Solar powered node charging via WisBlock Base Board charging circuit?

Hello everyone, I am planning to build 2-3 router/client nodes with solar power. I saw that the WisBlock Base Board has a battery and solar port. Does anyone know what kind of plugs are needed? JST 2.0? for the battery. Has anyone already worked with the integrated charge controller? First wanted to use external charging electronics.
A Li-Ion battery 3.7V 3000mA cell should be used. How much current should the 5V solar panel produce at its maximum for the board?
Kind regards from Switzerland

Hi Lun
I use JST ZH 1.5mm for solar connector and JST ZH 2.0mm for the battery. I have also found that a 6W 5V solar panel works well for my setup in the UK.

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Thanks for the help. I also looked at panels with 6-10W. Because of the snow here in Switzerland. I would like to mount the modules as vertically as possible towards the south so that the cells remain free. Since when have you been running your setup without reloading?

About 8 weeks without any power intervention. Using 4000mAh battery and it hasn’t dropped below 90%.


if you oder your stuff from rak wireless, just ask them to put free connectors for battery and solar into the package :slight_smile:
they do that
the specs of the connectors are described in manual of baseboard on rak wireless webseite
the solar controller is working fine here, just very important, that open circuit voltage of module is not more than 6V ! so you need to get a 5V module, that usually has open c 6V.

module of 1-2 W ( 150-300mA) is enough, for winter/snow time , install a bigger battery-pack.
500-1000mAh battery will be more than enough in summer time (just lora module, no sensors/gps)
in winter you might need 4000-10.000 mah, depending on dark-time, maybe snow on the module…

Here’s a RAK cheat sheet for voltages and connectors.


There is no maximum to have on the amount of current the solar panel can generate. The current will be limited by the board, not by the solar panel. So take the panel that produces the highest amount of amps at 5V or 6V.

About the batteries, I’m doing the same build as yours, using a 19007+4631 wisblock device, and I assembled 4 Li-Ion 3000mAh cells in parallel (for a total of 12000 mAh thus). I’m running it now since a week, using it almost every day with range testing and at the moment without a solar panel (I bought a 6W, 5V panel on amazon for 15 euros with mounting stand and I’m checking the panel for its performance before mounting it). The battery remains above 90% after a week, without solar. it is extremely power efficient.

The only potential issue is the extreme cold you may have in switzerland which will impact your battery capacity (protect them in a warm(ing) enclosure somehow or use another tehcnology than Li-Ion that does not do very well with cold. I have read that LTO batteries are better for cold weather)

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Just remember that if you use LTO cells they will need to use a different charging system and a boost converter to 3.3v. That said, they would be impervious to the cold weather in most locations.

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Thanks for your information. I use a standard Li-Ion 3200mAh battery. In the last 7 days (yes, it’s not a long-term test yet…) the capacity has never fallen below 84% and we also had 2 days with fog during the day. And up to -6°C at night. The wisblock board runs for 5-7 days with a full battery on the 3200mAh cell. I hope this works out in the long term. But the test is still ongoing

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December last year, after weeks of cloudy weather, my WisBlock went dead.
It had a 5V solar panel with a max current of 290mA and a 18650 lion of 2000mAh.
So a 1.5 W panel is likely not enough for the dark and rainy winter days in the Netherlands.
Maybe a much bigger lion would have overcome the rainy period.

I now have 3 solar routers running with RAK ​​19007 and 5W/5W Solar Panel direkt to the wisblock Charging Plug.
The first one has been running for 3 months now and has never fallen below 3.65V (1x3200mAh 18650) and the 2 newer ones for about 1 month (2x3200mAh 18650) have never fallen below 3.9V and also charge on a sunny day times up to 4.15V. So 2x3200mAh seems to work well for our latitude in Switzerland.
I forgot to set a router to router client, so the data traffic is not that high, the routing is certainly not ideal, but that means the router is always in the range of 90-99% battery capacity. I’ll try and configure it correctly.

Hi Lun, glad to hear that you have a nice working setup!

I’m about to build a similar setup with a WisBlock Meshtastic Starter kit, but got a bit scared about the solar panel and overcharge protection part…

So I thought it would be a good idea to experiment with a portable solar cell phone charger (think 4-5 hand-sized solar panels that unfolds and have a USB connector at one end) and connecting that to the USB connector of the board, with a 18650 battery also connected to the board.

As far as you know, will something like this work, i.e. assuming there is enough sun, will power on the USB connector actually charge the battery?


You can do it, but you will waste a certain amount of solar energy because the RAK solar charging works really well. In Central European latitudes, I would recommend 5W solar and 2x3200mAh as a suitable setup to get by without sun for 2-3 weeks. Greetings from Switzerland

Great timing, I actually just received the RAK enclosure and that solar USB charger.

Based on your input, I’m seriously considering connecting that 5V output from the solar charger directly to the solar JST pins. I initially thought there had to be a regulator circuit in between any solar panel and the RAK PCB, but even if that’s the case, I guess the product I got already takes care of this (it supposedly can charge anything phone-size via the supplied USB connectors).

Also, the enclosure is smaller than I expected and I fear the USB connector will actually be blocked by the enclosure wall once in the box!! A 90 degree connector might fit, but at this point, what the heck, might as well get a JST connector.

Greetings from Quebec!

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A single cell is not enough to hold the required number of days without sun. You could find a 5V solar panel with between 500mA and 1000 mA currents on amazon (6W panels) for cheap. That would double your charging power. So you should upgrade your solar panel and use at least 4 cells in parallel.