Looks as if I missed your posting last week. Sorry about that.
jarruda wrote:I'm really asking if "Leakage Current," as referenced in the data sheet, is the same thing as a circuit's quiescent draw.
This device also has very low quiescent current drain.
jarruda wrote:I don't really understand how the Arduino's analog inputs work,
I always run the risk of mis-leading someone with simplifications but, let's give this a shot.
Imagine that the Arduino has 1,024 resistors, all the same value, all in series.
One side of the string is at ground. The other side of the string is connected to a voltage reference.
The voltage reference could be the Arduino's internal voltage reference or an external voltage.
The voltage connected to the Arduino's analog input pin connects to one input of a comparitor.
A counter is used to connect the other comparitor input, sequentially, to each resistor in the string.
When the comparitor detects that the resistor string voltage is greater than the analog pin voltage,
the comparitor switches. This change is the signal that the counter value is the ratio of Vin/Vref.
In reality, it is done using binary sequences of capacitors but the concept is similar.
jarruda wrote:perhaps have to use a step-up boost converter to provide an AREF.
Assuming that you are powering the Arduino with 6 to 20-V, you do not need to create a separate AREF.
You may use the 5-V supply, 3.3-V supply or the Arduion's 1-V internal voltage reference for AREF.
jarruda wrote:3. Finally, how can I monitor the battery's current charge level? I thought about just plugging Vin into an analog input, but I realized that because my project is unregulated it will always be the same as AREF.
I do not understand. Normally, you provide an Arduino with 7 to 12-Vdc.
So, Vin will not = AREF. Don't measure Vin to measure the battery voltage.
Instead, connect an analog input directly to the battery.
If you are using a LiPo to directly power an Arduino then jump to the last paragraph.
I gathered that you are using a 3.7-V LiPo as the power source. But, since Arduino's
Vin is 6-20-V you must be using something to step up the battery voltage.
Connect A0 to the 3.7-V battery.
In your sketch, check A0 and compare the value to a 'low-voltage limit' that you select.
Let's say you want to turn on the charger when the battery reaches 3.0-V.
Using 5-V for AREF, and the battery connected straight to A0.
With 4.2-V on A0, a reading of the A0 register should provide something like '859'.
likewise, 3.7 will give '757' and 3.0 = '613'.
Turn 'on' the charger when A0 is less than 614.
Turn 'off' the charger when A0 is more than 858.
You also might consider alternatives such as the Adafruit LiPo charger.
It will take care of keeping the battery charged without involving the Arduino.
If you are supplying battery voltage directly to the Arduino, the Adafruit LiPo charger
comment also applies but, there are also other issues to deal with.
I hope I have not been more confusing than helpful or completely misunderstand your questions.
Good Luck, John