Hello i was wondering If my project is running off of 3.3v and I'm using a 3.7V lipo to power up my project and to monitor the Voltage will it hurt it?
Really hard to say without a schematic and all the other details that seem to be missing.
So for now I would have to say yes is a best guess.
Which Arduino are you using? The data sheet for the processor will have the accepable supply voltages specified. If the processor is a mega328 it should be OK as long as any peripherals can handle the voltage.
Its a 3.3V project yet your powering it with 4.2V ?
(the full charge volts on a LiPo is 4.2V not 3.7V)
I would expect it all to go pop, never to work again.
If you are especially unlucky, the 3.3 V circuitry won't go "pop" right away, when you connect up your freshly charged, 4.2 V Li cell.
Instead, it will "pop" at a critical moment, ruining an important experiment and maybe destroying some other equipment as well.
So from what I'm reading 3.7v when fully charge goes to 4.2v Is not safe to use. So i will need a Small buck boost converter so it can reach 5v out the output would be better? or is something else i can do to protect it from blowing up?
josephchrzempiec:
So from what I'm reading 3.7v when fully charge goes to 4.2v Is not safe to use. So i will need a Small buck boost converter so it can reach 5v out the output would be better? or is something else i can do to protect it from blowing up?
Maybe, maybe not.
Impossible to advise really, you have not revealed any details of your project.
My project is just a basic arduino pro mini with a oled screen and a current sensor. Just monitoring current that's all.
Ah yes the project that needs details to diagnose but none forthcoming...
I have a 10 foot ladder to get to the top of this 50 foot wall...will it work I mean its a ladder after all so it should be fine yes ?
Sorry i'm out trying to get details from somebody with almost 1400 posts.
All chips have a range of voltages they can operate at. Sometimes that range is very narrow (3.0V - 3.6V), sometimes it is very wide (2V - 30V).
Find datasheets for every module and IC in your protect, and look up their recommended operating conditions. Does a LiPo's voltage range (3.5V - 4.2V) fit in there for all of them? If it does, you're good. if it doesn't, you need a regulator.
Hello my fault you guys are right here are the parts I'm using is Current sensor, Voltage is between 3v up to 5v This is the Oled, That can run between 3.3v up to 5v also nd the Arduino is a Arduino pro mini. From what I'm seeing it needs 5v to run. But i have see others Run it off of a 3.3v lipo before So that is under voltage it slightly. But looking at it more Not sure what to do with that.
i have see others Run it off of a 3.3v lipo
You really need to be more careful with your figures.
LiPo batteries nominally output 3.7 V.
When freshly charged the voltage is 4.2V, but that drops very quickly to about 3.7 V (which will damage most 3.3V parts). During discharge the voltage remains near 3.7 V, but towards the end starts to drop quickly.
By the time the battery voltage has dropped to 3.3 or 3.2 volts, it is considered to be discharged.
Allowing the battery voltage to drop further than about 2.8 V will completely destroy the cell, so many battery packs contain shut-down circuitry to prevent such "overdischarge".
The plot below shows example characteristics for various discharge rates, as a fraction of the cell capacity C.
josephchrzempiec:
the Arduino is a Arduino pro mini. From what I'm seeing it needs 5v to run. But i have see others Run it off of a 3.3v lipo before So that is under voltage it slightly
There are 5V Pro Minis and 3.3V Pro Minis.
The each need around slighty more than the rated voltage at the RAW pin to allow the regulator to work properly.
josephchrzempiec:
So from what I'm reading 3.7v when fully charge goes to 4.2v Is not safe to use. So i will need a Small buck boost converter so it can reach 5v out the output would be better? or is something else i can do to protect it from blowing up?
To answer your question from way back. Yes..... Buck-Boost will be the safest, economical and easiest to implement.
Tom... 
Hello thank you all for this information it is helping me a lot to figure out what i need to do. I decided to use 2 doubble AA batteries with a Booster Step Up voltage Regulator.. This Regulator can take anywhere from 0.8V to 3.3V on the input and Output 3.3V at 400ma. Which is more then enough for my project. That way running it off of 2 AA batteries at 3V and even if Draining them both down to 0.8V i will still be somewhat working and Everything can be safe. I do have a 5V and a 3.3V Arduino pro mini so i will use the 3.3v one TO keep it all the same.