The 5 day old xrb i posted about earlier is now having issues. I was out flying about 2 hours ago.....i flew for about 5 minutes then set it down so i could go to a different location. I walked to the new location without turning the unit off (about 100 feet away), set down the xrb and throttle up.....just before it left the ground it powered itself down. No controls work??? I have checked everything.
The Battery is fully charged
The Crystal is in properly
The radio batteries are BRAND NEW
The gyro is set to the correct radio brand (stock)
The throttle is all the way down (For start up safety)...I have even trimed the throttle all the way down.

I dont have a clue whats going on. When you power on....the gyro sets because the servos twitch and it lights up.....you get a red or green light depending on how you move the tail (just like if you were flying) Any suggestions or anyone think they might know whats going on?

maybe thats the time of flying you get from a charge. it could be a voltage cutoff. inless you replaced the battery... maybe go back to the old location

Check all the connections like where the esc plugs into the receiver, and any soldered wires.
Could also be the battery isn't making good contact with it's plug.

thanks.....I talked to the distributor who fixes them in new jersey. we couldn't figure it out over the phone, but they fix them under warranty if i send it in. Now i have to ship my 5 day old xrb all the way to nj to get fitted with an all new electronics. The guy said that they replace the whole box and just transfer everything else, then test it and ship it back. This sucks, but maybe its better for the long run.

I know what you mean. I hate sending stuff back. Hopefully it will fix it though.

Sounds like you got one that was destined to fail... better to have it happen now and get it sorted out on warranty than later.

It should fly 10 - 15 minutes on a pack - although a 5 minute stop is a good plan to let the motors cools down.

yeah, i usually get between 12-17 minute flight times. I usuall fly twice with one battery.....1st flight 5-7min.....2nd is the same, so that the motors dont wear out as fast. I dont sit there and time it, but i generally know about the midway point....you get a feel for it after a while. I am about to tear it apart and check all the solder joints myself in a few minutes. If its somthing obvious, i would rather fix it then send it to nj. I was messing with it earlier today and i got some slight response which may eliminate one possible cause and that is the crystal set. I think somthing just may have a cold soder joint.

i may have a break through on what is wrong but i need your help....I just put the battery back on charge and it charged for about 5 min. before the light turned green (means fully charged) I hooked it up to my xrb and everything worked.......for 15 seconds, then it powered down like it does when the battery gets low. Good news is that everything responds, but i think this concludes that my battery is bad (its a stock lipo). I took it back out, and put it back on charge and it took about 5 min to turn green again i then put it back in the xrb and it worked again....for about 15 seconds. It then powered down again. It seems as though the xrb requires a certain voltage to activate the start up safety...(which wont allow any movement until pressed). It seems like my batt is bad and will only supply that power for x amount of time. i do not have a meter to check is the only problem. any thoughts on this????? I am hoping that if i can pinpoint the problem then i can just send my battery to nj and they can send me a new one. alot less hasle then sending the whole unit.!!!! Thank you.

Or....on second thought maybe its the stock charger??? the last time the xrb powered down (about 15 sec. runtime) i put the batt on charge and it took like 5 min for the green light to appear, and this time its been on charge for about 10 - 15 min and the red light is still on.........

your probably right on the battery being toast. NiCads and NmH batteries are fickle in their own sence of the term. I'm just learning about Lithium Polymer batteries myself.. but I know that if you had not discharged the battery correctly after first using it.. Those types of batteries have a memory, and if you do not exersize them properly they will fail. Especially with the demands of electric flight..

I just took the battery pack apart and found that the white wire was shorted out. There is a red white and blue wire and two cells inside the pack. i have fixed the short and am going to test it in my garage now....i think this is it. Ill let you know in a min. Thanks for the help.

I think in the movies.. James Bond always cuts the blue wire.. and there's a happy ending.. *crosses fingers *

in conclusion....The short may or may not have been the problem. It was probably the cause of the battery pack going bad (if its bad), and is probably why the problem was intermitent in terms of powering up when it wanted to. My best guess is that the pack has gotton weak because of the short and will only hold so much energy now??? A few minutes ago i got a 3 minute flight before it powered down like it used to when the battery got low. (except before it was 15 or so min. flight times) Oh, ....and when it does power down , i put the battery on charge and it only charges about 20 minutes before the charger says its done (i then have a 3 min. runtime. Thats about the same ratio as a 15 min flight on a 1 hour 15 minute charge! Make sense??

Good going to find the problem. If you had a good charger I would suggest discharging the pack slowly down to 1 volt per cell (assuming a nicad or nimh and not lipo), then charging it slowly at trickle charge rate, or about .1 or .2 amps. Sometimes this will recondition and balance the cells and bring them back. Not always but sometimes. Could be the shorted cells are out of balance with the rest.

instead of relying on the chargers green light take a voltage reading after the charger indicates full charge. a 3s lipo should read approx. 12.6 volts with no load when fully charged. a 2s lipo about 8.4 volts. if you don't get a reading close to these voltages then the charger is probably defective.

Thanks, ...i am going to try that later today. The output of the charger is 8.4v and the 2c lipo is 7.4v pack. I will test both and see what i can come up with. Is there any way to test it under load??

If you have an AstroFlight Watt meter you can plug it in between the motor and esc and get a reading under load.

If its a li-po and you ran it until it went below its safe charge level..3 volts I think,,then its ruined but your esc should have cut the power off before it got that low....that may be the problem...Rog

put a volt meter on it, and the charger. as said it should be around 8.4 volts. the charger should be putting out maybe a bit above that. i would recommend at least a good charger for lipos, bc the one you have may be killing your battery.

i got the results......but need your help. This will be hard to explain, but bare with me....I broke into the battery and put a meter on the cells. This battery has two different cells. It has a white, blue and red wire. The white goes to both -. The red goes to one +. The blue goes to one +. Voltage from white to red is 4.2. Voltage from white to blue is 4.2. Voltage from red to blue is 8.4. I dont understand the three wire system???
What happens to the 4.2V when it enters the xrb? does each 4.2V wire supply a motor or does voltage combine to the 8.4 and go in??? This is confusing because i dont know if the battery pack is supposed to have 8.4 volts combined cells or 8.4V per cell....
another strange thing is that the pack is only supposed to be 7.4V

The only way i could check the charge is to put the meter directly on the cells terminal as the pack was charging and it was reading 4.2V , so i am assuming that was the charge reading???. The chargers output is supposed to be 8.4 V. So, 4.2 V per cell is 8.4??? is this right? I dont know if this is making sense to any of you, but try please try to shed some light on this for me. Everything leads me to believe that this is a bad battery, but i dont know how if theese readings are correct.

........also, I was unable to test this battery underload, and i guess that could be a whole different ballgame.

The extra wire is so you can check the voltage of each cell individually, or of the whole pack. 4.2 volts is a fully charged cell. 8.4 is a full charge for 2 cells. 3 volts is a discharged cell, 6 is a discharged 2 cell pack. 3.7 is the nominal voltage for one cell, 7.4 for 2 cells. So, the operating range of a cell is between 3 and 4.2 volts. You don't want to see a cell lower than 3 volts or greater than 4.2.
Don't know if I'm explaining this good, but again, 8.4 is a full charge for 2 cells while on the charger. Off the charger the voltage will be less, but a reading of around 8 volts is a chared pack.
Like you said, the voltage under load can tell a different story. A cell or pack can show full charge voltage but not be able to perform under load, the voltage may drop too low under load if the load is too great for the cell's amp rating or if the cell is just too weak to provide for the demands of the load.
So, we are only half way there because we don't know how the cells perform under load.

Thank you for the help.. yes i understand what you are saying. Yeah, The Voltage now is 8.4 (4.2 per cell) and the green light indicated fully charged. Now i hook it up to the xrb and get a 2 min. flight. While the battery is under load the Esc has to be tripping the shutdown safety. This is the only thing that makes sense. The voltage has to be dropping under load. I will call the New Jersey shop which repairs the xrb and talk to him about just replacing my battery. Is this what you would conclude? At this point, i just dont think the problem is inside the heli. Thank you again for the help.

what is the batt. voltage when checked right after cutout??

Probably right. although it could also be a bad motor. As they go bad they can draw way more amps than normal.
Like hueyman said, check the voltage after cutoff. This will tell us more.