Battery Powered WISMO228


#1

What Li-Ion 3.7V capacity is suitable to power the WISMO228 directly?


#2

That depends how long you want it to last. The average GSM idle current is stated as 1.3mA. You can calculate your rough expected lifespan by using:

time (hours) = capacity (mAH) / average current (mA).

As long as your battery can supply the peak GSM current of about 350mA (most Li-ion can), you should be fine.

If you are powering directly from a battery, make sure you don’t exceed the recommended maximum voltage of 4.2V when charging, as this could damage the modem.