first "flight" battery hell

I took my new HoneyBee CP2 for its first "flight" in a square on
the ground as recommended by Radd's school of flight. I followed
the instructions in the manual, saying:
"It is recommended that you completely discharge the battery during the
initial test flight before following the charging guidlines outlined below."
After doing that the battery wouldn't charge. According to what I
was told (later) in other groups, discharging a LiPo battery completely
destroys the battery. What a fun manual! I wonder how many people
have been screwed the same way. It would be interesting to read a
school of flight written by the ass who wrote that manual....
This site was suggested and gives some good info about batteries:
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Another suggestion was to get a small E-Sky EC103A Li-Poly Balancing
Charger (EK2-0851) for about $10, in contrast to other suggestions
about getting a $100 range charger. Does anyone want to share
ideas or suggestions about how to deal with LiPo batteries? I'm
particularly interested in how to keep from over-discharging any
more of them.
Reply to
dh
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Was that stated in the HoneyBee's manual or on Radd's site? (I've never been to his site) If the former, I'd be on the phone with E-sky working out a free replacement battery..
I know it's too late, but a lot of people in the hobby make a lot of assumptions about a lot of things. I'd be willing to bet that statement was done up with NiCds or MiMhs in mind. It would be a VERY good idea to do a little research into the various technologies in the hobby before diving in.
The rule of thumb right now is to not discharge past 80% of the battery's capacity. For example, if you have a 1000 mah battery, don't pull more than 800mah out of it before you let it cool down then recharge.
That Esky charger won't tell you how much charge you're putting back into the battery, while something like a Triton will. Again, do some research on good, inexpensive chargers before you just plunk down $ on what might not do what you want. Also, most chargers today require a 10-15v power supply to use at home on the bench.
Charging LiPos is potentially dangerous and should *NEVER* be done unattended or on a flammable surface. Max charge rate should be 1C or 1 times the capacity of the battery. In the example above, the 1000Mah battery should be charged at 1 amp. A 1500 Mah battery should be charged at 1.5 amps etc..
I have several LiPos and I've invested quite a bit of money into their "care and feeding" *AFTER* doing a LOT of research on how best to deal with these things. Most RC helicopter forums will have a section on batteries and chargers and after doing some reading, feel free to ask questions. Also, look for any FAQs (Frequently Asked Questions) as well.
Reply to
The OTHER Kevin in San Diego
That MUST have referred to NiCD or NiMH batteries - definitely not for LiPo packs.
Ok, LiPo Batteries... :) To prevent deep discharging LiPo packs there are so-called Battery Eliminator Circuits (BEC), which provide an automatic cutoff. Some of them provide advance warning by artificially lowering power output and/or beeping so that your heli doesn't drop out of the sky all of a sudden - highly recommended. Others like the ones in my planes just cut the power to the engine as soon as the battery drops below a certain voltage. Okay for e-planes where you can glide down, but not for helis.
Chargers... two important things: Most chargers need about a 12V input, i.e. car battery voltage (probably so you can use your car battery to charge your batteries out in the field), which means you'll also need a 12V power source at home. Then there are different types of chargers. Balancing chargers are often more expensive, but better for LiPo battery lifetime. However, the LiPo pack needs to actually have leads for such chargers, otherwise you can't balance the cells.
And as Kevin already said... be very, very careful with LiPo batteries. I store and charge mine out in the shed on the concrete floor, away from anything flammable.
Remember the recent laptop fires? That's approximately what happens if you're not careful with that type of battery. These fires burn very hot and cannot be extinguished with normal fire extinguishers.
Jenni
Reply to
Jennifer Smith
We have run into problems with cells going bad in several LiPos of diff brands. Kind of a run on em lately in fact. My father bought a balancer from Tower Hobbies and I just bought one from the LHS that is made by Astroflight. His cost about $40. Mine cost about $25. The supposed advantage of the Astroflight one is that it is universal consisting of a PC board with a series of prongs sticking out of the end. You can just line up on the prongs you need to match whatever equalizing plug is on your particular battery. He hasnt received his yet and I only bought mine a couple of hours ago so I cant say how well they actually work.
Reply to
Fubar of The HillPeople
...
| > "It is recommended that you completely discharge the battery | > during the initial test flight before following the charging | > guidlines outlined below." | | That MUST have referred to NiCD or NiMH batteries - definitely not for | LiPo packs.
Of course, that's not even a good procedure for NiCd or NiMH batteries. And the original poster didn't actually tell us what the charging guidelines are ...
| Ok, LiPo Batteries... :) To prevent deep discharging LiPo packs there | are so-called Battery Eliminator Circuits (BEC), which provide an | automatic cutoff.
That's not actually what the BEC does. The BEC powers your RX and servos, and generally has no cutoff whatsoever. (Because you'd generally rather ruin your battery than lose control of your plane entirely.)
| Some of them provide advance warning by artificially lowering power | output and/or beeping so that your heli doesn't drop out of the sky | all of a sudden - highly recommended.
That's the function of the ESC itself. Your ESC may have a BEC built in (many do) but it's not actually the BEC that does this.
| Others like the ones in my planes just cut the power to the engine | as soon as the battery drops below a certain voltage. Okay for | e-planes where you can glide down, but not for helis.
Right ... cutoffs are not suggested for helicopters. A beeper or a LED to warn you when you're losing power isn't a bad idea, but suddenly losing power when flying low and inverted is.
Cutoffs aren't actually that important. As a rule of thumb, when you've dropped from 4.2 volts/cell to 3.0 volts/cell, you've lost half your power, which should be very noticable on any plane that's not flown far away (like a powered glider.) As long as you pay attention to how your plane/helicopter is flying, you'll generally know when it's time to stop and charge. An automatic cutoff is a nice safety measure, but it's not essential.
| Balancing chargers are often more expensive, but better for LiPo battery | lifetime.
They don't have to be expensive. For example, this one --
formatting link
is only $12.
| Remember the recent laptop fires? That's approximately what happens | if you're not careful with that type of battery. These fires burn | very hot and cannot be extinguished with normal fire extinguishers.
Yes they can. This isn't greek fire or anything like that. (And if you feel that I'm wrong about this, please, provide some references for this claim.)
Yes, LiPos can spontaneously catch fire when abused, which makes them dangerous, but the fires they create aren't more dangerous than other fires of similar sizes. (Though you may have a bunch more LiPo cells near by, waiting to catch fire on their own -- but that's not any different than many other things that can burn.)
Reply to
Doug McLaren

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