Burp/reflex charging

[Mosaic]

While there are commentary on both sides of the fence on this topic....I found this bit of empirical science that makes the case quite well.

https://corsair.flugmodellbau.de/files/elektron/NASA-II.PDF

What's interesting to me is the flooded cell discussion near the end of the paper which appears to reflect how a lead acid cell also works.

Thus I am wondering if burp charging during equalization can be more effective in reducing the time and heat gen. it takes to equalize such a battery.

Also of interest:
https://www.siliconchip.com.au/Issue/2014/March/Burp+Charger+For+NiMH+%26+Nicad+Batteries
https://www.google.com/url?sa=t&rct...xd8WxQW_6ADTgJQ&bvm=bv.91665533,d.cWc&cad=rja

 

[Tony Stewart]

Around the same time I did test on behalf of my client whose product our company was manufacturing and I applied my test experience on large motive power lead acid batteries and NiMH types.

His product was extreme risetime low duty cycle 10A spikes on a galvanostatic steady charger. Meanwhile another company flew into Winnipeg on their private jet from Lake Tahoe and wanted to buy his patent for something like $1m and he wouldn't take the offer. THey had a similar product that was a large burp charger like this Thesis and they have issues with Air-bags being deployed in cars from EMI in the parking lots of their battery operated chairlifts. at 1 or 2 grand a pop. They both agreed the de-sulfation process worked and we learnt it also reduced antimony leaching.

But this is the first I have read about Gas generated by "Burp, Pause and galvano charging" I'll have to read it someday. ALthough I understand it from the same ESR increasing process in Aluminum smelting with Arc smelter pots and gassing anodes.

All I can say is they agreed you don't need a "blow torch" ( nor want) (that they had) to have the same effect as a "Bic lighter" burp pulser.

AS to your questions, yes yes and yes., but dont need a blow torch

 

[Mosaic]

I have designed a fast risetime, low duty, pause charger which is meant to desulphate and dedendrite using the same pulses. Amperage spikes have been tested to 700A. Automotive lead acid sized batteries.
It does a couple other things to improve the state of the art which I can't state w/o an NDA.

I am considering including burp charging since pause charging has much less effect on flooded cell as opposed to starved cell batteries. The latency of ionic movement aka the surface charge in flooded cells seems to require burping based on the Thesis.

What do you think Tony!

 

[Tony Stewart]

One must know the withstanding EMF of any current pulse relative to warp restrain on weak plates to prevent particulate matter causing PD then BDV resulting in cell death from sustained short circuit until holding current reached.

A Bic is better than a Blow torch. But Burp is definitely the answer just dont breath continuously this way i.e. depend on this for fast charging, else other failure modes emerge.

And dont just test virgin batteries to find out. Choose ones corroded near end of life then extend it >2x cell ESR drops with temp rise, which is also a test variable along with desulph etc. there are methods to estimate plate temp and gassing... Just like measuring LED Tj but with longer thermal time constants involved.

i wish I worked for Tesla in Palo Alto.

 

[Mosaic]

Most of the batteries I test with have reached pseudo end of life. The purpose is to 'recover' batteries which merely suffered from sulphation as opposed to grid/buss corrosion or plate shedding. Thus blasting them with heavy currents causes the weak ones to fail and the robust ones to desulphate.
The survivors are rated and placed back into service.

I am building in a 32mS, 16A burp now to kick in once eq. voltage is reached.

 

[Tony Stewart]

Most of the batteries I test with have reached pseudo end of life. The purpose is to 'recover' batteries which merely suffered from sulphation as opposed to grid/buss corrosion or plate shedding. Thus blasting them with heavy currents causes the weak ones to fail and the robust ones to desulphate.
The survivors are rated and placed back into service.

I am building in a 32mS, 16A burp now to kick in once eq. voltage is reached.

Ok but compare it with a 20A -30A bipolar then unipolar burp with 1/1000 duty cycle at max rate and steady state battery charger, triggered by going above float voltage and left in vehicle. Then compare W-h , ESR before & after on 50% of population. Must be braid or Litz wire twisted pair next to battery in small box and listen to AM . Weak battery will radiate more on distribution wires. Unless two ferrite clamps used, one for high mu , one for low mu. And then it will still interfere on weak stations for truckers.

Using large polyurethane cap in series with yours to generate low duty cycle but watch for EsL resonance and tune to piezo sulphate resonance for max series resonant current., not for LC but motional capacitance. Some of the harmonics should excite it , if LC is tuned better, mo betta. With lowest ESR possible from source i.e. < bat ESR desired.

Lots of sulphated batteries in the gulf especially Cuba and Arizona and any hot climates. You can always modulate FM on the pulse rate with a prerecorded advert and the AM will detect on the slope. This reduces emission levels too with pseudo peak detectors with 10kHz BW, but if used on vehicle, keep in mind ignition will modulate your your ultrasonic carrier , so choke the ignition well as load dumps modulate the ESR.