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View Full Version : Hi, im a newb, Few questions Charger & Batteries


tripleflip18
11-09-2005, 02:05 AM
Well hello there, I am new to RC Flying. I recently bought myself a parkflyers Cessna 182 4ch. Crashed it like 5 times, before i got the FS software. Today I had my first successful flight(s). And can't describe you how excited I am about more flying. Totally amazing, I was able to do loops and everything. The Simulator on computer really really helped me.

The only thing that was sad are the batteries, I have the original 8.4 1000mah ni-mh and bought the 1800 Li-Poly 7.4 with proper charger for 1800 from Parkflyers.com. So the sad part was that each one didn't last very long. Point is i Want to stay up in the sky as long as possible with best performace from the batteries. I was expecting 25 min from 1800pack but only got about 10 min. with the 1000 i got about 8 minuits. I am wondering if i get a good triton Charger, will it work with these current batteries? Also the output (charging) cables with Triton, are they included, will they be compatible with these batteries, or do i need to buy that as well. Will I get any Benefit from Triton charger or current chargers just as good?

Ok now correct me if im wrong please. the 7.4 volt battery seemed to be a little weaker then the 8.4. I just felt that there was a little bit more power from heavier 8.4 battery. My Cessna has the 480 motor, if i put in a 9.6 or 11V battery, will that burn the motor or other electonics? Will I have more performance with higher voltage Batteries?

Last but not least, I am looking for a great battery that will last longest possible time, Fit into my plane, and great performance. There are Really a lot of brand Batteries, I have no experience with them. Can you point me out to some of your favorite sites for batteries and such? And just again to be sure this Triton Charger will be able to charge pretty much all of the batteries, right? Also, i am able to plug this into a regular 110V Jack in a wall right?

I always do my research so i have done a lot about everything in RC Airplanes, batteries., not everything but as much as i could possible do. Weeks of research before I bought my plane and spent all day today researching about batteries.. Still few things are not clear.

Any Help is greatly appriciated. Thank you!

hoppy
11-09-2005, 04:26 AM
See this thread for 2s vs 3s vs NiMH pack. http://www.wattflyer.com/forums/showthread.php?t=2321
The 2s lipo will be weaker than the 8.4NiMH.
The 3s lipo will be much, much stronger and could (will) burn your motor out if you don't make a prop or gearbox change.

The Triton will work with all batteries.
The Triton does not come with output cables. It has banana jack connectors.
The Triton needs a 10A, 13-15V DC power supply. It will NOT work on 120AC. It will work from your car battery.
Unless your present chargers are junk, a new one won't help extend your flight times.

The 1000mah NiMH battery should get better after a few cycles. Charge it one time at 100ma for 16 hours after it has been discharged flying.

We need to know a few more things.
What prop are you using?
What is the gearbox ratio?
Do you fly at full throttle?

A little math-
The amp draw of your setup can be estimated with this formula:
amp draw(A)=AH capacity of battery/flight time in hours

1000mah, 8min flight: AmpDraw = 1AH/0.133 = 7.5A
1800mah, 10min flight: AMpDraw = 1.8AH/0.166 = 10.8A

Since watts are what flies the plane, let's see how the watts of these two batteries compare.
1000mah NiMH - Nominal Voltage - 8.4V
8.4V x 7.5A = 63W
1800mah LiPo = Nominal voltage under load - ~7V
7V x 10.8V = 76W

The higher watt draw of the lipo doesn't make sense so something else is happening. Perhaps the LVC is kicking in with the Lipo. A 2s lipo can be discharged to 6V under load. What is the LVC set for on your model? Is there a LVC?

I'll let you catch up.....

hoppy
11-09-2005, 04:36 AM
Here is a review of the Cessna reporting as low as 5 min flight times.
http://www.rcuniverse.com/magazine/article_display.cfm?article_id=554

Does that equate with the type of flying you were doing?

tripleflip18
11-09-2005, 08:37 AM
Hi Hoppy, thank you for trying to explain things to me. Shoot i wish i knew so much about this technical stuff about batteries as i know about computers... Anyway I am using Everything Stock, Stock Prop(don't know which 1, its the 1 from parkflyers.com for 182 4ch plane) I have no idea what Is gearbox Ratio or how to set it, yes I did fly at full throttle but again a lot in half throttle as i love to glide the plane.

Thank you for that Amp Draw Formula, makes sence. I don't understand fully difference between 2 batteries 63W and 76W. What should the Li-poly be? Oh ok, i just got it, its drawing more power from a weaker battery...
So yes doesn't make sence.

I don't know if this is true or anything but this is what happened with parkflyers. I ordered the Li-poly batter, received it, was damaged and wouldn't even turn the prop. Emailed them, sent it back for a replacement. But a day after i placed my order they ran out of stock of Li-Polys, and thats when i got the damaged battery. So when i sent it back to them i received supposedly a new Li Poly while they were still out of stuck of out for another 1 1/2 weeks. Makes me think they maybe, just maybe they put in an old battery in. But not 100% sure... So maybe my battery is sort of dead?

I have no Idea what LVC is, can you plz explaine

also Hoppy, that is exactly the kind of flying i did, i'd say probably 50/50 Full throttle/and low-med throttle.

I will go out tomorrow if weather allows and test the exact time of the batteries as well as notice my throttle.

So if i change the prop and gearbox, put in new battery i will overall get more performance?

Hoppy really appriciate your explanation and help. Thank you

hoppy
11-09-2005, 08:14 PM
Does it have a gearbox? Is the prop on the motor shaft? Looks like it may be direct drive--prop on motor shaft. Never mind, it's direct drive.
OK, the product distributer says the charger that comes with it is a time charger..... which means the battery may or may not be fully charged. In this case, the Triton may give you a fuller charge.
LVC is Low Voltage Cut off. Discharging Lipo batteries much below 3V/cell under load can/will permantly damage them. The LVC is built into the ESC and is set to prevent this from happening. I take it the ESC in the Cessna does not have a LVC or it is set for the 7.4V NiMH pack. Your lipo pack should measure at least 7V 10 min after flying. That's the no load voltage.
Let's see what the next flying session gives you. The throttle control is the secret to long flights.

tripleflip18
11-09-2005, 10:21 PM
Hi there, After somewhat successful flights today, few perfect landings, and few not so perfect, as well as 1 crash into a building lol. the Elevator broke somehow, but easily fixable. Winds were 10mph with gusts to 20 lol, so flying was very jerky, enjoyed it much more last night when it was totally calm and everything was very predictable, yet today was good experience.

Anyway, today my Lipo Lasted 22 Min, with landings and breaks, so probably flight time was 19-20 min. Which im very happy about actually :) Second battery I didn't time :( Will do it next time. the thing I noticed Is Climb rate and height, with the 8.4 1000mah (heavier) I climbed at a better rate as well as was able to get higher so it was safer to do tricks. Is that suppose to be that way?
Yes its a direct drive from the motor, what does gearbox do? So you think Triton will be good addition for my batteries? actually its not because it has to be out of the car. Are there similar good ones that you can recommend that can be pluged into a wall jack?

Last but not least, i broke 2 props today.... 1 when i crashed into a bulding, even though i shut the motor down. and second 1 on unseccessful take of (i thought i was good and wanted to take off with the wind- winds direction) So i have right now 1 prop, will def need to order a new one just in case i break this one. @ http://www.parkflyers.com/html/body_propsgear.html

If i get the last 2 items Carbon 5x5 Reinforced Prop and 2.3mm Prop Adapter Will it work with motor, any improvement? Do i need a gear box or anything?

Thanks you Hobby. :) What do you fly btw, how long have you been into RC hobby?

flyranger
11-10-2005, 02:54 PM
Last but not least, i broke 2 props today.... 1 when i crashed into a bulding, even though i shut the motor down. and second 1 on unseccessful take of (i thought i was good and wanted to take off with the wind- winds direction) So i have right now 1 prop, will def need to order a new one just in case i break this one. @ http://www.parkflyers.com/html/body_propsgear.html

If i get the last 2 items Carbon 5x5 Reinforced Prop and 2.3mm Prop Adapter Will it work with motor, any improvement? Do i need a gear box or anything?

Maybe you need to invest in a prop saver? It's saved me bundles of money. You can get them at your Local Hobby Shop (LHS) or online. This is an e-flite model. Must be sized for the prop shaft and sometimes the shaft has to be trimmed off with diagonal pliers or with a hack saw. Look at the pics and you will see what I mean. Prop has many scratches and scars but still spinnin'! I comes with a couple of rubber bands, but I don't use them. Went to an auto parts shop and got a couple of o-rings for a quarter. Much better and won't break in flight.