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Old Jul 02, 2010, 12:46 AM
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cannondale1974's Avatar
Lexington, KY
Joined Oct 2009
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Killed my 5S Rhino pack on the first flight. My fault?

Well, bought the pack used but it only had 5 cycles on it. Motor and ESC are
Turnigy 5055-600 and Castle PH 60 ESC. Charged up the pack and it never would fully charge, must have stayed on the charger for 70 minutes plus. Flew the plane for about 6 minutes, all was well then it just quit. Motor would run at 75% throttle but full wouldn't run at full throttle. One cell is at 2 volts, all the others are at 3.7

Was this something I could have prevented or just a dud battery? I checked the ESC and it was at 140 degrees, battery was warm. Battery in question is a Rhino 4900 mah, 20C, 5S

Thanks guys for your input.
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Old Jul 02, 2010, 02:11 AM
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Xpress..'s Avatar
United States, CA, Alpine
Joined Oct 2007
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You could have gotten a previously cooked pack, which is why they were selling it...
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Old Jul 02, 2010, 04:13 AM
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Threshold's Avatar
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Did you balance charge it? do you know what the cells were after you charged it? Sounds like the one cell was down before you charged it, a lipo with a dud cell will take a very long time to charge, sounds to me Xpress is right
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Old Jul 02, 2010, 10:09 AM
Lou
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What charger did you use?

Did you take voltage readings of each cell before and after the charge?

Did you take voltage readings of each cell before and after the flight?

Did you balance charge?

Is your ESC set for the correct number of cells?

With that one cell at 2 volts, I would think that battery is cooked or not properly charged.

Some links that may be helpful:

http://www.batteryuniversity.com/

http://www.ampaviators.com/2007/04/2...tery-chargers/

http://www.rchobbies.org/lithium_bat...eakthrough.htm
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Old Jul 02, 2010, 11:00 AM
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cryhavoc38's Avatar
United States, WA, Woodinville
Joined Mar 2007
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Quote:
Originally Posted by cannondale1974 View Post
Well, bought the pack used but it only had 5 cycles on it. Motor and ESC are
Turnigy 5055-600 and Castle PH 60 ESC. Charged up the pack and it never would fully charge, must have stayed on the charger for 70 minutes plus. Flew the plane for about 6 minutes, all was well then it just quit. Motor would run at 75% throttle but full wouldn't run at full throttle. One cell is at 2 volts, all the others are at 3.7

Was this something I could have prevented or just a dud battery? I checked the ESC and it was at 140 degrees, battery was warm. Battery in question is a Rhino 4900 mah, 20C, 5S

Thanks guys for your input.
when you bought that plane along with the 2 packs, the previous owner may not have known that one pack was weak/had a bad cell.

Sounds like continued use cooked the pack if one cell is at 2v

You should change the settings in your castle esc to have a 3.7v low voltage cutoff (or is it that the max is 3.5v per cell for castles...)

Anyways, with your other remaining 4900 pack, time your flight to last about 5 minutes, and then check your battery to see what the cell voltages are at. It may be that your plane is amp hungry and stretching your flights out is too hard on the packs, given the motor/prop/flying style combo.

regarding the questionable pack, as long as its not puffed, you can put it on your charger and let it run to completion. That one cell may take a long time to get up to 4.2v, even when the others are sitting at 4.2, the charger should trickle that one cell until it gets there.

I had one new Hyperion pack that one cell was about .5v below the others when it was new. I let the charger do its work until all 4 cells were at the same voltage and the charger signaled "charge complete". It took about 95 minutes to complete, but that one cell is now in line with the other cell voltages and has not wandered astray since.
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Old Jul 02, 2010, 12:14 PM
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Lexington, KY
Joined Oct 2009
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Wow, thanks everyone for the replys! To answer some questions:

I used my Hyperion charger, been using it for 2 years and it's been rock solid. I did balance charge on 5S, 4900 mah but I never checked the individual voltage of the cells while charging. I bought the plane, motor, esc and batteries ready to fly so I have no idea where the low voltage cutoff on the castle is set at.
(someone have a link how to do this?

Previous owner seemed like a real stand up guy, I'm sure he didn't know if it had a bad cell. Oh also, a friend of mine who's really good with electronics said he could cut that one cell out and make it a 4 cell pack. Plane has plenty of power with the 5 cell, 4 should still fly it fine. What do you think?
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Old Jul 02, 2010, 12:20 PM
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Lexington, KY
Joined Oct 2009
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Quote:
Originally Posted by cryhavoc38 View Post
when you bought that plane along with the 2 packs, the previous owner may not have known that one pack was weak/had a bad cell.

Sounds like continued use cooked the pack if one cell is at 2v

You should change the settings in your castle esc to have a 3.7v low voltage cutoff (or is it that the max is 3.5v per cell for castles...)

Anyways, with your other remaining 4900 pack, time your flight to last about 5 minutes, and then check your battery to see what the cell voltages are at. It may be that your plane is amp hungry and stretching your flights out is too hard on the packs, given the motor/prop/flying style combo.

regarding the questionable pack, as long as its not puffed, you can put it on your charger and let it run to completion. That one cell may take a long time to get up to 4.2v, even when the others are sitting at 4.2, the charger should trickle that one cell until it gets there.

I had one new Hyperion pack that one cell was about .5v below the others when it was new. I let the charger do its work until all 4 cells were at the same voltage and the charger signaled "charge complete". It took about 95 minutes to complete, but that one cell is now in line with the other cell voltages and has not wandered astray since.

Great info, thanks! I tried to balance charge it after the flight but my charger won't let me, says "voltage too low". If I don't balance charge it the other cells will overcharge right? Pack doesn't seem puffed btw. Plane came with a 14-8 prop, I bought a couple spare props, 13-8 and 13-6. Would this be less "amp hungry"? Plane has plenty of power as is. Sorry for all the newb electric questions!
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Old Jul 02, 2010, 12:35 PM
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freechip's Avatar
Canada, ON, Rockland
Joined Aug 2008
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If your charger can lipo charge without balancing you may be able to get it charging up until the cell reaches 3.0 and then switch to balance charge.

You can also try to charge only that one cell until it reaches a level close to the others.

70min charge is that all crazy when the average is 60min. It may jsut of been taking longer cause it was trying to bring back the cell.

So to answer if its something you could of prevented, sure it is but its done now.

The question you need to be asking is do you still want to fly your plane with a possibly less then ok pack.
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Old Jul 02, 2010, 12:37 PM
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Canada, ON, Rockland
Joined Aug 2008
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Quote:
Originally Posted by cannondale1974 View Post
Plane came with a 14-8 prop, I bought a couple spare props, 13-8 and 13-6. Would this be less "amp hungry"? Plane has plenty of power as is. Sorry for all the newb electric questions!
If you stick with the same voltage then yes they would be less amp draw.

if you have a 14-8 then a 13x10 would be almost equivalent and so anything with less pitch will draw less amps.

IF you have a watt meter you would be able to tell exactly whats going on and you could make the perfect prop selection for your power system.

Depending on the plane and the type of flying you want to do a certain amount of watts per pound are required, you want to follow these recommendation for succefull flights.
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Old Jul 02, 2010, 12:47 PM
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Lexington, KY
Joined Oct 2009
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Quote:
Originally Posted by freechip View Post
If your charger can lipo charge without balancing you may be able to get it charging up until the cell reaches 3.0 and then switch to balance charge.

You can also try to charge only that one cell until it reaches a level close to the others.

70min charge is that all crazy when the average is 60min. It may jsut of been taking longer cause it was trying to bring back the cell.

So to answer if its something you could of prevented, sure it is but its done now.

The question you need to be asking is do you still want to fly your plane with a possibly less then ok pack.

I can unplug the balance lead and it'll charge the pack but I was afraid of overcharging the other cells. Maybe I could monitor the pack and make sure the other cells don't exceed 4.2 volts.

I bought a Sr. Telemaster with this motor/esc/batteries. Going to be taking aerial video over the ocean and beach so I transferred everything into an old beat up Sr. Falcon (didn't want to risk the Telemaster) Plane is a high wing trainer and weighs 7 1/2 lbs. Has virtually unlimited vertical with this sytem. (69 inch wingspan)
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Old Jul 02, 2010, 02:08 PM
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MikeRx's Avatar
Dallas, Texas
Joined Dec 2009
2,216 Posts
I switch to nicad mode to bybass the low voltage holdup.. when the affected cell is SLOWLY charged past minimum, I then switch back to lipo mode. Sometimes works.
Good luck!
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