Gen II Prius Individual Battery Module Replacement

Ericbecky, where would GreenTec be getting new cells? Wholesalers maybe can get new?

Prius 2004-2009 | GreenTec Auto

(Man, getting REALLY hard to post on an iPhone...)

 

So i'm pretty sure I messed up the settings on my Thunder T6 to charge/discharge my modules.

The first modules just finished with its cycle and this is what i'm getting:

Cell Voltage C D C D C D
1 6.2 2412 4815 7251 5917 7251 5986
2 7.4 462 4964 7251 5818 7250 5858
3 7.39 212 3314 6928 5170 2224 2187
4 7.26 849 4753 6464 4816 6176 4754

I'm guessing that the Thunder T6 isn't pushing the charge of 7250 that I thought I had programmed it to do on modules 3, 4:

I had it programmed this way.
NiMH Charge: Manual
Charge>Discharge
3 Cycles
Discharge @ 0.7A to 6V
Charge @ 5.0A
NiMH sensitivity D.Peak - Default
Capacity Cut-off: ON 7250 mAH
Time cut-off: OFF

Is my Thunder T6 just programmed wrong on these modules? Or are my cells just that crappy? The settings appear to be uniform across all of them, is there something i'm missing?

 

I do the discharge first that way the modules are charged when done. I charge at 2-3 amps. Your modules are probably weak and may need replacing. Try cycling a couple of more times.

 

Toyota dealership does not sell the "whole" pack. It is not a "whole" as such as it does not come with relays, ECU, etc.
If you mix any unknown modules - you have low chances of success - e.g. "scavenge from two Gen 2 packs" or buy from any vendor.
Although sellers would occasionly tell that their modules are "good" as opposite to being "dead" they have no information of what the capacity of your other modules is and rarely would they know what is the capacity of the modules they sell, which make those NO GOOD at all if you put for example 5.5AH "good" module from the fresh wreck into your pack where all otheres are 4AH.
What would happen, you wonder? During discharge your weaker but still good 4AH modules will drop in voltage quicker than the donor 5.5Ah one and the voltage difference between pairs will increase above threshold and your Prius will throw a trouble code.
So called "shellow capacity" range of operation is not shallow enough for that situation not to occur. We graphed that happening in the live tests.
Also bear in mind - capacity is rated at a particualr current, so if someone was testing modules by cheap RC charger/discharger - those normally do not discharge at currents above 1A. So - those in your pack and those you are buying must be tested under same load, e.g. 1A.
Note: I call 7,2v or 9.6v Prius/Lexus module - "a module". It may have 6 or 8 cells in it. Our Analyser has settings in "number of cells per module" to allow measuring from 1 cell module (e.g. AA/AAA battery) to 12 cell module (e.g. power tool), including everything in between. But beacause all modules are connected in series - it is guaranteed that the load current is the same regardless of what that current is - 1, 5 , 10 amps or higher. Other folks who do their reconditioning stuff - do the tests by load testing modules - one by one - no guarantee that the current is the same...

 

Hello there,

Just a quick question: How many individual modules ( or cells) can you charge/discharge at the same time with this type of chargers ? (DC 6 Multi function)

In this case, how do you link or group the cells together so that they get the same charging/discharging current at the same time as a group of cells ?

Thanks.

 

You never want to charge the modules (6 cells, 1.2 volts nominal for 7.2 volts each module) in parallel from a single output charger/discharger. I believe the DC6 can handle one module at a time. The Hitech X4's can do four modules at a time since they are charged/discharged separately. To make sure they are all balanced by voltage, after cycling your modules, wire the modules in parallel, connecting all the positive terminals to each other and the same for the negative terminals. You don't apply a charge at this point but leave the modules connected like that for about a day to give the modules enough time to equalize their voltage.

There is SO much helpful info in just this thread alone so you may want to bookmark it for quick reference.

LG-AS780 ? 2

 

Thanks a lot. I will read one more time the relevant info and will ask for more clarifications if needed.

 

While I applaud the coolness of DIY battery cell replacement, I just want to chime in a say this isn't something most shops will do for fear of near term failure (specifically electrolyte leaks).

I'm really impressed people are DIYing this though.

 

From Toyota ;-)

 

Jeff652,
If you know that, do you know by chance whether it is from the surplus - those EV Energy stopped manufacturing a year ago?

Rumours say there is a warehouse full of those somewhere in US - I was even offered by middlemen those for $1000 a pack but after my usual question of what the remaining capacity is, documented of course, they slipped :-(

 

You have all the settings right except it should be Discharge>Charge (you may have way overcharged some modules, I damaged a test module doing the same thing ) and keep the charge current under 3A (preferably 2A max).

 

Hello Ryousideways,
Isn't it safer to set the charging current to less than 5 amps to be sure not to damage the modules ? 2 amps or 3 amps for example ?
Thanks for your feedback.
Eddy2014.

 

At higher SOC, even 2 or 3 amps is too much. You will damage cells.

 

So then what's the best charging amps should I set the chargers for a Gen 1 Prius ?

 

And how come Mr. Ryousideways charged his Gen 2 modules at 5 amps ?

 

In this case, do I need to prolong the charging time if I charge my Gen 1 modules at 2 amps or less ? By how much ?
Thanks for your help in this matter .

 

Get a charger that will cut back voltage at higher SOC.

 

Don't use 5 amps, I did it and it didn't work out well on a test cell that got overcharged (too easy to do when you are first starting out, also make sure the charge is set to discharge>charge and not the other way around!!!). Most digital RC chargers (ex. Hitec and Thunder) are smart enough to taper the voltage on the upper end but using less current also helps in preventing damage in a DIY situation.......I would suggest staying at 2A for charge current (use less if doing this in ambient above 100F).