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Old Jan 31, 2013, 01:28 PM
Eternal beginner
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France, Alsace, Strasbourg
Joined Jun 2012
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Originally Posted by Zarrick View Post
Rollmops67 oh, so it could be dangerous... better not risk. About those 12V wall power supplies, I found a lot of them and the most powerfull has only 1A :/ ElectricAussie told me that for a 30W LiPo charger I will need +/- 2,5-3A power supply...
Yes : Power (Watts) = Voltage x Current.
So for 30 W you will need 30/12=2,5 A
But 30 W is the max power your charger can handle, it can also be less.
If you charge your battery at 1 A charging current your power supply will be fine. (but it will take 1,5 hours to charge the stock F45 battery)

Quote:
Anyway, I dont really understand these LiPos - a 2S LiPo has 7,4V what is 3,7V per cell. But on many places I have read something about 8,4V and 4,2V per cell. Also the stock charger has 8,4V output. Can someone explain me that?
That's simple, 3,7 V per cell is the "nominal voltage" (like 12 volts for a car battery).
4,2 V per cell is when a lipo battery is 100% charged (a car battery will be about 13,5 volts when fully charged).
You should under no circumstances go higher then 4,20 V per cell for a lipo battery, they don't like that at all. Loss of capacity, and in the worst case the battery could take fire, if your charger becomes crazy and the voltage don't stop to increase.
Quote:
Maybe my battery and charger is all right and only I'm dumb Right now I have 7,88V, 3,66V cell#1, 4,22V cell#2
Eeekk, something is not all right here, wheter your charger does not balance the battery (most likely), or your battery has a problem (but that's not sure)
The cell with 4,22 V is a little too much charged, and the one with 3,66 has about no charge.
If you fly with this battery, the flight wont last very long, because the voltage of the cell with 3,66 V will drop very quickly, and maybe under 3 V.
And another characteristic of Lipo batteries is they don't like overdischarging too.
I would not fly with this battery before having charged it with a balancing charger.

Roland
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Old Jan 31, 2013, 01:30 PM
Eternal beginner
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France, Alsace, Strasbourg
Joined Jun 2012
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Ooops, error
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Old Jan 31, 2013, 02:13 PM
THE TRUTH IS OUT THERE
Zarrick's Avatar
Slovakia, Veľké Kapušany
Joined Nov 2012
95 Posts
Rollmops67 many thanks for Your answer, so its the chargers fault. So if I dont charge this disbalanced battery with stock charger, a charger with balancer should still save him, right? Anyway, I ordered some 1600mAh Zippies, as I heard they mostly arrive fully charged and balanced, so if I charge them the stock charger, they shouldn't disbalance themselves, or yes?

About the power supply, You think that 12V 1A wall charger should work with HobbyKing DC4S? I dont care about the time it will take, just work



Anyone want to make the brushless conversion, I have Buddy Codes here for EH200 motor and Hobby King 18-20A ESC, available only today!
EH200
HobbyKing SS Series 18-20A ESC
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Old Jan 31, 2013, 03:07 PM
Goooo!!!! Get to da choppa!!!!
United States, NC, Albemarle
Joined Jan 2013
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Quote:
Anyone want to make the brushless conversion, I have Buddy Codes here for EH200 motor and Hobby King 18-20A ESC, available only today!
EH200
HobbyKing SS Series 18-20A ESC
For some reason, I can't even get to the HK website today. I had planned on ordering a charger, couple batteries, and the EH200 and ESC tomorrow. I just wanted to get a list together. Guess I'll try again later, but this has been happening all day for me.
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Old Jan 31, 2013, 03:32 PM
Scotsman in Germany
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Germany, BY, Schwabach
Joined Oct 2012
1,735 Posts
After starting the "car battery charger debate" the other questions in my post seem to have gotten overlooked (serves me right for asking too many questions in one post ). I'd appreciate it if somebody could have a look and see if I'm already beyond help.... To make it obvious where they begin and end I'll number them.

1. just bought this servo http://www.ebay.de/itm/111004679501?...84.m1423.l2649 to replace the jumpy aile servo on Big Bird I. Fits OK but when I plug it in it turns the wrong way (give right aile stick, gear turns CCW and servo horn goes up). Is there a way to reverse the aileron control on the tx, or to make the servo turn the other way, or have I just wasted my money?


2. If I was thinking about buying a bunch of servos to keep as replacements, how do I know before buying them which way they're gonna turn? I would have thought something like that would be standardised, i.e. "aile stick right/elev stick back, gear turns to the right to pull servo horn down" kind of thing.


3. does zdawg - or anybody else for that matter - have an answer to my previous question from post #6156?

Quote:
Just out of curiosity, any particular reason you have your RX and tail motor on a switch instead of them just being fired up when you plug the battery in? Bet I'll kick myself when I see the answer.
Unquote.

Thanks guys
Fin
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Old Jan 31, 2013, 03:33 PM
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United States, FL, Hernando
Joined Sep 2012
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Quote:
Originally Posted by kpinnc View Post
For some reason, I can't even get to the HK website today. I had planned on ordering a charger, couple batteries, and the EH200 and ESC tomorrow. I just wanted to get a list together. Guess I'll try again later, but this has been happening all day for me.
They are back on line, try again. Seems they had a problem today, so should be all good to go now.
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Old Jan 31, 2013, 04:44 PM
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Joined Dec 2012
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Quote:
Originally Posted by Zarrick View Post
Rollmops67 oh, so it could be dangerous... better not risk. About those 12V wall power supplies, I found a lot of them and the most powerfull has only 1A :/ ElectricAussie told me that for a 30W LiPo charger I will need +/- 2,5-3A power supply...

Anyway, I dont really understand these LiPos - a 2S LiPo has 7,4V what is 3,7V per cell. But on many places I have read something about 8,4V and 4,2V per cell. Also the stock charger has 8,4V output. Can someone explain me that?
Maybe my battery and charger is all right and only I'm dumb Right now I have 7,88V, 3,66V cell#1, 4,22V cell#2
they make 'wallwarts' that size... i seen 4 amp models... the 3.7 and 8.4 volt numbers are the max charge voltages.
and i have to agree with roll, without filtering i'd not connect my 50+ dollar Li-po charger
they can get away with no filtering because the lead-acid battery is a capacitor by its very nature. (a capacitor is anything with 2 metal plates seperated by just about anything [including air] and lead-acid batteries are loaded with that sort of thing)
gel cells are so much easier
cheers
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Last edited by BobTopofTheWorld; Jan 31, 2013 at 04:53 PM. Reason: dunno
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Old Jan 31, 2013, 04:58 PM
Goooo!!!! Get to da choppa!!!!
United States, NC, Albemarle
Joined Jan 2013
498 Posts
Quote:
They are back on line, try again. Seems they had a problem today, so should be all good to go now.
Got on just long enough to look around, then it went out again. Oh well, gotta wait until tomorrow anyway. Hopefully they will be squared away then.
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Old Jan 31, 2013, 05:09 PM
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Joined Dec 2012
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and... if you lot see the current tv news, you have seen the issues with boing's new 787 and batteries... guess what kind of batteries they use now... if you guessed Li-ion then you guessed correctly
i'd bet they
a) discharge them too far down (and, or)
b) overcharge them
Li batteries are quite harmless SEEMINGLY... ask then yourself why they make a 'charging bag' for the Li batterys. Best to never charge them unattended, and to remove them from the charger when the battery is 'topped off' (fully charged)
I must have got lucky, both my stock chargers work well, i do leave the battery on the stock charger for 30-45 min after the LED shows green to be sure they topped off.
Yanno, mjx builds thousands of these chargers at a whack, i bet they pull as little as 5 per thousand, test em, then pass the lot, so its not unbelievable to see a few failures. Personally with a stock charger that is so far off, i would contact the seller and see about a replacement. I'm thinking they would be glad to sort you (and keep a customer) i see the stock charger averages around 12 usd per unit
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Old Jan 31, 2013, 05:14 PM
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Joined Dec 2012
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4.22 and 4.21 vdc on a freshly topped nano-tech
4.18 and 4.18 vdc on a battery charged yesterday
is wot i get
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Old Jan 31, 2013, 05:33 PM
Fly Fast, Fly Hard, Fly Fun
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Canada, BC
Joined Apr 2012
1,498 Posts
Wet Crash!

It's a foggy but mostly windless day here in my neck of the suburban woods. I managed to get in some great flying time today and as luck had it, I have a sweet crash report. I got the crash on the belly camera but unfortunately I didn't get a shot of what the helicopter looked like completely jam-packed full of snow. I hope you all enjoy the video....

F45 Crash and Melt (9 min 7 sec)
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Old Jan 31, 2013, 06:44 PM
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United States, CA, Modesto
Joined Aug 2012
828 Posts
For those of you who have been following the F45/450, here is the link to the new thread on the subject and where this whole helicopter thing can lead. I just posted where I am at with the current build.

http://www.rcgroups.com/forums/showthread.php?t=1813325

For those new to this wonderful F45 thread, some of us have taken the PCB, rotor head and tail motor assembly from the F45 and addapted them to a 450 size helicopter, naming it the F45/450. These thing fly great to say the least. You can search this thread for the orignal build info and picts.

I started the new thread because of all the endless possibilities for the build and I soon only had the F45 rotor on the heli which now is a 450 conversion instead of the F45/450. I have now gone a step further by building a second one using flybarless 450 size rotor and blades, along with a 90 degree swash, so I will end up with a Flybarless Fixed Pitch 450 Helicopter.
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Old Jan 31, 2013, 07:13 PM
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Joined Jan 2013
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Thank you all for a warm welcome - I appreciate it. Keep in mind I'm a major novice...

BobTop -

I'll check out Techntoys too. I've heard of most of those mods....do you recommend doing them before really learning how to fly? I understand the soda can shim mod. Is the blade balancing just a weight checking? I read most of this long thread and I don't know what the dogbone guide mod is. Any info anyone can provide on that - I'd appreciate. Edit - will check reply from tigertoo later in thread.

Tigertoo -

I agree that both spare motors would be smart to order now....somehow just popping around in the basement I already managed to break one of the upturns on the skid. I'll add the other parts as well. I'm guessing the whole tail assembly includes the tail motor?

--- following up on Tiggertoo's post on chargers. I saw some good chargers that balance cells. What I don't get is what kind to buy. I saw the AccuCell referenced earlier in the thread - but I don't understand how the two prongs that come out of the AccuCell can be used with what I can only assume is a proprietary 3 wire plug on the charging part of the stock battery.

I think I saw earlier in this thread that someone went to a SS skid that will survive my inadequacies.....going to search for that now....and get those skid bumpers on order....

Here is what I know....I suck at flying this helicopter - but I'm having fun trying to learn.

Cheers,
GV
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Old Jan 31, 2013, 07:17 PM
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Joined Mar 2009
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Long Await

Hey to all here including new guys. I've been laying low with no parts, when today in the mail was a new tail minus supporting rods and both horizontal and vertical fin broken in shipping box plus bag, but got crushed enough to break those two pieces. I just used my the other ones. The $10.99 E Bay Tail does have the under horz stab piece to connect to supports on bottom under fin, a plus, Thank God. Anyway I did a short hover and it seemed all well, and tried 60% rudder, not sure about that. I need to fly it at the field for that. Was hoping HK Turnigy 2000mah would be here because stock was getting low after 5 min, and you could tell, so no power means crap stock battery for sure. I have not yet put heat sink on tail that I made cuz I ordered the ESKY one. OH YEAH, Y'all give me a yeaa or naye on the pictures. I decided to have the Micro LED HeliPad finished in time for parts no matter what it wound up like because Hey, Why not, You only live ONCE but you get to FLY HELICOPTERS a lot of times, and part of this flying addiction is sharing, especially some photos. I have read this whole thread and you people rock. I sure hope this new battery wakes this bird up, I need more power, especially in FFF!!! ENJOY ScottHeli: D
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Last edited by scottheli; Jan 31, 2013 at 07:20 PM. Reason: Photos
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Old Jan 31, 2013, 07:41 PM
Warrior
United States, AZ, Peoria
Joined Dec 2012
12 Posts
Hello all,
Just had my first flight with my F645. What a blast! Seemed so much easier than my DH 9116. Maybe I'm getting the hang of it? Who knows, who cares ....this is just fun!! I did the servo arm mod and added heat sinks to both motors on the MJX. I am about to drill some venting holes in the canopy since the motor did get pretty hot. Has anyone made Zippy 2200mAH's fit? Since it is longer than the OE battery, the canopy will not slide back far enough. Will I just need to cut the "restrictor" tabs off of the battery tray and slide the battery further back? Your advice is always appreciated!
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