Possible to disable solar charging in Wisblock code?

WisBlock
#1

Hello, I am deploying Wisblock in outdoor locations enclosed in waterproof container. I am powering the system with 18650 li-ion battery (3.7V, 5000mAh) and charging with small 5V solar panel connected to solar input jack on Wisblock.

This is working perfectly so far. But I understand that it is not good to charge the battery when it is extremely cold (< 0C). I also have the temperature/humidity sensor installed on the Wisblock. Can I enable/disable the charging circuit from within the Wisblock code, based on temperature to help avoid damage to the battery?

#2

Hello @thegpx
There is no possibility to disable the charger chip from the code. The charger is a chip on the base board that works independent of the Core module. It would even charge a battery if no module is plugged into the Base board.

#3

You can use an interface or relay module to enable/disable the solar circuit externally.

#4

Also, there is no protection when using the solar interface to charge the battery, you’d be better placed using something like one of these guys:

Solar Power Manager 5V– The Pi Hut

Solar Lipo Charger (3.7V)– The Pi Hut

We have used the 5V board with great success; obviously it increases the physical footprint of the solution, but not so much so that it becomes prohibitive for most applications.

#5

Thanks @billr I appreciate the pointer. What do you mean by “no protection”? Are you referring to overcurrent/overcharge or undercurrent and deep discharge protection?

I’m using a 5v solar panel with regulated output, so it won’t exceed the wisblock max charging voltage. I’m assuming the wisblock stops charging when battery reaches recommended li-ion max charge voltage; otherwise what would be the point of having a “charging circuit” right?

Thanks

#6

This is what I’m pointing at, we blew a couple of batteries whilst getting our solar charging up and running.

As I mentioned, we are using Solar Power Manager 5V, and this is the configuration we ended up with in a couple of units.

charger

A: connection to the solar panel
B: connection to batteries (2 * Samsung 18650-26H)
C: power out to battery input on RAK5005-0 base board (I think)
D: power in on RAK5005-0 base board

Perhaps you can forgive me if it’s wrong, but I didn’t wire it up.

#7

I have two WisBlock devices running on battery and solar panel since weeks without busting any battery. One is a soil moisture sensor with our small 5V solar panel working for 2 months now without any problems on the battery charging.
The other one is a water level sensor at my water tank with a much bigger 5V solar panel.
In both devices the battery and solar panel are directly connected to the WisBlock Base board and are working without problems.

But it is always good to have a “better” power manager than the quite simple TP4054 that is on the WisBlock Base board.

Here are my projects:

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#8

Maybe our “problem” is exascerbated by the charging rate … we have devices in equatorial and tropical locations where, quite frankly, charging takes no time and the throughput from the solar panels is, well … shall we say constant throughout the day

#9

I am living in the Philippines, so I am as well in tropical climate. One sensor in the front yard gets direct afternoon sun and shuts up to 60 degree soil temperature.

If my battery ever explodes, I let you know.

Soil Moisture Sensor
Watertank Level Sensor
Solar Panel Production

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