Gen II Prius Individual Battery Module Replacement

Wow another great post and lots of good info! Thanks very much. This sounds logical and I plan to get out my magifying headset and check the modules closely tomorrow. From a partial glance earlier this week, I found a module with definite signs of leakage, with green splotches on it, etc.

 

Well, I bit the bullet today and ordered 8 more replacement batteries at $25 per.. When looking at the 2 that had the charring under a magnifier, I could see a very tiny crack in the char mark. So I ordered 2 for those. Then today I closely examined all the batteries. I got a couple of faint readings of .01v from the + term to the body of a couple of them. Also, they had some greenish residue on them indicating corrosion. They were all clean a month ago when I installed them. Modules 8-15 all had this greenish corrosion, with many traces of it appearing to "run down" the side of the case and near where the metal bar runs underneath. Rather than try to guess which one(s) are leaking, I just elected to replace all with any signs. So this time I'm replacing 10 total. Last time I replaced 4, so basically 1/2 of the pack will have been replaced. Wish I'd just bought that complete new set I saw on here for $1600 to start with but lesson learned. Once they get in, I'll put it together, cycle charge all, balance and then see how it goes.

 

Latest update: Got battery assembled and cycle-charged the "new" cells. Then balanced all to (I think) 7.86v and installed in car. 2 weeks in and running great so far. I actually have Green bars on the display and all but 1 show up, so that's a first. Dr Prius shows good status also. Meant to take some pictures but haven't so far. We'll see how it goes!

 

Hey everyone first post here.

My main question is: When discharging the batteries with a discharger, is there any minimum voltage to look out for?

Another question: Aside from low voltage during a load test, are there any other reasons to not keep cycling the charge/discharge on a cell?

I've once "successfully" reconditioned my battery but after 8 months I got the red triangle with turtle mode and now I'm doing it again. I've already found and replaced the cell that fell below 7v during the load test. And now I am cycled the charge/discharge. Is there anything else to look out for in this process? It would be great if I could get this recondition to last a little longer.

Thanks!

 

First, you do not want to reverse a cell polarity during the discharge cycle. I would limit the discharge at first (the cells may be badly out of balance) to 6v (1 volt per cell). After the first recharge cycle the cell balance should be a bit better and you could discharge to a lower voltage, but take care.

I found that there are diminishing returns from cycling more than 3 times and each cycle does age the cells somewhat so don't overdo rebalancing modules.

JeffD

 

You seem to be confusing two concepts here, possibly inadvertently by mixing terminology incorrectly.

First, if you are load testing, you are not looking for a lower voltage to which to go per se. The purpose of load testing is to give you an idea of the capacity of each module relative to each other. So, you need to first fully charge each module so they start with a substantially similar voltage, you record the initial voltage, then apply a load for a given time (120 secs is quite popular), again record the voltage (while still under load) at the selected time, and then remove the load. The difference between the start and end voltage is what is important. You then compare the differences for all modules to give you a relative comparison. The ones with significantly higher difference values are the suspect modules. As a side note, if you started with a fully charged module, load tested it and you saw the voltage drop below 3V before the time limit, you could be fairly sure that the module was not a good one.

Second, if you are balancing a module/battery, you would first charge the modules with a gentle (325 mA, which is 0.05C) current so as not to damage the cells (within each module) and to minimize swelling before discharging it by applying a load (rather than load testing). In any case, modules should be clamped to stop them swelling as swelling can make them unusable if they get deformed.

The most popularly used discharge points for the three discharge cycles are 0.8V/cell, 0.6V, and 0.5V/cell. For a module, these are 4.8V, 3.6V, and 3V respectively. For the entire HV battery, these are 134V, 101V, and 84V respectively.

Let me know if any of this doesn't make sense to you or you need further information.

 

Hello teacher. I'm new here, I've seen several posts from everyone and especially yours, so I'd like some help. I have a prius 2013 3 generation, after a few years the error code PA80 appeared, I would like to know how to balance the modules.


I am using an imax B6AC charger with the following characteristics:


Settings:
Charge at 5 amps up to 7250mAhr
Discharge at 0.7 aMhr down to 6 volts
DSCH<CHG for 3 cycles.
Other settings: I set the timer limit to 720 minute cut off. I also set the cool down period to 5 minutes and D peak for default.


However the module cannot charge beyond 7.8v and when the cycles are completed the module has a voltage of 7.5 volts apenas.


I would like to know if everything is correct or if I need to correct something. please help me.

 

Hello everyone.
I'm new here.
I am glad that I found it on the forum, there is a lot of interesting information here.
@Hiroshi
Settings:
Charge at 4 A
Discharge at 4 A down to 6 Volts
CHG-DSCH for 4 cycles.
I got a discharge capacity of up to 7200mAh !
Refers to a fresh battery from the Auris II.
Charger "ICharger"

Have a nice day

 

Hello,
The Prius II and III have the same NiMh batteries (check with google).
Discharging 7250/700 = 10.3 hours!
Mine charges to around 9V and discharges to 6V.
One full cycle (charging + discharging) for 4A and with a good battery is about 3 hours.

 

ICharger @4A

 

@dolj
Thanks for the explanations, but I would like to know if I should, after the load test, do 3 cycles of discharge and charge, being the discharge up to 6v or up to 4.8, 3.6 and 3v as per your recommendation?

 

Minimum 6V.
There are 6x NiMh inside.
You cannot discharge below 1V per 1 NiMh.

 

@Priusoholik

Thanks for the explanations

 

I watched this 2hr video for professional battery rebuilding and they do not reveal the ideal settings. However, there many good points made:

1. The correct capacity in mAh is shown when a 3.25 amp current is used for discharging per Panasonic specs.
2. Remove modules that can not achieve 4000 mAh.
3. Remove modules that can not hold 7.2v
4. Highest mAh to lowest mAh should be less than 3%. For example a range of only 165mAh for a highest 5500 mAh and lowest 5335 mAh. I understand this is extremely difficult working with modules from a single battery but remember this is for professional rebuilders with hundred of modules
5. Real life conditions load test is needed. Like you put it in the car and drive it. A power load test can be done at 45 amps discharge for 8 sec to get any module that drops voltage more than the rest.
6. Module matching is done by Voltage not capacity. Highest voltage with lowest voltage and continue for all 28. Remember voltage should already be 0.05v or less between modules.
7. Block placement is also done from highest voltage to lowest sequentially. Block 1 is the highest voltage and sequentially you continue. The idea is that you put next to each other blocks with the smallest voltage difference.

 

whoa , you explained that shit like boss. John. Can you help me some more, im doing the same thing but i hve 1 dead battery and a dying one and i need to make one fully functioning.

 

I have a Prolong charger and manual decharger for sale. New , never used.
Price= 350$
Pick up Bloomfield NJ 07003, shipping also available.
Prius 2010-2015

Package include:
Prolong Battery Charger (HEV power grid charger)
Manual light Bulb Discharger (Two bulb for Toyotas, Single bulb for Hondas)
Discharge Ready Car Harness with integrated safety cap
AC power cord (for US, Canada, & Japan orders only)


The Prolong Battery Reconditioning Package has everything needed to easily recondition your hybrid battery at home for the lowest possible cost. This charger and manual discharger package is ideal for people who have already degraded hybrid batteries, or batteries that are showing a fault (DTC) code.




Posted via the PriusChat mobile app.

 

Do you know if this would work for a gen 2 prius (06)? besides maybe needing a different harness

Just checked it, yep it would but I would need the gen 2 harness. I also would prefer the deluxe, but best of luck selling.

 

Sorry guys, thank a lot.

Posted via the PriusChat mobile app.

 

Some quick thoughts and observations.

- In theory you should be able to charge modules at up to 1C (ie 6.5A). In reality I have had various modules fail on me after charging at 5A (ie heat builds up and the modules bubble).
I strongly recommend that you charge at 2A.

- You really, really want a charger that displays the mAh figures for all of the discharge/charge cycles. The iCharger range and Charsoon Antimatter chargers seem to be the only mainstream ones that do this.

- Charging rapidly builds up a lot of heat in the module, but you can discharge as quickly as you want. If you want to speed up the discharge/charging cycle process then discharging is where to do it. This means using a more expensive charger (ie iCharger DUO 308, 406 or 4010).

-Charging at 2A and discharging at 10-20A, an iCharger DUO will do two modules in 12 hours or less. You can do four modules per day.