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Lipo Battery Charging & Safety Guide

February 7th, 2008 · 62 Comments ·

Lithium Polymer or LiPo batteries are a great new way of storing energy for portable devices from cell phones to RC helicopters.

They’re great because they can store 350% (approximately) more energy than a typical Nickel Cadmium (NiCd) battery pack and weigh 10% – 20% less. They can also discharge much more current than a NiCd battery and be fully charged in about an hour. LiPo batteries also don’t develop memory or voltage depression characteristics like NiCd batteries, and do not need to be discharged before being charged.

But they’re not without their downside. Mishandling of these batteries can lead to fire, explosions and toxic smoke inhalation. In the rest of this guide, we’ll discuss how to charge, store and handle lithium polymer batteries safely so you can enjoy them again and again.

Please note that the information contained in this guide is for informational purposes only. You should consult your batteries manual for specific instructions regarding the handling, charging and safe usage of your lithium polymer batteries.

Controlled LiPo Fire In A Fume Hood

Charging

Lithium Polymer or LiPo batteries have very specific charging requirements and MUST only be changed by specific chargers designed to charge lithium polymer batteries.

A 1s or 1 cell LiPo battery has a nominal voltage of 3.7v. When fully charged it has a maximum voltage of 4.2v and when fully discharged, it should never go below 3.0v without risking cell damage.

A 5s4p battery pack means that the pack contains 5 cells in a series circuit and 4 cells in a parallel circuit.

Since each cell is 3.7v (nominal) a 5s LiPo battery has a nominal voltage of 18.5v, a fully charged voltage of 21.0v and a maximum discharged voltage of 15.0v before damage occurs.

When charging LiPo batteries, they must be charged at the voltage of the number of cells in series, therefore a 5s4p pack must be charged as a 5 cell pack.

The LiPo charger you’re using must be able to handle the cell count of the battery you are charging.

Most of the more expensive LiPo chargers will automatically detect the cell count of the battery being charged while the cheaper ones will require a manual setting. Wile some of the really good ones will allow you to manually select the cell count and then will double check it automatically for you.

Please also note that some chargers (such as those used for toys or cell phones) are made to charge a specific cell count and are not configurable for other cell counts. It is very important that these chargers only be used to charge the batteries they are designed for.

Also, chargers that auto detect the cell count of a LiPo battery can sometimes be wrong. They use the current voltage of the battery to determine the cell count and if the battery is fully charged or at a lower voltage than it should be, it may read the cell count incorrectly. This is why it is very important to double check that it reads he right cell count which is typically displayed on the LCD display.

For example a 5 cell 18.5 volt LiPo battery that’s been depleted to less than 15 volts may be confused with a 4 cell, 14.8v battery and thus charged as such. Also, a fully charged 5 cell battery at 21.0v may be confused as a 6 cell 22.0v battery and charged as such.

Charging a lithium polymer battery at a higher voltage than it’s rated for, or overcharging it, can lead to a fire or an explosion (see video below).

Overcharged Lithium Polymer Battery Fire

LiPo Battery Charging Tips

  • Always use a charger made to charge LiPo packs.
  • Double check that the settings for the lithium polymer charger are correct for the pack being charged – this includes the cell count as well as the current settings.
  • In general, most lithium polymer batteries should be charged to no more than 4.2 volts per cell or depleted to less than 3.0 volts per cell. There are new generation batteries available that can handle higher / lower voltages, but they are still new and thus are the exception to the rule.
  • Ensure that charging leads are connected correctly. Reverse charging can lead to cell damage or a fire or explosion.
  • Always charge LiPo batteries on surfaces that won’t catch on fire such as cement, steel, ceramic or stone. Wooden tables and carpeted floors are not recommended charging surfaces.
  • Do not charge batteries near flammable products or liquids.
  • Never charge a LiPo battery while inside your model or other electronic device. If it catches fire it can lead to total destruction of the item it is being charged in.
  • LiPo batteries should be charged within a temperature range of 0C to 50C. Batteries charged outside this temperature range may experience leakage, heat generation or cell damage.
  • Never leave a charging lithium polymer battery pack unattended.
  • Do not charge inside an automobile, especially while driving.
  • Do not store batteries inside an automobile.
  • Do not charge a lithium polymer battery pack at a rate over 1C.
  • Never charge a LiPo pack that has ballooned or swelled due to over / under charging or from a crash.
  • Never charge a lithium polymer battery pack that has been punctured or damaged in a crash.
  • Never, under ANY circumstances let the positive and negative battery leads touch. It can lead to cell ballooning, cell damage or fire or an explosion.
  • Have a fire extinguisher near the charging area or a large bucket of dry sand. Do not try to distinguish with water.
  • If you notice your LiPo battery pack is swelling, stop the charging process immediately, put the battery in a safe container and observe it for 15 minutes.

LiPo Battery Handling & Storage

  • Keep LiPo battery packs WELL out of reach of children.
  • Do not put battery packs in pockets or bags where they can short circuit.
  • Do not store or transport or store batteries where they can come into contact with sharp or metallic objects.
  • Do not store your LiPo pack in extreme temperatures below 0C or above 50C.
  • Always store your LiPo pack in a safe and non flammable container away from flammable objects. A LiPo Sack or metal / ceramic storage container is best.
  • Always store your LiPo’s partially charged. They will maintain their performance levels over time and there’s no need to cycle them unless stored for periods longer than 3-6 months.

Lithium Polymer Battery Ignites In a Cash Box

Lithium Polymey Battery Ignites In A LiPo Sack

Other LiPo Battery Tips

  • Do not immerse the battery in water or allow the battery to get wet.
  • Do not short circuit the battery.
  • Do not pierce the lithium polymer battery with a sharp object – it will lead to ignition or an explosion.
  • Do not short circuit the battery.
  • Do not solder directly to the battery.
  • Do not hit the battery with a hard object such as a hammer or rock.
  • Do not dispose of in fire or heat.
  • Do not use the battery with the positive and negative terminals reversed.
  • Do not disassemble or modify the battery.
  • Do not fully discharge your LiPo battery pack. Discharging a LiPo beyond it’s critical minimum voltage (often 3.0v) can cause damage to the battery.
  • Do not breath in the smoke fumes of a LiPo battery that is on fire. They are toxic.
  • When mailing or shipping LiPo batteries, always ship them at a 30% charged state for safety reasons.
  • When storing batteries for extended periods, store at a half charged state.
  • To dispose of a LiPo battery, discharge it fully then place it in a bucket of salt water for one week. To dispose of, follow your municipal battery disposal guidelines.
  • If your battery becomes damaged, do not place it on a flammable surface – it’s possible that a chemical reaction can take place which could cause a fire. Put the battery in a safe and non flammable place and observe it for at least an hour.
  • If the electrolyte in the cells gets on your skin, thoroughly wash with soap and water. If it gets in your eyes, rinse thoroughly with cool water and seek immediate medical attention.
  • Finally, always follow the manufacturer’s safety instructions and charging guidelines for lithium polymer battery packs.
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Tags: RC Helicopter Articles

62 responses so far ↓

  • name // Feb 10, 2008 at 4:08 am

    Thanks

  • ibudtz // Apr 10, 2008 at 7:56 am

    thx’s nice post

  • MIGIZMARK // Apr 12, 2008 at 1:32 am

    Very informative thanks for the heads up

  • João Freitas // May 26, 2008 at 9:15 am

    How much time should it be charged after just buying it?

  • admin // May 26, 2008 at 10:26 am

    New LiPo batteries should come partially charged, so when charged at 1C (1C = their capacity in mAh) they should need to charge for less than an hour.

    They LiPo charger you’re using should automatically stop charging when the battery is fully charged.

  • Manuel Tacsay // Jun 30, 2008 at 2:01 am

    I have a question, example, I have a 3.7V battery pack. I don’t have a charger but I have an adaptor in which I can attach the charging end. How Much volts do I need to charge the 3.7V battery?

  • admin // Jun 30, 2008 at 7:20 pm

    Hi Manuel, you need to use a LiPo specific charger to charge LiPo battery packs. Another charger with an adapter won’t work and can have disastrous results.

    LiPo batteries have very specific charging characteristics and overcharging can easily lead to a fire as you see in the videos above.

  • asdf // Sep 1, 2008 at 2:44 am

    I know that many sources say to never exceed 1C charge rate.

    But is there any benefit to battery longevity by charging slower than 1C rate?
    Say 0.5C or 0.1C?

  • James Dick // Sep 20, 2008 at 7:44 am

    Hi there—When charging lithium polymer batteries each cell should be at no more than 1c(1amp) so 2cells should be charged at2c and3cells at 3c is this correct
    Or should lithium polymer batteries be charged at no more than 1c(1amp) whatever the number of cells
    Regards James Dick

  • admin // Sep 22, 2008 at 1:35 pm

    Hi James,

    The entire battery should be charged at 1C no matter how many cells it has.

    For example a 6s (6 cell) 5,000mAh battery charged at 1C would charge at 5 amps and a 10s 5,000mAh battery charged at 1C would also charge at 5 amps. The charge voltages will reflect the number of cells in the battery – the amps are always the same.

    Hope that helps,

  • Martin Rutter // Oct 7, 2008 at 5:22 am

    How do I charge a LiPo pack> Constant voltage or constant current and at wht voltage for one 3.7v cell?

  • admin // Oct 7, 2008 at 11:56 am

    Hey Martin, you need to use a LiPo specific charger to charge LiPo batteries. It’s not something you can do yourself with another charger because it needs to read the battery voltage in a specific way while charging, so it doesn’t overcharge them and risk damaging or exploding the battery.

    Though to answer your question, LiPo batteries charge at a constant voltage of 4.2v per cell. Depending on the stage of charging the amperage varies and in the last cycle, the charger switches on and off to accurately read the pack voltage.

  • Emilio // Oct 12, 2008 at 7:08 am

    How long can a lipo battery be left at full charge before damagging?

  • admin // Oct 13, 2008 at 2:54 am

    Hey Emilio,

    Leaving a battery fully charged for extended periods doesn’t really damage the battery, but more diminishes its capacity to store a full charge.

    I can’t really give you a concrete answer because it depends on the battery brand and chemistry, but in general, I wouldn’t go more than a month or two.

    If you can and have the foresight, always store at a 50% charge.

  • Emilio // Oct 13, 2008 at 3:06 am

    Thank you!

  • Philip // Nov 10, 2008 at 3:13 am

    Thanks for the good article. I have one question though. I have seen many li-poly chargers sold together with balancers. What is the purpose of the balancer? As far as I can tell it helps to keep the current across each battery at the same level thus ensuring even charging

  • admin // Nov 10, 2008 at 4:13 am

    Hi Philip, you’re spot on.

    Balancers balance all the cells of a battery so they’re all at the same voltage, otherwise the cells can be damaged when charging / discharging by becoming over charged or discharged.

  • James // Nov 14, 2008 at 1:41 pm

    Hi, I love how you are answering all these questions, I have learned so much. I have a question myself. I just bought a Jabra BT3030 Bluetooth stereo receiver. The battery life on it is pretty lacking though. I can’t even go a full 8 hours with it before it dies. I opened it up and it has a 185mAh 3.7v lipo battery. I just ordered a 300mAh battery with almost identical dimensions (it’s for the ipod shuffle) and planned on swapping them out. My question is would the built in charging mechanism in the Jabra BT3030 would work on the new battery same as the old one? It charges from a built in USB port.

  • admin // Nov 15, 2008 at 10:44 pm

    Hi James, I’m not familiar with that Bluetooth receiver, though it should probably work. Here’s why:

    LiPo batteries are charged until they reach a certain voltage (4.2 volts) and then the charger cuts off, so the capacity of the battery really shouldn’t matter much when charging. The only thing that would prevent it from fully charging is if the charger has a built in protection circuit that will only put our so many mAh (to the capacity of the battery) then cuts off.

    It’s unlikely that the charger is that complex, but possible. I guess since you’ve already ordered it, all you can do is wait and see :)

  • Pat Cantey // Nov 23, 2008 at 7:09 am

    I have a 3 cell Li-po battery, li-po charger and balancer. How much difference should there safetly be between the 3 cells. Min – Max?
    When does balanceing take place, during charging of afterwards?

  • Dan // Nov 24, 2008 at 10:43 am

    My 3 cell 11.1 volt, 800 ma lipo according to my triton 2 charger has too low a voltage to charge. My volt meter shows not below the 3 volt maxper cell . Since I can’t set a very low charge rate on my charger can I use a wall type connected to my balancer for a short time and then switch to the triton? Thanks

  • admin // Nov 24, 2008 at 3:08 pm

    Hi Pat, when the cells are balanced, there should be less than a 0.05v difference between them.

    Balancing usually takes place during charging depending on the charger you use, and in some cases is will continue until after the charging is finished.

  • admin // Nov 24, 2008 at 3:14 pm

    Hi Dan, you can’t connect it to a regular wall charger as it could wreck the battery / cause it to catch fire. It is possible to do, but you need a deep understanding of the charging process and it’s not something I’d recommend trying without it.

    Are you using a balancer with the charger? If you are using a compatible balancer, try balancing the cells first then charging. If you still can’t get it to work, you may want to try a different charger from a friend or flying buddy.

    One other option you can try, is charging two 3s batteries in series as a 6s pack.

  • Dennis // Dec 1, 2008 at 6:44 pm

    I just purchased a Blade cx2 Heli.
    So far i recharge the battery after 10 minutes run time.

    How many charges can i get from this battery before i need to get a new one?

    The battery is a EFlite 7.4v 800mAh 2 cell Li-po

    Thanks Dennis.

  • tom // Dec 7, 2008 at 1:57 am

    Hi, I am new to the lipo sceen, and could you explain what the C means? Also in purchasing and chargeing? And why does the 5000mh lipo seem so popular? I have a traxxas E Revo, just put a Novak brushless system in, and now looking for the best lipo. 5000mh or 8000mh. any help would be greatfull. Thanks Tom

  • Brian // Dec 11, 2008 at 10:25 am

    Tom, I’m new to the LiPo scene too. Just started about 2 weeks ago. The C is the discharge rate and this always causes debates. I wouldn’t worry about that too much. I’d recommend whoever you are buying batteries from, tell them your setup, E-Revo and the Novak system. They’ll be able to tell you if the batteries they sell are good enough for your setup. 5000mh is probably popular because of the price. Mh (Milliamps) is the size of your gas tank, the higher the number the longer run time you will have.

  • admin // Dec 13, 2008 at 4:28 am

    Hey guys, sorry for the delay in getting back to everyone.

    Dennis, the amount of charges you’ll get will depend on how you fly your heli and will depend on the LiPo. Hard core 3D fliers can kill a pack after 25 flights, but any decent LiPo battery should at a minimum get at least 100 flights if you’re easy on it. If you balance it and treat it properly, you can extend the lifetime significantly.

    Brian, thanks for the reply to Tom’s question… I’ll elaborate a little on it. The C rating is how much juice the battery can provide relative it it’s capacity. If a 5,000mAh LiPo is rated at 25C, that means it can provide 125 amps of current (C Rating x Capacity = 25 x 5 = 125).

    5,000mAh LiPo’s are popular because of their price and they’re a good balance of capacity and weight. Heavier 8,000mAh batteries will give you longer run times but at the expense of weight which affects the power to rate ratio. Also, because they’re not as popular, they’re slightly more expensive.

    PS: for faster responses, please post your LiPo questions in our forum at: http://www.helirush.com/batteries-and-charging-f45.html

  • mars // Dec 19, 2008 at 4:14 am

    Hi there. I use a lipoly battery for my Airsoft Electric Gun. My battery is a 15C 11.1 v 1450 mAh type. I use a charger/balancer that has an output of .8A.

    How long does it take to fully charge my battery with this type of balancer/charger?

  • mars // Dec 19, 2008 at 4:15 am

    Sorry for the double post. I do hope you can answer my question although I am not into helicopters. Thanks in advance.

  • admin // Dec 19, 2008 at 5:05 am

    Hi mars, should take about 2 hours to charge at 0.8 amps.

  • sophie // Dec 21, 2008 at 8:41 pm

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  • Jamie TOnna // Dec 29, 2008 at 8:24 am

    Hi,

    I would like to ask a couple of questions.

    I have a LIPO battery which is 11.1v 1250maH and 10C…..which powers my electric RC aeroplane which uses a Brushless Motor 1250Kv……. First question is, I am looking to purchase a spare battery which are also 11.1V but 1500 maH, 2500 maH and I have even found ones which are 5000maH….What is the difference please and what will happen to the motor of my plane if the battery is too powerful? can the battery be too powerful for the motor?

    My second question is, that someone told me that there are LIPO batteries which exist which can give me up to 30mins flight time where as I only get 10-15 mins with my current one. Is this true? do they exist?

    I would really appreciate someone who has the knowledge to answer me..

    Regards

    Jamie

    MALTA

  • admin // Dec 30, 2008 at 12:10 am

    Hi Jamie,

    The 1,500 Mah and 2,500 Mah batteries have a larger capacity than the 1,250 Mah one you’re using, so they’d give a longer run time. If you’re getting 10 – 15 minutes right now, doubling the capacity of your 1,250 Mah battery to 2,500 Mah would give you 20 – 30 minute flight times.

    The downside of using a larger capacity battery though is that they weight more and will affect the performance of your airplane some (speed, maneuverability etc.) A 2,500 Mah battery will almost weight double that of a 1.250 Mah battery, though it will increase flight times almost double,

    Hope that helps,

  • mauneice // Jan 11, 2009 at 5:54 am

    Hello everyone, what an excellent and informative web site, thanks.
    My question is this :
    I have a lama v4 chopper with 2 battery packs. Both packs are origenal esky supplied batteries. The packs are 2 cell, 7.4v, 800mAh, 10c rating. I use the origanel esky charger that came with the chopper to charge the packs. No problems. I also have a walkera li-po charger, can I use the walkera charger on the esky packs. Both chargers look the same, both have charging ports for 2 and 3 cell packs, input and output voltages are the same. The only differance that I can find between the packs is the esky charger is rated at 0.8A output current where as the walkera pack is rated at 0.75a. I don’t just want to plug in a battery pack and have the thing explode or something. The charging plugs on the battery packs match the charging ports on both charges.Thanks

  • admin // Jan 11, 2009 at 5:07 pm

    Hey Mauneice,

    Both chargers would probably work with either pack, though to be on the safe side, it would be best to charge the packs with their original chargers since they’ll both charge at pretty much the same speed.

    Don’t worry, plugging it in to the wrong charger will not cause it to explode :)

  • airsofter // Jan 12, 2009 at 2:09 am

    hi sirs.
    question. i am using lipoly battery in airsoft. the currect specs is 1650mah 15c bremenhaus lipoly, my question is, is it ok for me to store the battery inside the refridgerator for it is much cooler in there? another question is, in storing lipoly batteries i heard a rumor that suggest that i need to wrap the lipoly in aluminum foil so that the heat of the room temparature will just bounce out.

    thanks.

    airsofter.

  • admin // Jan 12, 2009 at 2:21 am

    Hey, there’s no need to store the LiPo battery in the fridge, though it also won’t hurt it either.

    If you’re not using it for a while, discharge it to 50% and store it in a cool place.

    If it’s out of use for more than 3 months, cycle the battery every month or two to keep it fresh.

    The only real advantage of keeping it in the fridge is for long term storage (6+ months) so it won’t bleed off some of it’s capacity, but other than that, it won’t really affect the battery. Just keep it away from heat sources – I guess the fridge would be an easy way to do that :)

  • airsofter // Jan 13, 2009 at 12:50 am

    wow that was fast response. thanks admin. that was a great help. thanks thanks.

  • soma // Jan 15, 2009 at 5:45 am

    i’ve bought a Lipolymer battery for my mobile phone but i’m not sure if getting the fit battery charger is very necessary or not also time required to fully charging is not determined in the user guide
    thanx

  • admin // Jan 15, 2009 at 6:20 am

    I’m not familiar with the fit charger, but almost any LiPo battery for a cell phone should charge in approx. 1 hour.

  • Berkly Ng // Jan 21, 2009 at 8:25 am

    What will happen if you always store LiPo battery at full charge?

  • Berkly Ng // Jan 21, 2009 at 8:27 am

    What is the maximum charge rate for every LiPo such as 2s2p 20c 4800mah , 2s1p 20c 3200mah ?

  • admin // Jan 21, 2009 at 9:56 am

    Hi Berkley,

    If you store a LiPo battery for extended periods at a full charge, it will bleed off some of the charge and loose some of it’s ability to take a full charge at a later date.

    The maximum charge rate will depend on the type of battery, but most have a max rate of 1C or 1 x the battery capacity. Therefore a 4,800 MaH battery would have a max charge rate of 4.8 amps.

  • Berkly Ng // Jan 21, 2009 at 5:01 pm

    Hi Adim thanks for the info,

    So storing LiPo batts at full charge would only loose it’s ability to take full charge and no other danger like my friends say it would balloon and catch fire while in storage and charging them after storage?

  • Scott // Jan 27, 2009 at 1:05 pm

    Hey,

    This site has some great information – thanks for posting and answering all of these questions. One more that I have not yet seen…

    Is there any damage done by leaving a LiPo battery on the charger for longer than necessary? I have a mini-RC Heli thatI typically use at night (2 year old asleep) and then charge overnight when I am done. Is this bad? The pack charges in about 45 minutes if I stay up to take it off.

    Thanks,
    Scott

  • kartik // Feb 12, 2009 at 4:12 am

    hi
    i would like to ask you a question
    i have this LiPo battery (3 cells,11.1V,2100mah)15C
    im using it for my glider and im planning to make it solar powered ie chargin the LiPo by solar panel…..while the flight is on…..
    solar panel supplies about 200ma @ 15.4V and can vary till 19V.

    after goin through this article i don no how far its goin to be safe
    can u plz give some suggestion regarding solar……
    awaiting your reply

  • Sarah // Feb 12, 2009 at 8:25 am

    Hi,

    I’ve been looking into disposal options for LiPo batteries (3.7v 200Ah – Kokam SLPB 140460330) and I’m trying to find the safest way that poses the least risk to the environment. Is it possible to recycle them?

    Thanks!

  • kartik // Feb 13, 2009 at 2:23 am

    sorry for the double post
    The solar panel supplies 400ma 14.4 volts.and NOT 200ma 15.4V and
    LiPo battery (3 cells,11.1V,2100mah)15C
    hope you will help me out in this
    thanks in advance

  • admin // Feb 15, 2009 at 9:52 pm

    Hey Scott,

    As far ask I know, every LiPo charger should automatically shut off, so it won’t damage the batteries. Though I still wouldn’t recommend leaving it unattended unless it’s on a surface that can’t catch fire (metal, granite, stone etc.) because even though it’s unlikely, there is a very small chance there could be a problem charging that could cause it to catch fire.

  • admin // Feb 15, 2009 at 9:54 pm

    Hi Kartik, that’s not something I’d try with LiPo batteries unless you’re hooking it up to a actual LiPo charger.

    They can’t be charged directly like NiCd or NiMh batteries can – would probably be easier just to get a 2nd set of batteries and use the solar panels to power a ground charger if you’d like.

  • admin // Feb 15, 2009 at 9:56 pm

    Hi Sarah, best way to dispose of them is discharge them fully, put them in a bucket of sale water for a week, then give them to the fire dept. or whoever looks after battery disposal / recycling in your area. There’s no way that I know of to recycle them… but it doesn’t mean it’s not possible.

  • enki // Feb 15, 2009 at 11:49 pm

    I’m using an imaxb5 charger.
    I have 1650mah 11.1v 3-cell 15c lipoly battery

    My question is: what charge rating to be used?
    -charge at 1600mah or
    -charge at 1700mah

    Since imaxb5 charges at 100mah increments?

  • admin // Feb 16, 2009 at 12:00 am

    Hey Enki, just charge it as a 1600MAh battery…

    Many people only charge their batteries to 95% because it’s a lot quicker, so if your charger has a setting like that, charge it as a 1700MAh battery, but only charge to 95%.

    If not, just charge it as a 1600MAh battery.

  • enki // Feb 16, 2009 at 12:07 am

    got it…thanks a lot!

  • Sarah // Feb 16, 2009 at 1:54 am

    Thanks for the advice. I’m just curious… what does leaving it in the bucket for a week actually do to the battery?

  • Lee Jones // Feb 16, 2009 at 5:06 am

    One thing I have seen asked but haven’t seen clearly explained is C. C stands for the capacity of the battery pack, usually expressed in mAH (milliamp-hours) or AH (amp-hours) [1000 mAH = 1 AH]. For example, a 2S 7.4V 800mAH battery pack for a Blade CX3 has a C rating of 800mAH. When charging, the maximum charge rate is a continuous current of 1C or 800mA (or 0.8A) — take the capacity number (i.e. 800mAH) and remove the time component (i.e. H). Charging at 1C of 800mA, it will takes roughly 1 hour to replenish a completely empty pack (e.g. 800mA for 1 hour = 800mAH). Recommended LiPo maximum charge rate is always 1C. There is a separate maximum discharge rate, such as 10C. In this example, an 800mAH 10C battery pack can provide 10 x 800mA or 8000mA (or 8A) of current to run the motors. Remember that all these numbers are when the pack is new; the actual capacity drops with time & number of uses. [side note 1: letter C for capacity is used for all battery chemistries such as NiMH, NiCad, LiPo, etc.] [side note 2: a 2 cell pack is referred to as 2S, 3 cell is 3S, etc; where S represents one cell. I believe S was chosen since the letter C was already taken to stand for capacity.]

  • Scott // Feb 17, 2009 at 12:51 pm

    Hey,

    Thanks for the answer. I do have one follow up question. I have used this battery about 20 times at most and have started to notice a degradation in the strength and life of the battery. Is this normal? I was charging it as I described (leaving it overnight) and thought that may have been the reason, but it doesn’t seem likely given your response. Any thoughts?

    Thanks again,
    Scott

  • Nickg // Mar 5, 2009 at 8:30 am

    Hi,
    I stumbled across this site trying to find an answer, nice to see a site that is dishing out sensible information. Ok, to why I’m here and my question. I use 3S1P 2250mAh packs and have a charger capable of charging upto a 6S pack. I’ve researched and found a suitable harness to allow me to charge two sets together (as a 6S) connecting balance leads as well as the power. I normally charge at between 1.8A and 2A (70-80% of 1C) in the hope of increasing the batteries life but am wondering if I can double this rate when charging two packs together as the effective capacity has doubled or do I stick to the same rate, and gain nothing timewise?
    I am aware of the pitfalls (balance all cells 1st) involved in this but would like to lessen the charge time of my packs by group charging.

    Thanks in advance for an insight.

  • Dani // Mar 8, 2009 at 12:26 pm

    Hi there
    I have a little one cell 3.7v lipo connected to a little heli, i forgot the heli on and the lipo over-discharged, the heli’s radio wont allow it to charge and neither will my swallow, any hints to increase the voltage so that the lipo will charge
    Thanks
    Dani

  • mauneice // Apr 12, 2009 at 12:06 am

    hello,
    i have two battery packs for my lama v4. I have only ever used the esky charger that came with the chopper. these packs have work hard and I have flown them to their 6.8 volt discharge limit on more than one occasion. Now I am noticing that my flying time on each pack seem to be getting shorter, I am no longer getting 12 minute flying time but rather 8 minutes. Is there any way to revive the battery packs or extended their life span.

  • anndy // Apr 15, 2009 at 7:12 pm

    very good information, thank you for your good work!
    here I want to recommend you a good place:
    tradestead
    there you can find out the best chargers and batteries , I have mine there too!

  • ellz // May 9, 2009 at 9:00 am

    Hi

    I’ve been using lipo’s for quite a while now. I’d just like to know is it necessary to discharge lipo’s after every use.

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