Gen II Prius Individual Battery Module Replacement

Steve, first if I misinterpreted your response and reacted inappropriately. Mia culpa.

Second, thanks for your points. I'd already half conceded to myself that I'd have to do the modules individually instead of paired banks.

What sort of unreliability would you anticipate at the single module voltages.

I wasn't planning to order any modules until I'd completed the entire process, so 19 will certainly prove itself a loser, and 12 and 13 might. If this process doesn't overstress any of the others, then worst case is a purchase of 3 modules.

Thanks again,

Mike

 

Thank you for commenting. At the very least, you've at least confirmed what I think I've begun to understand.

Two questions, though:

1. I get your point about the middle of the SOC from various curves I've found on the internet. When you say the 'ends' of the SOC do you mean front end and back end of the curve, or just the back end?​

2. When you say I can count on doing it again in a few months, is that about reconditioning in general, or just my process?
​

Thanks,

Mike

 

1) Both ends, but much more so the charging end.
2) In general and more so with your process. Testing is not balancing, and you're doing nothing to address voltage depression or balance.

I'm not sure what you mean by this.

 

I've been working on balancing my gen2 Prius battery by referencing this thread and I think it would go smoother with some guidance from more experienced folks. I've already made several classic mistakes, popping in new modules without rebalancing and buying the terrible b6 charger/discharges.

I'm going to return those and order the Reaktors and accessories. This is what I'm planning on ordering:
X2

Are these correct?
will I need to order or make any cabling? The b6 cabling couldn't reach accross the modules.
Oh and what wattage headlight should I get for load testing?

Thanks,

Sam

 

That battery is woefully inadequate. Pick up a $90 marine battery from wal-mart.

With the regenerative function and 20A discharging capability of the Reaktor, you don't need a bulb for load testing as the reaktor(s) will pull more.

And pick up a basic charger with 2/6 or 10A settings. The ones with electronic control will shut off. The old analog Schumacher units are still sold at Walmart and most parts stores.

 

Gents, just to let you know - I am still vertical and above the ground. Visiting this thread to thank those 2 or 3 of you who had voted for me last August . Had won that Future of Energy Competition. Solar Panels (3kW) with SolarEdge Inverter had just been installed. Tesla PowerWall installation is scheduled for June and perhaps starting from July I will be charging Prius batteries from the Sun! Going Green in Battery Rebuilt. Also got Prius C for Live battery testing - perfect test car for my 20-channel Battery Analyser. In meanwhile I am observing other DIY-ers packs failures - last week a 38-module pack came in. My Scanner gave me idea in 30 seconds that modules used by DIY-er were a mix from 2007, 2008 & 2010. They put them together judging by the voltage only. Obviously they've missed my video on Youtube "Prius Individual Module Testing with Voltmeter for Dummies - OCV vs CCV" We'll see what Analyser will tell me. Play safe. Love you all..

 

Fun news Kiwi.
So glad you won.

 

Alright here's pics of my setup with wallmart battery and charger and Reaktor.

And the settings I have. Please let me know if one of these is wrong:

Wait time: 5 min
NiMh trickle: off
Delta v sensitivity: 20mv/cell
NiMh check delay: 0 minutes
Temp cutoff: 50celsius
Safety Timer: off
Capacity cutoff: 7500mAh
Charge: 20a auto
Discharge: 20a 1.2v
NiMh cycle: 3 d>c

 

Charging at 20 amps to 7500 mAh is asking for trouble IMHO.
You'll see.

 

What would you suggest as alternative?

 

Charging at 2 amps or less to 7500 mAh is safer. Less chance of damaging a weak cell in a module.
This is why most choose a grid charger or two or more mulitchannel balance chargers - it takes too long
to charge a 28 module pack with a single channel balance charger.

 

His modules will be dead before the charge has a chance to do any harm. A 20 amp discharge to 1.2 volts will ruin them.

1. 20A discharge to 6 V
2. 200 mA discharge to 4 volts
3. 20A charge for 4000 mAh
3. 500 mA charge for 6 hours.
4. Rest for 24 hours.
5. 20A discharge to 6 V. Record the capacity.
6. 20A charge to 3000 mAh. Do not let the modules sit empty.

 

Didn't notice the discharge to 1.2V at 20A . Wonder how he decided on that voltage?

 

oops! yup that's going to pick out the weak modules

 

Thought it was per cell. This is why I was doublechecking before starting things up.

 

Is 3 discharge ->charge cycles not the preferred method of balancing the modules anymore?

Is the 3 discharge->charge cycles not the preferred method of balancing a module anymore?

 

Individual cell voltages cannot be determined so that's why we were concerned for you. Many DIY rebuilders discharge modules to 6.0V (or less) before recharging them which of course is 1V /cell on average. 1.2V /cell would not be an adequate discharge for these modules to do a good rebalancing.

Three d>c cycles is standard practice to get the most out of the modules but not absolutely necessary - two cycles is enough provided you are able to reach 7500 mAh before dv/dt or dT/dt is reached which will stop the charge cycle early (unless you disable them which is not a good idea in my opinion).

 

Okay. In that case what should the delta peak sensitivity be set to? I had it at 20mv/cell in an attempt to disable it.

 

Only because he has his sensitivity set to 20mV. These things can take 20A w/o an issue and the higher charge current makes deltaV way more obvious and very safe at 3-5mV settings.

Most are wrong. IF you cycle, 30 minutes wait.
Never try to bypass DeltaV unless you're charging at < 1C currents.
Auto charging is a little flaky. I prefer manual.
Per Brad, 20A to 1.2V will destroy a module.
If you cycle, I prefer C>D.

You will get better results with Brad's recommended process.

Set the NiMH sensitivity to default.

 

Thanks. If I did C>D I would need to charge it again afterwards, yes? What would I charge it to?

I think I will stick to cycling just because I understand it better and it will run on its own.