Solar Charge Controller

 

DIY Solar Charge Controller Release status: experimental [box doku]
Description	Trying to build and optimize a DIY solar charge controller
Author(s)	Severin

There are plenty of cheap solar charge controllers out there, but most of them are crap, or just don't really fit our use-cases. And the good ones are expensive. So let's try to DIY one.

Brainstorming

• PWM is ok, MPPT would be much better
• Up to 32V battery voltage would be nice (24V Lead-Acid, 7S Lithium battery packs)
• Free selection of cutoff voltages to accomodate different battery configuraitons (e.g. 3S/4S Lithium packs)
• Data logging/telemetry

"Fancy" PWM controller

Starting point for the first shot at this is Open Green Energy's ARDUINO PWM SOLAR CHARGE CONTROLLER ( V 2.02) instructable. I started ordering some parts from AliExpress, and now "just" need to get the PCB manufactured and we should be good to go.

Group Buy

There were a few people who had shown interest in this project, so I ordered a bigger set of parts.

• Nico
• Uli
• Sebastian (only if MPPT)

Parts

Taken from the instructable, needs some better specification for sure.

Part	Amount	Got it?	Stock	Source	Notes
PCB V2.02	1	❌	-	JLCPCB
Arduino Nano	1	✅	10	AliExpress
IRF4905	2	❌	-	Reichelt
MBR2045	1	❌	-	Reichelt
MP2307	1	❌	-	?	step-down should be fixed to 5V for arduino supply? or better adjustable ones?
DS18B20	1	❌	-	Reichelt?	temp sensor for battery? maybe he meant this
ACS712	2	✅	12	AliExpress
P6KE36CA	1	❌	-	Reichelt
2N3904	2	❌	-	Reichelt
Resistor 100k	2	❌	-	Reichelt
Resistors 20k	2	❌	-	Reichelt
Resistors 10k	2	❌	-	Reichelt
Resistors 1k	2	❌	-	Reichelt
Resistors 330ohm	7	❌	-	Reichelt
Ceramic Capacitors (0.1uF x 2)		❌	-	Reichelt
20x4 LCD	1	✅	6	AliExpress
LCD I2C Backplane	1	✅	6	AliExpress
RGB LED	1	✅	50	AliExpress
Bi-Color LED	1	❌	-	Reichelt
Jumper Wires		❌	-	AliExpress?	which length? what for?
Header Pins		❌	-	Reichelt
Heat Sinks	3	✅	20	AliExpress
Fuse Holder	1	✅	10	AliExpress	incl. cover
Fuses	1	❌	-	Reichelt	No details as to what kind of fuse. Going with 4A fast blow for now
Push Button	1	❌	-	Reichelt
Screw terminals 1x6 pin	1	✅	10	AliExpress
PCB Standoffs	4	❌	-	Reichelt
USB Socket	1	❌	-	Reichelt

Open Points

• License is CC BY-NC-SA. If we want to build on top of this, we would need to clarify the NC part.
  • Email sent to OpenGreenEnergy to clarify this --Tiefpunkt (talk) 00:34, 8 November 2020 (CET)
• USB port has no fuse, and also no resistors on the data pins. That might be a potential improvement.