Now the question is, can we identify these possibly dehydrated cells quickly before we invest time in them ? We will find out, I have 28 modules ready to go I will discharge them then charge them at 10 amps for 5 minutes then discharge them to 6 volts at 1c then measure the voltage rise after 4 minutes as well as graph, and see if we can spot these possible dry cells. The X1 Pro charger will be a great help, it has a discharge charge cycle, combined with the max amps in safety I can tell it to cycle and insert 0.833 amps (10 amps five minutes) or i can use the max timer and go 5 minutes, probably easier lol. Then rock my way through the entire pack in under 3 hours Then use the CBA II and discharge and graph them. Should be one day for all of it.
Historically, I would have already placed these in service in the car, this extra 2 week step proved more than 50% have issues with a few having a catastrophic issue. Taking your time will save you problems down the road.
Great! If you solve the problem of “reconditioned” batteries being largely unreliable beyond a short period, this will be huge. Hats off to you for all this work, experimentation. And for sharing!! Aloha.John
And with this test we can assert a number of things, and accept them as FACT until PROVEN otherwise. 1- The vent opens at 90 psi. NO ONE SHOULD PURPOSELY PRESSURIZE THESE BATTERIES. 2- Drilling a hole in top, threading it, and inserting a 1/4" pipe thread bound with 10 laps of teflon tape will not blow out before the container vents. Of course, welding it in place using plastic weld which holds to 3,600 psi would be advised, also, the pipe should be nickel or nickel plated, brass is no good and aluminum will react violently. NO ONE SHOULD DRILL A HOLE OR TAP THREADS OR GLUE THINGS IN HOLES ON THESE BATTERIES, 3- The case DOES NOT SWELL FROM PRESSURE which I knew to be a fact, the case swells due to the electrolyte and collector assembly swelling due to resistance heat and overcharge. This should be avoided, it can be seen during normal end of charge as an opening appears between modules at the top ends/sides. If swelled, immediate discharge will reverse it as will time. Alternatively, and to reach true end of charge in an effort to achieve cell balance, remove the charge upon appearance of swelling, wait three hours, continue charging at 1/3 the previous rate OR 2 amps, whichever is HIGHER. The lowest amperage for end of charge cell balancing is 1.95 per panasonic. 4- The case can swell without venting & The case can vent without swelling, these are established FACT. These are reactions to completely separate processes which COINCIDENTALLY occur near the same point of time, near end of charge. One has to do with pressure build up from a chemical process that exceeds a cells capability to process and recombine, the other has to do with a totally different area in the cell and is due to heat resistance caused by too high amperage resulting in a mechanical reaction, swelling.
Now you’re talking!! My Priuses have seriously degraded mpg from bad batteries. This plus the technical aspects involved explains my interest in your work
One day, Honda and Toyota may catch up to the mpg in my geo metro xfi, maybe, it has ZERO TECH lol 84 mpg highway speeds virginia to detroit and back for geopalooza No A/C available on the XFI, I added it from a later model and built electronics to allow it to work with the small engine On the XFI the A/C now doubles as an ENGINE BRAKE going downhil lol, seriously
yeah, you’re the mad scientist alright, and I mean that in the most positive way! You really get things done!!
In the first image, that low voltage module, that's the one i did that 3 volt discharge on, prior to that, as we all saw when i chose these modules, it did not exhibit that low voltage behavior. Do not discharge below 6 volts !
It'd be way easier to simply put your modules on a digital scale... The dehydrated ones will weigh less than the ones that aren't.
That would require a large level of effort in removing and reinstalling the cells, and any meaningful data would be most likely not be realized. These cells are old and most have probably lost some water, those that have lost an equal amount in all cells yet provide 95% of the rated capacity could weigh the same or even LESS than a module that has severe dehydration in just one cell that performs poorly and has a high 4 minute resting voltage. I'll stick with my plan, lot less work and faster.
You missed the point... The weight of each module on an ordinary digital scale is slightly different. Dehydrated modules will weigh slightly less than well hydrated ones. You don't have to take apart anything, just put each module on a digital scale. And yes some battery packs will weigh a pound or more than others. I know that for a fact! And GreenTec rebuilds packs that not only never vent when they heat up but are way heavier than other packs. Why is that? Do they have a secret sauce? And if you want to prove the problem with old worn out NiMH is not crystallization but hydration you need to add a module weight data point to your spreadsheets to validate your argument.
lol, i would still have to disassemble all the modules, instead of just running a tool up and down the pack. and 2 modules could still weigh test incorrectly when compared to actual electronic test and measurement, its common sense. and crystallization is a unicorn in nimh, not a factor
You sure aren't very fun to work with... It seem like it's more important to you to not agree with anyone than it is for you to value the ways we can learn more together. It's just like your crystallization is not true assertion. I'm willing to explore that possibility rationally and logically. For example if it was hydration and not crystallization, most of us DIY folks have at least a 100 modules on our shelf to run tests on to help you explore your viewpoint. But even the most basic of many types of possible tests you claim you won't do because you'd have to take apart your pack? Even though the process of rehydration that you posted in your youtube video requires you to take apart your pack. How is that rational or logical? Only a rookie that doesn't want to agree with anyone about anything would behave this way about module testing. I'm out... I tried to give your work the benefit of the doubt but clearly you're too manic and adversarial for any of us to waste our time working with you anymore.
Yea, I get it... You're deficient in some specific social skills. I mean look at the some of the responses you're having with others in this thread? I thought we were here to work together to advance our knowledge and skills? Is that not what you're here for? See 'ya later!
deficient, no... TOTALLY DEVOID but the Americans with Disability Act protects me and requires / protects my inclusion in society, it does not demand I conform to some "group thought" lol