Killed a Cell

[Shannon Davis]

Well that set of batteries in the video w/ HC and Marcus then me flying-- 12 min in total were a little over-discharged, it took 7700 mah to bring the 7600 pack to full :shock: . Anyway, 5 flights later one cell in the pack swelled. I have sent the packs to Thunder Power and am awaiting their reply. I talked to them on the phone and it sounds like they maybe able to repair/replace the pack for not too much out of pocket. I will keep you posted.

If your packs are good for 12 min-- fly them 10 and stop. :D

"If your going to be stupid- You gotta be tough"--or well funded :D

ION-X Videos (http://www.helifreak.com/viewtopic.php?t=883)

[misskimo]

hey , :shock: sorry to here about that Shannon ,


Tony

[misskimo]

did it swell after a flight ?

[EricLarson]

Ya, you never want to get a cell under 3 volts unloaded or 2.5 volts under load. Right now I am able to fly the new packs for 9 min hard and temps are remaining around 180F on the motor and 130F on the batteries. We had a 2nd one flying at the field today and saw the same basic #'s as I am.

Eric

[Shannon Davis]

Swelled in the last 2 min of flight.-- I think I hurt these cells on the first flight-- live and learn.

[Russ McC]

OK, I have a question regarding battery performance, not the same issue as your speaking about but batteries none the less. Is this just in my head or is it real? It seems that if I charge the batteries the day before I fly the performance is soft, then after flying the first flight I charge and fly again and the power is awesome. I don’t think this is in my head. Has any one else noticed this? If I find this to continue being the case I will just charge the day I fly. I thought the Li Pos where not supposed to have this problem. Perhaps temp. related? I know they don’t perform as well when there cold but I am storing them at 72F to 74F in the house so I would think they would be ok. :)

[Shannon Davis]

The batts like to run around 110-120f. They are probably warmer on the second flight therefore better performance.

[Russ McC]

That sounds like the key. So have you noticed this to? We checked temps. For the first time today, we checked them on the first flight, the motor got to 151F and the batts only got to 105F, I bet if we check on the second flight they will be starting at a higher temp and maybe get into there sweet temp of 110F, I’ll check it out. :)

[EricLarson]

The batteries work better warm. In the winter I was preheating them in the car. I am seeing about 180F on the motor and 130F on the packs as normal for hard flying. I stop after 8 min or so as I find heat increases a lot after about 8 min of hard flying. I am sure this is due to the voltage drop in the packs and pulling more current. I am very confident I can not break it flying it as hard as I want for 8 min and from the temps I see, the packs should last a long time.

That does suck Shannon, but I am sure they will fix you up.

Eric

[misskimo]

hey , Eric , yep you got this electric down pat , do any of yall check the battery voltage after a flight to see if there is a difference in voltage? My batteries will be here tomorrow , and yes I have to warm my packs up to fly , still snowing up here in Alaska , damnit , I have the 601 servo combo going on , and the tempest head , now this heli is going south with me in 3 and 1/2 weeks , cant wait to test it in warmer weather , FL. here I come , Chris are you ready to see what its got ? if its not up to par , I have a 32-3 coming that I will carry with me , I might get a TJ for it while Im down there

Tony

[ChrisS]

Hello all

It has been said in the past that Lipo's perform best between 130 and 140 degrees. With these new gen 2's though, it's really hard to get them that warm unless you do it pre-flight with an external source. With the old gen 1's, in 50 degree weather, I would fly them for 5 minutes and then they'd start to come to life. In fact, for demo's, I'd do this and then hand the Tx off, people always looked at me like I had used the best part of the pack, but then they'd really like the performance. Eric, I like your approach, very safe, and you get peak performance and nothing but...

Chris

[Russ McC]

Thanks Chris,

If I find this to be an inconvenience I might try wrapping the batts in a heating pad before the first flight, I pride myself on doing my flights (freestyle/3d) with the greatest respect for the equipment, no over loading regardless of how much or how little power is available, flying like this the first run is peaty soft and the batts are only 100 to 105 at the end of ten minuets. I have two sets of batts so this means two soft flights in the beginning then it shreds the rest of the day. Last weekend I was down to Brooks Oregon to fly with a bunch of friends, after the first couple of flights they weren’t to impressed with the power I seemed to have but after the next flight having a freshly charged and recently ran set of batteries the guys suddenly had more interest and could see the power was there as advertised. They thought I was just pushing it harder but I was just using what was available to me at the time and really still did not understand why the performance seemed to vary so much. I am going to the first FF of the North West FF season this coming weekend and I want the first impression of the pilots watching to be wow! So I think I will try the heating pad this week and see if I can get that first run to shred like the second run. I will let you know how it works :)

[misskimo]

hey , man yall are haveing just to much fun in the heat , looks like I need a small blanket on my set since its still about 20 to 30 degrees here where Im at . my temps while testing the conversion out , the batteries never got about 105 in the gym , huh? theres some battery powered heated socks in the stores up here that run off of 1 D battery , huh? maybe Ill hook them up to a small lipo cell and see what happens :lol:

Tony

[z11355]

try those little handwarmer chempacks.

[misskimo]

thought about that , but I would have to put about 6 on there and still put a sock on it to keep them in place, with the heated sock all you would need is to recharge the lipo cell , I will have to check it out , huh? with electrics you have to worry about heat all the TIME , these lipo cells is not the only ones that have this side affect , the nimd 2600 act the same way, right off the charger these cells rock in my old joker I had ,right off the charger my packs would be hotter than after a flight . but if you ran them while they were cool , you would see about 20% less power ,

[misskimo]

hey , Shannon , Im back in bussiness , shes fly again , those new 6000s are better than the gen 1 6000 I had , and the things I changed so far , is the gyro , 601 with 9251 , and V blade 690 , and deans connectors , with a 3 way Y to hook all 3 packs up to it . man what a pop. its twice as loud as with my old joker useing 10s4ps . I looks like I will be changing out a plug every 30 flights or so . that 601 rocks , tested it in the gym and she still vibs the hell out of the floor, way cool.

Tony

[misskimo]

well , I was in bussiness , a nasty crash, :shock: pretty bad too. I was about 2 feet off the ground hovering and just getting ready to set it down for the end of the flight , 10 minutes. Lost one tail blade root or the grip . where the nut is broke on the tail spindle. heli started spinning and from my old airplane days when something happens , (CHOPTHOTTLE) , but the stick is just for collective. :arggg: She wodded herself up after impack. :bomb: carbon boom broke off at the mount , V blades gone , bent main shaft , spindle , flybar, tail braces shattered, stripped 2 servos , stripped main gear, bent aluminum landinggear brace, didnt hurt the tailblades sab 105 carbon, the one that flew off hit the ground straight down and thats where they stayed Nut was still in there with the threadded broke shaft. slung off all the batteries RX batteries too into the canopy , the batteries all check the same on the volt meter, but the packs are wrinkled and kinda bent out of shape ,but none are smashed in. Ill take the swrink off and slap on some new ones if thats alright with Charlie and Jason.
First time I put on that new painted canopy that MA painted. it has a few tares and rips in it , but can be fixed for a spare. Carbon frames , TUFF as nails, motor and esc fine , RX dont know , 601 , looks good , 9251 seams good , but broke the wheel off . Thats about it I think . kinda costly , but I will repare it when I head south. looks like the root cause is maybe a weak link on the tail spindle, too small for the 100% gov mode I was running , 10 minutes the headspeed never changed. sure runs sweet there, less heat build up too,
I recon I need to bump down the throttle to 85% from now own. :roll: or find out what tail spindle I have , this is the conversion fury , and I bought it used, so I will get the new tail spindle for it .

Back to the drawing board , :arggg:

Tony

[EricLarson]

If that was the original tail spindle and if it was EVER overtightened it will probably fail. The Hubs are made out of some very hard material and do not like to be over tightened. The new Hub is made quite a bit more beefy and it also is made so as if you overtighten it, you will destroy your bearings first. Get the new hub, and assemble per the directions and I am sure you will not have any more problems. Sorry to hear about the incident.

Eric

[misskimo]

Thanks Eric , it was the older version , I will get the new one next ,


Tony

[jwooten]

Tony,

Sorry to hear about the crash. I hope you can get it back in the air soon.

Jimmy

[Shannon Davis]

Tony, sorry about the crash-- fix it and fly it again.

I heard from Jason at Thunder Power today. One of the packs in the set where I had the problem is OK. It took 6950mah to bring it up to a full charge, Jason says that is fine, could have flown a littl bit more. He believes that the first flight on these packs- where it took 7700 mah to recharge-is what hurt the cell in the bad pack.

The pack was repairable for very resonable cost and will be back to me on Thur. I am not going to comment on the cost because every situation is different, and Jason says I was very lucky. But they have been great to work with and the repair cost was much less than I expected. :D A lot cheaper than what I did to that Tempest last week. :arggg:

[misskimo]

hey , great , sorry about the tempest , got all the parts coming , and the upgreaded tail hub 4mm instead of the weak 3mm ,


Tony

[Shannon Davis]

tONY, WHAT DO YOU THINK OF YOUR zOOM 400- i HAD A hORNET cp AND FOR ME IT WAS A TOTAL pos- TOO MUCH TINKERING, HOW IS THE ZOOM??

dAMN CAPS LOCK :evil: