I've been carrying out some tests on the Hetzer T057. I couldn't work out why it would run for a short period then stop. I think it might bge overheating batteries,. But do batteries overheat?I need some advice on how to extend power.
I carried out some tests over the weekend. The Hetzer is powered by 2 no. 18V de Walt drill motors. Witreasonably charged-up 6V and 12V batteriies (7.2Ah and 7Ah respectively) connected in series the thing managed 4 laps of the garden (ie about 195 yards in total) at a lively 3-4 mph, slowing down on the last lap, at which point it stopped due to lack of power. Motors were lightly warm, but batteries were noticeably warm, like a hand-warmer. I left them for 10 mins or so and then we got another 65 yard lap, but which time it was slowing down. It would then do the same thing- 10 mins break followed by 1 lap- for another couple of laps or so, by which time voltage was down under 17V and the batteries were just flat. I believe these motors are about 180W each, which at 18V means they are drawing some 20 amps (there is no speed controller so the motor is either "on" or "off"). Certainly the main fuse (30A) has never blown. That means that I should get some 20 mins run time, or probably about 40 mins battling, as you're not moving all the time. In fact I'm getting about 5-7 mins, though there's a lot of friction in the tracks so I may "lose" the later part. Can anyone advise on what I ought to do? When battling the tank should stay cooler inside as the batteries are right next to the gas bottle, which was warmed by the battieries during my test, but would be cold when fired and therefore a cooling element in itself. Will cooling help? I can try some experiments like using ice packs or leaving the top off (to simulate adding a fan and cooling vents) but I'm not sure if warm barrieries are (a) normal (b) mean defective batteries or (c) are the probable cause of the problem. Thanks guys Phil -- You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to [email protected] To unsubscribe, send email to [email protected] Visit the group at http://groups.google.com/group/rctankcombat
