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  1. #1
    Moderator CGRetired's Avatar
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    LiPo battery low voltage

    I was checking my LiPo packs last night and one of them would not charge, or the charger "refused" to charge it giving an indication of "voltage to low to charge". I assume that the pack is bad?

    I there a way to recover it?

    If not, how do I dispose of it?

    CGr
    Skylark 70 - OS .75 AX; Excelleron 90 - OS 1.20 AX; Venus II - OS 1.20 AX; And, I still fly my trainer, Hanger 9 Alpha - OS .46 FX! Some electrics. Airtronics RD8000 - Spektrum DX7 - DX6i. AMA 705964.
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  2. #2
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    RE: LiPo battery low voltage

    I have recovered several lipos over the years with success. Did you measure each cells voltage ? Do you have a charger that charges different types of batteries ?
    Here is what I did the first time I ran down a lipo. It was several years ago after I put a lipo in my transmitter. I left it on and when I took it out to use it the battery was dead. At the time I only had a cellpro charger and it wouldn't start the charge or even try and restore it. I checked the cell voltage and all were below 2 volts. Everyone told me the lipo was shot and there was nothing you could do about it. I thought about that and decided to try something as I knew the voltage increases when they get warm and decreases when cold. I put the lipo on top of the pavilion roof and left it there all day. At the end of the day the sun heated-up the lipo and raised the cell voltage enough so the cellpro charger would recognize it and restored it . It came back and has been working fine for years but it does not hold a charge as long as it did before the over discharge.
    A few other lipos I have brought back by using a multi-charger set to PB (lead acid) mode and connecting directly to the output leads of the lipo with no balance lead connected. I set the charger to the lowest voltage which I think is 3v and 1amp and start to charge it while monitoring it. After a minute or so I take it off and chack the cell voltage . Once it has raised it enough I put it on regular lipo balance charge and finish charging it.
    All these packs have come back and gave decent performance however not as good as when they were new.
    As long as the pack is not puffed or physically damaged I would say to give it a try.
    If you want to dispose of it cut off any connectors you want to save and toss the lipo in a bucket of salt water for a few hours then throw it away.
    Brian Ray

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    RE: LiPo battery low voltage

    Have you tried at higher charge rate?

    You can check the charge range at http://www.rcbazaar.com/products/133...ischarger.aspx

  4. #4
    Moderator CGRetired's Avatar
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    RE: LiPo battery low voltage

    The charger I am using is an Electrifly Triton 2 EQ.
    Skylark 70 - OS .75 AX; Excelleron 90 - OS 1.20 AX; Venus II - OS 1.20 AX; And, I still fly my trainer, Hanger 9 Alpha - OS .46 FX! Some electrics. Airtronics RD8000 - Spektrum DX7 - DX6i. AMA 705964.
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    RE: LiPo battery low voltage

    You can charge for a few minutes on NiMh to get the voltage up then switch it over to LIPO charge...monitor it closely
    If you decide to trash it soak it in salt water for a few days then pitch it

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    RE: LiPo battery low voltage

    These threads always bother me (mostly because of the answers , not the questions) and I have in the past always stayed silent , so my lawyer is just going to have to have the heebie-jeebies while I post.

    Let's first establish that the charger is protecting us from potential harm/fire/ect. It is doing it's job.
    Let's also establish that we aren't "recovering" , "reviving" a "dead" or "worthless" lipo cell or pack.
    Let's also establish that there's a good reason that one or more cell went below the normal range , it is our first job to figure out WHY.

    The very first thing to check is each cell's voltage and if they are fairly equal and close to the lower end of the voltage range then we can probably just charge the pack as a normal series pack.
    and airplanes were in

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    RE: LiPo battery low voltage

    ORIGINAL: CGRetired

    The charger I am using is an Electrifly Triton 2 EQ.

    Triton2 EQ is an excellent charger to do this job.
    Plug into balance tap (with or without main lead) and push both buttons simultaneously to read all cell's voltages. You can do this without charging.
    and airplanes were in

  8. #8
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    RE: LiPo battery low voltage


    ORIGINAL: jetmech05

    You can charge for a few minutes on NiMh to get the voltage up then switch it over to LIPO charge...monitor it closely
    If you decide to trash it soak it in salt water for a few days then pitch it
    This is exactly what I have done and it works well. I just watch the voltage as it is charging and when it gets to 3+ volts per cell, I then charge it on the lipo setting.
    DX-7,RDS8000. big Bingo,1/4 Scale Cub, SeaMaster 120, Forget the health food, I need all the preservatives I can get

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    RE: LiPo battery low voltage

    I've heard damaged packs have a higher resistance. Lowers your max discharge and heat dissipated is based on i^2*r. I haven't personally messed around with over discharged packs but be careful! I'd keep an eye on temps and puff when you discharge it. If the cells are imbalanced that could be worrisome.

  10. #10

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    RE: LiPo battery low voltage


    ORIGINAL: guver

    These threads always bother me (mostly because of the answers , not the questions) and I have in the past always stayed silent , so my lawyer is just going to have to have the heebie-jeebies while I post.

    Let's first establish that the charger is protecting us from potential harm/fire/ect. It is doing it's job.
    Let's also establish that we aren't ''recovering'' , ''reviving'' a ''dead'' or ''worthless'' lipo cell or pack.
    Let's also establish that there's a good reason that one or more cell went below the normal range , it is our first job to figure out WHY.

    The very first thing to check is each cell's voltage and if they are fairly equal and close to the lower end of the voltage range then we can probably just charge the pack as a normal series pack.
    I agree totally with the quote!!!

    Why would anyone take a chance with a BAD battery pack and if you left it on or over discharged it -it is a bad pack. Why CRASH when a new battery is your ONLY safe option. If you try to manipulate your charger to "revive" your battery I will be looking for your post on the crash and rebuild forum. [:-]

  11. #11

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    RE: LiPo battery low voltage

    I'm not saying to never charge or use it , but rather not to do it "blindly" One MUST know what is going on with each cell before proceeding. I'd also not say to throw it away , but rather don't throw it away "blindly" again one MUST know about each cell.

    Over the years there seemed to be 2 camps.

    One has always said to blindly charge it in series , the other has always said to toss it blindly. I guess I am in both/neither which is to say I'd like to check it out first before deciding what to do with it.
    and airplanes were in

  12. #12
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    RE: LiPo battery low voltage

    I had a dead lipo. Decided to try charging as a nicad for a few minutes. I have heard of this being done before. I know it has worked before.

    I also know that my pack got hot within seconds. I disconnected it and threw it outside. The next day it had swollen BIG and busted the hard case. I have never seen one swell like this. It couldn't have been far from exploding.


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    RE: LiPo battery low voltage

    Just putting this out there as it has worked for me when my big dollar charger says no go, I have one of the cheapy 2.3 and 4s plug and forget charges thru the balance lead chargers , when my big dollar smart charger says no go I'll put it on the cheapy for 5 minutes or so and then hook it up to the big charger and I'm off and running
    \"Q\" If you could have one super power what would it be?
    \"A\" The ability to leap tall blondes without them screaming

  14. #14
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    RE: LiPo battery low voltage

    I am for erring on the side of caution. A damaged pack is certainly not anything to mess with. If I were going to try to revive it, it would be in a place that couldn't catch on fire, like on a concrete driveway.
    Takeoffs are optional, landings are mandatory
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  15. #15
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    RE: LiPo battery low voltage

    I don't think anyone has said to try and restore a pack that was damaged. Oh course that's a bad idea. It's been said if the pack is physically damaged then throw it away. Same if it's internally shorted.
    The method has worked for me ....safely and I'll continue to do it if I stupidly leave my transmitter on again or get a plane stuck for several hours.
    If the OP or anyone else doesn't feel comfortable doing this then by all means don't try it and just disable and toss the battery.
    Brian Ray

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    RE: LiPo battery low voltage

    Same question different chem and cell structure. What about bring back a 2S Li-Ion?
    Listen!!! Do you smell something?

  17. #17
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    RE: LiPo battery low voltage


    ORIGINAL: guver

    ORIGINAL: CGRetired

    The charger I am using is an Electrifly Triton 2 EQ.

    Triton2 EQ is an excellent charger to do this job.
    Plug into balance tap (with or without main lead) and push both buttons simultaneously to read all cell's voltages. You can do this without charging.
    Thanks for this post and the previous one.

    The battery was never damaged. In fact, I only used it once or twice. I believe it discharged from sitting around for a while. I have both a fear and respect for LiPo packs and would much prefer to throw it away than take any chances with trying to recover it, given the controversy presented here. I respect everyone's replies and thank you all for them, but as I said, I am just going to throw it away (following the proper precautions of course). For the sake of a few dollars, it just isn't worth taking the chance.

    I was looking over the other batteries in my collection and have one that looks puffy. It's going to the same demise.

    Thanks again.

    CGr.
    Skylark 70 - OS .75 AX; Excelleron 90 - OS 1.20 AX; Venus II - OS 1.20 AX; And, I still fly my trainer, Hanger 9 Alpha - OS .46 FX! Some electrics. Airtronics RD8000 - Spektrum DX7 - DX6i. AMA 705964.
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    RE: LiPo battery low voltage

    Now that is a new one... is the salt water supposed to eat the metal jacket that encloses the lipo cells? Soaking the cells in tap water will not destroy the battery and make it inert for disposal unless the jacket of each cell is pierced. You should try to discharge the cells before piercing the jacket. A fully charged battery can be a bit dangerous to pierce and can result in flame and a lot of smoke... never do this inside your home unless you enjoy smoke and a metallic taste in you mouth.

    I agree with using a tester to insure all cells are functioning before trying to recover the battery by applying a short duration NiCd/NiMH charge to the battery. Then resume with a balance charge designed for LiPos. With a suspect battery, I would monitor the charge 100% of the time and charge in a lipo bag or another fireproof enclosure. I would recommend cycling the battery a few times before flying it. Write down the charge and discharge mahr readings. If the discharge reading is significantly less than 70% of the battery capacity, I would ditch the battery. I would not fly the battery in an expensive plane until proven.

    ORIGINAL: jetmech05
    If you decide to trash it soak it in salt water for a few days then pitch it

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    RE: LiPo battery low voltage

    Once all cells are around 0 volts then it can be simply tossed into the trash. If they are all about equal still then the discharge can be done in series (as a pack) with a charger or light bulbs,ect. The leads can even be twisted together and it put in a baggie. Just tossing it into saltwater is a bad idea.
    and airplanes were in

  20. #20
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    RE: LiPo battery low voltage

    I also have the same charger and have recovered a couple of batteries from over discharge only, and I would just throw out any battery that was damaged. First I put everything out on the drivway, never in any building, NEVER! Then I charge through the output lead on the battery on the Nicad setting at 1 amp and set the timer for 10 min, I attach my cell tester to the balance tap to monitor the voltage and stay with it while it's charging. When the timer goes off I let it sit until the voltages stabilize, and then start it over again. Once they all reach min voltage again I go to the normal balance setup and finish charging. Whats been said before is correct, the battery will not hold it's charge as well as before but since I use it in a transmitter it's not in a high drain situation and I just have to remember that my low voltage alarm will not go off until it hits 8v which is too low for a 3 cell lipo. LiFe batteries can be brought back in a similar fashion but if your not comfortable then discharge them and throw them out. They cost too much for me to toss them though,just because I made a mistake once and let them get too low. Very good battery info here www.hangtimes.com
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    RE: LiPo battery low voltage


    ORIGINAL: CGRetired


    I was looking over the other batteries in my collection and have one that looks puffy. It's going to the same demise.
    FYI:

    There was a MA article ( if I recall correctly ) not too long ago, where the author tried to get info about the gasses produced that cause the puffyness.

    He resorted to having the gases measured, and found that the bloating is caused by relatively inert nitrogen.

    Then he measured the effect on the batteries, battery life and output.

    Because he could not get a good explanation from the battery vendors, as they were much too vague, he concluded that if you have a slightly puffed pack, you shouldn't worry about it... but erring on the side of caution, he advised doing otherwise for more severely puffed packs.


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