joe123

I just build a Potensky eagle from hobby lobby, with the stock speed 300 motor and 7 cell nimh pack. The speed controller it came with like blew up when i tried to use it, it just made the motor speed up really fast then it like sparked and then it was no more... I just went to a hobby store, and bought a gws ics400 esc, good for 15amps (it was that or one good for 5 amps, i needed about 8-10 for that motor/battery). So i got it all back together, and the plane seems very underpowered. It barely takes off of the ground, and when i can get it to take off, i cant really go up at all, just straight till it glides to the ground. Also, the battery seems to cut out very early, after like a min or so of trying to get it to take off, its the emergency power cut off thing as i can still use the servos and stuff. Just wondering if for some strange reason this esc might be preventing me from getting full power, or the plane might be overweight, as i used a different receiver than the one that was recomended as I already had one, it is a little heavier. I weighed the plane, and it is about 15 ounces (The review of it says it is about 14) so I do not think it is very overweight, but it was a bad scale, so it might be still. I plan on upgrading to the pjs 500r with 2 cell lithium pack, as recomended on the hobby lobby site. Just wanted to know what you all might think the problem is, if the plane sounds overweight, and if the new set-up should fix the problem if it is overweight. Thanks.

Matt Kirsch

My Feedback: (21)

What kind of battery are you using, and what are you using to charge it?

The battery is probably not being fully charged. This would explain why the low-voltage cutoff kicks in so quickly, and your lack of power.

joe123

yes, I was thinking something like that. It is the one listed to go with this setup on hobby lobbys site (PC720N7 7 Cell 720 mAh NiMH) and I am charging it with the Hitec CG-340 16 Cell Peak Charger, which is good for nimh and nicd. How many amps should I be charging the battery pack at, it can charge up to 1.5 for nimh i think. if the battery is not fully charged, could this be why it has no power, or is this just why it doesnt last long. Thanks.

joe123

I just charged it again, at 1 and a bit amps, and it had enough power to take off and fly right after i unhooked the battery from the charger and put it into the plane. I then charged it again, and took the plane to a field to fly, and then it had no power again. The battery was not hooked up while i brought it to the field. The battery seems to die in after like 20 mins of just sitting there, not hooked up to anything. Is this normal??? I guess ill just charge it right before i fly then.....

scott88-RCU

My Feedback: (1)

For NiMh the charge rate is 1C(1 times the amperage). It also sounds like your battery might have two wires touching.. very dangerous and can damage ESC receiver etc. Do you have any other batterries you can put on? See if that works. Good Luck.

joe123

thanks. I dont have any other batteries that i could use, they are too big/small for that esc/motor. I did not have to solder anyhting with the battery, it came with the right connectors and stuff already installed. I checked it all, and there doesnt seem to be any wires touching. But that does sound like it could be the problem for my lack of power and battery run time. Im going to check all the other wiring in the plane, and try it, ill let ya know if thats the problem. Thanks.

joe123

I just tried again right after i charged the battery, and it was like the battery was dead. I think this is the problem, the battery doesnt seem to want to take a full charge, and that causes it to die right away, and not give me enough power to take off.

Matt Kirsch

My Feedback: (21)

This is a new battery that you bought from Hobby Lobby, right? Give them a call.

Greg Covey

Joe,

If you read my review on the Potensky Cobra and Eagle models [link=http://rcgroups.com/links/index.php?t=article&cat=198&id=4118]here[/link], you'll see that the Europeans wire there battery connector in reverse. This is likely why you blew up the original ESC.

The extra weight could just be your scale but it shouldn't matter much due to the larger wingarea on the Eagle.

I would recommend an 8-cell NiMH pack, not a 7-cell pack. I prefer the Wattage 8-cell, 800mAh 5/4AAA NiMH pack used on the Crazy Max because it can deliver an amp or two more than the standard 720mAh AAA cells. The 800mAh pack costs about $25.

NiMH cells get stronger after the first 3-5 cycles. Perhaps you'll notice this soon.

Good luck!

joe123

Hi, when i was building it, i was following your instructions on that site. I wired the battery to esc in reverse like u said. It worked fine, then when i turned it up, the esc just blew up. The new esc is gws, so i did not have to reverse the wires. The servos, throttle and everything works fine on it right now, but the battery seems to not have full power, or want to charge. After i charge it, and rev up the throttle, the low voltage cut off kicks in after about 4-5 seconds. I can tell the battery is dead cause i hear the speed of the propeller drop a lot in those 5 seconds, up intil it cuts off. I checked it all, and none of the wires seem to be touching. I am confused not on what to do, or what part might be the problem. Thanks for the help though.

Matt Kirsch

My Feedback: (21)

If any wires were touching, the battery would not charge at all. The charger would either show an error, or blow up. The battery would've gotten very hot, and the covering would've burned off.

At this point, there is nothing you can do to fix the battery yourself.

If you buy a new TV, and it blows up when you turn it on for the first time, you don't go out and buy another TV. You take it back to where you bought it and ask for a refund or get a different one. This is what you should do with the ESC and battery. You most certainly got it from Hobby Lobby, so CALL THEM.

joe123

yup, ive already done that, i called a few days ago and left a msg, just waiting for em to call back. I was just thinking... could the wires on the motor be reversed?? I would think that if they were wired wrong right now, the motor would not work at all, or it would spin backwards or something weird like that. I'm also going to try and cycle the battery a few times, just charge it, and run the plane on like 1/4 throttle till it dies. Maybe the pack just needs to be completely emptied, then charged a few times. Thanks for your help.

777

My Feedback: (1)

Greg,
Your site & review on the other RC board have been very useful. Thank you for those. About the battery, it sounds like your talking about the one near the bottom of this http://www.hobbypeople.net/gallery/128432.asp the one that leads you to this http://www.hobbypeople.net/gallery/128538.asp ? Am I right?

Thanks again.

joe123

Hello, one more question. The previous esc that the eagle came with was an 8 amp turbo controller. The one I have now is just a 15 amp gws ics400, and says nothing about turbo. Does this make a difference. I tried emptying the battery completely, and giving it a new charge, and it has a little more power it sounds like, but still not enough to take off with. When you hold the plane up, it supposedly should hover at full throttle, or at least come close to it, mine just wants to fall. After I talk to hobby lobby, and see if i can get a credit on my old esc and current motor and battery, I want to try the pjs550r setup with kokam 2 cell lipoly. what is the power difference between the speed 300 on 7 cell nimh and a pjs550r on 2 cell lipoly? Should this solve my lack of power problem (even though i think there is just something wrong with the current setup i have, and i should be getting more power from it). Do you all have any suggestions about installing the pjs550r motor with 2 cell lipoly??? Are the wires all going to be the same throughout (ie red-red...black-black, because the original setup needed the esc-battery to go from red-black and black-red). Should it be mounted in the same spot and everything. Thanks.

99pshop

Hi

Am having problems with under power with my Potensky eagle as well. I am using the stock motor and ESC with a li-ion 2cell 7.2v 1400mah battery and it just barely climbs. What will be a better battery to use with the stock motor to get a decent performance possibly hover?

joe123

from what I hear, that is about as good as battery as you should use what that motor/esc. To get more power, u would need a brushless motor and new motor controller. But dont take my word on it, im new to flying electrics and stuff, check with someone more knowledgeable. I finally fixed my plane. After trying to takeoff again, the battery fell out and the plane's nose went down, and the propeller broke. Luckily, i had ordered a spare propeller and geardrive. I replaced the propeller, and the gear drive, as some of the gears looked bent a little (on my original one). I tried taking off that day on my driveway, just to see, and all of a sudden it tookoff in like 2 seconds!!!!. The motor and stuff doesnt sound louder or anything now, but the plane vibrates a lot less. It climbs good now. The driveway takeoff ended in a minor crash with a small tree. I wasnt expecting it to takeoff, and it did, straight towards a bunch of trees, so i brought her down in a small patch just before them.

99pshop

what motor/ESC and battery have you got installed in your plane? are you using stock setup? I assume you have the potensky eagle?

99pshop

what motor/ESC and battery have you got installed in your plane? are you using stock setup? I assume you have the potensky eagle?

Matt Kirsch

My Feedback: (21)

What brand and model of LiIon battery are you using?

I suspect that you're trying to use a salvaged LiIon battery out of a cell phone, not a modern LiPoly battery designed for electric flight. Lithium-based batteries have a hard limit as to how much current they can produce. For salvaged cell phone batteries, that limit is very low, usually two times their capacity in mAh or LESS. A 1400mAh salvaged cell phone battery can produce about 2.8 Amps. Try to draw more, and the cell simply knuckles under due to the pressure. The Speed 300-ish motor on the Potensky Eagle can draw up to 8 Amps.

The right 2-cell Lithium Polymer, LiPoly, battery pack will make the plane utterly ballistic. Such packs are the Kokam 1500 and Etec 1200, for example. You can also go with an 8-cell NiMH pack.

99pshop

I am using a purpose built 2 cell li-ion from Enjoy Model International supplied by [link=http://www.jperkinsdistribution.co.uk/detail.php?JPNO=5510617&activepage=1&Navmain=Batteries/Chargers&subcatname=Lithium%20ion]J Perkins[/link] maybe its not up to the job. I will check with them. I may just have to go for the li-pol, I avoided it cos of the bad press regarding fire and all as am not a very careful person by nature.