[jdenenberg]

HighDesertHybrids said:

Okay, P0A80 is usually comorbid with codes for low battery block voltage. You'll probably find one or more modules that have a dead cell. This happens, usually, when a cell reverses, but why did it reverse? Temperature was ideal. The only other possibility is that one cell was at a lower SoC than the rest. The car manages the battery in blocks of two modules, or 12 cells. But, unless the battery ECU occasionally trickle charges a block to full SoC, there is no direct provision for restoring balance if one of those cells has a higher rate of self discharge.

Since the ECU never charges the battery to 100%, it is unlikely that the modules are ever rebalanced. This is the likely source of my battery failure. Maybe it would be useful to do a re-balancing every 50k miles or so as a standard maintenance procedure. Could this be done in car, perhaps separately for each half of the battery?

JeffD

[bwilson4web]

Did you have a chance to measure the individual module voltages in the old pack?

Also, it might be useful to use the ScanGauge to audit and document the current pair-voltages. There should be 28/2 ~= 14 pairs. What I would suggest is:

• practice ScanGauge traction battery recording - XGAUGEs for module-pair voltages, temperature, and current
• warm-up car - drive for 30 minutes
• descend a +500 ft. hill, slowest safe speed and braking to put a peak charge on new pack
• park car in "N" and survey the 14 pairs (SOC, traction ICE, temps too?)
• wait 5 minutes, survey 14 pairs
• wait 10 minutes, survey 14 pairs
• wait 10 minutes, survey 14 pairs

This will baseline the new pack performance, a data point, that can be replicated in the future.

Thanks,
Bob Wilson

[HighDesertHybrids]

Many owners of early Honda IMA (Insight, Civic) use an HV grid charger (200 - 350 mA) to improve fuel economy and to keep the cells balanced. IMA batteries are not nearly as robust. I don't know the effect of charging Prius battery to 100% SoC in situ but it is on my list. Reconditioning is time consuming, so I can't see it being any cheaper to do a preventative service vs. driving it until it dies.

[jdenenberg]

bwilson4web said:

Did you have a chance to measure the individual module voltages in the old pack?

I have to wait till after my courses end in mid May and get the grades in - Then I can play with the old battery.

Also, it might be useful to use the ScanGauge to audit and document the current pair-voltages. There should be 28/2 ~= 14 pairs.

Is there an xgauge the actually reports the module pair voltages with a ScanGauge? If so, I haven't seen them.

What I would suggest is:

• practice ScanGauge traction battery recording - XGAUGEs for module-pair voltages, temperature, and current
• warm-up car - drive for 30 minutes
• descend a +500 ft. hill, slowest safe speed and braking to put a peak charge on new pack
• park car in "N" and survey the 14 pairs (SOC, traction ICE, temps too?)
• wait 5 minutes, survey 14 pairs
• wait 10 minutes, survey 14 pairs
• wait 10 minutes, survey 14 pairs

This will baseline the new pack performance, a data point, that can be replicated in the future.

Thanks,
Bob Wilson

In my area a 500 ft hill is hard to find . I am on top of the second highest hill in Fairfield County at 530 ft above sea level (The highest spot is across a valley at 608 ft). The Re-InVolt battery is working fine to date. I'll report on the module voltages in the old battery when my young wife lets me play with it in a couple of weeks (I have to get a module charger/rebalancer in the meantime).

JeffD

[tpfun]

jdenenberg said:

... Under $2000 after 194,000 miles is a penny per mile (for comparison my tires also run about a penny a mile - $500 every 50k miles).

JeffD

25K miles/yr is relatively high. What kind of commute miles did you put on the Prius ?
I assume they are mostly flat highway drives which are extremely easy on the battery so the 194K lifetime is not surprising.

[jdenenberg]

Many round trips CT/IL so some mountain travels through Pennsylvania on Route 80. I actually average 28k miles per year.

I just received my Supermate DC6. Now I have to figure out how to set it up to refresh the battery modules. Yes, I remember that I should clamp the module while charging.

JeffD

[jdenenberg]

We had a issue related to the traction battery this weekend. We drove to Chicago (15 hours) for weekend family events with no issues. We then drove 2 hours Sunday morning down to Urbana IL (University of Illinois) and loaded up the Prius with "stuff" from our son's apartment.

When we started up to go home, no "ready" light and a brightly lit up dashboard ( triangle and a car with an ! on the MFD). My ScanGauge said "No Codes"! It was also difficult to shut down the Prius (you had to press "power" without touching the brake). After struggling for a while I called Steve Woodruff (at AutoBeYours.com. He answered his phone on a Sunday!) since he was only 3 hours away (in southern Indiana) and he suggested a reset via a 12v disconnect (I pulled off the neg 12v terminal for a couple of minutes). This got our Prius running and we drove to his shop (without shutting down the Prius on the way), parked the Prius and walked to a nearby (1.5 miles) motel for the evening. Steve and I met on Monday Morning at 7 am and recreated the problem (P3140 with a 350 subcode). He diagnosed it down to a loose connector in the HV battery (a Toyota dealer installed feature - They will get some constructive criticism from me next week.).

While there Steve read out the module pair voltages and resistances on the Re-InVolt HV battery. All 14 pairs were identical at 15 volts (I was surprised that the Toyota scan tool didn't read out more precisely) and 0.02 ohms. He also checked out all outstanding historical stored codes ( no critical issues) and determined that my 2004 Prius had healthy electronics at 198,000 miles.

Note that Steve did this for me for $40 (half hour of labor charge). I shudder to think what would have happened if I had AAA tow the car to the local Toyota dealer to handle this issue. Steve is one of the few independent Prius mechanics that you can trust to competently fix one of these wonderful cars at a reasonable price. I was lucky to have this issue when I could rationally get my Prius to him rather than relying on an unknown dealer technician.

JeffD