days and then proceed to reconditioning, unless you suggest otherwise. Thanks again.

 

He went through all the instructions and confirmed they were correct.

We are confident in one of two things:

1) your battery has lost capacity due to cycle/heat damage, and it won't recover.
2) your battery has substantial capacity loss due to voltage depression, and it may recover.

Either way, I recommend strongly that you conduct a discharge to no higher than 185V after balance charging. Note that you can accelerate this by doing the in-car Hybrid Assistant discharge test in "N" and consume 80% of the battery's usable capacity to help you expedite the discharge process. Would help to record it as well...

Here's how you make this go faster:
1) force charge in-car (somewhere north of 70% SoC)
2) grid charge for 12 hours
3) discharge test in-car in "N" to about 20% SoC (note estimated capacity)
4) bulb discharge per prolong schedule
5) grid charge for 4 hours.
6) start and allow car to idle-charge the battery until the ICE shuts off.
7) Repeat 1-6 for each cycle
8) Repeat 1 & 2
9) Repeat 3 to 60% SoC
10) drive for a few days and assess performance
11) Conduct Hybrid Assistant discharge test.

 

Thanks, Keith. I guess I would put the gear in "N" right after I hit the power button? Or should I wait to hear the beep that usually occurs 3 or 4 seconds after I hit the power button, before I place the gear in "N"? As I understand, the beep signifies connection of the HV battery to the system by the relays. Do I understand correctly, once the car is in "N" the initial run of the engine won't charge the HV battery? Thanks.

 

Place it in "N" as soon as the car will let you. Best if you can prevent the ICE from starting at all.