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Post by bucknut on Dec 16, 2008 3:13:32 GMT 1
I've been using (2 cycles) a 3S1P 2100 mAh 20-30C Zippy LiPo. I have a 30 Amp brushless ESC with a BEC that kicks in at 3.0V. I'm also running the stock SC motor with a 10x6 prop.
On Saturday afternoon the plane became sluggish after 15 minutes and apparently I lost power and then landed atop a 60 ft tree. I recovered the plane today, Monday, after the plane spent two cold damp nights in the tree. All electronics are working well, but the battery doesn't even have enough juice to allow my Electrifly Equinox to balance or interface for a charge.
How can I charge this battery or is done? Thanks....
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Post by flydiver on Dec 16, 2008 4:46:59 GMT 1
Man, wish I had a lipo for every time I've read this story.
Yes, no, maybe.....depends on how discharged it got. What's the voltage read? Since it was already sluggish, then spent 2 days in a tree my guess is it's gone.
Yes-it's been over discharged, probably seriously. It'll never be the same again - for sure. It could even be dangerous. Not in it's current discharged state but if you charge it. The conservative pundits will lecture, "What's safety and not burning down the house worth to you?" Think about it.
No-CAUTIOUSLY charge it, low setting, on a NiXX charger until it reaches 3.0v/cell. DO NOT leave it! Charge in a SAFE AND FIREPROOF SPOT!
Once it's up to that level the lipo charger should recognize it and finish the charge on a LOW setting. Charge in a SAFE AND FIREPROOF SPOT! MONITOR!
-if it puffs, it's shot. Discharge with a 12v auto tail lamp in a safe spot until its DEAD!!! Discard. DO NOT DISCARD A CHARGED LIPO!!!
-if it seems to be OK, no puffing, you can cautiously use it. BUT, it's damaged goods, will likely have a short life, and could go bad at any time.
Maybe-weigh Yes and No above. Make a safe decision.
Personally if it's got 0-3 volts total showing it's not even worth the hassle. 3-6v, pretty dicey, likely dangerous. >6v it may be somewhat recoverable. I'll bet you are no where near that.
BTW, not fried.....drained. That's different.
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Post by bucknut on Dec 16, 2008 7:09:51 GMT 1
I agree, I think it just continued to discharge while being in the tree for two days. Just because the transmitter was off doesn't mean the servos weren't chattering the whole time since the battery was obvoiouslly still connected.
I have a Dynamite Pirahna NIXX charger from my past life of Traxxas trucks. So you are saying I could set a low charge and monitor it until it gets to 3.0v and then hook it up to my lipo charger and it may work? It's a 3S1P 2100 pack, what amperage should I program the Pirahna to charge it at?
I think this is worth a try and I can charge it in the bathtub just in case it decides to get a little warm. As for the lipo itself, there are no cells that are puffed....nothing that looks physically wrong with it. It is just drained and my balancer won't even turn on.
Anything else I'm missing? Thanks for the info, this is great.
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Post by flydiver on Dec 16, 2008 7:15:29 GMT 1
Like I said, low setting - doesn't need much, 0.1, 0.2....You want to do this geeennnntly and watch carefully. It'll pop up in voltage amazingly fast even though the mA are still lacking, unless it's so shot it won't take a charge.
Even when not working the RX and all servos are pulling energy. Left my battery attached after flying (dumb). Puffed, dead battery the next day. That kind of oversight is not good.
BTW-Don't fly until your battery gets mushy like that. Not good for the lipo, 3.0v/cell is inadequate for today's high drain lipos, and you are more likely to get in trouble landing or other trouble like you did. You SHOULD land and have 11.1v RESTING at the end of flight if you don't want to be buying lipos all the time. The major cause of short lipo life is not crap lipos but uninformed pilots.
That said there really are some junk lipos out there.
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Post by bucknut on Dec 16, 2008 14:09:23 GMT 1
Thanks for the insight. I'll have to go dig up the ol' charger and see what happens. Good Lord, I don't even know where it is....LOL!!!
I'm hoping that this charger will bring it up to the 3.0V and then the LiPo charger will take over at this point. I think I'll mark this battery pack with a Sharpie so I know this battery needs a little more attention when both charging and discharging. Maybe I'll luck out and since the battery is so new it will end up being ok. I'm being very optimistic here, but I've heard a lot about these Zippy batteries.
You made an interesting observation about your pack "puffing" after you left it in the plane. I'm wondering since mine did not do that it might have a better chance of recovering? And I will definitely pay more attention to the lack of performance of the battery while flying. This was the first time I actually had been up for more than 30 seconds so I was just caught up in the moment. And I DID have a second rested pack just waiting, but I must of been in bliss and just kept flying...Jeez!!!!
Thanks again.....
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Post by flydiver on Dec 16, 2008 17:11:39 GMT 1
3.0v means PER CELL.
My pack was OLD. Yours is new.
It was sluggish when it went into the tree, meaning d**n near dead already. It sat for 2 days. It's shot.
Good learning experience, but don't get your hopes up.
BE SAFE!! This is EXACTLY the kind of stuff that gets lipos a bad name.
You've been warned.
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Post by bucknut on Dec 16, 2008 18:43:17 GMT 1
Just to make sure we're on the same page here. I understand the LiPos need to be 3.0v per cell. This is a 3 series pack with 1 in parallel.
When I charge this with NIXX charger I'm simply charging the LiPo pack by connecting the deans connector on my pack to the NIXX charger and then monitor the digital detection on the Pirahna charger until it reads 3.0V? Charging at 0.1 - 0.2 amps?
Other than the obvious of the pack starting to puff or get warm, are there any other warning signs I need to look for while doing this?
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Post by flydiver on Dec 16, 2008 19:00:06 GMT 1
3 series > 3v/cell x 3 = 9v. Your Equinox probably needs to see 9v to kick in. Charging through the power port, just like a NiXX. Lowest setting you got. Not familiar with the Piranha so can't help there. If it shows voltage that is excellent. Take a look at this graph: www.rcgroups.com/forums/showpost.php?p=4904168&postcount=1You are working 'backwards' up the graph so the voltage (hopefully) will come up fast but there will not be any real amperage yet when you hit an acceptable level for the lipo charger to engage. |
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Post by bucknut on Dec 16, 2008 23:27:56 GMT 1
I will let you know how this works out. Thanks for all your help.
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Post by ginginho on Dec 17, 2008 10:49:14 GMT 1
I'd suggest finding a way of keeping it still in your bathtub. Some of the youtube videos show that a failing lipo can have a bit of a rocket effect. A metal box of sorts that you put it in would do nicely.
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Post by bucknut on Dec 17, 2008 14:48:23 GMT 1
ok, the fact that I may have a "rocket' effect inside my home is not very comforting. I don't have a metal box and I'm not going to spend more money on protection from a battery that may be dead than what the battery cost new. It's a flippin' Zippy.
I'm thinking of taking this out to driveway and using an extension cord. If this pack wants to take off like a rocket at least the neighbor kids will get a kick out of it. Kinda like when these guys deep fry FROZEN turkeys......LOL!!!
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Post by mrmugen on Dec 17, 2008 15:56:55 GMT 1
I have had 8 packs not come back in 4 years and about 12 that did. I used a different process but the same method. Getting the pack to 9v or higher is the ticket. Most chargers won;t recognize it until it reaches 9v. My earliest attempt was the best so far. I used a 9v battery (plain and simple 9v for your smoke detectors) and connected it to the pack and did this for 20 second increments until the voltage read 9v+ and then hooked it to the charger. I never got a rocket or fire but it is possible. BTW it is hard to get a pocket to go anywhere when it is tethered....the cord charging it. Try and do any of these processes outside for obvious reasons.
Kevin
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Post by flydiver on Dec 17, 2008 17:45:11 GMT 1
My earliest attempt was the best so far. I used a 9v battery (plain and simple 9v for your smoke detectors) and connected it to the pack and did this for 20 second increments until the voltage read 9v+ and then hooked it to the charger. Kevin I'd suggest that the success had little to do with the 9v battery and most to do with the quality and charge state of that battery. Most likely it was fairly new and not discharged as severely. |
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Post by mrmugen on Dec 17, 2008 18:33:49 GMT 1
It was a new pack that had a total votage of 2.3v. The cells were not puffed and never did. I still use that pack to this day. If it had been an old abused it may not have turned out this way. There are too many variables to say if a pack will make it or not. Just have to try it or just toss it and say to heck with it.
Kevin
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Post by bucknut on Dec 17, 2008 22:17:39 GMT 1
Kevin,
You are kidding me, I may be able to fix this pack with a flippin' 9v battery??? How did you connect these? I mean, did you use the charging/balancing port or the dean's connector? Also, I don't have any way of measuring the voltage but you just did it in 20 second increments. How many times did you do this to get it to 9v or more? I'm just thinking that this is basically a new pack and I might have some success like you did. I will try this tonight after I hear how you hooked them up.
Thanks....
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