What photo of the circuit? Is this for septic sanitation? I would suggest a 120 to 15-24V transformer used in boost mode on the inverter. That will boost the peak line voltage to a normal 160 instead of the 140 found in most inverters.
Circuit photos
No, this is for field collecting of fluorescent minerals. That's why I wanted emphasis on portability. Unfortunately I won't have access to AC power as well. My lamp is just a standard worklight with UV bulbs put in. Then it is powered by a 13.2V LiFePo battery + inverter.
Here's some eye candy to illustrate what happens when you put things under UV light
What is the temperature "out in the field" ?
Indeed that's a possibility I considered and I do go regularly collecting at night in temperatures as low as -1C. However, I'm able to recreate this effect at home, leading me to believe that it's a problem on the electric side.
Indeed the best option in cold environment is to buy a LED based lamp on 12 or 24VDC directly from the car battery.
I wish!!! If 250-260nm LEDs were viable I'd have made one. I hate working with bulbs! Last I checked (October? November?) it was $250 USD for a 10 mw LED from CrystalIS, the current leader in the industry.