Review request for HKJ [Rechargeable Batteries]

The mosfet is the linear regulator, a linear driver needs a current sensor, a pwm driver do not. I have written the review now, I do not know when I will publish it.
It was some work, because I had to locate my test fixtures for led drivers and modify my script to use my current test equipment (Everything has been replaced since I last did driver tests).

As far as I understand, a MOSFET is a sort of high current solid state switch operated by driving its gate with voltage.
So that thing is a current adjustable linear design. This means unless you've found something wrong with it, far superior to the still predominant AMC7135 setups it must be.

Cheers ^:)

It can work as a switch, but also as a linear regulator, you just have to use lower gate voltages.
There is also another issue, not all mosfets works well in linear mode (Nearly none do), this means they cannot handle full power, but only a fraction of their rated power.

I did not see anything wrong with it, except the mosfet gets rather hot at full power.

Any update on the Imalent tests? Review request for HKJ [Rechargeable Batteries] - #267 by HKJ
Thanks.

They are still waiting for time on my test stations.
With my current queue I will soon get to them, but if I get large collection of batteries from some of the usual suppliers, they will probably be discarded (They will get too old). There is no indication that I will get a large collection of batteries at the current time.

Do you believe, HKJ, a proper high power linear driver could be implemented with a powerful high switching speed MOSFET used as a switch, plus a high power LC filter to smooth out the output? Sensing Vdrop at the coil would allow obtaining a reference voltage which, after the corresponding high/low comparison, would serve to dynamically adjust duty cycle to maintain constant current at the output for as long as high enough input voltage. I did not formally studied electronics, as you may guess, but the above sounds senseful to me.

Cheers :-)

You will need a diode in the circuit and use a resistor for current sense, then you have a standard buck converter.

I would be interested in a test of Klarus 18GT-36UR.
This is a high-capacity 18700 with a built-in charger. What is special about it is that Klarus claims 10A discharge. So it should have lower IR than other batteries with built-in chargers…but does it really?

I don’t see any source for it yet.
HKJ, if you’re interested in testing it, I can write an update when I find it available.

Please do, remember I am in EU, it limits where I can get LiIon batteries from.

0K LoL, I really didn't wanted to reinvent the wheel. :-D

With regards to the AON7520 MOSFET linear driver, my guess is that the microcontroller uses the sense resistor voltage to determine the MOSFET's VGS, does it? You also say it runs hot, probably because I²R dissipated power. This means it will probably cook itself if output current is raised by lowering the sense resistor value, bad stuff. I wonder if making some sort simple copper heatsink, or buying one to attach it over the thing, would at least make enough difference for up to, let's say, 4.2 or 4.8A (2 or 3 pieces R050 stacked over the onboard R010).

Thanks a lot.

Cheers ^:)

More or less, you usual do not care about Vgs, but simple increase/decrease it until you have the correct voltage drop across the resistor for the desired current.

Maybe, it will only be few watt, how much depends on the batteries.
I had the mosfet up to 165°C in less than a minute when I feed 4.2V into the circuit, but that was without any cooling (During test I had a fan on it).

Nice that you’re interested.
I’m in EU too so this should not be a problem. :slight_smile:

Don’t now if these have been posted earlier or if you have them on your queue to be tested, HKJ:
Sofirn 16340 900mAh

https://www.gearbest.com/batteries-railway/pp_009458338007.html

I have ordered them.

I have run out of small batteries to test (i.e. anything below 2800mAh) and are very open for suggestions.

Nice! I’ll be looking forward to your tests!
So far I have no other suggestions, but I’ll remember this if I see some ! :+1:
Thanks for your work! :beer:

Interested in Imalent results. These are supplied with RT35/RT70 kits. Rewrapped protected 30Q’s

Edit: guess I don’t get an answer because the Vapcells were mentioned before. Sorry, I retract my post then.

Hi HKJ, I’m here, HydrAxx, I’m helping the vape community with lithium-ion batteries of all sizes and types of discharges, I’m testing and analyzing for myself, too. sometimes helps Mooch in terms of results, comparisons and technical documentation on different cells, I come to you to suggest the test of a cell, which I have serious doubts about the capabilities announced by the rewrapper, he This is a 20700 cell probably made by Howell, but which is not yet referenced and documented, its capacity is 3400mAh and its continuous discharge announced at 30A by Listman, in short, I give you two links: the first is the official page on the rewrapper Listman’s website and the second, a page of the FastTech site, where you can order this rewrap individually, by two or even by four.

https://www.fasttech.com/products/1420/10015452/9629428

ps: I have already asked to perform the test of this cell to Mooch, unfortunately it is currently overloaded with work pending (many cells, chargers / dischargers / analyzers, various mods mechs, etc …) so it does not I do not really have a lot of time right now, knowing that I’m the only one to have her test this cell, personally I think if my fears are not based on Listman’s cell specs, it may that it is a good alternative to the Sanyo NCR2070C (20700 / 3500mAh / 30A), that’s hoping that you accept my suggestion.

Regards,
HydrAxx

I have not answered because I had not decided yet. Sometimes it is difficult to decide and I just let them stand until I am missing cells to review, then I look back and may order something.
In your case I am missing lower capacity batteries to review and the 2800mAh fit that bill and I have ordered it.

I have also ordered this cell.

I didn’t realize, but there are trustworthy sellers offering Sony US18650VC7 already. For example:

Would love to see the test…