Whats wrong with this procedure? The HV battery is connected in series , the ECU reads in banks of 2

On second look it is hard to see which side is up.

From the factory the concave side is up and the convex side is down. It seems like they should be the other way around.

You stated your charger runs at 8.25 volts and 6 amps. Did you measure the amps or is that just what the label says it's rated for? If the 6 amp charge rate is accurate then the pack received 8 hours X 6 amps or 48 amp hours of energy. 48 Ah is 48,000 mAh. If that energy was divided equally between the 28 modules then each module received 48,000/28 or 1714 mAh. A full reconditioning charge is in the 7000 to 9000 mAh range. So you charged to 20 to 25% of a full charge. I am not recommending you try for a full charge with this parallel setup because of the negative delta V at full charge and the uneven nature of the charge there is a risk of fire. Parallel charging NiMH is not the recommended method.

It's good that you checked for hot exhaust. Did you get any throttle response? Can you rev the engine?

A failing hybrid battery will not keep the engine from running.

 

No worries, you are here to learn.

I am going to stress the importance of cleaning the MAF sensor.

Cleaning just the visible bulb is not enough.


You have to clean the wires hidden inside the top cavity. A speck of dust on those hot wires will disable a Prius engine.

 

@strawbrad recently wrote:

You stated your charger runs at 8.25 volts and 6 amps. Did you measure the amps or is that just what the label says it's rated for? If the 6 amp charge rate is accurate then the pack received 8 hours X 6 amps or 48 amp hours of energy. 48 Ah is 48,000 mAh. If that energy was divided equally between the 28 modules then each module received 48,000/28 or 1714 mAh. A full reconditioning charge is in the 7000 to 9000 mAh range. So you charged to 20 to 25% of a full charge.

Thank you for posting this. I was going to, but just couldn't get motivated enough to explain it. You did it clearly. I was going to go the 6000ma into 28 modules is about 200ma per module and at ~85% efficient, possibly only ~170. Even a 10 hour charge would be ~1/3 charge. That's about enough for one round of a triple start cycle with an older battery before being depleted. And even then, it's very optimistic as most chargers (of that style) taper off on the charge rate. My son's 2005 (with one of my Gen 4 module batteries) actually went through 21 start attempts several nights ago while we were trying to find out why it wouldn't start and still had enough left in it to start the car once we got it sorted out..had me worried, but it handled it like a champ. Still ended up driving it onto a flatbed and having it taken home rather than risk it dying again while driving.

@strawbrad also wrote:
It's good that you checked for hot exhaust. Did you get any throttle response? Can you rev the engine?

Another thing I use is the MFD energy display. As soon as the engine is actually running, the energy animation instantly shows energy flow charging into the battery. So far, that has never let me down as an indicator of the engine truly running, not just cranking.

 

The long cable that connects to the (-) terminal of the module furthest from the ECU passes through the white current sensor and then to the contactor closest to the case. The short cable that connects to the (+) post of the module closest to the ecu connects to the contactor toward the inside of the case.

 

Original Question of mine "what wrong with parallel charging?" It can be done but I also do not recommend it nor condone it. But I have discharged and recharged for a 4th time ; this time only once in stages. Battery cells read 8.0 volts on every cell.

I understand this, but you are assuming that each and every module in your battery has an equal ability to take a charge. This isn't ever true, especially for an older battery. I have about 1500 modules sitting in the shop and there's two ends of the spectrum. I can take a bad module with huge internal resistance and a brand new module and make them each read 8 volts. The bad module may reach 8v with only 3 seconds of charging. The good module may take an hour to charge to 8 volts, using the same exact current. It's like using a wide open garden hose to fill a test tube and a 55 gallon drum. Those are the extreme ends of the spectrum. Parallel charging? Once the test tube is full, the flow goes to all the other 55 gallon drums. Emptying and filling the test tube will accomplish nothing. Just because a module has voltage, doesn't mean it has capacity. Series charging, I'm forcing the same value of charge current through every module. Once the test tube is full, it doesn't matter, it's still going to continue getting the same current pushed through it. This is what "works" the battery toward 'refurbishment'

Think of it as having (28) 8 volt capacitors with each having difference capacitance. The smallest one would be 8 volts, but maybe it's capacitance is only enough to make a small spark before it's empty. The largest one, also at 8 volts, may have enough capacitance to turn someone into a piece of charcoal. Your battery is only as strong as the weakest module, as that is what triggers the code out.

Now, if we forget about all that and follow the path of an engine problem, is the car currently still triggering the RTOD or CEL?
Have you already cleaned the throttle body? I have seen the TB blade stick, allowing the engine to run for a couple seconds and then shutting off on a P0A0F Engine Failed to Start and/or P3190 Poor Engine Power.

Unfortunately, it also looks like so many things have been checked, replaced, disassembled, inspected, etc that it's going to become even more of a guessing game until you can either get a Prius friendly scanner or Techstream.

 

Most get a Mini VCI cable and an old Windows XP laptop to run Toyota Techstream software. I recommend a VXDIAG cable. This cost a bit more but work much better. Either will give you the same code reading ability of a Toyota dealership.

Did you use OEM Toyota or Denso parts? Cheap aftermarket parts can cause more problems.

The ECU in my Prius is installed hanging by the wires with no additional grounding. They work fine like that. It's too cold here for pulling apart the dashboard.

 

It's too cold here for pulling apart the dashboard.

Unless you enjoy watching every single piece shatter during disassembly. I'm scared enough doing it when it's below 65, I can't imagine trying in in a real winter weather area.

 

Try replacing batteries when it's 20 below.

 

To check each module EASILY, I use this charger/discharger. Put a 30 amp draw on each module. Discharge 1000 ma from each one, and record the voltage. ( Purchased eBay for $30.)

As others have stated, that 6v/6a charger is barely putting any charge into the parallel pack. Measure the charge current with a test meter. Then do some math.

Lastly, nimh when fully charged, even at a trickle rate, will warm slightly. You can feel this with your hand/fingers.

 

So,

What codes have you been getting?

 

That Integy charger/discharger is a real beast but has been out of production for 20 years.

Hobbyking.com is a good place to find modern chargers. The Turnigy Reactor 300W 20A is powerful charger.

These chargers will work on individual modules, not the the pack as a whole.

A Turnigy 180A Watt Meter and Power Analyzer, also available at HobbyKing could measure what your power supply is producing.

 

It's always interesting to look at the date codes, but don't let it distract you from the end goal. The battery in my 2007 has modules date coded from 2003 and the battery is an absolute beast. When you're checking the modules, don't forget to check voltage between the terminals and the mounting insert on the bottom. There have been instances of small cracks in the battery housing that can cause that insert to act as a leakage path to the car body and put voltage on the battery case. I had a battery case over the summer that had 50ish volts on it.

When installed, the insulation quality of the HV system can be checked using Techstream. In the HV System tab, there is a reading labeled as Shortwave Highest Value. It displays as a value between 0 - 5 volts, with 5 being perfect. The lower the value, the worse the insulation quality. The battery mentioned above wouldn't even let the main relays go shut.