So the drivers were probably somewhere in between warm and cool during the multimeter tests. If we estimate 17W, then it is about 89% efficient, not too shabby I love these drivers. Most of my small drivers max out at 80% efficiency and get as low as 50% when powering single 3V LEDs (for situations where you need very small amounts of indoor lught or in cloning boxes etc). It is a bummer when your LED is putting out 180lm/W with a 50% efficient driver it almost defeats the purpose.
This little driver can give us very cost efficient output $1.50-$2/PAR W with great spread and very good efficiency ~(40-44%) with Veros or it can gives us ridiculous efficiency for about $5/PAR W CXA3590 at over 200lm/W (62%), amazing to me
You can get them bare for $2.50 but I like the case even if it is wrong about positive and negative sometimes LOL.