I can’t find the details of what frequency in the study and only this from Reddit.
I haven’t even found the results from the source to confirm the procedure but assuming it’s 2khz at 50% duty cycle what would that look like? 50% of the time is no applied voltage and no charge?
Is it hard to produce a square wave at such a high frequency?
2kHz isn’t that high…
Is it hard to make a square wave at that frequency? I’m trying to find something that makes 2khz square waves at 50% duty and 126v
Mouser didn’t have anything and say getting something to make a square wave at the frequency is strange.
Technically it’s easy to create a 50% duty cycle, 2kHz waveform. Heck, for a couple of dollars you can get a 555 timer and a 200V-rated MOSFET to pulse some current at 2kHz. Check for schematics for astable oscillators (preferably “gated” for on/off control) using the TLC555 or NE555 timer chip. There are lots of other timer chips and ways to create a square wave too.
But you”re probably not going to find an existing high-voltage, moderate power waveform generator at a reasonable price and there are practical concerns when pulse charging…
How would charging with common 110v 60hz ac go?
https://www.sciencedirect.com/science/article/abs/pii/S0306261920315932
Seems needs higher frequency to not be detrimental.
maybe with pwm…
Back before Lifepo4 began infiltrating the boating world, there were all sorts of papers and studies saying how pulse charging would magically return hardened sulfate back into solution, and magically restore lost capacity and performance of Lead acid house/leisure batteries.
Several chargers popped up with magical marketing around pulse charging, and there were no shortage of people claiming it worked wonders, especially in the automotive sector.
Perhaps some LA batteries, in certain states of sulfation, would benefit.
At the time I was basically living off of lead acid batteries, and borrowed one of these magical pulse chargers when my house batteries started to really show performance loss, judged by watching a columb counter closely, and the voltage maintained under load during discharge.
The pulse charger did absolutely nothing in my case, other than screw with my tv reception. Performance was unchanged after floating the battery for two weeks.
More skilled people tested these pulse chargers with proper skills and tools, accounting for the variables, and found there was no difference in performance between the pulse charged batteries and the ones held at the same float voltage by a power supply for the same period of time.
Obviously Lithium is a different animal, but it seems a profit motive is often not far behind such claims, making them all too suspicious, in my opinion.
I’m surprised you can charge with ac period. I thought the negative voltage applied to a cell would be bad news
having accidentally applied negative voltage to a cell, it should be bad news. even for half a second of contact, the negative voltage can completely drain a cell and reverse the electron flow inside it, ruining it permanently.
How are they charging with ac if reverse voltage kills cells?
This looks more to me like pulse charging. They’re alternating the current between 0 and x amps.
it’s
it’s almost as if we have devices that handle AC voltage in such a manner that the batteries only see positive voltage when charging 
Here ac is used to heat the battery
at 500hz.
I dont think says the voltage
In this paper below (same as I posted up in the thread) I assume when they say ac they don’t mean pulsed. I think can get the full paper and don’t have to pay.
https://www.sciencedirect.com/science/article/abs/pii/S0306261920315932
Why isn’t ac charging disasterous as is reverse charging?
https://www.sciencedirect.com/science/article/abs/pii/S0306261922003592
They are not charging with AC…
“As a result, lithium-ion, increasingly the battery of choice, must cope with superimposed alternating current (AC) across a broad range of frequencies.”
…comparison of DC profile with coupled DC + AC duty reveals that high-frequency superimposed AC does not contribute to ageing
There is some high frequency AC voltage riding on top of the DC charging voltage. Check the abstract for the paper, it’s described there.
It is, one of the best ways to force a cell into thermal runaway (catch fire and possibly burst) is to reverse charge it.
The details in the referred to research papers really matter here. The popular but brutally brief summaries done in so many web sites end up avoiding really important details.
A decent increase in cell life did happen with a couple cells but most only had a couple percent increase, it’s very cell and chemistry specific…which makes sense.
Weighted against that is the need for specialized hardware and wall power that can handle 2x the current (at least) in pulses unless only slow charging is done.
That’s a very real market opportunity though IMO…slow pulse charging that increases cell life a bit by pulsing and increases cell life more by slow charging. Stop at 4.15V and you have a setup for significantly extending cell life. But the pulse charging will be only a tiny part of that life increase for most cells.
Hi, I’m looking to buy this Ohrija 42V 6A charger from Aliexpress for my 10s3p Molicel P42A pack.
Anybody has experience with this brand? Are they any good. What should one look for in a good charger.
Ohrija is the same OEM as radium and SKP chargers. Hoyt/Metroboard also use them. They have been great, in my experience. Excellent size to power ratio, they don’t get too hot, they aren’t noisy.
Cool, thx for the quick reply. Ordering now 
