1. Connect the battery to the positive and negative of the charge regulator. 2. Connect the PV module to the positive and negative of the regulator. 3. Connect the user to the positive and negative of the charging regulator. The reverse order applies when uninstalling! Improper sequence can damage the controller! This is a lithium battery solar controller without current display Can charge 3 kinds of batteries, lead-acid battery (12V/24V battery automatic identification), lithium ion battery, lithium iron phosphate battery! The controller defaults to rechargeable lithium-ion battery (lithium battery), and the battery type is mode; when using a lead-acid battery controller, please set the battery type to B1; lithium iron phosphate battery is set to B3. For specific operations, please refer to the manual or customer service, thank you! Supported battery types: B1=lead-acid battery 12V/24V (automatic identification) =Lithium-ion battery (lithium battery) 3 strings 3.7V=11.1V B3=LiFePO4 battery 4 strings 3.2V=12.8V Material: ABS colour: As shown Package Contents: 1 x Solar Controller Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.