I know hobby grade equipment isn't super accurate, but half of what I find online states NiMH cells are discharge capacity tested to 1.0V per cell, and the other half 0.9V per cell. On a Prius module, this is a difference between 6.0V and 5.4V. In all of my testing, I've been setting my discharger to 6V, and now I'm wondering if I should be setting it to 5.4 to see capacity?
A professional battery rebuilder < https://2ndlifebattery.com/about-us/ > who has bought more than $40K in equipment over the past decade laughed at me when I first visited him 4 years ago and said I discharge modules below 6v all the the way to 0.06v. But then all these years later, the day before yesterday he texts me this, which makes me think there's still much more to learn on the subject. "I have personally found that if I take the cells down to 1/2 a volt per cell that I'm able to regain the capacity much quicker. I generally have to do it after the battery has been completely charged and then discharged but I am finding a 30% increase in recoverable cells and I am able to produce a quicker turnaround on batteries. Dr. Quarto Says that it should never be done, all I know is what I see. Curious if you've experienced this. I did run into one gentleman that read something in one of the blogs about it."
Correct, but I'm not asking about the cutoff voltage for discharging as part of the rebuilding process, but for measuring capacity.
Why not listen to Panasonic, since they engineered designed tested and produced the module for sale, they say, 6 volts. end of story.
Does it matter? I might think that as long as you pick one spec and test all modules to it, that's all you need. The overall end goal should be the "same" capacity, and the "same" voltage at any SOC . Posted via the PriusChat mobile app.
Matters to panasonic, they say do not do it or the cells will be at risk of damage, the question was should i go to 1 volt or some other lower volt, my answer was, panasonic says 1, thats the only answer anyone in industry is going to give, unless they are ignoring the manufacturer that holds the IP in secret, and probably knows better lol ,but whatever, choose your own poison.
CAPACITY is a DEFINED term in both the industry, and more specifically, by Panasonic for this module. Capacity is the Ah delivered from a 100% SOC under a 6.5 amp load to a 6 volt cut off. End of story Any deviation is NOT capacity, it it were, then I can market modules on ebay that deliver 110% of new virgin cells, and when i get sued later, and discovery finds I failed to mention i take them to 5.4 volts, i will be sued for fraud and lose,
Yes, this! Catch is every time you change the configuration of your equipment you're going to need to update your baseline data with a brand new OEM pack. And somewhere on here yesterday someone said Toyota now has 200 backorders for OEM packs. Hopefully once ProjectLithium is restocked at the end of the year we can leave all this ancient NiMH science behind!
It's an interesting question, especially since NiMH lose so much of their charge to heat that doesn't get stored for later use. Seems like the cooler the charging process is the more efficient the results. But I've never gotten into this research because ever since the first day I worked with SKYRC chargers some of them have been randomly shutting down / malfunctioning and taking all their charge data with them when they shut down. So I just bought the SkyRC BD250: https://www.ebay.com/itm/184266440118 and am looking forward to having a screenshot of the discharge data for every module, especially high amp discharge data, which I've not had in the past. Hopefully that leads to rebuilt packs that are way more reliable than without this device.
