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mr crispy

My first Lipo problem - looking for advice

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Bit miffed today. Had a new soft pack 5000mah 2s lipo in my Wraith over last few days. It's the first time I've properly used this lipo, and the Wraith had an ESC with lipo low voltage detection. I've only been running it around my garden in the snow so no big jumps or rollovers and it can't get that fast due to skidding about. Lipo had charged and preformed great but cut out last night so I assumed that was the low voltage working.

Went to charge the pack this morning and the 1st cell indicator just kept flashing fast. Checked the manual and this seems to indicate a fault. The 2nd cell was charging fine. I disconnected it and inspected the pack, it seems to feel a little more "spongy" than I remember and ever so slightly inflated. Tried reconnecting but after a bit of multiple LEDs flashing on the charger it now only shows the 2nd cell charging. I'm I right in thinking I should dump this ASAP before it burns my house down?

I'm annoyed as this is only the first real use of the battery and run until cut out. I'm sure the cut off is set correctly on the ESC as I followed its instructions to the letter when I got the lipo. Is it a good idea to run with a low voltage alarm as well? Is it more likely that the soft pack has been damaged and I should only run with hard packs from now on? I did buy this one cheap from HK (about £17).

Can anyone suggest a good source of similar spec hard case lipos in the UK?

Any help or advice from those with lipo experience would be appreciated.

Nic

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Hobby king have a large range of hardcase lipo's and a uk warehouse, just click on car hardcase batterys from the menu.

http://www.hobbyking.com/hobbyking/store/__411__85__Batteries_Accessories-Car_Hardcase_Packs.html

I have read that you can restore a low lipo cell with a ni-mh charger but I wouldn't reccomend it.

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I always use turnigy packs, ive got 7 lipo's at the moment and not had any issues, but i only used hard cased packs. what esc are you using, it may have discharged the pack too much.

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ESC is a Tekin FX-R. Thanks for the Hobby King link, they look good. Bought mine before I read about the advantages of hard cases. Just shows its not always worth saving a few £'s. Good timing as its my birthday on Wednesday so now I know what to treat myself to.

Can I dispose of this lipo in a normal battery recycling area? It's defo ballooned a bit more since this morning so I want it out of the house ASAP.

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Recovering over discharged lipos. This isn't my work and I don't recommend it.

http://www.rcgroups....d.php?t=1072324

And unless you can check the voltage of each cell, then you wont know what the problem is.Edit2add: I do own a cheapo soft cell pack which puffed up like a pillow after maybe 2cycles? but it still works fine. Since then I have bought a hardcase lipo from hobbyking, but I do still use a puffed softpack 3s and have had no trouble with it.

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hi, discharge it to around 2v per cell , this will take the power down to the point where it cant self ignite , some folks discharge further than this then leave them in salt water over night , the 2v point is IMO low enough and then drop it off at a suitable place , your local authority should have a list on their web site, my local tesco and co-op also accept used batteries , not sure what the low volt cut off is on your esc but its best to go for around 3.2v-3.4v per cell, the 3v that most battery manufacturers suggest is the minimum at 1A drain but when you are pulling 20A+ the actual voltage of the pack may dip far lower , always over spec the discharge C rating on future packs , if you have a 60A esc then think along the lines of 5000mah with a C rating of at least 50C continuous with 100C burst or more ,

from what i have had the turnigy , zippy and gens ace packs are the most reliable at the price , orion packs are very expensive but the pair i have are very old and still work fine after more than 500 cycles .

better luck with the new ones

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Just worth a note a hard case lipo won't stop the lipo from puffing due to being duff. It only offers a small degree of protection from the elements and mechanical damage peel the hardcase off and you have the same thing. In someways non hardcase are better because you can see this happening immediatly. Lipo is probably a duffer from the factory some just are do you have a warranty?

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I'd dispose of a puffed Lipo -- no need to take any risks. I always balance charge my Lipos, have the ESC cutoff set at 3.2V per cell, and stop driving as soon as the throttle response goes soft (even before the ESC cutoff).

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I have a couple of these - perfect for bashing as they are hard case - gave my silver can powered lunchbox a nice extra turn of speed :)

http://www.component...html/rd330.html

Link to price (16.95)

http://www.component..._car_packs.html

hi, this is just my experience of two vapex 5000 30c hard case li-po packs , they both puffed after about 10 cycles while being used at less than half there recommended continuous C rating , they were bought from vapex directly and they never replied to any of my very polite and undemanding emails that were only asking for advice rather than a warranty replacement , tried phoning but they never answer, take that as you wish .

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