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Electric Stunt => Gettin all AMP'ed up! => Topic started by: Ty Marcucci on September 30, 2012, 11:19:33 AM
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Well, all things being set up properly, you won't have an over run nor a short run. BUT, if you do a quick rpm test at home, and forget to recharge that battery, casually place it back in the pouch, then a week later install it in your super dooper electric flying machine, guess what. Yep, top of the outside squares, the motor just stops.
The real sudden true silence was one of pure amazement. I never expected this, ever, and was so dumbfounded I almost lost the plane. The previous flight was a joy, but the maneuvers were all a tad high, but first flights usually are for me. Well, I recharged that battery and it was WAY down. Lesson learned, never again a test without recharging the battery. D>K
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Sounds like your LVC needs changed to a soft cutoff.
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thats like havng fuel left in tank inside a plane - not checking and thinking you have enough. its not the system that shut it down -
operator error........ like 99% of computer problems y1
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If you have a KR timer that's what it will do when the battery is so low the motor drops below 1000RPM. The timer does not know if it's the battery or the motor just struck a weed. To prevent this from happening you buy yourself a battery tester and you ALWAYS check the battery before you use it. Would you start a gas engine without checking to see if the fuel tank is full? I am thinking no. Well it is exactly the same with a battery, that's your fuel tank and you need to check it prior to every flight. For what it's worth Ty I did the exact same thing which is why I bought a battery tester and use it every time before and after each flight.
Andy
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Yes I have tried to fly with a battery that was previously used but was lucky not to crash. n1
I believe it was Bob Hunt that suggested that you put a rubber band around your battery when fully charged. You then remove it when you use the battery. So any battery without a rubber band is deemed to need charging before you use it to fly.
This has worked for me!! ;D
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I have of these http://dx.com/p/digital-multi-cell-lithium-battery-voltage-led-display-for-r-c-models-10787. I also have one of these,http://leaderhobby.com/product.asp?ID=9394001226065. Both work well if you checkyour batteries before a flight. The first is a bit inaccurate but if you use it as strictly a GO- No Go gauge. its fine.
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I will say this Ty, you are in good company. I don't think there is an electric flyer who has not done the same think once. I was lucky too and was able to save the plane. I use the Hyperion battery tester, got it from Amazon for around $25. It's worth every penny, it has saved me a couple of times.
Andy
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I have the Hyperion tester, too. It's dandy, but at my stage of dementia, I forget to use it. I really need something built into the airplane. I made myself a little circuit that lights a green LED when the battery's charged and a red LED when it's not. One of the LEDs is lit whenever a battery is installed in the plane. Thus it also reminds me to take the battery out before I go home. I'm fixing to make a bunch of these circuits up and pass them around.
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But, does that really tell you a battery is fully charged or not? I like the idea of a separate battery tester.
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Howard,
Sounds like a good idea!!! Care to share the circuit so some of us can make our own?? ;D
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But, does that really tell you a battery is fully charged or not?
Yep.
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Care to share the circuit so some of us can make our own?? ;D
I did the last tweak with it installed in the airplane. I'd have to dig it out to determine the resistor values and thresholds. By that time I'll have some boards made up.
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Howard,
When you get them made up I'll buy one from you.With the lights maybe I will win a Concourse award someday LL~ LL~ LL~ LL~ Seriously...... LL~ LL~ LL~ LL~ LL~
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According to Robert Johnson, you need two lights on behind, a red one and a blue one.
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According to Robert Johnson, you need two lights on behind, a red one and a blue one.
Quoted for Truth.
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Howard, how did your LED display help on that test flight early Sunday AM in Salem when the motor shut off early? Did the lights signal for you to cool it, because the battery was running low?
Not being an EE or eStunt kind of guy, it seems that cold weather would require either bigger capacity batteries or setting the margin for auto-shutoff at less than 30%. Is there anything magical about 30%? Would 10% be safe for the batteries? I have turrible luck with rechargable batteries, which is the #1 reason I'm not going down that path. n~ Steve
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The LEDs only tell whether I've installed a battery and whether it's charged. That battery is a bit weak relative to the others. I've put three more flights on it since Sunday without incident. It's fine up to 2.3 amp hours.
Yep, cold air is denser, so there's more air in the air. Curiously, still air takes more electricity than does a breeze. Sunday morning was a bit extreme.
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I'm fixing to make a bunch of these circuits up and pass them around.
You're a good man, Howard. If your boards are costing you more than $2.50/sq in, then check out these guys: https://batchpcb.com. If they're costing you less -- please tell me who you're getting boards from!
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To show that Howard wasn't the only electron operator that had trouble with his electric on Sunday...an anonymous flier (I was launching for) had signalled and had the handle attached to his paw with safety thong installed. Motor didn't ramp up and do what they do. He had me push the button, and it went through the usual beep-beep, whir, shutdown, wait and vigorous whirring process. I guess I wasn't paying attention, because I thought he'd already pushed the button. ??? Steve
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Hey Ty;
I just posted notice of a new product, the Capacity Controller. This little gem will check the remaining charge in your battery (it also will check the individual cells). Nice and small, it fits into your flight box. This is what Andy & I use to check our batteries before every flight. We never have to worry about a partially charged battery going into the model.
I've got about 12 of them in stock right now.
Regards
Eric Rule