Hello i have a Arduino with Gsm module. I know this is a long shot from from what I'm reading the GSM which is a Sim800L needs 4.2v at 2a max current. Now i know most buck boost converters can do 1a or maybe 1.5a from 3.3v or higher. But i was wondering If it is possible to Run it from a Double AA batteries if Anyone has any idea please let me know thank you.
Oh i forgot one thing I also have a Oled and for the most part it is in off mode nothing is displaying to save power.
Alkaline batteries will give 3V when new, but this voltage drops as they are discharged.
NiCd or NiMH only 2.4.
I don't say it can't be done, but the boost invertor would have to act very fast - the transmit pulse on a GSM PA rises to 1.6A in about 3uS. Either that or a big reservoir capacitor....
why not use a suitable single Li cell? - that's what GSM parts are designed for.
regards
Allan.
Many of those ebay buck boost modules do 3A.
What you want to do is fit a 1000uf or greater at the power input to the sim800 so it has a power reserve for when it needs the 2A, which is gernerally only for a short while.
I have run it fine for sms with just 1A devices.
How long it will last on the AA batteries is another question, standby for some time, the number of sms it can send, not many I would suggest, unless you use several batteries in parallel.
What you want to do is fit a 1000uf or greater at the power input to the sim800 so it has a power reserve for when it needs the 2A, which is gernerally only for a short while.
The pulse is 270uS long and has a duty cycle of 1/8.. A 1 or 2 mF capacitor would be a great help
regards
Allan.
hello thank you all for the respond back. My ultimate goal Is to make a modern type of Pager for my father. He misses his and i have a chance to bring back his old one with a more up to date parts. It's basically a Birthday gift for him. I wanted to do something for him. I have the parts I just need to figure out the Power problem. He is so use to changing batteries in his old pager i wanted to leave it to something to that effect still. Everyday he looks at it and misses using it. So here is my chance. This is like the one he has Pager
So i have only that much room. I did take in a count for the GSM module and the arduino.
You could always buy a basic 2G phone....
regards
Allan
allanhurst:
The pulse is 270uS long and has a duty cycle of 1/8.. A 1 or 2 mF capacitor would be a great helpregards
Allan.
My google says 577us long. And 10mF would give about 0.1V drop per frame. And hurrah for saying 1mF, not 1000uF !
You're right of course.. 270uS was my target for synth settling time!
regards
Allan