Please Help. Confused on Gen 1 Batteries: New, Rebuilt, etc?

The diagnostic manual discusses a procedure that parks the car and shifts into "N". This prevents the engine from charging the traction battery and the SOC will decrease. One can also backup against a parking barrier and shift into "R". Same idea, run the traction battery down. Once it gets low enough, 45%, shift into "P" and the engine will recharge the battery. When the engine shuts off, put it in "D", hold the brake, and floor the accelerator to put a forced charge on the battery.

What this does is swing the traction battery from low SOC, ~45% to maximum ~80%. If there are weak or out-of-balance modules, they will show up.

That is my understanding.

Bob Wilson

 

I'm going to jump in here and describe my recent experiences. Hopefully this won't muddy the conversation...

I have a 2001 that has 162,000 km (100k miles). I bought it ten months ago and have driven it 23,000 km. No codes or warnings apart from when I was trying to hack the ODBC connection a few months back, and no repairs or abnormal maintenance requirements. I like this car a lot and am comfortable investing time and money to keep it fully operational for a while.

I've been reading discussions here and elsewhere on the HV battery over the past few months. As I've described in different threads here I have experienced a couple of charging cycles, and have also successfully set up Torque Pro, which I've found gives all the metrics that have been described here and elsewhere for evaluating the HV battery performance. I keep a close eye on minimum and maximum block voltages, and the difference for me is typically 0.2 - 0.35 v. The low block varies between about five blocks, so it seems clear that I don't have a single bad block.

I recently did some testing based on this method:
http://www.artsautomotive.com/publications/7-hybrid/140-predictive-battery-failure-analysis-for-the-prius-hybrid

I would post a graph of my results, but Bob and Art make my efforts look bad In any case, there are a few findings that I want to introduce:
1) my experience is that when the SoC reaches about 45% the ICE starts automatically, and in my case it triggered a full charge, taking the SoC to > 95%
2) When I did it I basically applied full throttle in reverse with the parking brake on. Next time I'll be a little more gentle, because a) the MG2 temperature rises alarmingly, and it may overheat significantly before fully depleting the traction battery, and b) in my case the HV battery is clearly not in prime condition, and the load (>30 amps) applied caused a fairly rapid change in SoC after getting below about 50%. The sampling frequency in the ODBC/Torque was not quick enough to accurately track the voltage differences as the snapshots across the block voltages varied by a few seconds during a period of rapid change in the overall battery voltage. So if I do it again I'll try to limit the draw to maybe 10 amps to slow down the discharge cycle and limit the sampling to key metrics. In any case my interpretation of the results is that I had a spread of about 1.0 v between high and low blocks when the ICE kicked in. during the charge cycle this dropped to about 0.1v at full charge.

My experience makes me question the conventional wisdom here that a voltage difference of 0.3v triggers a code. I have lots of evidence that I've exceeded this threshold regularly (although it may be transient) and haven't had any codes or warnings.

I've also come to the conclusion that a new battery is in my car's future - my diagnosis is that my battery is tired but not critical - and have been trying to determine what the failure cycle looks like and where I am on that cycle. For now my plan is to monitor while at the same time being prepared to act when the time comes. It strikes me that there's a good argument for waiting, given the knowledge and solutions that seem to be continually developing on the NWH11 battery replacements.

Hope this give some useful perspective. I'm happy to have feedback/comments.
- Jeff

 

Hi Jeff,

The 0.3V difference is the definition of P3006 found in Volume I of the shop manual. But I too have seen transient dV greater than 0.3V during state-changes while driving. I suspect the 19 module voltage readings are a fairly 'slow scan' of the voltage readings. Speculation, there may be a long time constant involved but the manual does not tell us how long or under what specific conditions the 0.3V difference has to be to trigger the code.

Bob Wilson

 

Wow u can't beat that.

 

Where in Tennessee? Anyone within a two hour drive of Huntsville and I'll drive up with my tools, books and scanner(s).

Bob Wilson

 

Cool, I live just north of Nashville (70 miles). We have a mini POG (Prius Owner's Group).

 

I doubt it but, we could form one. I know there is one in Long Island. They even have a website.

 

"another inverter"?

I read your posts in this string and did not see any mention of the inverter being replaced previously.

What were you charged for the replacement inverter?

Glad to hear that the car apparently is working now.

 

Thanks, so it sounds like you had previously purchased an inverter and traction battery from this supplier?