Hi
i have made a project with:
Arduino UNO R3
BME280 sensor
RTC module
Nokia LCD Display
I would like to tell me what battery to use to make it portable.
Thank you.
Without knowing your criteria you can use one of these.
It can be moved easily with a small hand truck.
But a smaller one may do, as well.
Yes a smaller one will work too.
I believe there are larger ones if more amp-hours are needed.
larryd:
Without knowing your criteria you can use one of these.
It can be moved easily with a small hand truck.
Thank you for your answer.
I thought that this was a forum for help people like me to solve their tech problems.
But it seems that i was wrong.
I wrote down what items i use just to calculate how much power i need from a battery.
Please if you don't know or if you don't want to answer to me just don't answer.
Just remember that no-one knows everything.
Anyway thanks for the help.
Well, we assume you measured the total current your project draws but you failed to tell us what that was.
You didn’t tell us if everything has to be turned on 24-7.
You didn’t tell us what your size restrictions are.
You didn’t tell us if there will be access to charging current, 120vac, solar etc.
You didn’t tell us if the battery was to be charged or if it can be disposable.
You must have some design criteria.
.
If you want sensible answers, then you should also tell us HOW LONG you want this setup to work.
A cellphone powerbank might be an easy way.
Connect it directly to the USB socket of the Uno.
A 5Ah powerbank might last about 24hours.
You might have to add a dynamic load, to stop the powerbank from turning off.
Leo..
It also depends on your sketch; you maybe switching the sensors off and putting the Arduino to sleep .
Measure your average current and decide how long you want it all switched on .
Then look at the Ah of your battery, and calculate how many hours it will last .
People here play fairly hard ball and it’s no good asking “ how long a piece of string do I need?”
jxid:
I thought that this was a forum for help people like me to solve their tech problems.
But it seems that i was wrong.
I count 74 posts against you at present.
Presumably you have read hundreds of discussions here.
Surely you know by now how much and what sort of detail you need to provide. 
It is explained in the sticky threads entitled "how to post to this forum", for instance.
Not every jokey comment has a smiley after it, you should be able to handle that!
Thanks for the suggestions.
Since i don't know how much power needs my sensors how can i find it?
I want to use a rechargable battery.
I have some 3.7 V LiPo batteries but i don;t know if it is enought to keep my project for 2 hours.
As for the size i would prefen something like a smartphone's battery.
jxid:
Since i don't know how much power needs my sensors how can i find it?
You have said you have made the project, so put a multimer in series with the sensors +V supply and measure the current whilst its taking a reading.
Better still put a low value rersistor in series withe the +V supply and measure the voltage across the resistor with a scope, that will tell you the current also.
Get/borrow a DVM.
Set the DVM to measure current.
With your project running as it would normally be, measure the total current being drawn from your power supply.
Watch these in order:
.
jxid:
Thanks for the suggestions.
Since i don't know how much power needs my sensors how can i find it?
Measure it. Or read the data sheet.
The BME280 and RTC take very little power. An Arduino anywhere from a few µA up to 70 mA depending on configuration and sleep mode. Unos are a terrible choice for low power projects.
I want to use a rechargable battery.
I have some 3.7 V LiPo batteries but i don;t know if it is enought to keep my project for 2 hours.
That's 3.2-4.2V depending on the charge level, and your BME sensor needs 3.3V (see data sheet for actual range - 4.2 is most likely too much). There are 3.3V Arduinos out there (the 8 MHz Pro Mini) that happily take that full voltage range. Connect it to the raw input and it's going through the regulator so surely no more than 3.3V. Check the regulator type for minimum drop-out, so you know how much voltage left, see if it's enough for the sensors.
RTC module: if it's the old DS1307 you have a problem as it needs 4.5-5.5V. But you didn't specify this.
Nokia display: check data sheet on how much voltage it needs, and how much current. It'll be a major current draw.