advice on very remote monitoring

[bobbybeans]

So I am trying to help my friend on a project. I have convinced him to use domoticz and a DHT22 for some of his stuff at home which he is going to get setup

He also has some land about 1 hour away that he wants to monitor things at, problem is no electricity no internet.
So I have a problem of trying to come up with a solution for him.

He will on his land have a solar panel and an array of 3-4 12v deep cycle batteries for when he is there he can run light etc.
He wants to monitor wind speed, rain fall, temp, humidity, soil dampness and some security window open sensors on his build

I was going to use an esp12 however I am running into 2 issues that I’d like your guys feedback on

here are the sensors I am going to use

wind speed - not sure
rain fall - maybe a pulse counter?
temp and humidity for inside and outside - dth22
soil damp -SEN-13322
window/ door sensors mc-38 reed switches

here are some problems I have
power and internet to put it blatantly

my solution for power put the esp12 into deep sleep and wake it up every X time collect data then send to server go back into deep sleep. This is a great solution I think however there are a few problems I see
1 the reed switches for windows and doors, if someone opens them then closes them while its asleep it will never register that it was open
2 pulse counter for rain would be incorrect unless I can store the information somewhere and when it queries it it gets how many pulses and clears it then sends it
3 since there is no RTC on the ESP having it wake up every X time will eventually become out of sync- possible solution add an ultra-low power RTC on it then it can wake it up reliably - does anybody know of one? and how would I set a specific time on it to wake the esp up?

internet solution - have one of those pocket mifi devices that output wifi and connects to 3g with a sim data package
problem - those take way to much power - does anybody know any lower power 3g options
What I was thinking was having a relay trigger to turn it on and turn it off based off the RTC switch but these things take a few minutes to boot up and acquire signal so I couldn't have them both turn on at the same time as the ESP would send data most likely quicker than the mifi could boot up.
Can you guys think of any solution to the problems I present?

I just recently thought of the RTC but still unsure of many factors, any idea/ input / better solution would be appreciated

[paxi]

Why not use an old smartpone for internet connection? For the small amount of data to transmit 2G is more than sufficient amd consumes less power than 3G.

With a sufficient solar panel it shouldn't be a problem to run phone and esp 24/7. Chose switching regulators for best efficiency of power conversion.

[bobbybeans]

Why not use an old smartpone for internet connection? For the small amount of data to transmit 2G is more than sufficient amd consumes less power than 3G.

With a sufficient solar panel it shouldn't be a problem to run phone and esp 24/7. Chose switching regulators for best efficiency of power conversion.

Hmm I will contemplate, I am pretty sure he is not going to have a huge solar array. it will probably be barely big enough to charge the batteries. His idea was have an array of batteries with a solar panel enough to charge them. So when he is there for a whole weekend it wouldn't be enough and the batteries would deplet but when he goes away it would be enough to charge them up over the course of a month till he is there again.
If I start putting a big load on it, it would most likely not be onugh power. I will have to converse with him about the size of the panel.
What I was thinking based on your suggestion would be to put a INA219 on the batteries and if it goes below a certain amount shutdown all equipment till he gets back the next month. not the most ideal but may work as what if it snows and covers the panels? no one is there it clean them off, or if its really stormy for a few days or week/ overcast. I realise that sun still shines through overcast skies but not as much.

for the INA219 I see that its max rated for 3.2 amps. To measure amps you have to put it inline with the load right? I don't really care about amp measurement. if I don't put it in line can I just have it measure the voltage?

where would I find a phone that has 2g? how would I go about even doing that .. haha I know about 3g and 4g
based on what I found here. I would imagine that would be plenty speed for sending basic data

2G networks (GSM, CDMAOne, D-AMPS) are the first digital cellular systems launched early 1990s, offering improved sound quality, better security and higher total capacity. GSM supports circuit-switched data (CSD), allowing users to place dial-up data calls digitally, so that the network's switching station receives actual ones and zeroes rather than the screech of an analog modem.

2.5G networks (GPRS, CDMA2000 1x) are the enhanced versions of 2G networks with theoretical data rates up to about 144kbit/s. GPRS offered the first always-on data service.

[paxi]

I'm not aware of a 3g/4g phone that has NO 2g ability. Just a matter of configuration to make it not use the faster networks.

[papperone]

I'm not aware of a 3g/4g phone that has NO 2g ability. Just a matter of configuration to make it not use the faster networks.

many chinese sellers/brand still keep seel/producing 2G only phones for very cheap prices...

[bobbybeans]

ok thanks guys i will look into this

[Zeric]

The power requirements for a 2G phone and esp are fairly minimal, certainly not anything that will require a huge solar array. He will spend more on the batteries in the long run than on the solar panel, as the batteries will need to be replaced more often.

A 100watt 12v panel can be purchased for $110 USD. Assuming only 4 hours of good light per day, and derating by 25% for inefficiencies of the charge controller, wiring, etc, and one still can produce 300 watt-hours per day with just one fairly inexpensive panel.

An old 2G phone charger puts out 500ma at 5v, and the phone will not use nearly this much on average. Likely under 250ma or about 1.25 watts or 30 watt hours per day. The esp power will vary depending on how often it transmits. My understanding is it peaks at about 1 watt, but most of the time it's only about 1/5 of that. Even if it uses a half watt on average, that's still only 12 watt hours per day. Throw in some more margin and say together 60 w-h per day.

The larger question is all the other solar requirements, in other words, how much power he uses when he is there from the batteries that needs to be replenished, and how many days will be available for recharging between visits. That will have a larger bearing on required solar power then the 2G phone + ESP.