McKrackin
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Flippin' the bird!
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Post by McKrackin on Aug 23, 2009 9:50:44 GMT -6
Besides heat,what exactly causes the lipo to puff? My EXI 450 is puffing every lipo I hook it up to. The motor and ESC are both literally cool to the touch after a flight and the lipo is just warm.Barely higher than ambiant. The outside temp today is 65 degrees. One lipo was about 10 minutes of idle up.2800mAh 30C Another was 10 minutes of spooling up and stopping to adjust the gyro.2100mAh 25C Both all puffed up. I'm at a loss here  |
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Post by mightyxxwhitey on Aug 23, 2009 10:16:36 GMT -6
how much more bigger is it then when you got it. I think its the chemical used to make liops. Some kind of semi hard gel.
Mine have only slightly puffed. but can hardly notice unless you put a new one next to it.
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Post by elkmaster01 on Aug 23, 2009 10:20:51 GMT -6
Ernie,,I have puffed a couple packs in my jets,,,,each time it was due to over-draining them. When I check the voltage on the puffed packs,,they are down to about 3.4 volts per cell. I can fly my packs down to 3.6 v/cell with no problem reguardless of heat. I 'think' that the packs go into a chemical breakdown when they are discharging below the 3.7 v/cell. I have my timers set to where I hopefully land at 3.7. I check my voltages after every flight and adjust my timer accordingly. I write the times on each battery. I have one of these cheapo testers,,,works great!! cgi.ebay.com/1x-Li-Po-Battery-Voltage-Indicator-Checker-Tester-2S-6S_W0QQitemZ250485916571QQcmdZViewItemQQptZRadio_Control_Parts_Accessories?hash=item3a521fc39b&_trksid=p3286.c0.m14 |
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19000rpm
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Post by 19000rpm on Aug 23, 2009 10:38:12 GMT -6
Elk's correct on over draining being the primary cause of puffed lipos. Over draining has the same affect as over charging. The lipo will puff.
Discharging or charging at too high a rate will also puff a battery.
High ambient temps just add to the puffing equation.
Happy landings
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McKrackin
First 30 Member
First 30 Member
Flippin' the bird!
Posts: 3,720
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Post by McKrackin on Aug 23, 2009 11:01:38 GMT -6
Puffed a third one.Also wadded the EXI up in a ball.lol....
They were all at around 11.2 and 11..3 volts at the end of the flight.
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McKrackin
First 30 Member
First 30 Member
Flippin' the bird!
Posts: 3,720
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Post by McKrackin on Aug 23, 2009 11:11:04 GMT -6
The first puffed pack just finished its charge and I put back 1323mA in a 2800mAh pack.
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19000rpm
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Post by 19000rpm on Aug 23, 2009 12:47:42 GMT -6
That's certainly in the ball park on volts after a flight. mAh is right on too. Do you have a low cell?
Only other thing would be, for some reason, the motors pulling more amps than the battery is able to deliver in normal C or burst C. Have you changed anything with the motor or ESC?
You're supposed to have a ball with the EXI not make it into one. ;D
Happy landings
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Post by Solitaire on Aug 23, 2009 13:39:37 GMT -6
That would be my guess, too. Too much amperage for the LiPo to handle. The confusing factor is the LiPo temp. Just "warm" as you put it. Perhaps these LiPo's cool off rapidly after puffing. Never actually checked a puffed one to take notes.
What motor did you eventually use on that EXI? And what brand of LiPo's? Reliable C ratings on both?
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Post by elkmaster01 on Aug 23, 2009 14:15:15 GMT -6
WOW....Ernie,,if you are puffing 25 and 30C batteries and still have 11.2,,,,you have a BAD electrical problem on your heli. 11.2 is perfect for a landing voltage,,,thats 3.7/cell. Your heli must be pulling some serious amprage to puff a pack. 10 minutes on a 2800mAh pack is expected,,I would think even longer.
Maybe Kent will pop in,,,that guy drinks electrons for breakfast and craps spark-plugs!! ;D
Hope you figure it out!
Randy
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19000rpm
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Post by 19000rpm on Aug 23, 2009 14:25:06 GMT -6
Just for fun I flew the crapolla out of a 2200 mAh in my 450 and pushed it a little longer, til I was losing lift, and 2 of the cells droped to 3.43 and the remaining one was 3.65 for a total of 10.51. And, yes the battery had a slight puff. Proving over drawing was the culprit this time.
I still think something in ernie's is causing a over load.
Happy landings
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Post by elkmaster01 on Aug 23, 2009 14:31:09 GMT -6
Just for fun I flew the crapolla out of a 2200 mAh in my 450 and pushed it a little longer, til I was losing lift, and 2 of the cells droped to 3.43 and the remaining one was 3.65 for a total of 10.51. And, yes the battery had a slight puff. Proving over drawing was the culprit this time. I still think something in ernie's is causing a over load. Happy landings 19K,,,,did you time that flight? 2200mAh should get you 8 or 9 minutes,,,yes? |
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19000rpm
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Post by 19000rpm on Aug 23, 2009 14:40:39 GMT -6
I didn't time the flight elk, but I'm sure it was close to 10 mins. I normally get 8-9 and this flight was longer. If I fly for 8-9 I usually come in at 11.1-5.
Happy landings
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Post by elkmaster01 on Aug 23, 2009 14:56:25 GMT -6
I didn't time the flight elk, but I'm sure it was close to 10 mins. I normally get 8-9 and this flight was longer. If I fly for 8-9 I usually come in at 11.1-5. Happy landings That sounds right,,,,so,,for Ernie to puff a 2800 pack in 10 is outrageous! Ernie,,,,,,,,,,chicken bones dude!!! ;D |
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McKrackin
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Flippin' the bird!
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Post by McKrackin on Aug 23, 2009 15:11:20 GMT -6
I got it all back together and took the GY48 gyro off and put the Mystery on.
Still can't get the tail but the lipos aren't puffing.
Next charge I'll use the GP750.
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19000rpm
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Post by 19000rpm on Aug 23, 2009 15:21:21 GMT -6
Can't see why a gyro would puff a lipo.  The amount of s!!t I don't understand is amazing. ;D Happy landings |
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