Gen II Prius Individual Battery Module Replacement

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I have not yet started work on this as the modules will not arrive for possibly a week or more. I anticipate the holes drilled will be about 1mm diameter 2mm at the most. I may drill and tap these holes depending on how thick the plastic is and use sealing washers or "O" rings on the screws. I may even counter bore the hole slightly to take thin "O" rings.
Looking at Bob Wilson's picture the area around the top center of each cell appears to be the thickest, and I am anticipating drilling in this area, but not directly in the center because there may be a valve positioned there. The cell plates appear to be at least 10mm below the top of the casing, but great care will be needed when drilling the top.
My intention is also to fill the cell and then draw off any water above the cell plates "the reason for using a plastic tube on the syringe". This will ensure all the cells have the same level of electrolyte at the end of the process.
As soon as I have found suitable positions to drill I will come back with details.

John (Britprius)

 

Do not forget to use long enough drill - you may find oil under another continent....

I would not recommend anyone to drill NiMH modules or create holes in them.
That is extremely unsafe...

Please read patent US 6936371 B2

 

Hi all,

I would like to thank everyone as this post was really helpful in my rebuild efforts.

I have a 40 mod pack from a 2006 Lexus GS450h. The modules are exactly the same a gen II prius modules.

I had one failed module. Diagnosed via load testing and also Techstream.

I am in the parallel equalization stage of my rebuild, hopefully everything back in the car in a few days time and back to nominal.

Its a heavy pack at 60KG..

My Lessons:

If you are in the UK and or Germany please be aware when you purchase

SKYRC QUATTRO B6 80W:

These chargers have a major limitation:

• They do not display the cycle information at the end of the CHG>DSG. (Even though their on-line manual says that the information will be displayed at the end, this is not true!)
• This really made the process a lot more time consuming for me and I was not able to get the capacity information as I needed.
• Also they come shipped un-calibrated (voltage) my chargers were off by +.5 volts. (not a bad to be + rather than -)
• You cannot switch off or disable the delta peak settings.

However they were cheap and for the money they still performed their function.

If I would do this again, I would buy the imax b6 chargers or even the cheap clones as my understanding is most of the imax b6 models are covered by a custom firmware that can even display internal resistance of a module. (search google for: cheali-charger)

For the same money as two b6 Quattro you can buy 10 good clones!

One again thanks to everyone for this valuable post and for sharing your experiences.

If you are in the Midlands in the UK then I may be able to help, get in touch.

 

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What's the situation in UK with the Resque Chargers for Lexus GS450/RH400 / Hilander (Hihy)?

(They are rated at 288v, 30x9.6v(8cell) or 40x7.2v(6cell), depends on the car model)

e.g. I was advised that in one particular state in USA (they have lots of Priuses/ Hihy's) there is only one rescue charger for the 800km area around.
That opens an opportunity to hybrid specialists in some regions to provide [mobile] service of charging depleted packs.

I have very limited number of Toyota Rescue Chargers for those types of NiMH packs.
Those are state of the art portable devices, made in Japan. I use them with my 20/40 channel HV Analysers.

They are constant current chargers (at about 1 Amps) with built-in timer, powered from 12V DC (operated at about 27 Amps).
In the Lab I power them from 100-240 AC to 12 DC 60 Amps IBM power supplies (have extra available).

The catalogue price (FOB Japan) for that device is about $2500 USD (excl shipment) but I can sell one or two at very discounted price to support further development of our HV Battery Analyser Testing Complex.

Tender is open. If interested - give me your best offer.
Shipment from New Zealand to USA/UK by NZ Courier post (professionals are welcome to visit New Zealand)

Note:

I am not in favour of installing HV chargers in cars for so called "preventive maintenance". I call them "greed chargers".
The way they are installed in the cars are presenting risk to users.
Was at wreck site recently and spotted hybrid car with the "booster" HV charger permanently installed in the trunk.
Of course I could not resist and bough the whole lot for "testing" with the entire battery pack it was supposed to "maintain".

As for the battery pack - 4 pairs were "dead" - "maintenance" obviously did not work in that case

Observed:
- No safety labels advising of the high voltage (saved on labels?)
- Insulation went off the HV wires which were unprofessionally soldered together (installers were using insulation tape which went off due to heat. Saved on high temperature heat shrink?),
- The hole drilled in the pack was not protecting the wires from damage (saved on rubber ring?)
- "Protective diode" was hanging inside compartment unfixed (saved on couple of nuts?),
- High Lethal voltage was permanently present on HV wires (not marked, looked like ordinary 12V wires to me) going into the charger (saved few bucks on extra relays and controller inside the pack?)
That is what I call "greed" - that is issue with many so called "grid chargers" or as in this case with that "booster" charger.

Furthermore, In my Lab, device revealed:

- No protection from brutal impact,
- Absence of constant current control,
- Under voltage (e.g. pack would only be charged to about 7.66/module),
- Very poor quality of internal componentry (made in China, unbranded)

Not cool, regardless of the price of "that solution”. What is most important - installation was far from being safe..

 

I would have to agree with the earlier comments about you kiwi.

You seem to be trolling and potentially scare mongering not really the best sales tactic now, is it?

Or have I misread your post which seems really off topic? In any case thanks for your offer but I am not interested.

 

Hey Many Thanks for your reply and the pdfs, reading your experience was also very helpful in my project.

I assume i can perform the ecu (calibration) updates via tech-stream?

I don't have the exact discharge and charge cycle information, i decided on monitoring the information every few hours to estimate what the capacity might be for a given module.

My cut off was 3000mah and all the modules discharged above this and most were around and above 4400mah. This is good enough for me for now. I drive a 350PS 3.5L V6 hybrid certainly not for economical reasons, if I am honest.

Two modules I could not balance adequately so i replaced them.

My car has 73000Miles.

Ahhh I need to check the CPU but i guess mine will be silabs also

 

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As a matter of fact you did. Being able to stare at printed letters and understand the content at the same time are not necessarily the skill one may possess.. There was a question about situation with chargers in UK. You have not answered that question which means - you have no idea.....Could've said simply something like that :"No eye, dear mate.."

That was "in topic" as the whole pack has to be charged even if you've changed one module.... and have discharged all modules to the same voltage.

BTW, I am not offering equipment to the general public, only to trained professionals.

As for this thread - I now have plenty of material, based on questions, replies and posts to produce educational video "Demystifying Individual Battery Module Replacement" (will be free on Youtube).
I am observing too much confusion, false expectations, dodgy sales practice. All combined that puts people's health and life at risk, wasting people's time and money.

Play safe!

 

I managed to get the pack in this morning and the first 29km were error free.

Upon plugging in the pack I had a DTC of "high battery pack delta voltage" I forget the exact wording and the code.

But looking via tech-stream all the battery voltages were showing 16.0 volts I started the car and then the voltages were all at 15.xx volts.
The error code was also cleared.

On the drive the battery bars via the info display were a constant blue all the way and near the end of my journey went to green. This is not normal for me. Normally the bars move up and down allot more during a journey. So I would say that the overall pack is more "balanced"

I will report back in a few weeks time if the car is still ok.

 

If when the battery was re-installed you did not bring the battery voltage down to a charge level of an equivalent of 80% or below this DTC will show. Once the pack voltage has been bought down to at or below this level the DTC will clear. The reason is the ECU does not expect to see a charge level of more than 80%.

John (Britprius)

 

Hi John we checked and the SOC was 60%.

Aqib.

 

John is telling you that 16v modules are charged to more than 80% SOC. That is why your ECU complained at first.

JeffD

 

Good work! Happy for you.
I'm still working on my pack. Down to the last 2 modules. Have to replace 8.
Keep us posted!

 

Thanks for the clarification. Jeff.

But shouldn't 14.4v be 100% SOC? i seem to not be understanding something.

I am now confused why the ECU states 60% SOC at 16v.

Is it because the lexus has 40 modules as apposed to 28?

 

Each cell has a nominal voltage of 1.2 volts, but the voltage varies with the state of charge from around 1 volt or slightly lower for fully discharged, and up to 1.48 volts for fully charged. These figures must be multiplied by 12 for the number of cells in a block (2 modules).
Toyota hybrids only use the battery in the range of 40% to 80% level. As can be seen from the graph below at that level of charge the voltage only varies by a small amount. It is the discharge curve that we are interested in here.

John (Britprius)

 

When I rebalanced my modules they all reached over 8v but then dropped back to 7.8 or so in a few hours as the "surface charge" dissipated and then held there for a more than a month. So I count 7.8v as "fully charged" (for a 6 cell module). I'm not certain why your ECU reported 60% as it should be higher with all modules at 8v (16v for two modules in series).

JeffD