Gen II Prius Individual Battery Module Replacement

hi amigo, Did you say 9.6 V it's the nominal voltage of your cells. So the bad cells you find drops from 10.73 to 10.51
if you look the difference between lower volt 10.51 and nominal volt 9.6 is 0.91 V this is about nominal voltage. How do you know this cell was bad, I saw the drop in the rest and is half of the bad cell, this is you main point

 

John (Britprius)

 

No, forget about nominal voltage at all, the nominal voltage doesn't matter, its the voltage drop (where it starts vs where it ends) that counts when you do the test. The nominal voltage was mentioned more to make sure someone with a Prius didnt use highlander voltages by mistake for comparison of their own modules.

 

From which end do you count modules?

 

Module 1 is at the hv-ecu side.

 

You can start counting the pairs of modules anywhere you want.

Toyota Tech Stream Software and any generic OBDII reader will start the count on the PASSENGER side. That is to say pair one is opposite the battery computer and pair 14 is next to the battery computer. This applies to Gen II Prius years 2004-2009. For Gen I (2001-2003) the count is in the opposite direction with pair one being next to the computer and pair 19 being on the far passenger side. I have not yet opened up a Gen III battery and do not know the direction of the count.

I make this claim on personal experience. The weak modules in the first Gen II pack I repaired just did not match what Tech Stream was telling me, until I started the count on the passenger side. I have repaired over thirty packs. The Gen II count starts on the passenger side.

Let the flames begin.

Brad

 

Since this form is worldwide terms like passengers side and drivers side are meaningless unless you qualify on which side of the road you drive. I drive in the UK on the left so the drivers seat is on the right hand side of the car. This is the same in Japan, "where the Prius is made and was designed" also Australia, New Zealand, India, and Pakistan. There will be others. So in those countries your statement that block 1 will be on the passengers side is correct, but after that your statement about block 14 being next to the computer is completely wrong.

John (Britprius)

 

Yea, I thought about that whole left hand right hand drive thing after I posted this. I am in the US. The steering wheel is on the left for us. In the US drivers side is left and passengers side is right. Of course that is from a view point behind the car.

All that fluff aside. For Gen II Prius, Tech Stream starts counting opposite the battery computer and finishes next to it. I have opened up many packs and confirmed this numerous times.

Brad

 

How do you explain a number of cases reported on PC where one of the sense wires have broken. From the fault codes issued in Techstream we have been able to diagnose not only the fact that there is a broken connection, but also at which block the connection has failed. These same wires feed back the block voltages reported by Techstream. In the instances I and many others have dealt with this information has been correct using the arrangement shown in the Toyota workshop manual where block (1) is at the ECU end.

John (Britprius)

 

It is good that you shared with the world your awareness that we drive on the same side of the road as you do in UK.
However crash stats here suggests that tourists coming to New Zeraland frequently drive as they got used to in Europe or USA - on the other side of the road. :-( Just to remind everyone to stay safe when visiting us here.

Instead of counting from the Battery Computer suggest you always use as a point of reference - the negative side of the pack. Logical and will be easier to remember where it is #1 (out of 19) or #14.
In my Help Manual how to use Battery Analyser - I have those scenarious covered and have included counting references - as this was anticipated FAQ.

 

Hello all,
first post. First of all, thank you to all who have done the groundwork and shared their findings. It certainly makes things much easier for those of who come after.

I am working on a 2005 Prius with about 160k miles that had P0A80 and P3000 codes. Followed info here to load test modules and found 2 that failed (#1 and #8 counting from opposite ECU end)

Followed instructions per above for 2 THunder T6 chargers. I have them hooked up to 2 12V power supplies that can go up to 10A each.
At first I was using little alligator clips, but was not getting good results on the mAh numbers, so I made up the leads as suggested in this thread with 14 ga. speaker wire, ring terminals and banana plugs. I didn't get much improvement.

I'm attaching my data sheet. The modules that have been cycled 6 times are the ones that I re-cycled after improving my wire leads.
I would appreciate your comments. suggestions, ideas? THank you!

THe modules that have no listed data yet are currently on the charger (Man, this takes a long time!)
I'm also attaching a couples pics of my charging/

I guess my main concern is the low numbers for discharge, and the fact that the chargers stop charging long before the 7000mAh cutoff.
I used the exact settings as above.

 

With that milage I would be very much surprised if your efforts would lead to any improvements. Please have a look at the load test of 2009 pack with that same mileage - from my opinion - too bad to justify working on it. Capacity is very low and pack it too much unbalanced. In that case load test took only 46 minutes. Contrary to widespread myths and even some US based patent personally I and our local battery gurus do not consider multiple charge/discharge cycles to be of any substantial use to the old tyred NiMH battery like yours - almost 10 years and 160K miles is the end of its life.

 

As much as I don't want to agree with "kiwi", he maybe right. But don't let that stop you. You can still rebuild it Gen II battery packs.

Well , it’s my turn to face the “Triangle of Death” on my 2007 Prius with 174,000 miles. But I was in a hurry to get it fixed, so after several online searching, I decided to opt for a reman module pack with 1 year unlimited miles warranty with mobile installation. The engineer came from Orange County, CA to the Bay Area and I was happy with his service before and after the install.

However, my curiosity has started and has to be satisfied because I want to take control the next time it happens. I have read, reread and reread again this post “Gen II Individual Battery Replacement” started by “ryousideways” last April 13, 2013.

For a start, I have ordered 4 Gen II module packs on ebay whose seller claims static voltage of 7.3V each along with mini VCI. Plan on ordering the Hitec X4 or the DC6 chargers plus other minor tools needed for dis-assembly.

I would like to thank y'all for these priceless information that's helping me a lot.

I'll be posting 3 questions that I need help on. Hopefully, although this thread is almost 2 years old, I'm hoping all the gurus are still here and still enjoying our Priuses.

 

Do not set the delta v cutoff when charging the modules set a maximum time limit. There can be 6 separate delta v peaks "one for each cell" so the first cell to reach full charge can turn off the charger before the other cells have caught up. Bear in mind that the charge efficiency of NiMh is only about 66%.

John (Britprius)

 

I have actually finished this car and so far it seems to be a success. I ended up running 6 cycles on all of the modules but they still didn't all reach the 7000mAh. I never read anywhere to not set a delta v cutoff, instead the instructions clearly said to set delta v cutoff to 7000mAh and not set a time limit.

I'm posting this so that future diy-ers can learn from it.



Nexus 4 ?

 

The 6 individual cells in the module all have a delta v. With the cells being at different states of charge it would be a miracle for them all to reach the delta v point at the same time. Each will give a small rise in voltage and then fall as it reaches full charge "the so called knee point, delta v" triggering shutdown of the charging early when the first cell "the one with the highest charge" reaches that point. This is the likely reason why the input charge never reached 7000 ma.
The idea of setting a charge of 7000 ma is for the charger to cut off at that point so that there is a slight overcharge on each cell in the module. This is something the cells can handle without damage providing the charge rate is not to high causing overheating. If 7000 ma is not put into the cells you cannot expect to get 6500 ma out particularly as the charge efficiency is only in the region of 66%. A charge of 7000 ma into a fully discharged cell would give an expected output of 4600 ma.
This is the reason you needed to do 6 cycles on your modules, and still did not get the anticipated capacity.
The grid charger sold here on PC works in exactly this way apart from the fact that it is charging 168 cells in series instead of 6 cells in series.

John (Britprius)

 

Quick update, it hasn't been six months yet but I deploy again soon so I wanted to let everyone know how the battery has been since rebuilding. I have put 7000 mixed miles on my Prius since the rebuild and I am happy to report no issues. 0.0V difference between module pairs from SC2 and still getting 50mpg average. SOC is very consistent now and does not decrease drastically like it used to. So far, so good.
I will update again when I return as it will be getting driven regularly while I am away this time.

 

I don't understand. If you only expect 4600 mAh from a discharged module, why do they tend to start out low but keep coming up to around 6500mAh? I had almost a whole pack that I guess was shutting my charger off anywhere from 700 to 2000mAh into the charge, and then of course I got less than that number on the discharge cycle. Is there any hope of getting the numbers up where they should be? Should I try it again without the delta v shutoff?

 

The cells within the modules when new have a capacity of 6500mah. In use some of the chemicals it the cells undergo a change in structure lowering the capacity of the cells (so called memory effect). By fully charging the cells and then discharging gently to a low level a few times this effect can be reversed.
If the charger is shutting off before the programmed 7000mah input is reached something must be triggering it's shutdown, and this is likely the delta v shut off. If you do not fully charge the cells you cannot expect them to to reach the target 6500mah level of discharge.

John (Britprius)

 

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