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Old Nov 06, 2012, 02:15 PM
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Thanks for the replies i dont really have the time to go though all that but i will do the first few charges at lower amperage.
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Old Nov 06, 2012, 02:18 PM
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Yeah I got loads of time because most of the time in England it is too windy to fly.
During summer time I pick out the flying days and I charge my batteries accordingly, e.g. flying next day charge at 1.5a, flying next week charge at 0.8a etc.
I also have sets of batteries. 4 batteries per set, I fly in sets so for the next day I have another set of batteries to fly on and any way I have only got about 1hr at the flying field before I have to go.
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Old Nov 06, 2012, 02:22 PM
An Aussie in Chicago
Joined Apr 2012
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Originally Posted by sss34 View Post
Yeah I got loads of time because most of the time in England it is too windy to fly.
During summer time I pick out the flying days and I charge my batteries accordingly, e.g. flying next day charge at 1.5a, flying next week charge at 0.8a etc.
I also have sets of batteries. 4 batteries per set, I fly in sets so for the next day I have another set of batteries to fly on and any way I have only got about 1hr at the flying field before I have to go.

You should get a Guardian 2D & 3D stabilizer and fly the windy days as well.

http://www.rcgroups.com/forums/showthread.php?t=1596644 or a cheaper HK version.

http://www.rcgroups.com/forums/showthread.php?t=1702672

Cheers.
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Old Nov 06, 2012, 02:26 PM
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Originally Posted by hendrnk View Post
You should get a Guardian 2D & 3D stabilizer and fly the windy days as well.

http://www.rcgroups.com/forums/showthread.php?t=1596644 or a cheaper HK version.

http://www.rcgroups.com/forums/showthread.php?t=1702672

Cheers.
I enjoy and good at flying in up to 20kph winds but usually its above that.
And I dont like stabilisers because they do the flying for me which is fun in the strong wind.
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Old Nov 06, 2012, 02:35 PM
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OK so i just plugged my charger into my battery and set it to balance charge at low amperage. it is saying that total voltage is 11.56 and each cell is reading 3.86 or something isn't this to high for a 3c battery. Im concerned? Any advise
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Old Nov 06, 2012, 02:37 PM
An Aussie in Chicago
Joined Apr 2012
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Originally Posted by dunc1055 View Post
OK so i just plugged my charger into my battery and set it to balance charge at low amperage. it is saying that total voltage is 11.56 and each cell is reading 3.86 or something isn't this to high for a 3c battery. Im concerned? Any advise
3S will top out at 12.6 volts or 4.2 volts per cell to be fully charged.
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Old Nov 06, 2012, 02:42 PM
An Aussie in Chicago
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Originally Posted by hendrnk View Post
3S will top out at 12.6 volts or 4.2 volts per cell to be fully charged.
4.20v = 100%
4.03v = 76%
3.86v = 52%
3.83v = 42%
3.79v = 30%
3.70v = 11%
3.6?v = 0%
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Old Nov 06, 2012, 02:44 PM
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So the 11.1 rating does that mean that is the lowest they will go, and should not be discharged lower than this?

Will the charger stop charging when full?
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Old Nov 06, 2012, 02:47 PM
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Originally Posted by hendrnk View Post
4.20v = 100%
4.03v = 76%
3.86v = 52%
3.83v = 42%
3.79v = 30%
3.70v = 11%
3.6?v = 0%
thanks for that very helpful
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Old Nov 06, 2012, 02:51 PM
An Aussie in Chicago
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So the 11.1 rating does that mean that is the lowest they will go, and should not be discharged lower than this?

Will the charger stop charging when full?
The charger will stop at 12.6 volts automatically. For a 3S, I try not to go below 11.1 Volts, but DO NOT GO below 9 Volts.

I have setup the ESC to cut the engine at 9.6 Volts, the last few volts between 11.0 & 9 go down very quickly so work out your flying time to finish around 11.3 volts to be safe and give you some reserve if you need to do a go around for a missed approach.
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Old Nov 06, 2012, 03:03 PM
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That is good to know.

I am a total beginner so i wont be flying my axn hard how long roughly do you think my flight times will be i know its hard to judge as there are so many factors.

Also why do you set engine cut so close to 9v instead of like 11v or something, is it just in case you need that extra few minutes or something.
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Old Nov 06, 2012, 03:13 PM
An Aussie in Chicago
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Originally Posted by dunc1055 View Post
That is good to know.

I am a total beginner so i wont be flying my axn hard how long roughly do you think my flight times will be i know its hard to judge as there are so many factors.

Also why do you set engine cut so close to 9v instead of like 11v or something, is it just in case you need that extra few minutes or something.
It depends on the ESC the max cut voltage on my ESP is 3.2V per cell. Also the voltage will be lower on load then in rest. So when it cuts the rest voltage will also increase some what once the load is taken off the batteries.

I was getting around 20min on a 2200 3S battery on my stock AXN. My Transmitter TX9 has a setting for a timer based on throttle usage, so I set the alarm for full throttle minutes, if I'm gliding it doesn't use any minutes, if its 1/2 throttle the timing decreases at 50% etc.
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Old Nov 06, 2012, 03:17 PM
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Yeah remember the 80% rule. Do not discharge your battery below 20%. This also gives you time to fly for a bit more if you get in trouble.
This is were to look:
http://www.rchelicopterfun.com/rc-lipo-batteries.html

Got my order today to UK.
8 days via HK post not bad.
BUT!! The record is 5 days from the time HK have shipped it and that was via royal mail. but they are crap now.
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Old Nov 06, 2012, 04:31 PM
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Originally Posted by dunc1055 View Post
That is good to know.

I am a total beginner so i wont be flying my axn hard how long roughly do you think my flight times will be i know its hard to judge as there are so many factors.

Also why do you set engine cut so close to 9v instead of like 11v or something, is it just in case you need that extra few minutes or something.
G'day Dunc1055,

I remember when I started in this hobby with electrics. In fact is is not so long ago now. After flying control lines in my younger years I came across RC again a few years back and found it actually affordable! There were so many question I had and so much seemingly conflicting information. Everyone had an opinion or I just didn't get answers.

This forum - RC Groups is full of useful information. You just have to trawl through and use search engines both in the forum and the various Google flavours.

A few tips I would impart:

Flying: - You need a SIM to practice. You need someone with experience(good experience) to help with your beginning.

Batteries: - CHARGE: Generally don't charge beyond 1c - this is the capacity of the battery i.e. a 4000 Mah battery is 4Amps = 1C for it. A 2200Mah battery is 2.2Amps = 1C for it.
DISCHARGE: Discharge is rated in C which means you can nominally (very nominally) draw say **30 times the Capacity for a short period i.e. 2.2amps x 30 = ~ 66amps.(**what ever the C rating)

Flight Times: - Your first flights should be very short. Take off, circuit, land. Initially you are checking your CoG your flight trim and your ability to land etc.. Then you should have a battery checker of some type (there are heaps) a timer (often on the Tx or a phone timer etc..) Fly for 3 minutes and land check your battery - work out how much it has lost. Extend the time for your next fully charged battery etc. etc. The AXN should give you a good 15 minutes with gliding and a good 8 minutes with lots of throttle use only.

Overall take your time seek assistance at the field you fly at and be logical and practice safety and routine.

Have fun
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Old Nov 06, 2012, 05:26 PM
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Quote:
Originally Posted by hendrnk View Post
4.20v = 100%
4.03v = 76%
3.86v = 52%
3.83v = 42%
3.79v = 30%
3.70v = 11%
3.6?v = 0%
Dunc:
This table above means that at 4.2V you have 100% left in the batteries, 4.03 76% left etc.
DO NOT GO BELOW 3.7V

The reason being the battery voltage will drop drastically once you get it this low. You will long term kill your battery if you let it get too low and in return get only another 30 seconds of flight. It's not worth it if you want your batteries to last.

RE: your original question: I can get 20 minutes of flight on a windy day with mixed throttle on some old beat up batteries. Set your timer for 15 minutes and measure your voltage left after 15 minutes and go from there. Maybe you can do 20 minutes. Maybe you can do 25. Maybe you can do 15 but I'm sure if you start at 15 you'll have plenty above 3.7V / cell left.
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