SDG #262 DIY High quality 20 W/m 90CRI LED strip with Cree LEDs

Off the shelf LED strip is cheap, but colour rendering, binning consistency and thermal design are usually where corners are cut. This build addresses that directly by designing a custom strip around Cree JB2835A mid power emitters at roughly 20 W per metre, fabricated on aluminium backed MCPCB rather than the flexible polyimide tape most strips use. The choice matters: an aluminium substrate gives the LEDs a real path to transfer heat into whatever the strip is mounted on, which is what keeps junction temperature down and lumen depreciation slow over years of use.

The 90 CRI target is the other headline. Higher CRI phosphors trade efficacy for spectral quality, so the design has to budget for slightly more heat per lumen. The video works through per LED power dissipation and current selection, then verifies the assumptions with thermal measurements on a finished board instead of trusting the datasheet curves alone.

Assembly is instructive in its own right. Aluminium PCBs are a thermal sink for the iron as much as for the LEDs, and the segment on using a high power soldering cartridge for MCPCB rework explains why an ordinary station struggles. There is also practical coverage of 63/37 leaded solder paste stencilling for a long, repetitive footprint layout, and thoughts on a home made SMD vacuum pickup tool for placing dozens of identical parts.

Diffusion and driver selection complete the build. Bare mid power emitters produce visible hot spots, so a diffuser channel is fitted and evaluated, and the closing discussion covers what to look for in a constant voltage or constant current supply for a strip of this length. Anyone building high quality task, shelf or workshop lighting will find the trade-offs here more informative than a specification sheet.