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Electric Stunt => Gettin all AMP'ed up! => Topic started by: Heman Lee on September 24, 2012, 06:08:21 PM
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I don't know if any of you done this, but I was in a bind this weekend at the Meet 'N Meat contest. My starter battery just went completely dead and I could not get to a Hobby Shop. So I hook up my 3s(11.1v) 2200mah Lip0 which would give me close to the 12V I needed for my power panel. You may ask "Why do you even need a power panel for CL'". That is because I am flying a 1/2a model - actually is a .061. Since I was only using a 1/2a type starter, I felt very comfortable that I would not drain it beyond the low voltage limit for a few starts.
I am wondering if I could just make or find a LOW COST< $10, "Low Voltage Cutoff" curcuit without have to purchase a entir ESC/BEC for this purpose?
The other cheap alternative is to use one of those $5 LED voltage indicator that a lot of you already have, connect that into battery balancer curcuit with a test switch.
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I have been using a 1000mAh 3s pack to drive both my power panel and starter (Miller RC) for some time. Two or three weekends and it is down to the high 80% charge! I have never come close to running it down. I think I posted a thread on my 1/2A starter box in the 1/2A forum. I am using the mini power panel from Tower. It needs two modifications. First, bridge the leads to the starter with some heavier wire, second, cut the plastic away from above the control Transistor and the bottom of the plastic cover so it can get some airflow. I have fried both (burned out the power lead, and melted the plastic cover!). With the improvements, no problem.
I looked up the thread, here it is: http://stunthanger.com/smf/index.php?topic=26484.0
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This will work. http://www.hobbypartz.com/fm23-1416.html there are many others. Helicopter pilots use them as they cant exactly have their speedcontrols shut the motor down in flight.
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We have guys using 4s and 5s on there starters, does not seem to do any thing to them. They say that under voltage is bad for them. I have not seen one on a power panel.
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If, after all that, you still want a low-voltage cutout, I'll send you a free schematic. Free of charge and free of any significant testing, that is. It's a pretty simple circuit, but the way things are these days you may well have to buy some parts mail order.
Basically you need a honkin' big transistor (or a relay) to turn things on, held on by a comparator that looks at the battery voltage and shuts down when it falls below your desired threshold. Or maybe just a voltmeter and a brain, plus a fuse in case you short something out.
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I have been using a 1000mAh 3s pack to drive both my power panel and starter (Miller RC) for some time. Two or three weekends and it is down to the high 80% charge! I have never come close to running it down. I think I posted a thread on my 1/2A starter box in the 1/2A forum. I am using the mini power panel from Tower. It needs two modifications. First, bridge the leads to the starter with some heavier wire, second, cut the plastic away from above the control Transistor and the bottom of the plastic cover so it can get some airflow. I have fried both (burned out the power lead, and melted the plastic cover!). With the improvements, no problem.
I looked up the thread, here it is: http://stunthanger.com/smf/index.php?topic=26484.0
Yes, you are probably right about running the battery down. It really makes my 1/2a a lot lighter.