Testing out the Watkins & Doncaster 30W LED 12v Heath Trap

I have eventually invested in an LED moth trap - namely, the 30W LED 12v Heath Trap from Watkins & Doncaster.  This is a standard "heath" style trap, with vertical vanes and the LEDs a arranged in an upright configuration.  I have two other heath traps very similar to this but using a single 6W actinic bulb, so I know the general trap build works well.  I have been wondering about LEDs for a while now after seeing other mothing friends use them with good results, so I was pleased to see this setup at such a keen price.

I already have a range of batteries for trapping away from home - mostly Lithium Iron Phosphate LiFePo4 types which work really well and are a lot lighter than the lead acid alternatives.  I used my 30ah 12v version for this, as it would take that capacity to run a 30w lamp all night.  If you need to work out how long a battery will a specific power of lamp for, here's the math:

So for my 30ah battery it would be 30ah x 12v / 30w = 12hrs.  More than enough time in the summer, right?  However, battery systems are never 100% efficient so you do need to bake this in this to the equation in the form of an efficiency factor η  (usually 85%):

This works out like this for my 30ah battery and 30w LED setup : 

(30ah x 12v)x0.85 / 30w = 10.2hrs.   This is still more than enough in the summer evenings for trapping, and I usually set the trap at 9.30pm and open around 7.30am and the lamp is still running.

So on Saturday 6th June I headed out to my local peat bog and moth trapping site to road test the new trap, a site that has always proved to be fruitful for moths.  The temperature was to be 10° overnight which wasn't great, but would be a good test for the lamp. 

I used the same location that I traditionally would put the 6w actinic setup, knowing that the habitat hosts a good few species of moths to attract.  I was pleasantly surprised at the performance given the low temps with 119 individuals across 34 species showing up:

The Small Seraphim is a noteable species for the site and NI, being very locally distributed.

This is an excellent trap to use in the field, easily portable and runs a treat on my current batteries.  At under £80 it is priced really well for LED technology, especially compared to competing setups from other suppliers.  Well worth it in my opinion!