Hello.
Which are the characteristics of the solar panel included with the RAK10700.
It is not shown in the device specs.
If you have the new version with the Unify enclosure: Solar Panel HX-80X45多晶层压板规格书.pdf (261.1 KB)
If you have the old version with the RAKBox-2 Solar Panel规格书-60x60mm.pdf (115.0 KB)
Hello, thanks.
I wonder we have an issue with the new RAK10700 devices and the solar charge.
The panel is able to supply 0.4W when in sun and it is connected to the charger IC according to schema but measuring the battery voltage under sun conditions it keeps dropping.
The device actual device consumes around 0.035W and the panel produce 0.4W so it should charge.
What voltages do you measure at the battery.
The charger is using different charging methods depending on the battery voltage.
The RAK19007 Base Board is using the TP4054 charger and in the datasheet you can find the different charging modes:
To know whether the solar panel is working, you need to measure the voltage on the battery over a longer time.
Here is an example graph over 2 weeks of the same solar panel on one of my devices in my front yard.
And what is this resistor doing here?
Is it 1K Ohms ??
If it is 1K Ohms with the maximum solar panel current, that is 80mA it will have a voltage drop of 80V that is crazy… V=R*I → V= 1000 * 0.080 → 80V
The led is not having specs so I have no clue which is the voltage drop and final voltage arriving to the TP4054 finally.
My issue is that I see the battery voltage keeps going down even under sun, it never charge.
My device consume 10mA
I didn’t design that circuit, but I know it works, I have 4 devices re-charged just from the solar panels running since months.
Check your solar panel, sometimes the cables directly at the panel are not soldered or broken off.
Check the connector for any damage.
Check the voltage on the connector, what voltage do you get when the panel is exposed to full sun.
They are powered up by the panel, I see the red light is on, but even with that it is not charging.
And the schematic is non sense, it is incorrect.
Contact whoever is the designer please and share my comments, it needs to be clarified because between version 1 and 2 of the RAK10700 something is different.
Video in the link, even the light is not behaving the same : https://file.io/FLZctuqS0JEr
The LED has nothing to do with the charging current. It is controlled by the CHRG pin of the TP4054 and just shows the charging status.
If you read the datasheet, you can see that R2 is limiting the charging current to ~600mA
From the datasheet:
But it will never reach it because the output current of the solar panel is 90mA max under perfect conditions.
Did you measure the actual voltage and current output from the solar panel itself?
Did you measure the charging voltage and current going to the battery with the WisBlock Core module and the WisBlock modules removed from the WisBlock Base Board?
There is no change in the charging circuit between “old” and “new” RAK10700, the only thing changed is the solar panel and enclosure.
Hello.
It is a really weird issue, we are checking battery specs to know if it could be the battery and the ambient temperature.
I have bought a tester and some other electronics tools, I am in Malaysia and without access to my lab that is in Europe.
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