Need Advice - Small Easy Off Grid Solar Panel Set up for a Remote Place with NO POWER

[Allen]

I am trying to find the best alternative for an easy (Plug and Play if possible) Off Grid set up for an internet tower.
I am installing internet in a VERY REMOTE area. But the tower that will be in the mountains...needs power.

I don't need much power, because this proposed system will only give power to a few antennas in order to receive the internet and then send the internet to the house a mile away to the receiving antenna on that house.

Any suggestions or help would be greatly appreciated.

 

[MisterSandals]

Any suggestions or help would be greatly appreciated.

I suggest you first determine how much power your equipment needs.

 

[snoobler]

Welcome to the forum. Define the power requirements, and it's a piece of cake. What do you want to power?

 

[ianganderton]

What’s your minimum and maximum daily power requirement?

Where about is the location? How much sun does the location have? Does it get full sun? (solar won’t work without it)

What temperatures are you looking at (min and max)

1- Calculate your daily power requirement

2- decide how many days cover you will need from the batteries to deal with low solar days (rain etc)

This will give you your battery size needed

4- calculate how much solar you will need to charge the batteries based on solar available in the worst time of the year you need the tower to function

5- design system to charge batteries based on battery and solar specifications.

 

[Rocketman]

Also. How bad is it if the tower loses power. Critical vs connivence.

 

[Allen]

Thanks everyone for your replies...Based on the info you've given me...I hope this is the info you need to assist me.

At the moment...I will install 2 Antennas (but will probably add more antennas later maybe up to 5 more) and the data sheets say:

Antenna #1
Max. Consumption: 9.5W
Supply: 24V, 0.5A Gigabit PoE Adapter

Antenna #2
Power Supply -- 24V, 0.5A Gigabit PoE Adapter
Supported Voltage Range --- 20 - 26VDC

It appears to me that it will require very little power...am I correct?
**************************************************************

#1 - What’s your minimum and maximum daily power requirement?
Whatever it takes to power those antennas 24/7

#2 - Where about is the location?
Costa Rica --- exact location at the Google maps link below:
Exact Location of Tower

#3 - How much sun does the location have?
A - lots of sun almost every day, 6 months out of the year during dry season
B - at least 3 to 5 hours sun every morning during rainy season

#4 - What temperatures are you looking at (min and max)
Temperatures range from 50 degrees to 75 degrees year round

#5- decide how many days cover you will need from the batteries to deal with low solar days (rain etc)
At least 3 days...but seldom does it ever go more than a day without sun.

#6 - design system to charge batteries based on battery and solar specifications.
I don't know what answer here...but YES, I need the system to keep the battery charged.

#7 - How bad is it if the tower loses power. Critical vs connivence.
The tower MUST keep power. If we lose power, we have NO WAY to communicate with the outside world. No phone signals, no electricity, no internet.

If you need any other info, please let me know.

I greatly Appreciate your advice and recommendation on what I need in order to supply this tower witht he power needed to get internet working.

Thanks

 

[snoobler]

Going to assume 12W due to 24V/0.5A

12W * 2 = 24W

24W * 24H = 576Wh

That's a very modest requirement.

Link #5 in my signature for your location, panel orientation and tilt. Pick the lowest month and divide 576Wh by it, and that's the minimum array Wattage you need, e.g., if you only get 4 hours of sun, 576/4= 144W. You'd probably want to go to 200W.

Size battery based on 576Wh/day. If you want 4 days backup 2304Wh.

Given that you are dealing only with 24V devices, you don't need an inverter. I would propose the following:

12V system
12-24V 3A step up converter to directly power the 24V devices at a steady 24V (this will provide 72W of 24V power).
200W of solar +100W each additional day of battery backup (800W max)
20A MPPT charge controller + 10A for each day of battery backup (80A max)
12V/100Ah AGM battery for each day you want to run without charging (1 week max)

The 100Ah 12V takes into consideration that you shouldn't discharge a battery below 50%. The reality is that in an emergency, you will have twice the actual battery capacity if you need to take them below 50% in an emergency.

With the exception of the charge controller, you could scale it up as needed, i.e., start with a single day's backup and then add days as needed. The charge controller would need to be replaced, or you could add charge controllers as you go.

My only concern is the converter. a 1.5-2A one would be better if you can find one. Running a converter at 50-70% of its power rating is pretty efficient. Efficiency drops off quite a bit at low % power.

 

[Rocketman]

Wow! That is not much power needed. Now what is your budget?

you need up to 3A of 24v power that is So very little ?. You need about 75 watts of power per hour * 24 hours = 1800 watts per day.

Probably one large solar panel or 2 smaller ones. A high quality solar charge controller.
Batteries- Lithium or AGM?
Reporting... what do you want for reports? (Can you send messages on the antennas)

 

[snoobler]

Since you may want more than 2, here's a Google Sheet calculator for you:

Radio Tower

Sheet1 INPUT # of Antenna,3,AVAILABLE SOLAR FOR THIS LAT/LONG: Days,5 Antenna consumption,720,W OUTPUT Daily energy,51840,Wh 1.5 Daily solar,20197,W Daily AGM,8640,Ah Daily LFP,5063,Ah TOTALS Solar,20197,W AGM, 12V Batt or,43200,Ah LFP, 12V Batt,25313,Ah MPPT Charger,1683,A

docs.google.com

The solar array is 50% larger than it needs to be to ensure that you can power your needs AND recover an additional 1/2 day of battery capacity.

I welcome any corrections.

 

[Allen]

Wow! That is not much power needed. Now what is your budget?

you need up to 3A of 24v power that is So very little ?. You need about 75 watts of power per hour * 24 hours = 1800 watts per day.

Probably one large solar panel or 2 smaller ones. A high quality solar charge controller.
Batteries- Lithium or AGM?
Reporting... what do you want for reports? (Can you send messages on the antennas)

I knew it I wouldn't need much power...as for budget...I don't have one. I don't have any idea what something would cost. I would prefer something simple. Do you have any idea or a picture of what a simple power supply for what I need might look like? Thanks for your help. Since this is going on a tower...it would be better to have ONE solar panel...and I would hope one batter would serve the purpose???

 

[snoobler]

You have design requirements, and hope isn't part of the equation.

Try the spreadsheet. You just change the # of antenna and # of days. Everything is calculated.

Panels can easily be on the ground on their own mounts. Batteries could likely be on the ground as well since you're passing 24V at low current.

 

[Allen]

Going to assume 12W due to 24V/0.5A

12W * 2 = 24W

24W * 24H = 576Wh

That's a very modest requirement.

Link #5 in my signature for your location, panel orientation and tilt. Pick the lowest month and divide 576Wh by it, and that's the minimum array Wattage you need, e.g., if you only get 4 hours of sun, 576/4= 144W. You'd probably want to go to 200W.

Size battery based on 576Wh/day. If you want 4 days backup 2304Wh.

Given that you are dealing only with 24V devices, you don't need an inverter. I would propose the following:

12V system
12-24V 3A step up converter to directly power the 24V devices at a steady 24V (this will provide 72W of 24V power).
200W of solar +100W each additional day of battery backup (800W max)
20A MPPT charge controller + 10A for each day of battery backup (80A max)
12V/100Ah AGM battery for each day you want to run without charging (1 week max)

The 100Ah 12V takes into consideration that you shouldn't discharge a battery below 50%. The reality is that in an emergency, you will have twice the actual battery capacity if you need to take them below 50% in an emergency.

With the exception of the charge controller, you could scale it up as needed, i.e., start with a single day's backup and then add days as needed. The charge controller would need to be replaced, or you could add charge controllers as you go.

My only concern is the converter. a 1.5-2A one would be better if you can find one. Running a converter at 50-70% of its power rating is pretty efficient. Efficiency drops off quite a bit at low % power.

Thanks greatly for your suggestion and that Google Sheet. The sheet you attached in there with the Solar Radiation per month...where can I find that data. I did check that 5th link in your signature, but that appeared to bring me to as sight where I could only put in city and etc, not one like you show with Lat & Long.

I hate to admit it, but most of what I am reading is like understanding a Foreign Language??? So, I have a lot to learn, but I don't mind learning.

If you had a link to a SIMPLE solution that I could buy,...would it be possible to send me a link???

The challenge I am facing...is, I am going to Miami in a couple of weeks. So, I need to buy everything EXCEPT, the solar panel and battery. Those because of size and weight, I will have to get in Costa Rica when I return.

Your help is greatly appreciated!

 

[Allen]

You have design requirements, and hope isn't part of the equation.

Try the spreadsheet. You just change the # of antenna and # of days. Everything is calculated.

Panels can easily be on the ground on their own mounts. Batteries could likely be on the ground as well since you're passing 24V at low current.

I did play with the google sheet and changed the days and antenna. While I can safely assume that changing the # of antenna is however antennas I need and the Days are how many days....incase of NO SUN???
The rest (sadly for me) is gibberish??? I have no idea what the other abbreviations mean or what I should do with them or how I would use them to determine what to buy or not to buy.

Your help is appreciated.

 

[snoobler]

Yes. Days of no solar charging at all - backup power or whatever you want to call it.

You input the values in yellow. You buy the values in green.

2 antenna, 3 days.

You need:
224W of solar panels
288Ah of 12V AGM or 169Ah of LFP (Lithium Iron Phosphate) batteries
19A MPPT charger

You can then price components meeting those requirements.

 

[Rocketman]

If you search Amazon (USA) for “Din POE 24v” you will find a Din rail mount power over Ethernet adapter (from CZH-LABS) that takes 12 v in and I believe puts .7 amps of 24v on the POE.

(I know nothing about that adapter other than it looks like it will work).

From snooblers spreadsheet you need probably
A 250 watt solar panel
A solar charge controller - like Victron 100/20.
A box to Mount stuff into.
Batteries - Lithium (expensive) or AGM.(Heavy)???
200ah of lithium batteries or
300ah of deep cycle AGM batteries
A POE adapter
Wires
Fuse holder & fuses
Mounting hardware.
etc.

Another choice that could be made is to go with a 24v system. (may make it simpler). Start with your POE adapter (your load) and work from there.


Since you said you may want to move to 5 antennas you may want to play around with the spreadsheet and make sure the stuff you buy can be expanded to include more antennas. For example you may want to consider a 100/30 solar charge controller so you can expand to 440 watts of solar power - enough for 4 antennas (and maybe the 5th).

My guess is even during bad weather days you will get some power from the solar - so you probably have more than 3 days of reserves.

Once you have your specs now figure out your equipment- for example 250 watts of solar. Is that one 250 watt panel - one 320 panel or three 100 watt panels? That will be a local supply question.
Draw a diagram of how you are going to connect everything and we can review it.

Good Luck!

 

[snoobler]

I selected 12V because the antenna input was limited to 26V max. To me that says it needs to be a regulated voltage as charging goes well above 26V.

 

[Rocketman]

Very good point.

 

[snoobler]

Very basic schematic (edited from Will's site):



You would power the antenna from the 12V-24V converter.

 

[Hedges]

I would do 24V of AGM batteries, linear voltage regulator to drop voltage to 24V ... 26V max.
Don't know about reliability of the 12V to 24V DC/DC converters others suggest, but I've had a lot of AC/DC switching supplies fail.

up to 7 antenna drawing 0.5A each, 3.5A x 24 hours is a bit over 100 Ah to last one day. 300 Ah or more.
My battery bank is 48V, 405 Ah and cost $5000 so yours could be 24V, 405 Ah for $2500. That would be 75% DoD if 3 days without sun.

Sun Xtender Solar Batteries - Photovoltaic Battery

The Sun Xtender Battery line consists of specialty lead-acid solar, photovoltaic batteries, and renewable energy storage batteries manufactured by Concorde Battery Corporation.

sunxtender.com

2400 Wh/day is about 500W of panels.
Two panels, 400 to 500W each. One aimed at 9:00 AM winter sun and one at 3:00 PM winter sun should produce enough power and keep battery well charged until evening, reducing cycling at night for longer life.
Maybe four 300W panels. Summer and winter tilt, morning and afternoon sun. PV panels are now the cheapest part of the system so you can over-panel to make up for overcast days.

Will internet connection be available at the tower? That would permit telemetry.

You might use PTC fuses to feed each tower so if one shorts out the others stay up.
There are various sorts of redundancy that can be implemented if you have an idea of what components are less reliable. For instance splitting panels across multiple charge controllers. If one dies the others keep it working, and you'll see the change via telemetry.

 

[Allen]

Very basic schematic (edited from Will's site):

View attachment 31685

You would power the antenna from the 12V-24V converter.

THANKS...this image is really helpful. If you have a link to an MPPT Controller that YOU suggest or recommend that will work for my application. That would be greatly appreciated. I have NO idea what a MPPT Controller is...and I CAN google it...but that still doesn't tell me if I'm buying anything reputable.
Thanks