There was a time when off-grid communication was all about hefting a large radio and making do with frequent battery changes. Meshtastic put an end to that, and the advent of solar power has altered the dynamic once more.
With their solar powered gear, Meshtastic provides a means for hikers or those in disaster response to remain in touch, as do ranchers, without the need of a wall outlet or cell tower. The sun is what fuels these unassuming, low-power units; they put the energy into a rechargeable battery and can send a message over a mesh network for miles. Whether one is in the process of putting in a fixed relay on his property or assembling a backcountry repeater chain, it is something of an oversight not to have the proper solar arrangement in place.
This guide explains what solar powered Meshtastic devices are and how they operate. It also covers what separates a dependable unit from one that fails after the first cloudy week.
What Are Meshtastic Solar Devices?
Open-source Meshtastic firmware is what drives the radio nodes known as Meshtastic solar devices. They are put to work by a solar panel in place of disposable batteries. The platform is free and operates on LoRa radios of modest size, providing a means to exchange text or GPS data in the absence of cell or internet.
Put a battery and a solar panel on such a radio and it becomes a node fit for the top of a vehicle, a fence post or a rooftop. With no wires and not a wall outlet in sight, it will continue in operation indefinitely. One does not need much from a panel to see a node stay charged in any weather, given that the hardware is not much of a power consumer to start with.
In effect, after installation there is no cost to run the mesh radio system. Forget subscription fees, cellular bills or having to change out batteries at the end of every few days. For many a fixed Meshtastic node the solar option is an obvious upgrade. You will find ranchers, hobbyists and volunteer emergency organisations making use of this very arrangement. It is simple hardware with an ongoing expense of virtually nil.
How Solar Meshtastic Devices Work
A solar Meshtastic device combines two systems that each do one job well: message relay and power management. The sections below break down both halves.
The Hop Limit and Message Relay Process
A Meshtastic node is attuned to packets put out by radios in its vicinity. Should it not have come across the message before, the node will rebroadcast it. With each retransmission the hop limit on the packet is reduced by one; at zero the message is no longer propagated. In this way a message can make its way over a meshtastic lora device network from one node to the next, well past what any one radio could cover on its own.
Solar Charging and Battery Capacity
There is no telling the difference between a solar and a battery-only unit in this system. One will simply recharge on its own while there is daylight, obviating the need for a wall outlet or to put in a fresh battery. Most builds are done with a lithium battery and a modest panel of perhaps a few watts. With 2,000 to 3,200 mAh of capacity one can expect the radio, if it is of the low-power variety, to last all night and be back to full strength come the following day, even if it was overcast.
For those wanting greater reliability, larger panels and battery banks are employed. In some cases, a builder will put in an additional panel at another angle to make the most of the available hours of sun; a useful redundancy where the weather is not to be trusted.
Why Solar Power Matters for Off-Grid Networks
Batteries alone work fine for short trips, but they run out. A long-range communication device meant to sit unattended for months needs a way to recharge itself. Solar is the simplest option available for that job. This holds especially true for fixed installations. Think of a rooftop meshtastic repeater or a relay point on a remote property line. Nobody checks on those units every day.
There is value in solar power come an emergency, should the grid be out for a week or more.
Put a solar node in the proper location and it will continue to put messages through during a storm or while responding to a wildfire, well past the point where one can no longer count on cell towers or home internet.
Preppers, ranchers and those in search-and-rescue will tell you that such independence is what a mesh network is all about; one sound node in the right place is enough to have the whole property connected.
Volunteer organisations with few people to cover a wide area in their searches put stock in that sort of reliability.
With a solar node they can trust, there is no need to be concerned with the equipment, and they can give the search their attention.
Key Components Inside a Meshtastic Solar Repeater
A typical meshtastic solar repeater has four main parts. These are a LoRa radio board, a rechargeable battery, a solar panel, and a weatherproof enclosure. The two sections below cover what each part needs to do.
Radio Board and Battery
With the Meshtastic firmware in operation, the radio board is what manages the antenna link. For power storage there is a battery of the lithium-ion or lithium-polymer variety; this will see the unit through the night and make up for any shortfall from the panel on an overcast day. Daylight hours are when the solar panel puts charge back into the battery, its wattage being commensurate with the climate and the radio’s demands.
Solar Panel, Enclosure, and Temperature Control
An enclosure is put in place to shield the components from the elements be they rain, dust or changes in temperature; one would expect at least an IP67 rating for anything installed outdoors. In cold climes extra care is called for as a lithium pack can be damaged by sub-zero temperatures and does not take a charge well. Insulation or some form of heating is frequently incorporated by way of protection in those parts of the country.
Then there is the matter of ventilation in the summer to prevent heat from accumulating in a sealed box. A bit of a vent or a coating to reflect the heat will keep the electronics in their safe operating zone.
Meshtastic Relay, Repeater, and Node: Knowing the Difference
People often use these three terms loosely, so it helps to separate them.
What Counts as a Node
A meshtastic node is any device on the network. That includes the handheld unit in your pocket.
What a Relay Does
A meshtastic relay is the action every node performs when it rebroadcasts an unseen message.
What Makes a Repeater Different
One does not find a screen or any buttons on a meshtastic repeater for the most part; it is a purpose-built device. It has but one function, to be put in a stationary position and pass on packets to put more coverage in place. Being unobtrusive they are well served by solar power, as builders make them to operate for long periods with no need of an operator.
This is something to bear in mind in network planning. A few solar repeaters placed at an elevation will see to more ground than would be the case with some score of handheld nodes down below. Get the right combination of relays, repeaters and nodes sorted out from the start and it will be time and money well saved.
Meshtastic Devices for Sale: What to Check Before You Buy
When browsing meshtastic devices for sale, a few details matter more than the marketing copy.
Enclosure and Battery Capacity
Start with the enclosure rating; for an outdoor installation you want proper weatherproofing. A case of merely rugged appearance is no match for actual conditions. Then put the battery capacity in perspective with what the radio will be drawing in power, as a battery of insufficient size will be depleted quicker than the panel has time to put back into it.
Frequency Band and Firmware Setup
Then you will want to see that the frequency band is in keeping with what your region allows. There are LoRa frequencies for every country and straying from the correct one is an invitation for interference, if not legal issues. As a last step, find out if the unit comes with Meshtastic firmware already on it; where manual configuration is called for it can put a delay on getting your network up and running.
A good seller will have no trouble putting those specs in plain view and will not obfuscate them with a poorly written product description. And do not be put off from perusing some verified reviews from other customers to get a sense of how the equipment performs in practice prior to buying.
MeshCore vs Meshtastic: Which Suits a Solar Setup Best
Anyone comparing MeshCore vs Meshtastic should know both run on similar LoRa hardware. They handle message routing very differently, though.
How Meshtastic Handles Routing
With Meshtastic one can easily get on the network since it has every node rebroadcasting. A straightforward way to go for an ad-hoc affair or a casual group. In the main, most will find Meshtastic the more accessible option; the phone app is uncomplicated and there is a bigger community to draw on so you are up and running in short order.
How MeshCore Handles Routing
Then there is MeshCore which is built around dedicated repeaters and a degree of structure in its routing. As the network expands this is what conserves airtime. It is a matter of some consequence for power consumption with a solar installation, more so than the hardware itself, for less time on the air translates to a lower average draw from each node.
One might put MeshCore to use in a planned deployment of any size and have a handful of stationary repeaters do the heavy lifting. There are builders who will put both to the test on different pieces of hardware to see how they fare. But come down to it, whether one or the other, it is all about having the battery, enclosure and the sun perform as they should.
Long Range Communication Devices for Vehicles and Fixed Sites
Solar nodes aren't limited to rooftops.
Meshtastic Vehicle and Car Nodes
A meshtastic vehicle node mounted on a truck or camper can extend a mesh network while traveling. It uses a small panel to top off the battery. This happens whenever the vehicle sits parked in daylight. Similarly, a meshtastic car node setup often pairs a compact antenna with a battery pack. A dashboard-mounted panel trickle-charges that pack during the day.
Fixed Solar Installations
There is an advantage to fixed installations in that they are not on the move, so one can put in larger panels and batteries of a greater size. The builder has the freedom to place them where the sun will be at its best throughout the year.
But it is all governed by the same principle: panel size and battery capacity have to be commensurate with what the local sun provides. And there should be a buffer built in to see one through a few days of cloud cover. It is wise to run some numbers on the area’s sunlight averages prior to purchasing any hardware; that way there is no risk of an undersized system down the line.
Choosing a Rugged Meshtastic Device for Outdoor Conditions
One sees cheap hardware give way in an outdoor setting before anything else. For a meshtastic device to be rugged it must have connectors that will not corrode and an enclosure of the sealed variety, with components rated for any temperature.
A box from the hardware store made of plastic is seldom adequate by itself. Then there is the matter of salt spray in coastal regions; without a proper seal this will eat away at exposed contacts in short order.
The mounting hardware is of consequence as well. One wants a repeater put up to a wind or rain, or some inquisitive animal, to be able to stand up to it. Put in a good quality enclosure and the trouble is avoided down the line.
There is no reason to be on a roof or up a pole over a corroded connection, or to be replacing what has been damaged with the turn of the season.
Best Meshtastic Device for Your Off-Grid Network
Finding the best meshtastic device for a given setup depends on the goal. A lightweight handheld suits hiking, while a solar-charged repeater suits permanent coverage.
Spec5 Relay Specs
From SpecFive comes the Spec5 Relay, a solar-powered Meshtastic LoRa relay of Texas origin. Whether for a tower, building or pole, it is shipped in a condition to be put to work right away. A 12-watt solar panel and a pair of 18650 lithium batteries are housed within the unit to see to its charging on an ongoing basis with no need for manual input.
An IP67 outdoor antenna of 50 cm is part of the package as well; in an urban setting one can expect a range of some 1 to 3 miles from this arrangement. Put it in rural country with an unobstructed view and that extends to between 5 and 10 miles, though mounting height will have its effect on the outcome. The 915 MHz band is what the unit is designed for, as is customary with US Meshtastic. As for firmware, there is support for ATAK-Meshtastic, MeshCore and plain Meshtastic.
Who the Spec5 Relay Suits
With this kind of set up, a rancher or prepper, not to mention an emergency team, has something they can use right away; there is no need to go to the bother of building from scratch. If one is in the process of establishing a fixed node network, hardware which has been put through its paces in the elements will be the quicker way to go.
Frequently Asked Questions
How long can a Meshtastic solar device run without sunlight?
Take the Spec5 Relay: on a given charge it provides about 24 hours in standby mode. The majority of Meshtastic nodes running on solar have two or three days’ worth of reserve to see them through overcast weather. And a panel of the right size will make good on that charge in a sunny day.
Do Meshtastic solar devices work in cold weather?
Lithium batteries do not take a charge well in subzero conditions and are liable to be permanently damaged. One will find that builders in cold regions put some insulation or a heater of sorts in the enclosure so as to maintain a temperature at which the battery can be safely charged over the winter.
What's the difference between a Meshtastic repeater and a MeshCore repeater?
As for a Meshtastic repeater, it is wont to rebroadcast all messages up to the hop limit. MeshCore is different in that it adheres to routing rules of a more structured nature and will only forward on certain paths. The range is extended with either, though on a large network MeshCore is designed to be sparing with its airtime.
Do I need a phone to use a Meshtastic solar repeater?
A repeater is a standalone piece of equipment; it does not require an app or phone to be paired with it. You will find that only the client nodes, i.e. the handhelds one has on hand, need a companion app. As for the solar repeater, its function is simply to put in the work of forwarding packets.
Is Meshtastic legal to use in the United States?
Then there is the matter of the 915 MHz ISM band which Meshtastic devices use; being license-free, and under the purview of FCC Part 15, a ham radio license is not called for. Compliance is ensured by those very rules which also see to it that power output is no more than 1 watt.
Final Thoughts
There are only a handful of practical decisions to be made in putting together an off-grid network with some resilience. You need hardware you can count on; solar panels suited to the climate and a battery of sensible proportions. Then there is the matter of traditional radios and their principal shortcoming; Meshtastic solar devices put an end to that, doing away with the necessity of having a power outlet at hand or making regular battery swaps.
Whether one has in mind a lone repeater for the top of a barn or to string a series of nodes over an expanse of property, the approach is no different. The principles are the same: see to it the enclosure is properly rated, match the battery to what the radio will draw, and choose a panel good for a few consecutive days of clouds.
Do that and the mesh network, being solar, will give years of dependable service. When cell service and the like are not an option, it is still there online.
