Higher Charge Rate for Solar Charger on RAK19007

The Meshtastic users currently struggle to find a good setup for providing several months(ideally even year-) long solar and battery powerd power supply for Meshtastic Routers. The limited charge rate of 19007’s on-board charger for Li-Ion batteries typically does not allow for full charging of several (for example 6) 18650 Li-Ion-type batteries in parallel.

May I suggest that RAK develops one or several solar charge controllers that fits the RAK Wisblock 19007 and allows for at least 3 amp charge rate? If such would be available larger solar panels and several parallel aligned batteries could be used for storing more power. This is highly important in areas where there are longer periods of bad weather for example during winter time.

Such a controller should also support the charging of batteries that can be charged below 0° C like sodium batteries (Na+ → -10°C) and LTO-Batteries.

The availability of such an officially supported solar charger would highly increase the acceptance of RAK Meshtastic starter kit.

Are there any plans to come up with such a solution? Thanks.

Welcome to the forum @FJF130

I think what you are looking for (at least for Li-Ion) is something like the Solar Power Manager 5V
If going further down your wishlist, a charger that can handle multiple types of battery (sodium, LTO, …), such a charger is getting even more complicated.

We are not planning to develop something like this. Our focus is on LoRa and LoRaWAN products.
A charger like you wish to have is overshooting the usual requirements, doesn’t fit onto a WisBlock Base Board and is not our expertise.

You will be better off with an external charger, external battery and then supply the WisBlock Base with 5V through the solar connector.

Hi beegee,
I appreciate your answer. It is a bit disappointing though.
I understand that RAK does not want to develop something without having the necessary expertise for. However I would like to point out that most of the RAK Meshtastic Starter Kits are favoured by those who want to build Meshtastic router nodes as the Wisblock seems to be one of if not THE least power consuming Meshtastic device that are currently available. This makes it currently clearly the prefferred device for solar powered router nodes.

Solar powered router nodes are playing a very important role in increasing the range of Meshtastic devices. Many of them need to be placed on high elevation places where no grid power is available. So, members of any local/regional Meshtastic mesh network will want to set up such router nodes. I expect that at least a third or maybe even around 50% of such routers will be placed in climate areas where temperatures easily can drop below 0° C. That would include majority of USA, Canada, Alaska, Central and Northern Europe, Russia, … So I really do not think that a solution to this is overshooting the ‘usual’ requirements.

Offering a Solar Router Package/Set that includes solar power chargers for higher capacity battery packs would defenitely sell very well as Meshtastic is currently just trending massively at least in the U.S. and Europe.

Another reason why RAK should engineer such a charger module or at least support a specific third-party product is compatability within RAK Wisblock specs and warranty. The availability of one or several product set(s), be it implemented onboard or provided separate from the Wisblock, would heavily support the Meshtastic related sales numbers.

I encourage you to look into the work currently done by https://www.youtube.com/@The_Comms_Channel as well as Andreas Spiess https://www.youtube.com/watch?v=dBx-g1dkdDQ&t=925s that highlight some of the issues around this topic and reconsider RAK support in this regard.

All your efforts would be highly appreciated.

We are discussing internally some options for better solar/battery support for router/repeater nodes.

Thank you. Looking forward to what the RAK team comes up with.

I am installing 12+ meshtastic starter kits typically on TV antennas in a rural area. Is there a downside to plugging a solar panel into the usb-c to charge the single 18650?as opposed to using the solar port
Will the fluctuations/fading light cause issues on the usbc circuit?
Will the panel sap power at night (diode)
Will it cause issues with rebooting eg OTA Updates

Welcome to the forum @RPAS

Assuming you solar panel is not sending anything over USB, it is the same whether you connect your solar panel to the Solar Panel Connector or to the USB port.

You will not get a higher charging current when using USB, it is simply the same.


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Hi Beegee, I had a feeling you might be the one to chime in and thank you. This is the definitive answer I was after. I am trying to minimise the penetrations in the enclosures so this is great new. It also dictates using less components and sourcing usbC panels rather than DC plugged panels. Sp Thanks again.

In the search for a possibility to charge several ( 1 to max 6 pcs of 18650 LiIon cells in parallel) I started using and testing the following solar charging modules, having them connected to Wisblock’s battery port (circumventing the integrated charger):


Just to give you an idea of what I am looking for (initial question of this thread).

Not sure if it is a good idea to connect BAT output of the external charger to the battery connector of the Base Board.
I would rather connect it to the solar connector of the Base Board to avoid having the onboard charger “fighting” against the external charger unit.
From the specs it looks like BAT Output is 3.7 to 4.2 V so it would be save to connect it to the solar panel connector (can take up 5.1V or 6V (upper limit).

Could you confirm how many amps the solar panel connector can cope with at maximum? The whole point of using an external charger is to be able to charge with higher amperage than the wisblock supports.

Please forgive my beginner’s questions. However, as non-expert I do not understand what Wisblock’s on-board solar-charger whould have to “fight” if no “competing” power is connectet to neither solar- nor to the USB-C port?

You are planning to use an external charger, so you connect your batteries and solar panel to the external charger and the “BAT Output” will be supplying the WisBlock. There will be not much current flowing through it, only what WisBlock is consuming.

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You are right, unless you connect the USB it would work.
But it would not be the first time that someone forgets to disconnect the battery before he plugs in the USB.

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Ahh, that is why. Now that makes sense of course.