How I Recondition Cells

Never said what you do doesn't work, but drilling into modules isn't safe. What if the bit goes down too far and causes an internal short? The pack is going to swell up like a balloon and go ka-boom, or possibly catch on fire.

I doubt your hobby store epoxy is going to hold whatever rat turd plug you patch those dehydrated modules with, you DO realize the internal pressure can exceed 100PSI, right?

Know what is safer and much easier than dicking around with dehydrated modules, dealing with caustic potassium hydroxide (which I guess is as safe as water in your opinion, try it as mouthwash next time if you think it's so benign), potentially causing a fire/explosion, trying to replug a module with two part epoxy which I highly doubt will hold?

Buying another damn module....

Your "insertion" of 9Ah is also equally silly. The rated capacity of these modules are 6.5Ah. I limit my charging to 7.2Ah because I take mine below 6 volts which I believe requires a bit more of a charge to fully charge as ratings are made for a discharge to 6 volts.

If you are charging a total of 9AH above a rate of 1A, you are going to be cooking your batteries, which might explain why they need more water..

You are trying to put 10 gallons of water in a 5 gallon bucket by "inserting" 9Ah into a 6.5Ah module. Waste of time. Try putting 100Ah into a 65Ah car battery and let me know how well that works..

Then you have the brass to tell me that discharging below 6 volts is a waste of time, when YOU YOURSELF admitted "oh golly gee willikers it does release some hidden capacity, wonder where that came from?"

How I Recondition Cells | PriusChat

Then later on..blame me for "ruining a good module" when you repeated this process...and when I explicitly asked you WHAT CURRENT LOAD DID YOU USE?! It fell on deaf ears. You can NOT apply a high current discharge below 6 volts!

I am leaving this thread. I feel like I'm talking to a insane asylum patient with schizophrenia.

 

Tracy, keep doing what you're doing. This is highly educational and informative. I am , and probably many others are, learning a lot, thanks to you. Your methodology and explanations are very helpful. Ignore the armchair critics - some people are simply closed minded and that's it.

 

My vote, it will be very anti-climactic - if there really is eventually 100psi in the case (do we have a valid source for this?) the case and plug and vent will hold. It will be a little like a "slow leak" when you get a screw embedded in your tire. No blow out, no screw fired from the tire, just loss of pressure over a fairly lengthy period.

And, to add fuel to the fire (figuratively), my guess, without anything to source this from, is that you could drill right through the entire module, or even punch through it with a metal implement, without unleashing the fiery demons of hell!

 

Thanks, I found it and successfully downloaded it... Still haven't figure out where the chapter on NiMH is?

Also I appreciate your perspectives that aren't the standard ones because I'd rather learn more than be dismissive, especially challenging the commonly held notion since NiMH were first introduced to consumers in the 90's that they need periodic deep cycling/reconditioning.

Even messaged Professor Joe who teaches hybrid repair and EV technology in college and mentioned your point about there being no papers published about crystallization in aged NiMH only NiCad and he said what many other on here have said, which is: "Obviously the guy has no idea what he's talking about regarding the crystallization build up on the plates."

 

Combined "some" NiMH sections, there may be more. Searches for crystallization and recrystallization, show many instances.

 

Thanks Alf... You're always so dang helpful!!!

 

Can't imagine any book that costs $3,000 unless it's an antique. Heck, even all of my college textbooks didn't total close to $3,000.

 

You probably haven't been in college for a long time... It's really bad these days! Never underestimate the corruption of capitalism when "higher learning" students can get loans without collateral or decent credit ratings and can never get out of the debt via bankruptcy. This link highlights plenty of text books that cost more than $500, some more than $1000: The Most Expensive College Textbooks - BookDeal

 

You typically won't see a memory effect, properly known as "lazy battery effect" in NiMH cells, when used in other devices that fully deplete and recharge the cells. For an example, Sanyo Eneloop rechargeable AA NiMH batteries.

The lazy battery effect is especially caused by constantly discharging to a non-depleted state of charge, and then charging to a level that is not the full SOC. The hybrid battery management system neither fully discharges or charges the batteries.

This may be the reason Toyota switched to Li-ion batteries around 2016, although I am not entirely sure for their reason.

PriusCamper, you might message Professor Joe and ask what exactly goes on inside a NiMH cell when subjected to multiple cycles of full discharging and charging.

Crystals or not, there is obviously something going on inside these cells chemically that restores capacity.

Also..I am not familiar with programming automotive computer modules, and I'm not sure if the BMS is "read only" or has something like an EEPROM, but it would be interesting to see if it's technically possible to write code to the BMS to fully discharge and charge the batteries, which would then not require any removal of the battery from the vehicle, and the ability to monitor everything from Techstream or Dr Prius.

 

Yeah Subaru and Honda nerds long ago figured out to hack and reverse engineer/reprogram code in auto computer modules but not enough Toyota nerds to do that for us at scale yet. Closest thing I've read of someone finally starting to figure some read-write functions out is the guy putting a Lexus engine in his plugin Prius over at: https://black.jmyntrn.com/ He's still in the early stages but feeling confident about it, so you might want to reach out to him?

 

Would be cool to drive a 1st gen Insight. Always wondered how it would be to drive a hybrid with a manual transmission.
They also use only a 3cyl gas engine, and it's a coupe as well.
I've heard as high as 70MPG if you drive it carefully.
I could never figure out why Toyota never made a hybrid subcompact or coupe. They do make a Yaris Hybrid, but it's not available in the US.
US seems allergic to city cars. Be neat if Toyota made something like a Ford Festiva looking hot hatch in a Hybrid.