Hi Antonino, thanks for sharing this interesting project.
Since renewable energy can only grow in importance, and I believe it will become very important, I am looking at your project as a good starting point for an "Open Source Battery Charger" project, which I think can be part of a kind of "Open Source Renewable Energy Toolbox" project/iniatiave…
My current thinking is to use QuiteSmartCharger as the charger MODULE together with a SOLAR MODULE and a BATTERY MODULE (could be 1 single 1.2V Cell), working as some kind of Renewable_Solar_Power_Unit (and also later, as Renewable_Wind_Power_Unit, etc)…
Solar Module + QSC + Battery Module = Renewable_Solar_Power_Unit

What I am thinking is the creation of a "Desktop Renewable Solar Unit", simple enough and cheap enough for the common citizens to use, manipulate, adapt, etc… where "desktop" means personal scope, small size, stuff that can be manipulated by the individual (like a desktop computer) using a single desk as the "workshop", and also, because the design is intended to be something to work with personal computers and Arduinos, Raspberrys and microcontrollers...
So, the word "desktop" just means "around the scope of a personal desk", like the PC (personal computer), that took computers from big scientific and industrial arenas and made its benefits available to common citizens...
This is a good way to look at this possibility:
i) Mainframe Computer <==> Big Power Utility Companies
ii) Mini Computer <==> Hundred of thousands Dollars solar farms and wind turbines
iii) Desktop PC <==> (kind of) "DESKTOP" RENEWABLE ENERGY TOOLS
QSC, at least in my point of view, looks a very interesting project to consider for this "category"...
I still learning about the subject of recharging batteries (Ni-Cad, Ni-MH, etc), so I am going to get a LM2941 and build QSC and do some experiments first… after that, I am thinking about experimenting also with LM317 with a MOSFET switch, since the LM317 is a popular IC, easy to get and very cheap…
For this first round of learning, I am reading a lot of information before going to the practical side of it, and I have some question that I like to ask, perhaps the answers can also help others…
[Questions]
If you can, or anybody that has experimented the (QSC) circuit/software, or anybody with enough knowledge, please give us a little input on the following questions:
1. What is the minimum (stabilized) IN-Voltage needed for the charger-circuit to work, considering just one 1.2V Ni-MH cell as target?
2. On the photo, are you using 2R7 Resistor for R* and also for Rd?
3. As for Resistor Rd (discharge resistor), 2 resistors of 0.5 Watt in parallel will fit the job?
4. For the discharge circuit (target 1.2V single cell), does it work with 1Amp, N-Channel, Low Rds-ON, (Power) MOSFET, or do I need to use something with higher Power capability like 5Amps, 20Amps?
5. Does the discharge MOSFET(s) need heat-sink?
[3 extra questions]
a) Is it correct to "break" your scheme into the "charger block", "discharge block" and "voltage reader block" according to these picture I am posting below?




b) Is the LM317 circuit below enough to work as an equivalent constant-current charger, so that we can adapt/use it with QSC software (preferable keeping both options with minor change in the soft)?

c) I am seeing some information about a new (?) Ni-H2, nickel hydrogen, type of batteries, does this new (?) type have, more or less, the same features as the Ni-Cad and Ni-MH, so that we will be able to use QSC hard/soft with them, as well?
Thanks all,
Valter
PS [Dedicated IC(s) versus MCU Controlled]
As you pointed, a dedicated IC can take care of every important aspect, so that the job can be accomplished without us having to worry about all these aspects, but I want to go on the direction of microcontroller basic designs because they offer much more in terms of flexibility, easy to modify, simplicity to understand, higher capacity to provide information (in digital form) and the ability to respond to control in a wide variety of forms, which means that they are much more "intelligent" in relation to the environmet... so, even with initial cost higher and using more complex set of hard/soft than the dedicated ICs, the MCU based design can EVOLVE (in the OpenSourcistic fashion) and adapt to a wide range of needs, thus justifying the initial cost and a little complexity...