High power LED modules are designed to move large volumes of heat away from the LED as quickly as possible, which also means that soldering connecting wires to the module is going to require more than the typical 25W to 50W soldering iron/station used for standard PCB work.
Instead, you will need to use a temperature-controlled soldering station with a minimum wattage rating of 95W. Wattages in the range of 120W to 150W are better. Here are a couple of soldering station suggestions:
Some additional tips and recommendations for soldering connecting wires to high power LED modules.
- If you ordered several LED modules, we will sometimes ship them as a v-scored connected array. Always separate the modules from the array before you try to solder them. If the module comes with a carrier tab, you should also separate the module from the carrier tab as the extra mass will make it much harder to solder.
- Solder the wire connections to the module before you fasten the module to the heatsink.
- Place the module on a thermally non-conductive surface while you are soldering. Don't place it on an ESD mat as it will get hot enough to melt the mat.
- Use a small chisel type soldering tip to help focus the heat on the pad. We use ones like these.
- When soldering, be sure that everything is kept impeccably clean.
- It can sometimes be helpful to add a very small amount of solder flux to the pad using a flux pen like this one.
- Use a small diameter solder. We typically use .020" diameter solder wire.
- We recommend stranded hookup wire not larger than 26 AWG. Be sure that the stripped end is kept very short (not more than about 1.5mm long), and is thoroughly pre-tinned before soldering it to the pad.
- Ensure that you bring the base (not just the solder pad) up to temperature before creating a solder puddle on the pad. Your initial preheat and dwell time will be longer than what you are used to.
- Have your wire prepped, tinned and ready to attach as soon as you have a molten puddle on the pad. Don't pre-tin the pad, then let it cool down, and then try to reheat it again to attach the wire. The entire solder operation should be one single process.
- Attach the wire so that it is perpendicular to the pad rather than lying flat and coming out parallel to the board. This helps to ensure that the connection does not touch the edge of the LED module.
- On smaller modules, it can sometimes be difficult to keep the module in place as it will tend to want to stick to the tip of the iron. To help hold the base down, use the tip of a small flat-bladed screwdriver with a third-hand holder.
- Sometimes when you attach the second wire to smaller modules, the first wire connection can be weakened as the heat will quickly travel across the base to the other side. The same flat-bladed screwdriver can help prevent this by acting as a thermal block.