Gen II Prius Individual Battery Module Replacement

If doing multiple modules simultaneously, then charge first since they are likely not at the same state of charge or capacity .

 

Great tip Eric, Will do!
Any other advise you can share with me? Have you been successful restoring these prius modules?
Appreciate the info.

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I've worked on hundred of batteries . Ad have few others on these forums .
Dig through and read some of the threads. You'll find lots of details and opinions .
There is some good info from strawbrad, skeith, hybridautomotive, etc.

But feel free to call me during the week days if you have questions .

 

Thanks Eric!
Appreciated man!

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Dolj, sorry about my delete last night I keep having HTTP errors with PC lately its a pita.

Discharging to 6v even at high rates is pretty normal, below 6v you might run in to trouble at high rates but discharging to just 7.2v is the opposite your not going to prove a lot for balancing from what I understand most of the balancing magic happens well under 7v

I balance or "recondition" via the usual charge/discharge cycling methods mentioned earlier in this thread by people like S.Keith and Strawbrad, i don't claim to do anything special or know anything more than anyone else here im just another copy-cat lol, sometimes I grid charge and taper discharge with a selection of different globes it really depends on exactly what im doing and how much time I have.

yes delta peak is where the charger detects the battery is full because voltage has peaked and started to pull back its difficult if not impossible for the charger to detect dv for nimh cells charging far under 1C (cant remember exact rate) If charging at 650ma your going to be above 80% for something like 90 minutes due to battery inefficiency but if you hit them at 1C your only above 80% for 13 or maybe 15 min, either way they will produce heat and swell above 80% soc that's the price you pay to balance and the reason to always charge modules clamped and cooled.

as for damaging cells good modules are reasonably hearty just dont be a total brute lol if you have to push both upper and lower limits a little to get the job done so be it

 

Thanks for the input

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What kind of numbers you're looking to see give or take on the charger when you're in discharging mode as far as Mah? Thanks!

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most people on here with gen1 cars seem to rebuild their pack with gen2 modules, gen1 modules usually end up in the rubbish

 

No worries, been happening from time to time –my worst latest attempt quadruple posted, then had a frustrating time trying to edit to delete the three superfluous posts. lol.

I'm in the same boat. I should also disclose I don't have direct experience reconditioning at a module level (as yet), but want to be prepared in the event it is necessary. Hence my questions and opinions. I have read this thread in it's entirety (I think it was only 30-40 pages at the time) and have continued to follow it as it has grown. I, also, have learnt a lot from the likes of Brad, Steve, Jeff, Eric and not to forget ryousideways, who started it all. If I comment on something you said, it is not necessarily that I think the statement is wrong, but does raise questions against what I understand (which I concede may not be right), so I raise the question from the point of view that I am trying to clarify my understanding. I don't mean it to challenge your knowledge or cause offence, but raise it humbly and (hopefully) graciously in the hope of (selfishly) improving my understanding. So, in that context, some questions.

My understanding is that balancing happens at both ends of the charge/discharge cycle. My understanding is this:
Top end balance: Steady, gentle charge (0.05C; ~340 mA) continuing passed the DV point so that the out of balance cell or cells in the module can "catch up". As the full cells will convert this excess charge to heat, you want to use a very gentle charge in this phase to minimise the possibility of damage, as heat is the enemy.

Bottom end balance: Gentle and controlled deep discharge at a gentle rate (depending on the level of discharge, 1.5 A down to 7.2 V; 500 mA down to 5 V; 200 mA below 5 V) usually done in successive tranches to a lower level each time (1st discharge to 4.8 V; 2nd discharge to 3 V; 3rd discharge to 0.6 V). The reason for this is to recover lost capacity due to crystal deposits/voltage depression which will inevitably happen over time when the battery is shallowed cycled in the 40-80% range (a good thing for longevity).

I know some have an aversion to discharging to 0.6 V (0.1 V per cell), but if that will destroy the module, then it was going out anyway. IMHO, better to whack that mole now while the pack is open rather than later.

I would question whether reconditioning has taken place, if at least top end balancing was not done. A full condition would require both top and bottom balancing, IMHO. Otherwise it is just a charge up.

It would seem, using RC charges utilising the DV cutoff feature, that unless the an additional timed gentle charge is done, there is no opportunity to top balance. Hence my questions on this.

On the notation 1C, 2C, etc, the C means capacity and relates to the normal notion of rating batteries in mAh or Ah, being the rate of steady current a battery can produce for 1 hour (at standard temperature, usually 20℃). Therefore (using a Prius module as an example) a 6500 mAh (which is also 6.5 Ah) module should ideally produce 6.5 Amp for 1 hour. The 6.5 A becomes the basis for 1C meaning 1 x C (Capacity–6.5 A for 1hr).

In terms of voltage would you agree that 1.2 V per cell is 0% and 1.44 V per cell 100%? Or, to put it in terms of a 6 cell Prius module 0% = 7.2 V; 100% = 8.6 V.

If that is true, I'd be looking to attempt a top balance if the DV voltage was less than 8.6 V.

Anyway, I have a lot of thoughts racing around my head and can't quite get them into any cohesive concepts. I dare say looking at the above, some might already be saying "what the ....?", I hope it is not too shambolic.

If you (or any others) were happy to bash this about a bit they might come out with a bit more coherence. lol. So will leave it here for now.

 

Hi Dolj ..

Its difficult (for me) to accurately answer all this when there is so many differing opinions around here and I don't want to go against anything the real gurus say! I wont attempt even half your questions for i am no professional I just copy others (lol) and mess about in my spare time its nice to have the ability to fix my own and friends cars. Myself and a few others here seem to be somewhat drawn in by and almost fascinated with these batteries lol? highly addictive geeky auto-guy stuff! put a few good modules away for safe keeping, a rainy day kind of thing if you have a few prius around your friends and family its a nice idea to get handy with modules but realistically how long will they last before they all go stale anyway lol .. long term storage is always on my mind.




Everything you say is pretty much around about as i see it other than discharge 7.2v @ 1.5A, I go a bit harder!.

everyone does this a little differently there's no "set way" but for me im inpatient and have wasted enough time on these batteries! if battery is too much of a pussy to offer me some reasonable 18a discharge numbers after a chg/ deep discharge & a cycle or two or it wont hold above 7.2v open circuit, i bin it no second chances.. that's a good enough comparative test for me to throw away the duds and build a reasonable and even pack with confirmed good modules that should work ok for quite a while especially if looked after once back in-use. Much rather a brand new pack fresh in retail box but can save lots of money by buffing the old one geek fun

Yea it will spike a little past 8.6 not much! all good show it you aint joking lol

"Thoughts and concepts" man it really is nuts to think about how much time and money humans have spent on these modules to date.. lol the mind boggles! toYo are still using these fine modules too so this thread will likely go on for a bit longer haha props rusideways.. & long live this awesome auto-leckie-geekie thread

cheers geeks

 

CAN someone tell me where is block 13 located in my 2007 Prius? I attached a picture i took, is it located on the left side where the power supply is at or a the right side where the letter paper is at?

 

Block 13 is the 25th and 26th modules starting the count opposite the battery computer (the battery computer is on the LHS in your pic). So the opposite count to that that is shown in your pic–the unmarked one and the one marked 3.

 

I need some help. I followed the various guides on this thread and I successfully restored all of my 34 cells in my Hybrid Camry 2006 (which incidentally use the Prius cells). I see the 272V (34 cells by 8V per cell) showing up on the input end of the junction box but nothing shows up on the output end (the end that connects to the vehicle input wires no matter what I do. Is it possible one or both of the solenoids are burnt out? Anyone have a similar problem and any thoughts what I need to do?

Thanks in advance for anyone's help

 

It sounds like the orange safety plug is not fully installed. It's a three step process. Push the plug in. Flip the lever up. Push the lever down. It's the third step that trips people up. The Camry plug might have a different orientation than the Prius.

Brad

 

Hello Everyone,

I am going to attempt my first cell replacement and before I start I have been trying to figure out if I can replace a bad cell in my gen 2 prius pack (2008) with a gen 3 cell? I have been unable to locate a direct, definitive answer to this and wonder if it will make no difference or if it is a no-no. If it makes a difference to the answer, because of where our prius battery gave us trouble, I will not be doing any kind of reconditioning and balancing and will just try to replace the dead cell and drive away as soon as possible.

Thank you for any knowledge you can and don't mind sharing .

 

hi daikon ..
everyones going to have a different opinion on this, its not ideal but personally I would do it if I was desperate to get the car going asap, just dont expect it to be a long lived repair without balancing

 

Thanks OzMatt,

So to be clear, is it the 1 gen 3 cell in a pack of gen 2 cells that will make it short lived too, or just the lack of balancing? thank you.

 

Just the lack of balancing!

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Guys, Hope all is good!
Q. If i charge a module first before discharge it and charges up to 7500 mAh on the first try. Is it still recommended to discharge and charge again to balance it ??
Thanks again for the help!!
Ed

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Just the lack of balancing!

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Thanks EddieAtl! Turns out I may go with a gen2 cell in the end. The Gen3 cell seller that was local offers no warranty or guarantee of any kind, so I may get one shipped from Cali. Thank you so much and wish me luck!

 

Good luck!

 

yes ..

usually if one module has failed there is a few more pending and balancing helps wake em up