Lipo Tips for newcomers to electric flight
Just a guide to help people get started with lipo batteries. The club accepts no responsibility if you have a problem with your own lipos. Follow this at your own risk.
Basic lipo rules:
0. Gain a basic understanding of your lipos and charger.
1. Always use a quality charger (cheap chargers can go bang and catch fire.)
2. Always balance charge (i.e. connect balance lead and ensure charger is set to balance charge).
3. Never charge a battery to over 4.2v per cell
4. Never charge a battery faster than its 1C rating (eg a 2200mAh battery should charge at max 2.2A).
5. Always store, transport and charge batteries in a fire safe bag or box.
6. Always charge in a safe place where an outbreak of fire can be easily managed.
7. Never discharge a battery at a faster rate than that indicated by its C rating (Eg a 2200mAh 30C battery should discharge at max 2.2×30=66A).
8. Never short circuit a battery unless you are tired of life.
9. Never discharge a cell below 3.3v
10. Always dispose of batteries which have become very “puffed”.
Lipo tips for longer battery life:
11. Always store your batteries at 3.85v per cell (best to have a charger that can also discharge to this voltage).
12. Never charge a battery to over 4.15v per cell (rather than the safe max of 4.2v).
13. Never charge a warm/hot battery.
14. Never use a recently charged battery which is still warm/hot.
15. Never discharge below 3.7v (rather than below 3.3v for max fly time).
16. Never store your batteries where they might become very hot or freezing cold (batteries best stored between about 5c and 20c).
Message from Ian P. - a new WHMFC member, May 2020
Well, where to start! After a twenty year gap between projects, a global pandemic left me with time on my hands and a six year old son to educate. We started with a small Guillows kit, and it all came flooding back, so I decided to treat myself to an early thirty fifth birthday present and come back to flying.
Having commenced building, I went online to check the new rules and regulations I was dimly aware of, and learned just how much things had changed in two decades! Absolutely the safest, and most responsible way to fly now is in a club, if only to stay on the right side of the CAA.
Having joined the BMFA, I used their portal to express my interest in joining WHMFC, who right from the off were enthusiastic to have me, and took a very quick initiative to make me feel welcome and confident. Now, here in lies the rub: I’ve invested the best part of £400 and six weeks work in this model, and all that expense and effort was saved within ten minutes of my first arrival at the flying field, where two very experienced, knowledgeable members carried out a pre-flight inspection and found a loose elevator hinge.
Due to my budget transmitter not having a buddy box port, Mr H took the plane for it’s short maiden, in less than perfect conditions, and performed a perfect take off, circuit and landing. Armed with the knowledge that the plane will in fact fly, and my now reinforced control hinges, in just one session the club has given me the confidence and reassurance to relearn lost skills and hopefully be in a good position to get the most out of the hobby, for myself and both my boys in the years ahead.
Helping to describe where a plane might have come down
Scenario is.. club member has lost plane and is asking for help finding it from people not at the field at that moment. Those people need to know where to start looking. The photo below can be used to give an approx position of where the plane might be in relation to the centre of our flying field.
For example “E 150m” might mean the area around the bridge and road junction.
Setting the Failsafe
Something a newcomer to RC flying may forget to do – configure the failsafe settings.
So what are failsafes? If an aircrafts receiver loses its radio signal connection with the pilots transmitter then the receiver should have been configured to reduce motor/engine power and move control surface servos to some particular position(s).
In other words a failsafe is just a guess that you have to make about what you want your aircraft to do if your transmitter stops wotking. And transmitters can be dropped, their batteries can go flat and aircraft can fly out of their range – so its worth setting failsafes.
In fact CAP658 says:
“Any powered model aircraft fitted with a receiver capable of operating in failsafe mode should have the failsafe set, as a minimum, to reduce the engine(s) speed to idle on loss or corruption of signal.”
How you go about setting the failsafe of a particular aircraft depends on the make of the radio equipment. Please refer to your manuals for specific instructions. Or even easier – just google for a Youtube video.
Faster than the wind (would be better)
Ever seen a fast moving RC plane suddenly tumble to the ground out of control? This video looks at one possible cause – and you get to see a spectacular crash as a bonus 🙂
If an aircraft is flying in the same direction as a strong wind is blowing then the aircraft may be moving over the ground quite quickly. – this can confuse the pilot into reducing power until the airpseed is too low and a stall occurs. In other words – fly faster than the wind when the wind is pushing you along.
Is it worth £20 to find your plane?
In the summer months when the farmer’s crops are knee high and taller… anyone who has ever searched for a downed plane will know how difficult it can be.
And of course it’s important to avoid disturbing farmer’s crops as much as possible during the search.
There are a number of devices available on the market which can be used to find lost RC aircraft. There are three basic types of device – wireless trackers, GPS trackers (typically using mobile phone signals) and straightforward “beepers” which use an audible signal.
This is about the DroneKeeper Mini 2 – a “beeper” device.
I prefer simple solutions. I don’t want the hassle of extra gear to bring to the field like a wireless detector and I don’t want to worry about mobile phone coverage. I don’t want any more batteries to charge. I just want to stick something in/to my plane which will help me if I lose it. So I’ve gone with a beeper – the DroneKeeper Mini 2.
Overview of DroneKeeper Mini 2
Made in South Korea and sold by NicheMall.
The device has two modes in the way it can be used – Wireless Mode and Wired Mode. These are confusing names not least because in both modes the device can be wired using its USB lead for continuous recharge (DC 5v to 9v from a BEC or receiver channel).
Wireless Mode is about sounding an alarm if a period of time elapses without any movement being detected.
Wired Mode is about sounding an alarm if the pilot moves a switch on his radio.
Which is the best mode to use? It depends.
If you have a spare channel on your receiver then probably Wired Mode is best – you normally decide when it beeps and you can shut it up from your transmitter if it does start beeping (unless its beeping is due to power failure).
In Wireless Mode it can start beeping because you have been waiting too long for your turn to take off. And to silence the device in Wireless Mode you have to switch the device off using its tiny red slider switch. On the other hand with Wireless Mode its possible to simply velcro the device to a model with no wiring needed.
Weight: 9g with battery and with USB lead connected for continuous charging.
Length 35mm (additional 16mm with USB lead connected), Width 15mm, Height 12mm
Wireless Mode (better name might be “No Movement” mode) [default mode]
In Wireless Mode you can charge the device from a USB port of a computer and then simply velcro the device to a model without needing to connect anything electrically. But probably better to connect it up in the plane for recharging so you don’t need to remember to charge the device before leaving home.
According to the maker when used only with its included rechargeable coin cell battery (i.e. not connected for recharging):
o takes 1 to 1.6 hours to charge,
o lasts 20 to 40 hours if the alarm doesn’t go off,
o lasts 3 to 5 hours sounding the alarm. It has a low voltage alarm if no external battery is connected.
Wireless Mode sounds alarm:
• If no movement after configurable time interval (choices are 30secs [default], 1min, 3mins, 5mins, 8mins)
• If no power (if connected for continuous charging)
• Regardless after configurable time interval from switch on (choices are 20mins [default], 40mins, 60mins)
I think the “regardless after configurable time interval” is about covering for the situation where the model is dangling from a tree and being blown around by the wind.
Wired Mode (better name might be “User Triggered” mode)
Must be connected to a PWM channel of the receiver. This provides both a PWM signal and power to the device.
Wired Mode sounds alarm:
• If signal received from receiver (caused by flicking switch on transmitter or by failsafe. *See note below.)
• If no power
*Note: In Wired Mode you should configure the receiver’s failsafe to tell the device to start beeping in the event of radio signal loss – otherwise if you drop your transmitter then you may need to wait a long time for the aircraft’s battery to die before the beeping starts. Always good to check your failsafes occasionally anyway.
Early days for me with this thing. I’ll update this article at some point in the future when I know how well they work in practice. But so far I’m quite impressed. It seems to have been well thought out with all eventualities covered.
You don’t need a special programming card or battery charger. Configuring it (modes and times) is a bit fiddly but not too bad – its about touching a contact with a wire and counting beeps to move through the available options. Should only need to do this once before installing into an aircraft.
You can fix it to your plane in such a way that you can almost forget about it until you need its help. You do need to turn it on and off for each flight – and (as long as it’s connected for continuous charging) the device reminds you to do this by beeping in both cases.
The alarm beep isn’t as loud as I expected but loud enough. I’ve installed the device inside a foam fuselage and inside a plastic fuselage and the sound is still penetrating enough to be heard across my house.
When installing you need to remember to give yourself easy access to the red on/off slider switch. My only quibble with the device so far is you move the switch to the left for on and to the right for off – seems the wrong way around to me!
Connecting for continuous charging makes a lot of sense to avoid the hassle of charging up the device before each trip to the flying field. Connections for charging can be made to a 5v/6v BEC or to a spare channel on your receiver. Connecting to a spare channel gives you the choice of Wireless Mode or Wired Mode. If there isn’t a spare receiver channel and your BEC is buried inside the aircraft then it’s possible to use a Y servo splitter cable to tap into the power being used by a channel already in use – although this would prevent the use of Wired Mode. By the way the device is protected against Over Voltage. Don’t ask me how I know.
The device comes with its own special USB cable. To connect this to a receiver you will need a male/male servo cable.
For Youtube review see CurryKitten video:
For full details, user instructions and order form see NicheMall website:
As of 28/2/2019 the price is about £20 including postage. Mine took a week to arrive from ordering online.
And no, I’m not on commission and will not benefit in any way if you buy one!