I'd like to charge my lipo batteries with this:

[link]http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXKAU0&P=ML[/link]

Should I use a lipo balancer like this?

[link]http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXMGS7&P=ML[/link]

Is lipo balancer really important?

Thank you

While not essential, a balancer makes Lipos a lot safer, makes them last longer, and give you noticably more power. I strongly recommend one.

Since I've been using balancers I've noticed that new packs can very quickly start to go significantly out of balance. It depends on each individual pack but an out of balance pack WILL be permenently damaged in just a few cycles not to mention the progressively poorer performance from your batts. Factor in the safety aspect and, yes, they are essentially necessary.(I personally think it was irresponsible for manufacturers to ever sell multicell packs with no provision to balance them!) Best of the season, Cheers!

freestyle, we wrote this [link=http://www.rctoys.com/pr/2006/12/05/lithium-polymer-battery-balancer-information-and-benefits/]Lithium Polymer Balancer Article[/link].

I think it contains information you'll find useful. It's an explanation of what a balancer does, and why one would use it.

Adam Glatt
Draganfly Innovations

Could I balance 4 lipo batteries with one equalizer and after charge them at the same time with this charger?

[link]http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXKAU0&P=ML[/link]

Thank you

When Li-pos first came out, there was no such thing as a balancer. When I did start to balance them the biggest thing I noticed was the way the batt would hold its charge to the end of the flight. Before that one cell would poop out before the other two so the last quarter of the flight would act like you were running on two cells. The charger you show will work fine, just get a Blinky balancer to work with it. Another good one is the Cellpro but will do only one at a time but balances them in the process.

I personally believe that due to the nature of Li-Po cells a balancer is ABSOLUTELY essential. It only needs one cell in the pack to drop below a non-recoverable voltage and the pack is a write off.

Cheap cells tend to be less well matched than their more expensive brothers, but it is possible to get weak cells in any pack.

I use a FlightPower V-balance module attched to an Ultramat 14 AC/DC charger. The balancer can be used to equalise a charged set of cells without connecting the charger. It has a particularly interesting set of LED's which indicate the balancing action going on during charging. Once I started using the balancer it did not take me long to note that cells such as Thunder Power are particularly well matched compared to other cheaper makes. This is obvious by the amount of balancing activity displayed by the LED's

You might hear comments that people have been charging LiPo's for years without one and that they are unnecssary. True, you can charge Li-Po's without one, but you may be significantly shortening the lifespan of yours packs without knowing it.

No, they are definitely not a fashion accessory. I cannot recommend them strongly enough

Hope these comments help.

Good luck

I have mounted in this plane [link]http://www.sussex-model-centre.co.uk/shopexd.asp?id=5383[/link]
AXI 2808/24 with 11x5.5 prop and Multiplex LiPo battery 3s 2100mAh 18C 11.1V

Flight time seems to me too short, only 5 minutes.
Perhaps I have put in my plane the wrong motor. What do you think about?

Thank you

Then electric flight with lipo batteries is not really wonderful as many say.

It's expensive and offers short run time.

However I'm building a little electric plane too, to evaluate things personally.

Freestyle2000

Texas:
Something very wrong. I'm running the same motor on 10-6 prop, which is the upper limit for the amps that the motor can handle. Runs for 10 to 12 mins. on a TP 1320 batt. Try a little smaller prop and make sure the batt is getting a full charge. Should read about 12.5 volts off the charger. Should be getting about 20 mins on that batt.

I begin to think that electric power isn't good for 3D.

We hover at half throttle and manage the engine continuously in the other maneuvers, and we use large props.

Electric motors instead spend low energy when run at max speed with small props.

For this reason 3D flying time is short.

Freestyle2000

I think you have the wrong impression Freestyle. Electric flight when properly setup, even on planes as big as 40%ers, is almost always more powerful than glow/gas, and for the same weight as a gas setup, gets 20min or more flight times. Only downside is the cost and the 1 hour recharge. Electric motors, especially outrunners, turn LARGER propellers than glow planes, making them BETTER for 3D. In my opinion, anything under 55" SHOULD be electric, because it costs roughly the same as the glow version to get flying, you don't have to buy glow fuel, and you'll turn a larger prop too for similar flight times. Foamies in my opinion are the best flying planes out there for 3D, and I can get 20 minute flight times on them with a 3:1 power to weight ratio if I felt like it while still having acceptable flight characteristics. However, I prefer 4-8 minute flight times and more like 1.5:1 power to weight ratios just in the intrest of saving weight. Try a 6 oz glow plane, it'd fly like crap.

Ryan

I think you said a lot of nonsense.

In fact, at the end, you say that you fly for 4-8 minutes with your foamies.

4 minutes are a poorest thing.

I Llike 20 - 25 minute flight times.

Freestyle2000

Go back to glow if you don't like it. Everybody has choices.

I fly that just like I'm planning on putting a .46 in FuntanaX50 and a fuel tank that'll get me only 8 minute flight times. That'll get me enough power to hover it and pull out, regardless of how slow, and still keep the weight down as much as possible. With any foamy you can put a motor on it that'll get you rediculous power and hour long flight times, just like glow. I've flown glow planes, but hate them compared to electrics. They're too darned heavy. To each his own, but at least give E-flight a chance. There's no turning back!!!


PS: I personally like getting shorter flight times. I've had planes that get 15 minute flight times or longer. However, I find that after 7 or 8 minutes I start getting careless and try stuff TOO low. Thus, those planes have a much shorter lifespans than ones I set up for less flight times.

I take 3 or 4 planes and a chopper with me and fly each one 7 or 8 mins. Hard to take that many glows with you. Flew glow and gas for 45 yrs and I ain't goin back.

No, you are wrong.
Let's do some calculations: AXI 2808/24 weight: 76g - Esc 35 weight: 32g - Battery 2100 mAh weight: 150g = 258g
OS .15 weight: 170g - Receiver battery Futaba 250mAh weight: 56g - Sullivan tank 2 oz weight: 60g = 286g
Difference: 28g

But OS .15 engine has output: 0.50 bhp @ 18,000 RPM - much more powerful than AXI and has the same power till the end - and flight time is more than 15 minutes.

In this time of nice little electric planes, I think it's a good idea to convert them to glow.

Freestyle2000

Let's do some honest calculations
2100 batt on easy throttle would run you half an hr.
1320 weighs 86 gram.
You'd be lucky to get one decent flight out of a 250 batt.
decent one weighs 114 grams.
What does a full tank of fuel weigh?
Plus what does the oil weigh that's spread over the wing and fuse?

I think you said a lot of nonsense yet.
2100 battery offers to AXI 2808/24 (Max efficiency current 15A - > 75%) 8 - 10 minutes of flight with 11x5.5 prop depending on 3D maneuvers.
600 mAh receiver battery is good for standard servos (3.2 kg cm), 250 mAh is very good for micro servos (1.1 kg cm).
2 ounces full tank weighs about 60g.

How many bhp does AXI motor offer?

Freestyle2000

P.S. However I'm building an electric plane.

HAPPY NEW YEAR

It's not about the horsepower though. The OS spins a MUCH smaller prop than the AXI, and the AXI isn't even a good motor these days. I'd like to see you even try to hover with a 7-8 in prop that the OS would turn, compared to a 11 incher the AXI would. The thrust on the OS would be much less too. Granted, the OS would fly the plane much faster, but speed on aerobatic 3D planes is not what we're after. Plus, 1 horsepower is something like 725 watts. You could easilly prop a similar motor, weighing the same (2.5-3 oz), (the AXI isn't quite up to par) for 350 watts, which is the same as the .5 HP the OS puts out.

Not to mention the additional vibration that goes along with the nitro engine, requiring a heavier airframe to withstand it, and the additional mess of glow fuel, and the constant cost of fuel vs. the one time cost of batteries.

It has been "proven" many times that you can equal performance of almost any aircraft (even quarter scale wouldnt surprise me) at a much lower rate.

Remember a lot (in fact I would say more foamies are being flown than built ups and glow fuel +foam = goo

Hey freestyle, what plane are you building?

Where do you live?
Have you never mounted an APC 12.25x3.75 in your .40 engine? This prop isn't suggested but works very well.

Suggested props for OS .15: Aerobatic: 8x4, 8x6. Sport: 7x5, 7x6, 8x4, 8x6, 9x4.
I think 11x5 would work very well.

I'm building this plane:

[link]https://shop.graupner.de/webuerp/servlet/AI?ARTN=9551[/link]

What motor do you suggest?

Thank you

Freestyle2000

If A 12 in. prop works a 18-6 should work even better. Better plane for your 40 would be a GWS Slow Stick.