Overkill Solar 120A 4s 12V BMS, Instruction Manual

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B.2 Current Calibration
You will need an accurate current meter to perform current calibration, and it must be able to measure the
maximum current that the BMS is capable of withstanding. Most handheld meters will only measure up to 10
amps; these are not sufficient. We recommend a clamp meter capable of measuring DC current at greater
than 100 amps, at an accuracy better than +/- 2.0%. If purchasing a new clamp meter, always make 100%
sure that it will measure DC current. Cheaper models only measure AC current.
Note: At the time of writing, calibration can only be done via the iPhone app, or the JBDTools USB Windows
application. These instructions cover the iPhone app.
Open the app. Click on ​
Config​ . Then ​ Current Cal​ . A warning message will appear. Heed its advice and only
continue if you know what you’re doing.
B.2.1 Idle Current Calibration
Start by temporarily disconnecting all loads, and charge controllers. Double-check to make sure that nothing
is connected to the battery. The current displayed should be zero milliamps, or very close to it. Do not
proceed otherwise.