1) Circuit design. The commonly used input voltages of LED bars are 12VDC and 24VDC. Circuits worked under 12VDC are generally combinations of three series branches and multiple parallel branches, while circuit under 24VDC are combination of six series branches and multiple parallel branches. Since soft LED bars should be connected in series, the particular length of these bars all depends on the width of the circuit and the also the thickness of the copper foil. For the reason that the maximum current density per unit area is closed related to the cross section area (CSA), we have to take this point into account during the wiring. Otherwise, soft LED bars will work in overheated conditions due to excessive current. It is cleared that LED lighting products are not sustainable in constant high working temperatures. It will cause unrecoverable damages to circuits and meanwhile reduce the service life of LED lights chips.
2) Problems in production process. Since LED bars used series-parallel connections, failure of one branch will increase the input voltage in other branches. Under such circumstance, LED grow lights will send out brighter light, but in the meantime, generate more heat. The clearest example is 5050 soft LED bars. Short circuit in any one of the branch of 5050 bars will double the working current in other branches (from 20mA to 40mA). Users may observe an instant and obvious light enhancing and all together sharply increased working temperature. Circuit may probably be burned up with several minutes in server cases. However this fault is relatively obscure than other problems and hardly be discovered. If testing technicians only concern about whether LED chips work (sending out light) but pay no attention on whether LED chips work in a normal state (sending out normal brightness light), branch short circuit would be frequently occurred. That is the reason why most LED bar producers frequently received feedback from customers complained that their products were overheated and over-bright with unknown reasons.
Solutions:
1) Increase the distance between wires on circuits as much as possible. It is proved that the ideal condition is larger than 0.5mm. Increase the thickness of copper foils without violating the customers’ requests. General thickness should be 1-1.5 OZ.
2) Avoid short circuit during the patch.
3) Double check the patch location before switching on.
4) Performing electrical testing after switching on. Measuring the light intensity gradually.