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SoftPower: Universal Version for Panels <21W and panels <300W.

rin67630

Solar Enthusiast
Joined
Apr 29, 2020
Messages
1,066
Location
Nort-Rhine-Westphlia Germany
I think this will probably be the last hardware iteration of my SoftPower project:
This final version is built around a three channel power measurement module INA3221.
I managed to get everything into a rather lean schematic diagram:

https://github.com/rin67630/Soft-Power-MPPT/blob/main/Hardware/SoftPowerUniversalINA3221.pdf

The diagram is explained here:
https://github.com/rin67630/Soft-Power-MPPT/blob/main/Hardware/SoftPower Schematic Analysis.md

In the next days, I will probably complete the explanations with a few pictures and, as soon as the missing HW813 buck converters arrive from Asia with the next camel caravan, I will provide a picture of the prototyping board and get the whole thing enclosed in an IP65 case.

Meanwhile, I will continue testing with the slightly less performant D-SUN buck converters and commence finalizing the software...

Stay tuned!
 
Can you explain a few things about the schematic assuming SZBK07 (U6) is used in a high solar input situation?
  1. Are U1, U3 and U7 optional?
  2. Where is U6 load Gnd?
  3. Which Oled pins are used (assume I2C - vcc/gnd/sck/sda)?
  4. LM75 temperature sensor for lead acid charging - I2C requires 4wires as above ??
I trust instructions will be provided for loading multiple *.ino files.
 
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You absolutely need U3 to power the ESP.
U7 is optional, just nice to have...
U1 is strongly recommended to be efficient in the low power range: The SZBK07 has 40mA no-load. That is considerable! ~ 0.7W just wasted for many hours. If your panel is frequently shaded, you can harvest that power and more with U1, while U6 is disabled.

> Where is U6 load Gnd? Not used, since it carries the current measuring shunt voltage. (I will explain that)
The OLED pins are not diplayed since the OLED shield is backpacked on the top of the ESP. If you want to use another OLED display, you need to connect 1:1 GND, 3V D1 and D2 (I will explain that)
Same if you want to add an I2C temperature sensor. (I just take the outside temperature out of the weather report.)

> multiple *.ino files.
Just download the project as .zip and upload it as a .zip to the Arduino IDE.
Then start SoftPowerMPPT.ino. (I will explain that in the folder Software...)
 
Thanks for keeping us updated on the project progress and the explanations.

Consider my use case a stress test. I assumed the other side of the planet, so reversed almost all your key assumptions in terms of solar radiation and heat, and assumed efficiency could be sacrificed. The sun still shines only during the day but I suppose further north of you the day is six months and the night the other six months! I'll throw one more in there - occasional internet access (so no reading weather reports) but you [almost ??] covered that.



I few comments about what is optional in the circuit, and I accept it would impact efficiency and functionality.

You absolutely need U3 to power the ESP

Only because of the circuit design to power the microcontroller efficiently.

I'd expect C6 would require `sck` for I2C.

I assume U1 could be an SZBK07 and [forgetting about efficiency] suggest essential is:
  1. U1 Buck converter
  2. ESP8266 (WEMOS1 is a power-efficient module)
  3. U6 current/power monitor
  4. various connectors and components
  5. PV1 PV array
  6. B1 Battery
I've forgotten your explanation for the ideal diode only being required on U6, ie optional.

The font size is hard to read off GitHub. Can you increase font size on some of the labels, eg U1?
 
Hi, Thanks for the DIY Project.
I read the Readme.md in here https://github.com/rin67630/Soft-Power-MPPT/tree/main/Hardware
there is 3 varian, and in the first varian using INA-226, its hard to ge INA-226 in local store.
Its is posible to eliminate INA-226 like this project Adam Plavinskis - Arduino-MPPT, just using 2 resistors.

ps: i want to build Adam Plavinskis Arduino MPPT, but its hard to get IR2104 and i need to buy arduino nano.
since i have Wemos D1 & NodeMCU from smart watering project , i want to use it for this Solar Charger.


Thanks
 
I have reworked the schematics in 6 different flavours and updated the hardware documentation:
Hardware description at GitHub
No basic change to previous builds, only schematics that are hopefully easier to follow and better explanations.
Thanks for the reply.
JFI, There is Fake LM25116 on SZBK07, see the comment in here

right now, i'am ordering:
1. XL4016 10A 300W Conventer
2. 12V-24V to 5V DC Conventer
3. BMS 3S 40A Balance


I don't have INA 3221 and Solar Panel, i need to save some money first.


Thanks.
 
Please come on Discord (no need to install, runs in the browser) to discuss further: We are 4 persons already, and might organize an audio.conference.
I just log in to the channel, as Petani Teguh ( ps: Petani means Farmer ), just read the chat log.
I got nice info in there.

Thanks.
 
I think this will probably be the last hardware iteration of my SoftPower project:
It was not.
The Soft-Power Project now provides several possible hardware variants:
  1. The preferred design "Soft Power 1xINA3221 w Power Extension", measuring voltage and current for panel, battery, convenience output, the A0 analog input is free for extra usage.
    https://github.com/rin67630/Soft-Power-MPPT/blob/main/Hardware/Soft Power 1xINA3221 w Power Extension.pdf
  2. A minimal version "Soft Power 1xINA226 Minimum", measuring the battery voltage and current, used as a device power supply. https://github.com/rin67630/Soft-Power-MPPT/blob/main/Hardware/Soft Power 1xINA226 Minimum.pdf
  3. A passive display and logging version "Soft Power 1xINA3221 Passive Logger", used to retrofit existing SCC's with Soft-Power's powerful dashboard and logging functions.
    https://github.com/rin67630/Soft-Power-MPPT/blob/main/Hardware/Soft Power 1xINA3221 Passive Logger.pdf
    (The SCC must however have a common ground level between panel and battery, which is mainly the case for real MPPT devices, but not for cheap PWM modules or those just pretending to be MPPT)
The hardware is now precisely described:
https://github.com/rin67630/Soft-Power-MPPT/tree/main/Hardware
including detailed and pictured instructions to wire the prototyping board.
https://github.com/rin67630/Soft-Power-MPPT/blob/main/Hardware/SoftPower Prototyping.md

Last but not least: I give very detailed explanations and pictures on how to solder Soft Power on a common prototyping board valid for all variants. It got now very close to become a full blown 5x6cm PCB.

I just have not time to learn how to handle a PCB CAD and must concentrate on software.
It would be GREAT, if someone familiar with KiCAD or other ECAD designers would contribute...
Common board.jpg
It's soldered in half an hour:
PCB soldered.jpg
PCB Top view.jpg
 
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