Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

I got my 08 HyHoe about 3 years ago and I have never been able to go over 10MPH on battery mode unless I am going down hill and every couple of months I have issues with taking off from a standstill as the rpm's increase, but I don't move. I notice this happens most often when I am going slow, but then stop suddenly and then take off again...much like you move up to a stop sign from being the #2 car...move up, stop, go. Since I bought it my Hwy mileage has been about 20 HWY and City is about 18.

A couple of times, infrequently, it completely stalls out and I have to restart it. During these events, it throws the POAC4 and PO61B. I have cleaned the HV Bat screen of any obstruction (which there was some).

I have recorded my driving since yesterday and attaching in hopes someone with more knowledge can tell me if the battery is about to go.

The log starts out at night (air con going and lights one) and I believe rows 246-279 are where I got about a 1/2 miles of driving on only the HV Bat (about 10MPH) before the I hit an incline and the gas engine kicked in. About a mile later, around 285-310, I pulled into a school parking lot that had a slight decline. This is when the HV Bat had some cells down in the 11 range, but stayed in AutoStop.

The Next Day
Rows in 560-range is while I was in the drive-thru and I actually had the high rpm, but the no go occurred.



Any comments are appreciated!!

Re: Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

Your taps don't look good, but it may be a symptom of the sampling rate. I'm seeing points every 5 seconds, which is a useless rate for diagnostic purposes. Can you increase the sampling rate to something closer to 1-2 times per second?

When you look at the values around line 800 (43:58 to 46:18) where your current is a pretty consistent ~10A with the engine off (A/C?), your voltage taps are all over the place with deviations up to 2V.

Line 572 where the current is a constant -0.05 for about 7 minutes with your aux voltage at 11.3V, your deviation is 0.8V, which is terribad, and there is a range of values from 14.5 to 15.3 without any obvious outliers. I would not attribute this to sampling since all block voltage readings do not change.

If this were a Toyota, you would have coded long ago due to diminished battery capacity.

If the battery data are accurate, IMHO, your hybrid battery is total junk.

Re: Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

As poorly and as many posts as I've made, I have not been able to articulate it as well as dawgfan1606, but this is EXACTLY my problem.

Re: Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

Again, if the above pack data is an accurate representation of the actual battery block voltage levels, that pack is junk.


If your block voltage levels look like that, then your pack is junk regardless of what the 'hybrid expert' said.


personally, I would ask him for all of the data he collected during his testing. If he didn't/won't provide it to you, he didn't do the testing he claimed.

Re: Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

He's got it. He's supposed to be coming on here to share...

Re: Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

Hmmm. That seems odd. Why wouldn't he just give you the data?

Re: Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

I have no idea. I never asked for it.

Re: Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

Keith - I really appreciate you looking at my data and your insight!!

Ok - I have more data for at least every second during a 5 mile trip. It includes driving about 45 mph on cruise, a brief stop light and ends with me going into Auto Stop as I entered my neighborhood. I agree that things aren't looking good.

My next question, are all of the cells going bad? Does it make sense to get 40 cells of Prius Gen 2 and rebuild it myself (I am able to do this kind of work)? Are some of the cells still good? I understand this battery is going on 10 years old and my novice look at the data shows the battery wearing out pretty evenly across all of the cells.

In you experience, will this gradually continue to decay or will one day a cell just die and I'll have a sudden issue? I'm trying to determine an immediate need or if I can push the expense out about 6 months. Other than the infrequent, occasional stall and not being able to go over 10mph on battery, I'm not having any issues.

ALSO - does battery reconditioning really work - like The Hybrid Shop?

Re: Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

Please see the attached.

In the Current, SoC and dV chart, you can see that for currents inside of ±20A, the gray line representing the maximum block voltage deviation routinely exceeds the red line (0.3V). This is bad.

Of note is that there seems to be some tendency for dV to narrow as the drive progresses.

In the Current, SoC and blocks chart, I have identified 3 peaks. As you can see the peaks start to clean up as do the valleys as the drive progresses.

Both charts suggest that your pack is suffering from:

1. Varying degrees of self-discharge (SD) within cells/subpacks. As they sit, even for short periods of time, they lose their charge at high and varied rates.
2. Gross imbalance resulting from #1.

This level of SD is extremely atypical of Toyota cells/subpacks.

This is typical of Honda NiMH "D" cells (also made by Toyota) subject to extreme heat AND Ford Escape Hybrid cells + heat.

The following power supply:

http://www.mouser.com/Search/Product...709-LPC150-350

could be used to slowly charge your pack to full and balance all cells at 100%. You could then use 3 light bulbs wired in series to DISCHARGE your pack to progressively lower levels over a long period of time followed by a very long charge (24-30 hours). The pack would need to be cooled in a way that simulates its normal cooling system operation to ensure the pack doesn't overheat.

Steps:

1. Charge for 24 hours
2. Discharge with 3X 100W bulbs in series to 240V, record discharge time to 288V
3. Charge for 30 hours
4. Discharge with 3X 100W bulbs in series to 192V, record discharge time to 288V
5. Charge for 30 hours
6. Discharge with 3X 100W bulbs in series to 192V, record discharge time to 288V.
7. Charge for 16 hours
8. Install

A harbor freight cheapo multimeter in 10A mode in series with the charge/discharge would allow you to compute charged/extracted capacity over time and actually estimate pack health.

The above is similar to the Hybrid Automotive reconditioning process used for Honda and Toyota hybrids.

Replacing all 40 modules would likely be a comparable cost to a new pack. You would also have no idea if the modules you purchased were good or not.

Testing each individual module will require confirmation of capacity, SD and internal resistance with load testing. In short, you're going to invest a lot of time and/or money into the effort.

The above process will take you about a week and cost you about $50. It will either work, or it won't.


EDIT: I have nothing nice to say about the Hybrid Shop and its affiliates based on direct personal experience and knowledge of their franchising practices and the equipment they use. the process I describe above will give you results at least as good as any Hybrid Shop affiliate you can find that will ACTUALLY agree to recondition it for you (most don't anymore because it's a horrible model for a garage).

Re: Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

EXCELLENT information. So, that I completely understand. I can leave the HV Battery in the truck (removing access panel to get to the + and -, connect the LED pwr supply to the + and - for the mentioned charge times (which should get the pack up to 300v). Once it is reached, discharge until voltage reaches what you show, BUT record the time it takes to go from 300v down to 288v. And have a fan constantly blowing over it to keep the battery pack nice and cool. Is this correct?

THANKS!!!

Re: Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

Really? I actually put it in numbered steps for you. No. That's not what I said at all. I made no mention of 300V. 300V is nowhere near fully charged. You can see that for yourself in your own data. I can't remember the specifics, but a fully charged 40 module pack at 350mA charge current will read 336-344V when full while actively cooled to < 90°F.


A fully charged pack that has sat for a week after charging will be at about 316V.


I said charge for a time and discharge to target voltages. I even laid it out in numbered steps for you. I didn't do that for my benefit.


Follow the instructions exactly as I laid them out and provide a means for cooling the battery pack in a manner comparable to its own system, i.e., air is flowing up or down through the modules at a noteworthy rate.


The fan is likely PWM controlled, so without a PWM controller you can't run the battery fan. If you could run the battery fan while charging, then your in-truck situation would work. If you could replace the fan or even just blast air into the inlet or the exhaust with some rigged dryer hose contraption or similar - that would work as long as you're getting noteworthy flow through the pack from bottom to top or top to bottom. "noteworthy" would be enough to float or displace a piece of 8.5" x 11" copier paper placed on a pack being subjected to upward flow. More is better.


Please note that it took me about an hour (my lunch hour) to generate those graphs, research that power supply and type the post. I'm not doing any of this for my benefit. I do it because I want to be helpful, but I've dealt with too many "askholes" to be tolerant of it anymore.


I don't mind being questioned at all as I make mistakes too, but when someone takes a step by step procedure and breaks it down into something barely based on it, I kinda wonder why I bother.


askhole - someone who repeatedly asks a bunch of different people for advice and takes none of it.

Re: Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

I certainly appreciate your time and helping. I didn't mean to offend or question...just making sure I understood and you telling me it isn't 300v helps.

Re: Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

As I said, please question me as I make mistakes. If something I type doesn't make sense to you, again, please ask for clarification.


It's how you took a detailed process I presented and turned it into nothing like it. That's what makes me question how I use my time.


What is not understood by most is that NiMH voltage is a bastard. It doesn't tell you much of anything, and ratings are misleading.


NiMH cells are 1.2V nominal. Note that you will almost never see a working cell at 1.2V unless it's under load. At rest, if it has any charge, it will be notably higher than 1.2V.


Any time you see "nominal" associated with a voltage, you should think of it as the "average" voltage. if you ever actually measure a resting NiMH cell at nominal 1.2V, it is actually depleted of useful charge.


A healthy battery that has sat overnight will be at about 7.7V per module or 308V for the pack - this is when it's at about 60% charge.


For the scenario I presented, I will give two caveats to the 24/30hr charge time: 1) if the voltage hasn't risen by 0.1V in the last 8 hours, you can terminate the charge as it's close enough to full and 2) if the pack is > 20°F above ambient with active cooling, it is likely full.


Lastly... cooling. That's not negotiable. You have to provide adequate cooling, or you will make it worse.

Re: Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

NOTE to ALL.


If a GM 2-Mode throws the dreaded P061b...


YOU NEED A NEW BATTERY.


Or a real specialist like S Keith to find the bad module and replace it.

Re: Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

Finally took to dealership and explained everything. They kept it for 6 hours.

They tightened the 12V battery terminals and gave it back. So far (2 hrs) so good.

Re: Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

Dealer ticket...

Re: Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

heh... I appreciate the confidence, but I am confident that I could not find the offending module based on the provided data without full pack processing. Without a full regiment of module level testing/reconditioning to determine performance parameters, I would identify the entire pack as bad due to severe imbalance from varying rates of self-discharge and/or peculiarities with the GM battery management.


Frankly, that data looks a lot like an Arizona HCH2 pack. It's shockingly common to see an HCH2 pack fail with nearly every cell losing almost all charge in a very short period of time. The pack mostly functions as each first-drive of the day get's the battery back into a working range. Heat is hard on cylindrical cells.


I have not see prismatic modules behave this way - ever; however, it is common to have notably different SD rates, but that can be mitigated by battery management. NiMH is self-balancing to a degree at higher states of charge. As SoC increases, charge efficiency decreases. As cells get fuller, a larger portion of the charge current is lost as heat compared to what is stored as capacity. The cells at lower SoC lose less current to heat and store more as capacity. Systems that manage SoC at lower levels get less of this benefit.


Is this effect dramatic? No, but it can go a long way to keeping all cells operating within the intended range, even if not well-balanced.


This pack is an enigma in my experience with prismatic modules. That's why I have some hope that grid charging to true 100% SoC may help restore balance.

Re: Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

That would be fantastic if that fixes it. Sometimes, it's easy to get focused on the bigger problem, and we forget...


12V system MUST be in good heath for proper diagnostics.

Re: Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

Y'all will be the first to know the second I can post the next time it shudders.

Meanwhile, if anyone new to this forum is looking for answers, here's my "check this first" list that I would perform before starting anything major:

1) Have your Hybrid battery cleaned professionally. It's imperative that every corner of the battery pack gets a constant flow of cooling air. Ensure that the cooling fan is functional. My battery pack had a lot of dog hair from the previous owner all around the fan, and inside the housing. My MPG boosted from 16 to 19 with that work alone.

2) Ensure that you not only have a good 12V battery, but that the leads on the terminals are TIGHT. You may also want to get the harness system checked for opens and shorts. Sometimes, even if the 12V tests good, it may have some fluctuation in output which WILL mess with your computers.

If these two steps don't curb the stalling out, then start to get a full evaluation of the hybrid battery. Then, decide whether it's time to replace the battery or, if you're able, follow S Keith's procedures.

FWIW, Greenbeanbattery.com offers a fully reconditioned battery swapout for the 08 Tahoe for around $2500. It's only available in the East, and they come to you. That's out the door. They don't diagnose, though. So, if your 12v battery terminal is loose, it ain't gonna do you any good to replace the whole battery.

Good luck!

Re: Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

I've assembled all of the necessary tools to rebalance the battery and followed the wiring diagram by sharrq27 (image below) but something isn't quite right. I have insured all the wiring is fine and I get a tone when checking continuity.

Prior to attaching to the HV battery with the LPC-150-350, my Harbor Frieght voltmeter is reading 419 (my good meter is reading 429) and the Harbor Frieght is reading 0 amps. When I connect it all up to my HV battery and reinsert the orange plug, the volt meter is reading 419 and the amp meter is still at zero. I have confirmed that I do have the 429 volts at the hv posts. Have I wired something incorrectly and it isn't completing the circuit or does the HV battery need to charge back up after I pulled the HV orange plug? I'm starting to think this isn't as easy as connecting + to + and - to - !!

My setup is exactly like this picture (except I have the LPC-150-350 transformer)


https://www.greenhybrid.com/forums/a...ng-diagram.png

https://www.greenhybrid.com/forums/a...g-img_0992.jpg

Re: Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

I found a wiring diagram for the GM charging system, but I have no idea other than the + and - post (on the HV battery) to connect to. I'm about ready to close put it all back together and drive it until it dies. :D


Pages D-48 through D-51 show the Hybrid charging diagram.

https://www.gmupfitter.com/files/med...hassisCabs.pdf

Re: Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

Here is my battery pack, I assumed I would connect to the external posts, on the left side. Then I tried the internal posts. Neither worked on changing the meters to see the battery volts/amp. Any thoughts on where to connect?

Attachment 4028

Re: Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

I have no idea how the wires are routed in that pack. I've never seen the insides of one, and I can't tell from your picture.

I have attached your picture with the main (+) end circled in green. The main (-) is on the same side of the pack at the extreme far end.

With the safety plug installed, you should get full pack voltage between these two points. If not, then the pack may also rely on a relay as well. However, knowing those two modules are the end points, you should be able to figure the circuit out.

Re: Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

Thanks for the info! I'll tackle it once I have another free weekend. One more question, shouldn't the electronics be isolated so they don't fry during the charging?

Re: Infrequent stalls and sometimes POAC4 and P061B (Battery Data Included)
 

The car likely charges at 90A and discharges at 150A. I doubt there will be any issues. Toyota and Honda packs have grid charger systems with no issues.

You're using an isolated power supply. Provided you don't accidentally short something, you should be fine.

You also need a diode in the HV lines of the PSU, or you will damage it.

Furthermore, you need 3 light bulbs wired in series.