update 1
ok it charges / balances the 3 x lipo with a 19v solarpanel connected but… the output is not constant at 12v as I expected (no buck/boost on board) or not working.
I’ve contacted the manufacturer
update 2
got a factory answer and indeed this product has no constant voltage out… So no buck/boost.
its a 19v solar 18650 charger/balancer.
you could charge a supercapacitor that in turn powers a mini TTN node notifying water is used/running
hmmm… if you make a bigger system and mount that between the watersupply pipe in your house, you generate energy evertime you open a tap or go to the toilet maybe enough to slowly charge a little lion battery …
somebody wrote that it generates a few uA … now with current node consumption getting under 1 uA that maybe interesting again, maybe in combination with a super capacitor to build a lowcost selfpowered thing.
https://hackaday.io/project/21342-bpw34-solar-powered-led-watch Charging: Charging is very simple because vinatech scap are 3V, just I use 3V fixed voltage LDO MCP1700T3002ETT with 10R resistor to limit charging current + shottky diode for protection reverse current to LDO … charging voltage drop to acceptable 2.95V Discharging: Heart is fixed 3V version of MAX1724 extremely low 1.5µA quiescent supply current Step-Up DC-DC Converter which can work until 0.4V imput voltage I can use about 87% of stored energy. In all operation time I have stable 3.001V for MCU. I also have on board space for newest MAX17222 … 300nA Iqc bu I am unable to solder 6-Pin μDFN Average consumption is now about 7uA. MCU: I am using PICOPOWER Microchip/ATMEL ATMEGA328 standby consumption with runing RTC is 0.9uA
finally found an affordable waterproof enclosure that fit’s all the components for the mobile gateway build (i’ll hope)
a few of these bad boys as power source
I will use 2 of these enclosures So that the powersource and 4g gateway electronics are separated.
Main use will be ‘field’ experiments and not a selfsustained solar gateway hence the separated
heavy ‘12v - 5v battery pack’… the two units ‘click’ together because inside are strong magnets.