Hhmm an hour. Well I tried the CG-340 today, I hooked it up to my company's van. The engine and battery is right under the front seat and I have no problem putting the charger safely to one side if you ask me.
I let the engine run and travelled for about 15-20 mins. By the time I reach my destination, my batt is charged and as it's niCad, the CG-340 switch to trickle mode. The charger, felt really hot. Safety first, I unplugged it and let it cool down. That was in the afternoon. I got back around midnight and use the battery I charged earlier on. Surprisingly, the run time is normal, about 5-7mins.
Question is, do you think it's really safe to charge it while driving? I'm not sure....