1. The circuit board of this spot welder can be used for welding 18650/26650/32650 lithium batteries. Advantages: portable, stable, reliable and durable.2. Users need to bring their own 12V battery for supply, the welding current is about 90A~130A, and it is easy to weld the common 01mm~012mm nickel plated sheet. Please make that your battery can have a current greater than 90A, otherwise you will not be able to weld 3. A battery with a discharge current will directly affect the welding effect. The following batteries are recommended: 20-45ah Lead-acid batteries with good performance and small internal (internal less than 10 milliohms, discharge current greater than 90A), such as a new car battery 35-55ah model airplane lithium battery pack around 45C; 30-35ah capacity pack.4. requirements: Spot welding is welded by the principle of rapid local heating and cooling by high current, Need sufficient current supply, generally 01-015 nickel plated sheet welding current About 90-150A, so the working of the circuit board must be greater than or equal to 150A.5. The following battery packs can be used as working : 12V car starting supply, high-rate battery pack for model airplane, three-string high-rate lithium battery pack, 40900 3-string battery pack, lead-acid battery with good performance above 12V 20A.Calculation formula: capacity X discharge rate = load capacityTake 4000ma aeromodelling battery as an example, the discharge rate is 45C (4AX45C = 180A)Instructions for use:Function buttons: 1, used to switch the machine, 2 used to switch gears When the is turned on, the default is the first . Press the button for 2 seconds to releaseThe is increased by one , and the buzzer sounds and the LED flashes corresponding to the number of gears.For example: the 3rd , the buzzer sounds three times, the LED flashes 3 times, a of 5 gears. The spot welding intensity is gradually strengthened from the 1st to the 5th 5 is the strongest After the 5th , press and hold the button again. It will off. In the off state, press and hold the button to on, and the will return to the first colour: blackMaterial: PCB+plastic+metalPackage Contents:1 x Circuit board4 x Bronze noses4 x Screws1 x Buzzer1 x nickel sheets1 x Capacitor2 x Welding pens2 x Input wires2 x Heat shrinkable tubesOnly the above package content, other products are not included.Note: Light 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.