mA required for arduino

I'd like to take this

which will output 5V at 100 mA
and use it with a 3.7V lithium ion battery to power the arduino, my only question is, is that enough mA or does it need to be higher?

because I'd prefer to use that DC step up over this one 5V DC to DC Step Up - VPack PCB - PRT-08290 - SparkFun Electronics
because I don't know how to wire this one as it is not labeled as well as the one listed above, however, it outputs 5V 300mA.

So is 100mA enough or do I have to use 300mA and If I do can anyone explain where the in, out, and gnd is?

So is 100mA enough or do I have to use 300mA and If I do can anyone explain where the in, out, and gnd is?

It depends on what you wire to the Arduino I/O pins what the overall current draw of the board will be. The basic board will probably draw 40ma, maybe a little less. So what are you going to wire to digital output pins and how much current do those output devices require?

As far as how to wire up to the 300ma model, the SparkFun link shows which corner pads are in volts, out volts and two ground pads. you will have to solder power wires in and out to those pads.

So is 100mA enough or do I have to use 300mA and If I do can anyone explain where the in, out, and gnd is?

When downloading to the board you may have to disconnect this power module because the USB connect supplies 5vdc to the board when plugged in and it's not a good idea to have both voltage sources both on at the same time.

Also you should be aware that you can damage lithium cells if you allow their terminal voltage to drop below a certain amount, say below 3volts. Many devices that the use lithium cells have a automatic disconnect when cell voltage drops to a set value. Without such a circuit you are responsible to make sure you don't over discharge the cell.

Lefty

hmm is there a product name for a circuit that would have this automatic disconnect?

hmm is there a product name for a circuit that would have this automatic disconnect?

Probably not, that is usually designed and built into the device or into a custom battery case. You might try goggle search on "low voltage cutoff circuit" or some such wording. Your Arduino has analog inputs that could be wired to measure the battery positive terminal voltage and with added external relay or MOSFET transistor, turn off the battery positive lead when the voltage gets too low.

Lefty

Lefty