GMRS Repeater - Solar Powered

[JeepZJ]

We are in need of communications between our hunting cabin (0ff Grid) and our hunting grounds. They are 2-10 miles away from each other with a significant hill between them and lots of other hills in the area. This is a very heavily forested area far from civilization.

I want to put a repeater at the top of our hill, which is part of our property.

I'm considering the following equipment for the repeater site:
(2) 25 Watt  UHF radios
Celwave 633-6A Duplexer
Comet CA-712EFC Antenna
Renogy 50 Watts 12 Volts Monocrystalline Solar Panel
PowerStar 12V 35AH U1 Deep Cycle AGM Solar Battery
Genasun GV-5-Pb-12V, 5A MPPT solar controller with LVD
1/2" Heliax Hardline Cable

What I'm not sure about is the need of a repeater controller. They seem to offer lots of bells and whistles, but do I need one with modern radios?

[WRZT743]

1 hour ago, WRUE951 said:

ihere are some install pics.   My wallet will prove it did happen. 

looks nice and clean

[WRUE951]

On 10/16/2016 at 7:50 PM, JeepZJ said:

What I'm not sure about is the need of a repeater controller. They seem to offer lots of bells and whistles, but do I need one with modern radios?

I don't use a controller for my portable repeater, which is two Maxon 8402 radios. These radios can be daisy chained and programed to work as a repeater.   Most off the shelf mobile radios when paired will need a controller to allow them to function as a repeater.   I do have an ID O Matic controller. and used that on these radios when I had them set up for my home repeater.  However I only used the ID O Matic for CW Call sign annoucnement.   If CW Call sign announcements are important for your remote repeater than a controller such as the ID O Matic will do that.  For me, my portable temporal set up does not need the CW announcement.   If your two 25W mobile radios can't be daisy changed by design to make a repeater then you will need controller to make the two rides function as a repeater. 

[WRZT743]

The raspberry pi controller does more that just Id it also gives me the time on the hour every hour and I have skywarn so when there is a noaa weather alert for my county it reads it off and changes the tail squelch  tone and repeats the alert every 15 minutes

[SteveShannon]

Sometimes resurrecting a nine year dead thread brings interesting new perspectives. 

[Lscott]

10 hours ago, WRZT743 said:

This is the solar system for my cabin very similar to the one I built for my dad but its a 24v system 1200 watts of solar mppt charge controller  looking to upgrade from 24v 100ah to a 24v 320ah 

Looks like enough power to run some small power efficient appliances for a weekend on battery power, assuming you only use the cabin on the weekends. The solar panels are enough to recharge the battery system over the work week.

Upgrading to 320Ah battery system at 24 volts gives you about 6KWH at 80 percent capacity drain. If you keep your power usage to 2KWH per day that gives you at least 3 days of power assuming zero input from the panels. With a decent amount of sun light you could run maybe a full 7 days per week. 

The real challenge is the winter when the total number of sun hours is markedly reduced. That’s when most solar power systems come up way short. Solar panels have gotten way cheaper so it might not be a big deal to double the array size.

What I don’t see is the special DC fuse.

https://viox.com/how-to-properly-fuse-a-solar-photovoltaic-system/
 

Also can’t tell from the photos but all the circuit breakers and cut off switches must be DC rated. If they are AC/DC type then the DC rating is noticeably below the AC ratings. Typically the DC voltage rating is below the AC one to ensure any arcing when the device opens under load is extinguished. With AC the voltage goes through zero thus helping to quench the arc. Of course with DC this doesn’t happen and why you must use the properly rated devices. Same with fuses. 

This really looks like a great system if you budget your power usage carefully.

[WRZT743]

Yes breakers are DC for the dc side of the system and the two breakers above the transfer switch is ac.

Solar panels have inline fuses on the wires coming into the system and the battery has a marine terminal fuse also. so system has fuses and breakers.

Breakers as size smaller than the fuse so hopefully it trips before blowing the fuse and all wires are also oversized because why not other than cost and it was a small project so using 12g instead of 14g wasn't to bad. 

I run a mini fridge 24/7 during the spring summer fall it uses about 50watts an hour when running . And the tv and lights don't take up much electricity so the 24v 100ah has been doing great for 3-4 day trips 

I did leave my coffee pot on when I went out hunting once it used about 1/2 my battery in 4 hours that morning

 

 

[Lscott]

32 minutes ago, WRZT743 said:

Yes breakers are DC for the dc side of the system and the two breakers above the transfer switch is ac.

Solar panels have inline fuses on the wires coming into the system and the battery has a marine terminal fuse also. so system has fuses and breakers.

Breakers as size smaller than the fuse so hopefully it trips before blowing the fuse and all wires are also oversized because why not other than cost and it was a small project so using 12g instead of 14g wasn't to bad. 

I run a mini fridge 24/7 during the spring summer fall it uses about 50watts an hour when running . And the tv and lights don't take up much electricity so the 24v 100ah has been doing great for 3-4 day trips 

I did leave my coffee pot on when I went out hunting once it used about 1/2 my battery in 4 hours that morning

 

 

Sounds like you did your homework on this project. 

There are charts for breaker operating time and fuse clearing time based on over current. If you want a deeper dive you can try to obtain those for the specific items you have and check the time delays based on your max fault current. That would be the best way to ensure the system will function as you expect.

I've attached some sample fuse datasheets for those interested to see what they look like and they have the arc clearing times curves.

I don't have any sample breaker datasheets. Most of what we use were I work are simple disconnect switches inline with high speed "semiconductor" type fuses. The few "breakers" we have used are based on magnetic overload detection. A lot of the small breakers use thermal overloads. Those you have to watch and make sure they will trip before the fuses open. Of course fuses are strictly thermal overload detection based too.

Bussmann JJN 300Vac, 1-1200A, Fast-Acting Fuses.pdf FKS ATO - 80V.pdf

[Lscott]

On 10/16/2016 at 10:50 PM, JeepZJ said:

We are in need of communications between our hunting cabin (0ff Grid) and our hunting grounds. They are 2-10 miles away from each other with a significant hill between them and lots of other hills in the area. This is a very heavily forested area far from civilization.

I want to put a repeater at the top of our hill, which is part of our property.

I'm considering the following equipment for the repeater site:
(2) 25 Watt  UHF radios
Celwave 633-6A Duplexer
Comet CA-712EFC Antenna
Renogy 50 Watts 12 Volts Monocrystalline Solar Panel
PowerStar 12V 35AH U1 Deep Cycle AGM Solar Battery
Genasun GV-5-Pb-12V, 5A MPPT solar controller with LVD
1/2" Heliax Hardline Cable

What I'm not sure about is the need of a repeater controller. They seem to offer lots of bells and whistles, but do I need one with modern radios?

I think your power budget is way under unless your usage on the radios will only be a few hours per day. 

Before you start purchasing hardware I strongly suggest you do a power consumption analysis using a realistic duty cycle on the radios. also being up in Idaho the usable number of sun-hours in the fall, I assume is when you'll be hunting, will only be a few hours per day. 

The definition for "sun-hours" is the solar radiation over the course of a day, which varies from morning until night, and assumes it a fixed value at the max for a given number of hours. This makes the calculations easier.

See a sample for charts for Michigan where I'm at. It's shocking to see the difference between summer and winter. It's not uncommon for solar installations to over produce during the summer and way under produce during the winter. 

I was going to build a small portable solar power system for field use with a Lithium Iron Phosphate battery. The attached calculations I did because I wanted some idea of what the likely endurance would be. The calculations are a bit more detailed than what you would need to do. I went a bit overboard with it.

   

Michigan Cities Solar Radiation Data.pdf Renogy RNG-50D 50 Watt - System Sizing Rev 3C.pdf Renogy RNG-50D Latest.pdf

[WRUE951]

21 hours ago, WRZT743 said:

The raspberry pi controller does more that just Id it also gives me the time on the hour every hour and I have skywarn so when there is a noaa weather alert for my county it reads it off and changes the tail squelch  tone and repeats the alert every 15 minutes

Depending on the software and the controller board, you can do a lot.  Open Repeater paired with an ICS board will do tons of stuff, even time announcements etc. I have one of these boards but never used it, My built in repeater controller does what i want.  

[Bogieboy01]

On 12/14/2025 at 12:14 PM, WRUE951 said:

ihere are some install pics.   My wallet will prove it did happen. 

Very nice setup! I am currently running 2 310w panels on a renogy adventurer 30a mppt controller for my radio shack... have 250a worth of lead acid currently but looking at changing to lithium this summer... also have somewhere around 700ish gal (if i recall correctly) of rainwater collection 

 

So far i have not been able to run the batteries out monitoring the radio and powering a 600w invertor for lights... if i try and use a circular saw for a while on the invertor it taxes the batteries pretty hard, but it still will do it...

[LeoG]

I have a single AGM 105Ah battery connected to two 100 watt panels on my truck so I can work off the back of my truck.  For the most part I rarely run out of energy.  It's mostly used for the chop saw, jigsaw and belt sander.  None of them are on for longer periods of time.  I try to have the panels in the sun when working so the battery self charges during the down time.

For a repeater that is only being used for a couple guys during hunting I doubt much of a battery system is needed.  The RTs have the advantage of no fans running, constantly drawing current.