Gen II Prius Individual Battery Module Replacement

How is that calculated? For example:
My module 1- Charge 8724 less discharge 5558 = 3166 mah ?

 

Per previous post, the charge number is really only useful to confirm it is fully charged. Its what clued me in on the 12v issues you had previously.

 

Steve
Wow that's great data sharing! Updated.

CJ

 

You've already gone to a lot of effort. If this were my pack, I would be pleased with the results, particularly with the replaced modules as they are in reasonable health.

 

Steve
That sounds great! Thank you for your help.

CJ

 

You will finalize the charge after installation by starting the car and letting it charge at idle until it stops. Then you will force charge it to max.

 

That is correct. Look how close across the two cycles were...

 

You should be able to proceed to completion. I would recommend you do the idle charge as soon as you place the battery and can make all relevant connections. If you find you need to remove the pack again, it's much more convenient than pulling all the trim and seats... again.

 

Steve
I still had not performed step 7, do I still need to?
You mentioned you are an Engineer in AZ. I used to live in Phx and worked at America West Airlines...US Air... American Airlines.

CJ

 

Put some miles on it (a full tank?) and run a charge/discharge test with techstream.

Steve

 

As I read this (and other) threads about "simply"replacing a module" to fix a battery pack I am always aware of how much time people put into the effort. It is certainly more than 1 or two hours of time.

Yet, when people ask me to do this service for them, they expect to pay only a couple hundred dollars, including "a few" replacement modules.
Doing this on your own, when labor is free, is a lot different than when you put me on the clock and want me to charge you for time spent on the endeavor.

Interested in how things go for your CJ.

 

Eric,

My wife would be thrilled if I got even a single nickel for every hour I've spent on IMA or Prius batteries in the last 16 months... It might buy a new pack...

Steve

 

I can tell from your posts that you are having a good time. A fun hobby at this point, and don't we all need a fun hobby?

 

I think we've had this discussion before... There can be a fine line between hobby and obsession.

It's analogous to flying... long periods of boredom punctuated by moments of shear excitement/terror... i.e., it's long periods of boredom/frustration punctuated by moments of joy when something useful is discovered.

 

According to Techstream, block 6 was weak on my hybrid battery. When I got the battery out of the car, sure enough module 11 was low at 6.45 Volts.

All the other modules except those on the very ends showed 7.7 Volts. (A few were 7.69 or 7.71) Module 1 measured 7.61V and module 28 measured 7.62V.

I'm about to order replacement modules and start the rebalancing process. My question is: should I replace the 7.61V and 7.62V modules as well as the 6.45V module? Or is it likely the rebalancing process will bring module 1 and 28 back to full health?

Techstream ahows block 6 with an internal reaistance of 0.024 Ohms, blocks 1 and 14 0.022 Ohms, and most all others at 0.021 Ohms. I have not tested internal resistance manually on each module, and I got my Voltage readings with no load.

Thanks for any assistance!

 

The end modules, #1 and #28 always run a little different than the rest.

 

+1 to Brad's statement, and to drive it home, no. You shouldn't replace them based on the voltage difference alone.

They are generally the healthiest modules as they have only exposure to 2 heat sources vs. 3. All other modules in the pack have exposure to the heat of the two adjacent modules and themselves. The end modules experience heat internally and on one side.

Concerning rebalancing any of the modules, results depend a LOT on how you approach rebalancing. If you read above to the process Chris Jones went through, you can see it's fairly involved. Most don't go to that length.

Steve
merged.
Speaking of Chris... How's it going, Chris?

 

Thanks for the feedback guys. I'll go ahead and replace just that one module. I'll update the thread with my results, but I am not expecting any of my outcomes to be unique. My fingers are crossed!

 

Hi Bob - going through the same process now please post results. Did you balance or just replace? In my situation I have;
-- 25 modules all at 8.1 +/- .01
--#1 7.9
--#28 7.65
--#21 6.96 --replace here?

Appreciate any input - Thanks

 

Did you do any diagnostics with MiniVCI? Decisions based purely on voltage readings that are within the normal range are less reliable than those supported with in-car performance taken from Techstream.

7.65V isn't inherently bad, but the disparity of #28 from #1 makes it suspect.

#21 is done for.