About that glowplug driver, I always used the connector from my fieldbox battery. One year my sister bought me a DuBro glow starter, the aluminum one with the red disc, for Christmas. I stuck it in the field box, after charging on my HiTec 335 until it blinked. Don't know how long it charged, but the HT, I believe, peak charges.

Anyway, it wouldn't hold a charge for 2 days. I puzzled over it for a while, and used it on my TwinStar (to start both engines quickly) but discovered I had to charge the night before every flight, and sometimes it wouldn't work through the evening.

Another guy borrowed it, and rather than charge it he just stuck a spare battery in it (I guess he had some laying around for that purpose.) Lo and behold, it now holds a charge for weeks. SO... maybe it's your battery. The DuBro disassembles for replacement. I see some don't, what's yours like?

Good luck,
Dave Olson