PA080 Replace Hybrid Battery Pack on a 75k mile 2012 Prius

Hi guys,

This is my first post on PriusChat.

I need your expert advice to make up my mind;
- replace defective cells, or
- buy a used complete battery pack.
Please note that buying a brand new battery pack is out of the question, at least for now

Sometime in August (2018), my 2012 Prius threw a P0A80 code. Upon scanning, it showed "Replace Hybrid Battery Pack." I was pretty surprised since I didn't receive any prior warning or DTCs for the HV battery pack. So my first question is,
- Is there a gradual step by step process of HV battery failure, and if so, is the Prius capable of detecting this gradual failure/deterioration?

The reason I'm asking this is that I've seen many posts here where fellow Prius owners have got DTCs like "Battery Block 8 becomes weak". I never got any of those.

Anyhow, I cleared the code and the car ran fine for about a week or so before throwing the same DTC again. Cleared it again and now the frequency of DTC detection seems to increase, from 2 weeks, to 1 week to 5 days and right now, it's at multiple times a day! When I don't have access to an OBD2 scanner, I simply disconnect the 12V battery to clear the code.

I purchased the Toyota Techstream MVCI package off of eBay (the counterfeit version, of course! ) and hooked it up today. The battery voltages (in pairs) seem to be range from 14 to 17.5 while the ignition is on (both at idle and normal cruising). Last month, I removed the HV battery and tested each module for voltage and 26 of them were above 7 volts (7.2 to 7.7). two of them (I believe one in block 6 and another in block 8) were at 6.8 ish). However, when the ICE charges the HV battery, these two modules (their respective blocks - 06 and 08) are the first to reach 17+ voltages.

I can't for the life of me figure out what's wrong with my battery. Is it completely beyond saving? or would replacing the faulty modules help me survive for at least 06 months?

I have the Freeze Frame Data from the P0A80 DTC extracted from Techstream, but am unable to attach it since this is my first post. I could PM it if anyone of you guys would care to have a look. Your expert input would be highly appreciated guys. I'm usually DIY kinda guy and would like to take on this project, if it's worth it.

One last question... is there anyway to do a load test on the HV battery via TechStream? I know Dr. Prius app has that function, but I don't have the bluetooth OBD2 scanner anymore (long story short, the dog's to blame! )

I know it's a long post and I'm asking a lot since this is my first post and I'm yet to contribute to the community, but I'm pretty lost right now and your assistance would be extremely helpful!!!

Thanks!

 

I've made the Freeze Frame Data into a PDF and attached here. Battery Block 08 is at 13.03V. Could that be the culprit?

 

Thanks! I’ve read that you need to purchase a NiMH battery charger and discharger to condition the battery and go throught at least 3 complete charge/discharge cycles. Do you have any idea on how much this would cost me? (The charger).

Also, I did replace the two faulty modules. Prior to replacing, Dr. Prius app showed a Delta SOC at 37% and in red color. A tech guy informed me that ideally, this value should be at 0%. Is that true? After replacing the modules, I got a 41.5% Delta SOC, which went down to 41% after driving in POWER mode for around 15 minutes. I was asked by the same technician to keep driving in POWER mode for around 500 KM and then test the Delta SOC value again. According to him, if the value had decreased, then the battery is good. If it had increased, a re-conditioning would be required.

Any insight into this Delta SOC figure would be greatly helpful (i.e. what it is, how to get it to ideal value, etc.)

Oh, and I had the same technician rebuild and balance my battery pack and now all modules are at above 15V at the all times, tested with TechStream live data (i.e. the lowest each module would reach is just above 15V before the ICE kicks in to charge them to around 16.95V and then shut off. The charging time is pretty fast as well. It takes around 45 seconds for the ICE to increase the battery bars from 2 to 3 on the HSI before shutting off).

Thanks again!

 

Thanks!

Sadly the warranty here is 50000KM or 01 year, whichever comes first. I KNOW, right? The least Toyota Lanka could do is offer at least 150K KM on a new battery.

 

Thanks bisco!

 

Thanks ARSDogman! I will give the prolong a try. So just to make sure, there's no "magic" to charging/discharging and balancing a battery pack, right? Anybody can do it?

 

Does anybody know how to measure the Delta SOC via Toyota TechStream? I tried combing through the "Hybrid Data Live" section while the car is in Ready mode and couldn't find a "Delta SOC" reading.

The readings that I do get include;

• State of Charge (All Bat)
• State of Charge (Max)
• State of Charge (Min)

Is there anyway to manually calculate the Delta SOC using Min and Max SOC readings?

Also, on a side note, the Freeze Frame Date from my P0A80 DTC shows a Delta SOC reading, but not the live Hybrid Data feed. Strange...

 

Thanks ASRDogman! You’ve been very helpful. Do keep me posted on the results of your battery conditioning process.

 

I didn't get a chance to try it out yet. However, one more module failed and was replaced under warranty (I gave it to a professional who does reconditioning. He offered a 01 year warranty and unlimited kilometers, which is pretty cool). I've been driving in POWER mode ever since. Not much difference in fuel economy, and it's fun to drive.

I didn't get any DTCs yet, however, I believe that's largely due to constantly driving in POWER mode (clocked around 5000 kilometers so far).

Since I'm pretty busy with work, I don't have time to test the battery at the moment. Once I do get some time, I'll try driving the car in NORMAL mode to see if the DTC pops up again.

Any update on your end? Did you try re-conditioning your battery?

 

Yeah.. but the guy who conditioned the battery did the same thing... He hooked up the entire battery to the charger/discharger (it wasn't a ProLong), and did ONE cycle of drain/charge, and balancing. It took around 6 hours or so for him to finish.

I'm getting the same vibe. I'm feeling that the only permanent solution is to replace the battery or entire 28 modules with NEW or FAIRLY NEW (post 2015) battery pack/modules.

Conditioning would only take it so far, it's sort of like a band aid. Replace a faulty module with a better one, and the rest of the pack falls out of balance. Then, the weakest module in the pack would go out pretty soon. I was afraid of this, but hey! I've got a warranty now! Let the guy do his thing. Keep replacing modules. Once the warranty runs out, which is in another 11 months, I'd get a new battery.

I could replace the entire 28 modules, but it's nothing like a new battery, is it?

 

You're correct. Time is the issue. It takes an entire day out of my calendar to go one cycle (travelling to and from, disassembly and reassembly included). I believe 04 modules have been replaced so far.

However, as you mentioned, the warranty is golden here.

The issue with running three cycles is that I have to leave the vehicle at his yard for at least 02 days. Safety of the vehicle is not an issue since I can lock it and leave, plus it's a reputed company. But travelling to and fro without the vehicle is the issue..

Anyways, you make a valid point, better get it right once, rather than repeating multiple partial cycles.

I'll have a discussion with the guy and see what he thinks.

Cheers mate!