ameyam

Dear All,

I have been flying glow for about 3 years now and was considering going electric with a backyard flier. Two questions here:

1) Lipo battries: they come with a warning that they should not be charged unattended. Hold on a minute, no one can sit all day with the battery in hand waiting for it to charge[]. So actually how much and what precaution is needed and what can be done to to make charging as safe as possible

2) What airplane to take? Foamy or balsa. I want a sturdy plane that I can 3d with (did I just say that in one sentense?) Right now only Great Planes is obtainable. And what power loading will 3D require? I intend to fly outdoor in light winds

Ameyam

el-John-o

Ameyam,

To answer the first question, there are two parts I see from that. 1- covering their butts, lipos have a greater risk of leaking or exploding if improperly charged then say, a nicd, so when the fire department shows up and says your house burned down because of a lipo sitting on the shelf, you can't go and sue the lipo manufacturer.

The second part, and the solution for the first part, is the use of a cycler or 'smart' charger, something like this. I personally, would never mess with lipos without something like that, those will intelligintly tend, charge and discharge them. It will also greatly increase the life of the battery over time.

Good luck!

John

(Sorry, I have no suggestions for a stable 3D electric).

CGRetired

My Feedback: (1)

The best choice, in my opinion, when charging LiPo packs is to charge them outdoors and to put them in some sort of fireproof container. I have a ceramic pot with a cover that was made to charge LiPo batteries by a friend. You can get something like that at lawn and garden shops everywhere. Another choice is a LiPo Sack.

http://www.liposack.com/

You can put your LiPo battery pack in either one of those, or others for that matter.. a concrete pad with four cinder blocks forming a bowl will work just fine too. Or outdoors, on something that won't burn, and leave it exposed to the air.

The main point here is "outdoors". Keep it away from your car, your house, or anything else you care not to burn down. No, this is not trying to convince you that LiPo's are bad, it's just that they take a bit more care and feeding than other packs and a bit of caution is always a good thing.

As far as a stable and sturdy 3D is concerned, well, one main characteristic of a 3D plane is light with a lot of power. So, light means build them light with light materials. Balsa.. well, something like a Reactor 3D Electric is light, but it is also very fragile as most light aircraft are. If you want something that can withstand some abuse, balsa is not the way to go, but Depron or some such foam airframe is.

CGr.

ameyam

Just probing a bit:

If I get hold of a smart charger like el-John-o suggested, the risk is very much reduced? Is this something similar to glow fuel manufacturers stating that the fuel is highly inflammable? In day-to-day use, we never need to worry about the risk of fire, though we do take precautions for it

With a good charger, is the fire-proof cylinder needed? I normally charge my NiCds overnight and in the same room that we sleep in. Outdoors charging is not possible, I live in apartment type setup.

And finally, is it recommended to go electric anyway or get a profile like the Mojo or the Aeroworks ProX 260s?

Ameyam

RCKen

My Feedback: (9)

Even with a "smart charger" that is designed for Lithium chemistry batteries there is still a risk of fire. These batteries need to be observed as they are charged and they need to be charged in a fire safe container. I use a Lipo sack to charge my batteries in. This will contain any flames that may occur if the fire bursts and catches fire. As far as watching them?? that simply means you are present in the room while they charge. I charge them in my shop while I am working using the lipo sack sitting on a concrete block to contain them if they burst. Lipo's can be safely charged in an hour so it's not like Ni-mhs where you have to charge them overnight. If you live in an apartment building you could charge them on your balcony if you don't want to do it inside the house

The risk from Li-po's is real, but it is not common if you give the batteries proper care. However, they should be handled with care in the event that they do burst and catch fire. You don't want to burn down your apartment building if they are handled improperly. A few simple safety steps go a long way here

Ken

ameyam

Thanks everyone for the help. Though electric is a good way to go, I think I am going to be restricted to glow for now. I will get hold of a shall profile and put a 46 on it for off-day flying, thats better for my setup for now

Ameya

faulknej

My Feedback: (9)

Lipo's charge much faster than your other batteries. Charge at 1C usually takes less than an hour, depending on how far you drew them down. Iusually fly for about five minutes, takes 15-20 minutes to charge back up. (11.1V 2250 mAH 40C) You'd probably use more doing 3D, but it's not like you have to charge it for 12 hours to fly again. If you have 2 or 3 batteries, you can get multiple flights in an hour.

ameyam

I am going through this again due to the sheer frustration of not being able to fly this weekend again due to problems with my local field.

Again two questions[&o]

1) Can LiFe battries be used with electric motors? For eg, the GP Extra 330SC foamy recommends a 11.1V battery for outdoor flying. However, LiFe battries are only available in 6.6V. How then dou you use with that plane? Also what ESC to use?

2) Again a airplane selection. Though I am good at glow, electric I am new to. I can probably hover, waterfall, flat spin but everything else in 3D in need to learn. Should I go for Foamy (Such as GP Extra 330SC, GP UCD 3D EP or go for the XLC like Yak54 EP or Edge540 E-performance? The XLC s are a bit larger an I dont know how much space they will require to fly, considering the local ground is about half a football stadium

Ameyam

Geardaddys

Another suggestion for charging lipo batteries is to get a charger that has a temp probe option.. I always velcro my temp probe onto my batts when I charge.. I have the temp cutoff set pretty low, so it will shut down the charge process if the batter get's even a little bit unhappy.. That being said.. Be careful about where you put your probe.. if you put it on the top or bottom of the battery it will only see the temp of one cell.. I think it's smarter to put it on the side of the battery so that it can get a small cross section of each cell..

Also using a lipo sack w/ Hyperion Duo for a charger (Love this charger)..

Campy

My Feedback: (1)

You can use lipo, life, lion, A-123, etc batteries to power your plane. Which ever battery type you decide to use MAKE SURE YOUR CHARGER WILL HANDLE THAT TYPE OF BATTERY. These battery types have different max voltages per cell and over charging them will most likely damage the battery. MOST intelligent chargers can handle these types of batteries.

As for the ESC - the ESC is used to regulate the amount of power (amps) to the motor, and should be based/sized according to the motor specifications (amps) AND the number of cells (volts). Your LHS can provide specific amp/volt specs/ratings of the ESC based on the motor/prop/gearbox (if any) used and number and type of cells (volts).

I am not certain about LIFE batteries, however the various brands of ESC's I have used will all handle LiPo, Lion, and A-123 batteries. If you are using a separate BEC for your servos you MAY need a voltage regulator in line with the BEC to insure that the servos do not get excessive voltage if you are not using LiPo, NiMh or NiCD batteries.

I would suggest a "foamie" for the plane. They are light weight, can handle a fair amount of abuse and are USUALLY easy to repair using foam safe CA or epoxy.

ameyam

Ok, hold on. I need a technology primer with electric airplanes. As in what components make up an electric system and how these 6.6V battries can be connected to get the 11.1V that the motor wants

Ameya

CGRetired

My Feedback: (1)

First of all, the motor will take just about any battery pack you wish to feed it through the ESC. The difference being the voltage applied for different cell configurations. The KV rating of a motor will tell you what it will do with various voltages. That is RPM/ Volt. So, if it's a 1000 KV motor, then a 6.6 volt battery will give you a free running 6.6 X 1000 or 6,600 RPM. If it's a 3000 KV, then you get 6.6 X 3000 or 19,800 RPM maximum with that particular battery. There is a limit so check with the manufacturer of the motor. For instance, a motor may say maximum of 4 cells LiPo (14.8 volts) or 6 cells NiCd/NiMh or 7.2 volts NiCd (more likely more cells but that's just an example).

The electric components of any E powered RC aircraft are the receiver (all have that), the battery, the ESC or Electronic Speed Control, and the motor. Of course the prop comes in there but that's not an electric component.

Some ESC's have BEC's or Battery Elimination Circuitry which is used to power up the receiver via the throttle channel. It acts as both a throttle for the ESC and the power for the receiver and servos.. and is limited in available power so check with yours to see if it will handle the servos you are going to use.

CGr.

Gray Beard

My Feedback: (-1)

Down at the bottom of the header is a site called Watt Flyer, that's where I went when I built my electric and it's worth going there. I went Lipo and charge them in a fire proof container right next to me while I'm watching TV or reading. The charger I'm using beeps to let me know when the battery is charged. Problem is my hearing isn't all that great but my wife hears it before I do. I know of several charging accidents that have happened to friends so I'm very careful with them.