What will be the total power needed?

Other Hardware Motors, Mechanics, Power and CNC
1

In my project , I interface ultrasonic sensor with arduino, and I will send the sms through using simcom's gsm module SIM900,
Because I am going to keep the total setup in the field I want to use solar power supply. So, please help me in finding the total power needed so that I can buy particular capacity solar panel.

Required combinations are:
1.Ultrasonic sensor + Arduino UNO + simcom's gsm module
2.Ultrasonic sensor + Arduino Mega 2560 + simcom's gsm module

In the datasheet of gsm module it is shown that,

The powersupply of SIM900 is from single voltage source of VBAT= 3.4V TO 4.5V. In some case, the ripple in a transmitting burst may cause voltage drops when current consumptions rises to typical peaks of 2A. So the powersupply must be able to provide sufficient current up to 2A.

Thanks in advance.....

2

Its better you use voltage regulator circuit. Either use 7809 ic . to tun on your uno board/ & 7805 to turn on gsm. Just check input range for ultrasonic sensor and gsm module.

Check this condition That much current really consume???

The power supply of SIM900 is from single voltage source of VBAT= 3.4V TO 4.5V. In some case, the ripple in a transmitting burst may cause voltage drops when current consumptions rises to typical peaks of 2A. So the power supply must be able to provide sufficient current up to 2A.

3

The power supply of SIM900 is from single voltage source of VBAT= 3.4V TO 4.5V. In some case, the ripple in a transmitting burst may cause voltage drops when current consumptions rises to typical peaks of 2A. So the power supply must be able to provide sufficient current up to 2A.

Yes, that is correct. The peaks are of brief duration but unless the supply has sufficient capacity you can have intermittent problems.

4

So, 3watt solare panel is enough?

5

Which field will you be in? You might want to look up met office records to see whether you should budget for two days of batteries or seven, and how much oversized your solar panel needs to be depends on how close to the artic circle you plan to be using it. Inside the artic circle is bad news as that would need months of battery capacity.

I'd suggest being noncommercial about it and go way oversized, using an automotive 60Ah 12V battery, which is a lot more than you really need but cheap and available, and then sizing your solar collector to get a bit more than the leakage current in a 3 year old battery; probably 50W(peak) rated.

Do you have other essential and desirable properties?
How many hours of downtime in a year are tolerable?
Should you have duplicate redundant power supplies bussed in parallel so that your arduino is not unpowered during the battery swap at year 3 in the maintainance schedule?

If the size and weight of that is a showstopper for your application, one PP3 rechargeable might do overnight if your hardware is not greedy, and one 2Wp panel can just about recharge one of those in a sunny day.

So, the correct size depends on balancing your other unstated requirements of
i) uptime (hours down per year)
ii) weight and portability
iii) cost

6
  1. Here field refer to - canals from which we want to monitor the water level.
  2. My system will be working throughout the day.
  3. On my gsm module it is given that Use DC IN 7V to 15V, 1A.
7

I want to buy solar panel, which is required for my system consists of

  1. Arduino UNO
    2.Simcom's gsm module SIM900

for Arduino UNO

Operating voltage: 5V
Input Voltage (recommended) 7-12V
Input Voltage (limits) 6-20V

On my gsm module It is given that Use DC IN 7V to 15V, 1A

Available solar panels are 12volts, 3watts, 5watts, Please suggest me which one I have to buy?

Thanks in advance...

8

A lot depends on where you are in the world and how much sunshine you get.

A lot depends on whether you want it to work through the winter or just in summer.

A lot depends on how long (during each 24h period) you want your Arduino to operate.

Do you intend to use the solar panel to chage a battery that drives the Arduino?

I don't think it would be practical to drive an Aduino directly from a solar panel without a battery because it would probably stop everytime clouds pass in front of the sun - even for a few seconds.

One practical test would be to run the Arduino system from the battery and measure the current iit requires. Then by working out the watt-hrs required by the Arduino system you would know how many watt-hrs are required from the solar panel (allow at least 100% extra for inefficiency).

...R

9

There are plenty of examples around, of small solar panels which will charge a 12V battery, which you can then use to power your arduino. That might not the be most efficient way, but certainly the most straightforward if you don't have the time and ability to re-invent the whole process yourself.

Try ebay with the search "solar battery charger". Countless examples starting around 20 USD. You will then need a suitable small 12V battery - countless examples of those.

10

OK. 1A 12V needs 16Ah per night, and a 60Ah car battery gives you a bit over two days in which to find some sun.
I'd go a little larger; probably one 90Ah "leisure battery" and one 50W(peak) "12V" (actualy up to 21V) solar panel; those are a bit smaller than a square metre and make a convenient shed roof for you monitoring, and a pwm battery charge controller. That arrangement will give yor 24h monitoring on most days of the year and has enough spare capacity for a fewaddons, should you think of any. If you need no days of downtime in the year then two of those batteries might do that, with no need to buy them both at the start. The arduino power consumption is negligible by comparison to your GSM device.

11

The arduino power consumption is negligible by comparison to your GSM device.

Possibly the other way round, and you need to do some research into running Uno on solar, as I believe they take about 40mA just idling quietly.

The only way you are going to get anywhere with this is to map out exactly what you want to do, how you are going to go about it, and then possibly do a couple of dummy runs in order to properly measure things. You probably have not seriously considered if the Uno is the best choice, and you haven't even told us how many messages you want to send. Is it one a day, one every ten seconds, or what? So, at the moment, all you are getting is a load of arrant nonsense about 90Ah batteries and 50W solar panels, all based on nothing, and if you take that on board without properly considering it you might find yourself spending a couple of hundred dollars unnecessarily. Simply running a Uno off a 12v car battery would have to be particularly stupid and, if you find that you are throwing away more energy as heat than the Uno+SIM900 actually consumes, remember where you heard it first. The least you would need is a separate regulation system but, since 5v DC is God's own power there are surely better ways already available to supply it in the field and I guess they would use a 7.2v, or 8v deep-cycle, battery or possibly as low as 6v.

The first thing you need to consider in any situation like this, is the load cycle required of the battery, which depends entirely on your gear and how it is to be used. So far, all you have is that the SIM900 draws 2000mA at peak load, so I guess now is good time to remind you that they draw 1.5mA in sleep mode.

Therefore, it would pay well to consider how much time is spent on peak load, and how much time is spent sleeping. I imagine it wouldn't be too hard to ensure there is lot more of the latter than the former.

I believe the SIM900 is a 3.3v device. Therefore you might find that your best approach is to make up a barebones job with no LEDs and a Micro running on 3.3v, the whole thing being maybe so frugal that it is fine with a lithium battery - the solar panel is unwarranted, and the device less likely to be stolen.

I doubt that the SIM900 is so very different from an ordinary mobile phone and it is possible that battery in the phone has to deal with similar peaks. This could be indicative of the battery you really need and, if you do need a solar charger, it could be indicative of that too.

12

Why are you wasting our time by double posting. I have already commented on this here.

I have reported this to the moderator.

...R

13

You have to be careful with GSM modules, the peak current demand is a lot more than
the average, since they time-slice transmission. If in doubt reckon for 8 times the
transmit average current (as measured by a multimeter). If you don't it will misbhave
on transmit. Or consider large smoothing capacitor to provide the peaks.

14

@shivaaprs, do not cross-post again. Threads merged.

15

The big power consumer will be transmitting the SMS messages, so a good start is to figure out how many of these per day
will have to be sent.
From there its fairly easy to work out the daily power consumption overall, which will set the battery size and the panel size.
Base the panel and battery size on the worst case scenerio, which is middle of winter and 1 weeks worth of cloud cover.