@NickAlexeev I go for the shortest suffix possible, A, B, C, ... or 1, 2, 3...

@adamaero Your table shows about 4.3W total for your sensors and the Arduino. 4.3W * 24 hours gives 104 watt hours for a single day's operation.

@adamaero With the duty cycle you have, looks right. By the way, 1 Watt-second is 1 Joule

@glen_geek

Hi

Hi @glen_geek

It should only take a couple seconds for the Arduino to wake up. Then, sending the data via satellite (Rock BLOCK), I just guessed everything would take 5 minutes. This occurs four times a day. The rest of the time it's in sleep mode.

2-5 watt hours per day

^ rough calculation.

@adamaero Sounds much more reasonable for a sleeping system than 250Wh.

=)

Did you follow the link?

(6113 J)/(60min*60sec) = 1.7 watt hours

Yes, I read it. Very intuitive. Thx.

@adamaero Weird, that. I just put it up the day before you asked about energy calculations.

Wow

I had that can of play-doh sitting on my workbench for a week, waiting for a chance to write that up.

@ThePhoton Now that I'd like to see. I can relate play-doh to numerical integration, and from there to mathematical integration, but I'm not seeing a connection to polynomials.

14Ah at 12V is about 168 Wh of energy. If you are using 2Wh per day, then your fully charged battery (from 4 hours of full sunlight) will power your Arduino-maboby for like 80 days.

But an AGM battery needs to be kept at 90% capacity...

So it's 16.8 Wh.

Agh, still don't get how to relate these quantities.

@JRE It wasn't play doh, it was bricks of size 1x1 and 1xX. But when you started cutting slices off the play-doh it had a similar effect.

@everyone Does that seem right?

@adamaero Eh. No. Wait a minute.

If you use a 5W solar panel, and have 4 hours of light, then you will capture some 20Wh of energy each day. That is 10 times what your Arduino-maboby is using. That gives you extra capacity - if the sun doesn't shine, you have a few days before the charge in the battery drops below 10 percent.

All of this ignores losses, of course. This is all the theoretical best case.

But, yeah a 5W panel could well do the job.

Figure 70% efficiency for the switching converter that goes from solar panel voltage to the battery charge voltage. Figure 50% efficiency for the battery, and again 70% for the conversion from battery voltage to the 7V for the Arduino. Maybe 30% efficiency overall.

If the sun don't shine, you have maybe three or four days before the battery gets too far down.

Thanks JRE. What's an Arduino-maboby?

An "Arduino-maboby" is a thingamabob made out of an Arduino.