Solar on Philly Mesh

Updated Low Priced Solar Node (Harbor Breeze)

Emily Boda — Fri, 10 Jul 2026 00:00:01 +0000

After building my Medium Priced Solar Node, I wanted to explore cheaper options. I wanted to be able to build nodes to give to friends or community members to place in advantageous locations, and not feel like I was losing $100+ if it doesn’t work out.

If you’ve been around the Meshtastic community for more than a month, you’ve almost certainly heard of the Harbor Breeze Solar Light hack. This involves using the solar panel, solar management board, battery, and enclosure from a low-cost solar light available in the USA at Lowes for less than $10. The availability of these lights can vary, but if you search hard enough you can find them.

Variations

I’ve seen many variations of this hack. I believe the first came from Tavis Gustafson. This is the one that is documented in the Meshtastic docs and was featured on Hackaday.

Since this hack exploded in popularity, Harbor Breeze no longer manufacturers the original version of the Solar Light and has been replaced with a new version that has slightly different wiring, but is the same price. It has a smaller battery because the light is more efficient, and there were originally concerns that the battery wouldn’t be able to sustain a Meshtastic node. We have done almost a year of testing with the new light and we can confidently say the new version works just as well as the old version!

These instructions work great with the RAK4631 board. We have explored using a Seeed Studio Xiao, but we have found that the cheaper board is prone to brownouts (where the battery charges just enough to boot up the Xiao, but then the battery drains fully during start-up and the node gets stuck in a boot loop until a human intervenes). Mitigating this would require adding a battery management system (BMS) to the circuit, which would negate the cost savings of using a Xiao.

We also have found that the battery pads on the Xiao are very difficult to solder to, even for those experience in soldering. Since this is a beginner-friendly guide, we decided to recommend using the RAK4631 board which requires minimal soldering.

The approach I’m going with today can be applied to just about any solar light.

Parts List

Essential Parts

Parts	Price	Description
WisBlock Starter Kit	$24.99	This is the Meshtastic node. You want the RAK19007+RAK4631 (not -R) version. Pick the frequency for your region, USA is 915. This node does not come pre-flashed, you will need to flash it yourself. For $5 more you can purchase this version that comes pre-flashed with Meshtastic firmware
Harbor Breeze Solar Light	$9.98	Make sure you verify that the Item number is 1234868. If you purchase in person, the item number will be displayed on the packaging. This is technically $14.98, but it’s almost always on sale for $9.98
Heltec GT-800 868, 915 MHz Whip Antenna	$3.90	These are cheap clones of the MuziWorks 17cm Whip Antenna that have tested just as well. You can also use the more expensive 8dbi antenna from the Medium Price Solar Node, but in Philly this will be all that is necessary for a roof node.

Essential parts cost: $38.87 + shipping

Parts you may/may not need or already have laying around

I break this section out because 1) you may already have some of these parts laying around, 2) you could get many of them individually for very cheap if you buy local, 3) if you do have to buy online and in bulk, you will have some on hand and they will not contribute to the cost of your next build, and 4) you may not need some of these parts.

Parts	Price	Description
IPEX to SMA Female Cable	$6.94 for 2	The RAK kit comes with a cable, but it’s not long enough if you intend to run the antenna through existing holes. You’ll need a cable that’s at least 8 inches. Make sure to buy a cable that matches your antenna; this one works with the Muzi antenna from above.
JST PHR-2 2mm connector	$8.39 for 20	The WisBlock board uses a 2mm JST connector. You will need one of these to solder to the solar board and connect to the Wisblock battery terminal.
Waterproof Sealant	$6.34 for lots	You will need to seal up some holes in the case to make them waterproof if you want to install this outside. You can also get this from Lowes if you want to reduce shipping costs, just make sure the variety you go with works with plastic.

Total cost: $60.54 + shipping (or about $43 per node if you make lots)

Instructions

Before opening up the node, make sure the power button is off. Face the solar panel flat on a table to make sure it doesn’t charge while you’re working on it.

Press the power button and verify that the light comes on, then press it again to power it off. If the light doesn’t come on, charge it up and then make sure it does.

Unscrew the plastic stake and the light.

You may snip the light wires off close to the board. Make sure they don’t touch any other part of the board accidentally now or when you close it back up!

Open up the node.

Unscrew the four screws on the underside of the board.

Remove the battery and turn the solar panel upside down on a flat surface to ensure there won’t be any electricity running through the circuits while you solder.

Cut and remove the cables to the light.

You can cut them close to the circuit board.

Review the intended wiring.

Plug in the JST connector to the port that says “battery” on the RAK4631. Take a look at which wire is on the side with “+” etched into the board. This is the positive wire! This positive wire is the one we want to connect to the positive side of the battery holder.

Are you experienced at wiring up circuits? Do not skip reading this paragraph! The RAK’s polarity is backwards for some reason! Do not assume the red wire on your JST connector is the positive one or you will let out the magic smoke when you power on the RAK and you’ll need to buy a replacement of the most expensive component in this build.

Again, look to see which wire is on the side with the “+” etched into the board. That is the positive wire! Solder that one into the positive side of the battery holder. Solder the other wire into the negative side.

Test fit the wiring.

I usually place the RAK4631 upsidedown to the left of the circuit board inside the light housing. See if the JST connectors will reach the battery holder for solering, or if you need to extend the wiring.

If you need to extend the wiring, use wire from the female JST cables that came in your JST wiring pack. You won’t need those.

With the JST wire disconnected from the RAK, solder the JST connector wires to the battery holder.

Solder the negative wire from the JST connector to the spot marked negative on the battery holder and the positive end to the tab on the positive side the battery holder.

Plug in LoRa and bluetooth antennas.

Your Bluetooth antenna will be plugged in to the push connector labelled “BLE”. Push the two circular parts of the antenna and connector right on top of each other. It’ll require quite a bit of force, but too much force can break it.

Your RAK4631 kit came with a tiny LoRa antenna, but we’re going to use the better one we ordered.

Snake the IPEX to SMA Female antenna cable you ordered through the hole where the light cable was and connect the circular end to your RAK where it says LoRa. Screw the antenna into the other end.

Plug the JST connector into the RAK4631.

Warning: if you accidentally power on your RAK board without the antenna connected, you can irreversibly damage the board!

Place the battery back into the holder and verify the RAK powers on.

If it doesn’t power on right away, you may want to allow the battery to charge for a little while. While you wait you can verify the RAK is working and set it up by powering it with a USB-C cable. Again, make sure the antenna is connected when you do this.

Waterproofing

You will want to waterproof any holes that you’ve made in your case, including the original one that the light cables were running through. I also ended up adding a little extra sealant to the screws on the rear of the case.

Mounting

If you plan to mount to wood or something else you can screw into, this mount will work well.

Low Priced Solar Node (Harbor Breeze)

Emily Boda — Sat, 21 Jun 2025 00:00:01 +0000

UPDATE

You can no longer buy this particular Harbor Breeze node! As a result, we need slightly new wiring. We have a new article with new instructions here.

Original Post

Variations

I’ve seen many variations of this hack. I believe the first came from Tavis Gustafson. This is the one that is documented in the Meshtastic docs and was featured on Hackaday. This one is tried and true, but does not allow the user to press the included power button to turn on/off the node.

These instructions work great with the RAK4631 board. We are exploring a new version that uses a Seeed Studio Xiao. Unfortunately, if you wire up a Xiao the way we have in these instructions, the node can often suffer from brownouts (where the battery charges just enough that the Xiao powers on, but then the battery drains fully during start-up and the node gets stuck in a permanent boot loop until you can go and charge it up yourself).

There is an alternate wiring to avoid these brownouts that requires scraping off the R6 resistor so you can use the Harbor Breeze node’s internal solar management system (which may or may not have a brownout-preventing feature, we’re still testing it) but prevent the board from turning the node off during the day. I’d consider scraping off a resistor and wiring to the Xiao’s absolutely miniscule battery pads to be a “hard mode” node, so once we vet that this way prevents brownouts, we will make a new article for the Dirt Cheap Hard Mode Solar Node.

The approach I’m going with today is very beginner friendly. It is the one that I found in the description of this 3D printed mount for the light. This allows us to use the power button and doesn’t require any modifications to the included solar management board. Even if you’re new to soldering, this should be pretty easy.

Parts List

Essential Parts

Parts	Price	Description
WisBlock Starter Kit	$24.99	This is the Meshtastic node. You want the RAK19007+RAK4631 (not -R) version. Pick the frequency for your region, USA is 915.
Harbor Breeze Solar Light	$9.98	Make sure you verify that the Item number is 2483282. If you purchase in person, the item number will be displayed on the packaging. There is a newer version of this light and whether it works with this hack has not yet been verified.
Heltec GT-800 868, 915 MHz Whip Antenna	$2.99	These are cheap clones of the MuziWorks 17cm Whip Antenna that have tested just as well. You can also use the more expensive 8dbi antenna from the Medium Price Solar Node, but in Philly this will be all that is necessary for a roof node.

Essential parts cost: $37.96 + shipping

Parts you may/may not need or already have laying around

Parts	Price	Description
IPEX to SMA Female Cable	$6.94 for 2	The RAK kit comes with a cable, but it’s not long enough if you intend to run the antenna through existing holes. You’ll need a cable that’s at least 8 inches. Make sure to buy a cable that matches your antenna; this one works with the Muzi antenna from above.
JST PHR-2 2mm connector	$8.39 for 20	The WisBlock board uses a 2mm JST connector. You will need one of these to solder to the solar board and connect to the Wisblock battery terminal.
Waterproof Sealant	$6.34 for lots	You will need to seal up some holes in the case to make them waterproof if you want to install this outside. You can also get this from Lowes if you want to reduce shipping costs, just make sure the variety you go with works with plastic.

Total cost: $59.63 + shipping (or about $42 per node if you make lots)

Instructions

Before opening up the node, make sure the power button is off

Press the power button and verify that the light comes on, then press it again to power it off. If the light doesn’t come on, charge it up and then make sure it does.

Open up the node

Remove the battery and turn the solar panel upside down on a flat surface to ensure there won’t be any electricity running through the circuits while you solder.

Cut and remove the cables to the light. Remove the weather-proofing here, too.

You can cut them close to the circuit board.

Determine which is the positive and which is the negative side of the JST connector

Don’t skip this step! The JST connectors don’t have a standard and the one’s you ordered are likely BACKWARDS from the standard that RAK uses. This means it is likely that the red cable is negative and the black cable is positive. Plug the JST connector into the Battery connector on the RAK, look at which color is on the side with the plus symbol. This color is positive and the other color is negative.

Solder the JST connector to the light circuitry.

Solder the negative end of the JST connector to the spot marked negative and the positive end to the tab on the positive side the battery. You might need the JST connector cable to be a little longer (do a test fit before soldering), if so you can use the wire from one of the extra female JST cables that you don’t need.

The above picture is instructions I found online, the color of your wires may be reversed!

Make sure you haven’t accidentally turned on the power button and plug in the JST connector to the battery connector on the RAK

Warning: if you accidentally power on your RAK board without the antenna connected, you can irreversibly damage the board!

To be safe, you should connect your antenna to the RAK before plugging the JST connector into the battery connector. Verify that the RAK didn’t power on (that the power button is still off) and then unplug the IPEX connector and feed it though the hole where the light cables used to be, then plug it back into the RAK. Then put the battery back into the battery holder and hit the power button.

You can see the original IPEX antenna cable at the top of the image, it was not long enough to reach back out the pre-drilled antenna cable hole.

You can also see that in my case, the wire running to the positive end of the battery is black. That’s because my JST connector is reverse from the standard and my positive wire is black. In this picture I left the original light cables long in case I wanted to try a different variation. However, I got lucky and this variation worked well!

Waterproofing

Mounting

If you have a pole to mount to, you may be interested in printing a remix of the original 3D printed mount that I made. If you plan to mount to wood or something else you can screw into, the original 3D printed mount would be better.

Many of the 3D printed mounts online, such as the example below that another Philly Mesh member made, do not include an antenna mount, so you’re required to drill an antenna hole directly into the case. Oftentimes this requires the antenna to be bent 90-degrees. The Muzi antenna I linked does not offer this option and in practice many of the cheap plastic antennas have reduced range when bent. Make sure you test your antenna and confirm that it still performs well when bent, if that’s how you plan to use it.

Medium Priced Solar Node

Emily Boda — Wed, 14 May 2025 00:00:01 +0000

I’m calling this a “medium priced” node because I didn’t really budget and just bought parts as they became necessary. There are also many examples of cheaper nodes, such as the Low Priced Solar Node (Harbor Breeze). The low cost node depends on the availability of the Harbor Breeze solar lights, whereas this node uses more generic parts that will almost surely be available in the future.

For now, here’s a reasonably reliable node that costs around $110 for just the essential parts.

Parts List

Essential Parts

Parts	Price	Description
WisBlock Starter Kit	$24.99	This is the Meshtastic node. You want the RAK19007+RAK4631 (not -R) version. Pick the frequency for your region, USA is 915.
Unify Enclosure 150x100x45mm	$46.00	This one comes with pre-drilled antenna holes and is the right size for our RAK4631 and some batteries.
Enclosure Mounting Kit	$4.00	I picked type A, the vertical mounting version. This is optional, but great if you want to mount on a pole. Keep an eye on the recommended pole diameter (65-89mm).
Alfa 915 5dbi antenna	$17.97	I picked this one because I’ve tested a couple and they seem to be well-tuned and the quality seems consistent. YMMV.
Adapter from RP SMA Female to N Type Male	$8.99	The enclosure comes with a waterproofed RP SMA female adapter (reverse polarity) which is atypical, and the Alfa antennas are N Type Male. The included is an example, but you may also want one with a length of cable between them so as to separately attach the antenna to wherever you’re mounting it.
Two 18650 rechargeable batteries	varies, maybe $10?	I bought mine from Amazon, but this is not recommended. Check out this list that someone made of reputable distributors.

Essential parts cost: $111.95 + shipping

Parts you may already have laying around

I break this section out because 1) you may already have some of these parts laying around, 2) you could get many of them individually for very cheap if you buy local, and 3) if you do have to buy online and in bulk, you will have some on hand and they will not contribute to the cost of your next build.

Parts	Price	Description
Antenna Tape	$8.80	Although the antenna connector on the top is waterproofed, your adapter connections are not. This is a great option to waterproof your connections.
Battery holders	$7.99	I bought this pack of a million from Amazon. I had to solder them in series. If you’re not good at soldering find one that you don’t need to solder. Make sure the ones you buy are in parallel (not in series!). When I doubt, check the voltage with a multimeter before installation.
JST PHR-2 2mm connector	$8.39	The WisBlock board uses a 2mm JST connector. Depending on what kind of battery pack you buy, you may need to solder these JST connectors on.

Total cost: $137.13 + shipping

Picking a Meshtastic Node

nRF Meshtastic devices (like the RAK4631) are far superior to other types when it comes to power efficiency. While an ESP32 Meshtastic device (like a Heltec v3) might last 24 hours on a battery, that same battery will power a RAK4631 device for a week. For that reason, for solar powered devices, the RAK4631 is a great pick.

You may also wish to add environmental sensors to your RAK4631. See this page on Meshtastic’s website for supported sensors. This will allow your device to report measurements like temperature and humidity. Keep in mine those measurements will be from inside the enclosure, so they’re better for reporting the status of your node’s environment than the outside weather.

What about high/low temps?

18650 batteries generally have a stated temperature range for charging between 0 and 45C (32 to 113F). While your summer might top out at 90F, the temperatures inside a sealed enclosure in the direct sunlight might be closer to 135F. I’ve actually seen nodes in the Pioneer Valley reporting that temperature in the summer. On the other end of the spectrum, most of North America reaches below 32F in the winter for weeks at a time.

From what I understand, these recommended charging temperatures aren’t as big of a deal as they might seem to be at first glance. A group from Alberta wrote a great article about their node deployments in the frozen Canadian winters. They recommend overspeccing the battery capacity (three 18650s instead of two) in your node due to reduced charging performance during the winter, but other than that their nodes are pretty much fine. There’s no long term capacity effects.

I’m not as worried about high heat either. I’m of the opinion that I’m likely going to have to open up this node probably once a year to do firmware updates, so I might as well take that opportunity to replace the 18650s as well. If you buy them in bulk, the cost will be closer to $2-3 each, so it’s a relatively small maintenance cost.

Installation Location

The best place to install a node is very high up. Unfortunately for most of us, this means mounting the node somewhere like the roof, which is difficult to get to.

Wherever you mount your node, plan to have to update the firmware at least once a year, perhaps more often.

Updating firmware

Currently there are two options to update your firmware:

Connect to the device via a USB-C cable
Connect to the device via Bluetooth and update OTA.

Option one isn’t very practical in a solar node: if you’re already keeping your node connected to your computer, why not just power it from there? Some builds install a Raspberry Pi in the enclosure and connect that to the node via USB-C, but Raspberry Pis are very power-hungry and not a good fit for a solar node. Neither will work well for this particular build.

Option two is outlined in the Meshtastic docs here. There are a few disclaimers to consider before trying this. First, as of the time of writing, this only works with the iOS app. And second, if the firmware update fails, you’re SOL. Your device isn’t bricked, but you will need to connect it to a computer to get the firmware back up and running.

There currently are no other options. Even if you power your node via POE, there is no way to update the node via Ethernet. You may be able to power a Pi via POE and use option one from a more suitable location, however it is likely the Pi will not be able to survive summer heat in the enclosure. I am testing that this summer to see. Regardless, the Pi takes too much power for a solar node.

As a result, at least for me, I am planning to retrieve my solar node from its mounting spot and update its firmware about once a year.

Management

If your node is easily within bluetooth range, you can manage it from your phone. However, if your solar node is installed somewhere where it’s inconvenient to connect via bluetooth (say, on the roof of a public building you don’t have regular access to), it’s recommended to set up an admin channel on your node so you can manage it via the mesh.

The Meshtastic docs explain this here.

Other best practices for unattended nodes

If this device is outside the range of bluetooth and you won’t be able to regularly check DMs, it’s recommended that you make sure a casual mesh user will be able to figure out how to contact you. For example, if the node is your roof node and you also have a handheld mobile node, you might want to make the long name “JS Base Station” and the mobile node’s long name “JS Mobile” so users can try to contact you on the mobile node if you don’t respond to the base station. If you have a personal domain or an identifiable username, you could put the URL or your handle in your long name. A recent version of the Meshtastic firmware (2.6.8) allows you to designate your node as “unmessagable”. This is located in the User section of the settings.

In Philly, all of our phillymesh.net nodes are named as such! This solar node is phillymesh.net-08. We also add secondary and tertiary management keys of other members so that if one member is out of town or unable to reach the mesh, the nodes can be administered by other trusted members.

All of these best practices make the mesh a friendlier place!

Putting all the pieces together

The WisBlock board has a spot in the top left of the enclosure where it screws into the backplate. I printed a small plate to hold my two battery holders together, and they fit snugly at the bottom of the enclosure. They fit so snugly that duct tape might also work. I don’t think that more than two batteries will fit inside this enclosure, so if you want more buy a bigger enclosure.

When soldering the battery holders together, you want them to be in parallel. Some battery holders on Amazon don’t specify whether they’re in series or parallel. It’s worth checking the voltage with a multimeter before connecting to your WisBlock, as your WisBlock will let out magic smoke if you connect too high a voltage. The voltage should be around 3.7V (if it’s closer to 7.4V, that means the batteries are in series and you do not want that).

You battery holder will likely not come with the correct JST connector for the WisBlock board. Even if you buy a battery with JST connectors, they’re usually smaller than the correct size. Also, very important to note: the WisBlock battery connections are reversed from the standard (the solar connectors are normal). Rak claims “there is no standard”, but considering all the JST connectors I order on Amazon are the opposite of Rak’s choice, I disagree. Check the connectors you buy! I had to solder the red lead to the black lead and the reverse to make the connector attach properly, which continues to confuse me every time I open the enclosure. To reduce confusion, I wrote in sharpie on the interior of my enclosure which color is positive and which is negative. You will kill your board if you reverse the connectors.

Source: https://meshtastic.org/docs/hardware/devices/rak-wireless/wisblock/base-board/

Update 6/21/2025

I’ve had this node outside for about a month and each time I’ve opened it up I’ve noticed water inside the supposedly sealed node. This is likely due to humidity, Philly is very humid. I plan to add a weep valve to the node before installing on the roof. I will test for a while and then update the page again with more details.

Solar on Philly Mesh

Updated Low Priced Solar Node (Harbor Breeze)

Variations

Parts List

Essential Parts

Parts you may/may not need or already have laying around

Instructions

Mounting

Low Priced Solar Node (Harbor Breeze)

UPDATE

Original Post

Variations

Parts List

Essential Parts

Parts you may/may not need or already have laying around

Instructions

Mounting

Medium Priced Solar Node

Parts List

Essential Parts

Parts you may already have laying around

Picking a Meshtastic Node

What about high/low temps?

Installation Location

Updating firmware

Management

Other best practices for unattended nodes

Putting all the pieces together

Update 6/21/2025

Happy Meshing!