I bought a single 4000mah sub-C cell NiMh for my glow driver and it works for days... albeit my engines start immediately as well... which is probably due to the igniter battery being in great condition. I got that cell over 4 yrs ago and it still works like new.... It's literally one less thing I have to deal with now...I actually charge it at 4 amps, with the cell being 4000mah, 4 amps is a 10c rate if I'm not mistaken, and it takes about 45 min to an hour and stays charged forever it seems... several weeks I do know. I think I paid about $5 for that cell... well worth it in my mind... but hey.. there's many ways to get power to the plug. I remember soldering a 4-pack of D-cell batteries in parallel (well before nicads were mainstrem), and having that last for months.. and with the D-cells being 1.5volts that really lit up a glow-plug... but you don't want to go over 1.5v...(..some/most plugs used to be rated for 2volts even)...these days though, they start fine with the 1.2v cells.. that's all you need.