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Twin electric setup the battery is getting hot and puffing

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Old 11-17-2012, 06:32 PM
  #1
HUNTERANDJEFF
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Default Twin electric setup the battery is getting hot and puffing

Twin electric setup the battery is getting hot and puffing



If anyone can help that would be great!
I have a twin setup on my OV-10 bronco.
I am using two ntm propdrive 35-48 1100kv
2 hobbyking ss series 90-100 amp escs (opto)
for rx power,
flite max voltage regulator with a venom 1200mah 7.4 volt lipo.
I have the escs hooked up to the motors with the stock leads (they are next to the motors in the nacelles

From the escs, I have the battery leads going into the middle fuse from both sides into a dean's connector. that way I can run either a single large mah battery or batteries in parallel (with of course a parallel adapter).

this system worked great on the first two flights. One using Two 3s 2600mah batteries in parallel and the other flight with two 4s 2200mah batteries in parallel.

On the third flight, I used a 4s 50000mah battery. It flew great for 5 minutes and I was doing the last turn to land, I lost power. The motors didn't stop but just lost power. I made it back to the runway but landed very hard doing a fair bit of damage to the underside of the plane including ripping out my retracts.

Upon inspection, the motors were not hot, the escs were not hot. But, the battery was very hot and puffed.
The battery still had 14.9 volts still in it. What the heck?
If someone might know what is wrong, that would be great if you would give me some advice.
Here is a video of the 2nd flight
http://www.youtube.com/watch?v=476k7Ag3iJw
Thanks in advance,
Jeff
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Old 11-17-2012, 07:07 PM
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Default RE: Twin electric setup the battery is getting hot and puffing

My best guess is that if your battery was fully charged then it is being over taxxed (over current). If so then an average of 10-12C on the 4sx5.0 pack is too much. A bench test would confirm if it isn't too bad damaged already.
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Old 11-17-2012, 08:05 PM
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Default RE: Twin electric setup the battery is getting hot and puffing

Oh the battery is a turnigy 4s 5000mah 30-40c. How could it get over current?
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Old 11-18-2012, 06:09 AM
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Default RE: Twin electric setup the battery is getting hot and puffing

Ignoring the label of course. IF it was fully charged then your 5 minute flight pulled nearly 100% of capacity. This is an average of 10C or so regardless of the actual capacity of the pack.

I enjoyed watching your other flight and it was maybe 8 minutes? I'm guessing the flight with the 5000 pack was a bit more aggressive? Nevertheless , if the pack was hot and puffy then it is being discharged too fast. Since it had around 3.7 per cell when landing that tells us that it's nearly depleted , but not getting too much capacity pulled out of it in the 5-6 minute flight.

LOTS of 40C packs won't do a 10C discharge because of mis-rating,age,damage,ect. I'm not sure of the "why" the pack can't sustain over 12C. If you send it to me I can overlay CBA graphs showing 1,3,5,10,12,15,20C discharges. Upon overlaying the graphs we can easily see the voltage sag and the temp increase at the 10-12C level. Perhaps you or a friend may have an i-charger or device that measures IR. IR is also an excellent predictor of performance and the real "C" rating can be estimated pretty accurately.
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Old 11-18-2012, 08:03 AM
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Default RE: Twin electric setup the battery is getting hot and puffing

That is some great info.
I have a great charger but I don't know if it will do the ir thing. I have the Multiplex x2 multi charger. If my charger has that, where can I find it?
The video was 8 minutes. I think the flight was only around 6. In that video, the battery doesn't puff up or get hot but in the next one I am going to upload tonight shows what happened to that flight. There was a very hard landing and I had to completely rebuild the retract mounts, front and rear cones, re-sheet the bottom of the a/c and re do the monocoat.
I am thinking go back to 3s? It flys it but not super great like the 4s does.
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Old 11-18-2012, 11:12 AM
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Default RE: Twin electric setup the battery is getting hot and puffing

I'll stay tuned for the 4s video. Maybe you can get away with using a 4s pack for power , but it's probably going to have to be a very good quality pack. TP , Haiyin , hi-country, spyder, FMA , or even the Nano-techs might do better than the turnigy.

Unfortunately your charger doesn't measure IR. The FMA and i-chargers do (maybe some hyp chargers do too)

Your pair of 4sx2.2 packs must've been ok , right?

Your plane has much more power than any of mine , but if I had to use one of my packs (and I buy cheapos only) I could use the turnigy hardpack 2sx5.2 (use a pair of them in series) They have very low IR and can be discharged very quickly without getting hot. http://www.hobbyking.com/hobbyking/s...ipo_Pack_.html
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Old 11-18-2012, 05:06 PM
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Default RE: Twin electric setup the battery is getting hot and puffing


Quote:
ORIGINAL: guver

I'll stay tuned for the 4s video. Maybe you can get away with using a 4s pack for power , but it's probably going to have to be a very good quality pack. TP , Haiyin , hi-country, spyder, FMA , or even the Nano-techs might do better than the turnigy.

Unfortunately your charger doesn't measure IR. The FMA and i-chargers do (maybe some hyp chargers do too)

Your pair of 4sx2.2 packs must've been ok , right?

Your plane has much more power than any of mine , but if I had to use one of my packs (and I buy cheapos only) I could use the turnigy hardpack 2sx5.2 (use a pair of them in series) They have very low IR and can be discharged very quickly without getting hot. http://www.hobbyking.com/hobbyking/s...ipo_Pack_.html
Thank you!
I looked back at the video and noticed that I didn't use the 4s 2200 x 2 packs. I used the 4s 5000 on the first 4s flight. I did change props today and it is a bit cooler but I need to fly it again to see for sure.
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Old 11-18-2012, 06:28 PM
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Default RE: Twin electric setup the battery is getting hot and puffing

If you can "keep your foot out of it" so to speak you may be ok. It's too bad that it got damaged, you fixed it already? Great fast repairs.
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Old 11-19-2012, 07:50 AM
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Default RE: Twin electric setup the battery is getting hot and puffing

My kid uses those hard case pack in his 1/8 monster truck. I think they are 45c discharge. I will have to try them. Yes, I will now keep my "foot" out of it lol.
What battery should I use If I want 6 minutes of flight with my "foot" in it?
I did have it repaired within the week. I worked on it after I got off my day job in the evenings. I really hate putting a damaged plane away for the winter.....
Here is the video of the 3rd flight - the one that I started having problems with the battery power. Seems like I will have to get a couple of 4s 3000mah and run them parallel if I want longer flight times with no puffing and over heat issues? I have to get this sorted out soon because my next project is a Canadair 415 electric!
http://www.youtube.com/watch?v=V1zTX...ature=g-crec-u
j
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Old 11-19-2012, 05:54 PM
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Default RE: Twin electric setup the battery is getting hot and puffing

If you want ONLY 6 minute flights then you'll need a good quality battery like TP , Haiyin , hi-country, spyder, FMA , or even the Nano-techs
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Old 11-23-2012, 04:43 PM
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Default RE: Twin electric setup the battery is getting hot and puffing

I'd suggest that you look at airflow across the battery. An initial flight with an Advance 25 trainer with a power 32 motor caused noticeable heating of the 60A speed control and the 4s 4000mah battery. adding an air scoop into the battery and speed control compartment, and an exhaust hole in the fuselage bottom cured the heating issue completely.
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