EEVblog Electronics Community Forum
Electronics => Power/Renewable Energy/EV's => Topic started by: Mosaic on May 20, 2022, 05:25:57 pm
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Hi guys.
Just built a device for a guy down under in TIWI. Shot a video of it. Works so well i am thinking of offering it as a kit.
Have a look...and pls comment! I'd be willing to send one to Dave to try out as a DIY effort.
https://www.youtube.com/watch?v=Dd0HBqpBgok (https://www.youtube.com/watch?v=Dd0HBqpBgok)
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It won't work. This has been tried so many times by so many people. Kind of like a perpetual motion machine. There are companies that do lead-acid battery repairs but there is much much more to it than just sending pulses into a battery.
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I've taken apart a few dead lead acid batteries and in every case so far one of the plates has completely crumbled to dust. I don't think sulfating is as simple as it is often described.
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There's ten different reasons lead-acid batteries fail. Metal in a strong acid solution?! Most failures are mechanical due to corrosion.
Sulphation is one reason, and those non-conductive crystals are stubbornly stuck in the plate's pores. TEM photos show various crystal chunk sizes form.
Decades of chemicals, additives, new electrolyte, overcharging tricks tried etc. and nothing can really remove them.
There is mention adding carbon graphite to the plates in a few patents decades old but it seems there's really no need to improve lead-acid battery technology.
I tried building sulphators and find they don't do anything beyond a gross charging session for the battery, which might help with mild sulphation.
Holding on to a bad stock, hoping it goes up - this is human psychology. Holding on to a trash battery and hoping it will come to life, well it's dead Jim.
Even "12kW pulses" can only induce current around the passive sulphate crystals, short enough pulse to not cause heating and gassing but IMHO that crystal ain't moving without losing plate material as well.
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To make a real and lasting impression, find a moderately to severely sulfated telco cell with clear plastic housing and make a time lapse series showing actual results along with actual load vs. voltage graphs at different stages of the test.
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Pulse charging seems to be far more effective at prolonging the life of lead acid batteries than trying to fix a bad one. My understanding is that the high peak voltage prevents sulfation from forming while the lower average voltage slows down corrosion. It works better than a constant voltage which tries to be a compromise at minimizing both common failure modes.
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Modern lead acid battery's are made cheap/shit and they always fail from the metal falling off the plates.
It's a mechanical failure so you cant fix it without taking them apart.
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Batteries that have a pure sheet of lead for plates might be worth a try. :-+
Those (the majority) that have a lead grid with paste spread in the gaps, nah. The paste expands and shrinks with the state of charge and eventually pulls away from the lead grid and loses contact, or simply crumbles away as others have said. :horse:
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It's one thing you often notice with low mileage Japanese imported cars.
The Japanese brand battery they come with lasts 8-15 years even after you get the car,
but once you have to replace it with a local battery they last 3-5 years.
The Japanese car batteries always seem to be built way better.
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Yes I find the OEM Japan car batteries are really good but you can only buy junk for replacements that last just a few years.
How do you pump in 12kW to a 12V battery? Hit it with 500V impulses? Point is you have to zap the battery past the point where you can get breakdown (arc) in the separators, sediment, and risk an explosion. Any of us worked with hydrogen know it has the lowest ignition energy and wide air/fuel ratio so it lights up very very easy. Even with the cell covers off, there's lots of trapped hydrogen under/in the plates, just tip a battery to see that bubble out.
All these boneheads are working dangerously, sulfuric acid isn't great for your eyes or complexion. Bubbling, boiling stirs up the sediment and a short can happen within a cell during "regeneration".
The guy whose chinese charger with bad firmware overcharged his car battery and when he came out to check, it had exploded. Nobody wants that.
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Pulse charging seems to be far more effective at prolonging the life of lead acid batteries than trying to fix a bad one. My understanding is that the high peak voltage prevents sulfation from forming while the lower average voltage slows down corrosion. It works better than a constant voltage which tries to be a compromise at minimizing both common failure modes.
No. The failure mode of lead acid is overcharging from crappy chargers (which are used in abundance). Overcharging causes the sulfation. With a good charger, lead acid batteries don't go wrong. I got this info from a client that repairs lead acid batteries for a living.
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Bad chargers are one of many different factors. Some batteries are much better than others even under identical conditions, I strongly suspect impurities in the materials inside the cells is largely responsible for that. As far as I know sulfation occurs not when a battery is overcharged but when it is deeply discharged. Overcharging causes gassing and boils off electrolyte.
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No. The failure mode of lead acid is overcharging [...]
I can highly recommend trawling the papers from the BATTCON conference for both ancient wisdom and actual science on that topic.
To call it "clear-cut" is not even an approximation.
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I have found Battery University to be reliable: https://batteryuniversity.com/article/bu-403-charging-lead-acid
The jury on pulse charging of lead-acid batteries is out. I do not mess with it.
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OP, I dislike your stretching the truth, all over the place.
"M.I.T certified Engineer designed", wait it's the MIC Institute of Technology Green-Tech Facility battery regeneration project.
It seems to be 36VDC power 35usec pulsed through three power mosfets into the battery. Scope shows 640Apk yet it's 20V power not 36V, so what's the real power supply there?
"Now HEV (NiMH capable and soon Li-Ion ready)" as well as "TESLA compatible" - those batteries don't have sulphate issues, and Li-Ion will make a nice bonfire when thinking high current pulsing them does any magical rejuvenation.
You've pushed this concept too far, into debunking territory. Pulsed desulphation only works with rare types of sulphation, small crystals that a decent charging will get rid of anyway.
https://hackaday.io/project/25741-battery-desulfator-kit-tesla-12v-compatible (https://hackaday.io/project/25741-battery-desulfator-kit-tesla-12v-compatible)
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The Japanese brand battery they come with lasts 8-15 years
Everything is built better when it's made in Japan !
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The guy opensourced this
https://hackaday.io/project/25741-desulfator-engine-for-climate-change-mitigation
So nobody has built this desulfator to say their opinion on if it works or not ? Why not?
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See my reply to your other post.... https://www.eevblog.com/forum/oshw/desulfate-regenerate-lead-acid-batts-a-new-diy-guide-overnight/msg4732406/#msg4732406 (https://www.eevblog.com/forum/oshw/desulfate-regenerate-lead-acid-batts-a-new-diy-guide-overnight/msg4732406/#msg4732406)
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See my reply to your other post.... https://www.eevblog.com/forum/oshw/desulfate-regenerate-lead-acid-batts-a-new-diy-guide-overnight/msg4732406/#msg4732406 (https://www.eevblog.com/forum/oshw/desulfate-regenerate-lead-acid-batts-a-new-diy-guide-overnight/msg4732406/#msg4732406)
Come to Lithuania, everybody is like you here, they would be thrilled to get new friend.
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No, seriously, personally I have no need for one (whether it works or not). If you do have a need then go ahead and build one and let us know how well it works.
That's my reason anyway, I can't speak for anyone else.
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But this one is advertized to work over night, not weeks or months needed. I'm puzzled that it's opensourced but there is no interes in even testing it, there are more qualified members for it, I don't even have a scope, so what can I measure?
The date is Year 2017, so nobody built this in 6 Years?
Somebody with proper equipment could measure the output, test it.
I just have 2 UPS 12AH batteries that over 6 years did not loose capacity, they both are 13Ah 14Ah, but CCA dropped 30% from original value.
All I can say that I tested the Megapulse, and it did not work at all. Also how Megapulse got all these certifications and is fitted to Volvo, Mercedes, MAN, etc. etc. I do not know are all these companies idiots? Is there some money laundering scheme going on? Why use device that does not work yet cost 150CAD
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In the years past I found a circuit that pulsed the sulfated battery at 2000 hz. I built it and i was shocked it actually worked. Over a week or so time the battery could hold much, much better charge. The pulser had gotten stolen from one of my so called friends and I have never built another. :-//
Information from a local battery expert dealing with all kinds of batteries for 40 years stated that all batteries on the market today are pure junk lasting from 3 to 5 years if you are lucky. The problem is the plates are now thin as hell and some even put holes in them stating this is an improvement :-DD |O
Very few manufactures still make thick plate batteries especially in the broken US. Yes a pulse circuit would work if the right frequency was hit to cause the sulfur to dislodge and be reabsorbed into the sulfuric acid.
Problem is the plates self destruct before that happens. |O
If I can find the circuit i will post it.
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I had mixed results taking batteries from a boat yard dump site and permanently charging them backwards.
It takes 4 to 6 times the nameplate amp hours to do it. One of them lasted 2 years in my moms Jeep. Some had great initial capacity but failed quickly, for example, a GNB 90 amp hour totally sealed battery designed for standby use. It was open circuit as recieved. Was able to recover 70 amp hours after reverse charging for 2 weeks, (top was cut open to add water), but it quickly decayed logarithmically to like 10 amp hours capacity after less than 10 cycles.
I got 2 extra years of use out of a car battery (it had decayed to about 3 amp hour capacity after at least 6 years of use in a truck) by dumping the acid out and replacing it with water and leaving it on a float charger for 2 months. (Nominal polarity, not reverse) The acid concentration rose to 1.2. i have heard others say this works as well, the usual advice is to dump the water out and put the original acid back in, i did not do that.
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I have looked at the PCB and schematic, while my knowledge is limited, the Eagle throws errors:
This thread started May 20, 2022, the files are from 2017 :-//
Very strange that files are not updated.
I do not know how to use EAGLE, seems crappy software from 1995, no 3D no way to flip the board. no wonder nobody wants to build this.
Imported this to Target 3001, but it does not import right.