Introduction: Lithium Polymer Etiquette: a Comprehensive Guide to Working With LiPo

Picture of Lithium Polymer Etiquette: a Comprehensive Guide to Working With LiPo

In this Instructable I will be going over the basics of proper charging, discharging, handling, usage, storage, and care of lithium polymer batteries so you can use them safely and effectively in your future projects.  Now, this is by no means the be-all and end-all of information, and it's always important to consult the instructions for your specific equipment, but I think this Instructable will provide a good basis of knowledge on the subject of these awesome batteries.

Step 1: Terminology

Picture of Terminology

If you're new to lithium polymer/LiPo/LiPoly batteries, there are a lot of terms you will need to know before we get started.  Everything may seem a bit daunting at first, but with some basic understanding, it's all pretty simple, so let's jump in.

When you look at a LiPo's data sheet or casing, you will notice it has a lot of specs.

Cell arrangement - Described using the format xSyP (where x and y are integers), this tells you how the cells in the battery are wired up.  Batteries are made up of cells, whose voltage is determined by cell chemistry and whose capacity is determined by energy density and physical size of the cell.  S stands for series and P stands for parallel.  As you may know, series adds the voltage of the cells and parallel adds the capacity of the cells, so a combination of cells in series and parallel results in a battery.  The battery shown in the second image reads that it has an arrangement of 3S1P, meaning it has 3 cells that are all in series with no parallel wiring.  This may seem confusing because it says "1P," but think of the arrangement as a grid.  By multiplying the 3 and the 1, you get the total number of cells in the battery, which in this case is 3.  If it were a 3S2P battery, there would be 2 sets of 3 series-wired cells in parallel, resulting in 6 cells total.  Often times the parallel arrangement is omitted when discussing batteries, because most packs are 1P (so instead of saying you're using a 3S1P pack, you may as well just say 3S).

Capacity - Usually measured in mAh (milliamp hours), this is determined by the cell arrangement (parallel) and tells you how long you can expect the battery to last on a charge (although it's not quite that simple).  2600mAh as shown on the battery in the picture is equal to 2.6Ah (amp hours), a format you may be more familiar with on larger batteries, like the SLA (sealed lead acid) one in your car, which is probably around 50Ah.  A capacity of 2600mAh means that the battery can discharge at 2.6 amps for one hour (hence "amp hours"), 1.3 amps for 2 hours, etc., before it runs out of "juice."  Because the battery shown has a 1P arrangement, each cell has a capacity of 2600mAh.

Voltage -The voltage of a battery is also determined by the cell arrangement (series), and there are a few common voltage measurements worth noting:
        Charged - the voltage of a fully-charged LiPo cell is 4.20V, and charging above this will damage the cell.
        Nominal - this can be considered a sort of "half-charged" voltage, as it is 3.70V, in between charged and discharged.  Nominal voltage is what manufacturers use when describing the voltage of their batteries.
        Discharged - the voltage of a discharged LiPo cell is 3.00V, and discharging below this will definitely damage the cell.
Because the battery shown has a 3S arrangement, it is marked with its nominal voltage of 11.1V (3.70V*3 cells).  A fully charged 3S pack is 12.60V and a fully discharged 3S pack is 9.00V.

Constant C Rating (Discharge) - The constant C rating (in relation to discharge) tells you how many amps can be safely drawn from the battery constantly.  The "C" in a rating of xC (where x is an integer) actually stands for the capacity of the battery in Ah.  By multiplying the C rating's coefficient by the capacity of the battery in Ah, you can determine the sort of amperage you can draw.  In the case of this battery, with a capacity of 2600mAh (2.6Ah) and a C rating of 55C (that's pretty high, FYI), I can multiply 55*2.6 and get the max constant output of my battery, which is 143A.

Burst C Rating (Discharge) - In addition to the constant C rating, there is also a burst C rating, which is higher.  Most of the time, the "burst" is rated for 10 seconds.  Although it is not marked on the battery itself in the picture, it says in the documentation that this battery's 10 second burst rating is 80C.  So, 80*2.6 is 208A burst. That's a lot!  It's worth noting that your LiPo won't last long when that many amps are being drawn from it.  At 208A, a 2600mAh LiPo will last approximately 45 seconds.

C Rating (Charge) - Determined in the same fashion as the C ratings for discharge, the C rating for charge tells you at what amperage you can safely charge your battery.  This information is generally listed on the back of the battery with all the safety information.  For the battery shown, it happens to be 5C, which means that it can be charged at 13A (2.6*5).  We'll be talking a lot more about charge rates later...

Step 2: The Battery

Picture of The Battery

Now that we have some battery theory behind us, let's take a look at a few LiPo batteries.

All LiPo batteries (should) have 2 sets of wires coming out of them: discharge leads and balance leads (sometimes called balance taps).  The discharge leads are the thicker wires of which there are a positive (red, +, anode) and negative (black, -, cathode), and are used to discharge the LiPo as their name suggests.  The balance leads are used when charging the battery to ensure that all the cells in the battery are charged equally.  There is generally a common ground connection on one side of the balance connector, as well as a positive connection to each cell in the battery.  Therefore, depending on the number of cells the battery has, it will have a balance connector with a different number of pins.

Step 3: The Charger

Picture of The Charger

In order to charge LiPo batteries, you must use a LiPo-compatible charger.  If you try to charge a LiPo with a non-LiPo charger, something WILL catch on fire.  As this isn't a buying guide, I won't go into specific charger models or recommendations, but I will say that 90% of LiPo chargers out there use the exact same UI and have the same basic internals.  Let's compare 2 chargers and talk about specs and differences:

Charger #1: Dynam Supermate DC6
Charger #2: Thunder AC6

Power Input -
You need to supply more power to your charger than it outputs due to inefficiency.  My Thunder AC6 can plug directly into the wall because it has an AC adapter built into it, while by Supermate DC6 requires an external PSU (The Thunder AC6 can take power from an external PSU as well but there's not much point for home use).  Both these chargers have 50W max output, which means they need to take more than 50W input... say 60W at least, probably more just to be sure.

Power Output - Like I said, both the Thunder and Supermate feature 50W maximum output.  Remember that wattage is the product of voltage and current, so your maximum current you use to charge your battery depends on your battery's voltage and vice versa.  However, chargers also have a max/min voltage and max/min current output in addition to their wattage limitations.  Both these chargers have a current output range of 0.1-5.0A and a voltage range of 1-6S for LiPo (4.2-25.2V charged).  That means that while you'll be able to charge a 2S battery at 5A (8.4V*5A=42W), you won't be able to use that same current to charge a 3S battery (12.6V*5A=63W).  For a 3S battery, max charge current on a 50W charger will be 3.9A (50W/12.6V=3.968A).

Balancing - Balancing cells is quite possibly the most important part of charging a LiPo battery.  As LiPo batteries are used, their cells may discharge unevenly and become "unbalanced."  To combat this, balancing chargers like these plug into the balancing leads of the LiPo battery as well as the discharge leads, allowing them to individually charge and "balance" the cells within the LiPo battery so that all the cells are the same voltage (4.20V, remember?) by the end of the charge.  Some LiPo chargers don't have balancing capabilities, and when this is the case, it is necessary to buy and use a separate balancer.  As I don't have much experience using standalone balancers, I won't go into detail on them.

Extra Features - Some chargers have extra features like temperature sensing or USB connectivity.  Both of these chargers have a temperature sensor input, which can be useful if you want to stop charging your battery if temperatures exceed a predetermined value (we'll come back to this later).  The Thunder AC6 has USB which works with a Windows application for data logging.  Kind of cool, but not especially necessary most of the time.

Step 4: Other Gear

Picture of Other Gear

In addition to batteries and a chargers, there are a few other things you need in order to take care of your LiPos:

Digital Multimeter - Sometimes the voltage readings on chargers aren't totally accurate, so it's good to always be able to fall back on a trusty multimeter to verify.  When I'm using a new LiPo battery, I always check the voltage of each cell with a multimeter after I take it off the charger to be sure it's charged correctly.

Low Voltage Alarm/Cutoff -  These are used in conjunction with your LiPo battery when its being discharged.  A low voltage alarm or cutoff, or LVC as it's more commonly known, plugs into the balance connector on the battery and monitors the voltage of each cell. When any cell below a safe voltage (this threshold depends on the LVC but is generally between 3.3V and 3.0V), the LVC or LVA will either alert you with lights and/or a buzzer, or will cut off power to prevent further discharge.  Electronics meant to run off LiPo batteries will generally have this feature built-in, but if you're using a LiPo with something not designed for it, you'll need to use one of these or something equivalent.

Charging Case/Bag - LiPos should NEVER be charged in an open space for safety reasons.  If something goes wrong within a LiPo, it will quite literally shoot flames out of it, easily setting anything on fire.  Most people charge their LiPos in LiPo bags, which are padded, fireproof sleeves that can vent smoke out but keep flames in.  I, however prefer the ammo box method, mostly because it looks much cooler and properly scares people.  For illustrative purposes of this Instructable, I am charging my LiPos in open air, but I would never do so otherwise, as keeping your LiPos safe while charging is probably the most important thing you can do to.

Step 5: Balance Charging Setup

Picture of Balance Charging Setup

Charging LiPo batteries, especially balance charging, is a very precise process.  If you get it wrong, something bad will happen, but luckily LiPo chargers do their best to not make fires.

When setting up a charger to balance charge LiPo batteries, you're presented with 2 main parameters: current and voltage.

Charge Current - The current at which you should charge your LiPo battery depends on the battery's capacity and charge C rating.  Regardless of charge C rating, though, most people charge their LiPos at 1C, as that is the safest rate, both from a fire danger and battery longevity standpoint.  Charging your LiPo at a higher rate will make it charge faster, but charging at high rates will also decrease the life of the battery in the long run.

Charge Voltage - This is the nominal voltage of the battery you want to charge.  Often times the charger will state the cell arrangement (such as "3S") next to its nominal voltage for easier recognition.  My chargers check the battery by counting its cells via the balance plug and will not charge if your selected voltage and the battery's voltage don't match, which is a very good safety feature.

Here are a few real-life LiPo balance charging scenarios:

2600mAh 3S LiPo charged at 1C
1C*2.6Ah = 2.6A charge current
3S*3.7V = 11.1V charge voltage
2.6A*12.6V (fully charged voltage) = 32.76W power draw

1800mAh 2S LiPo charged at 1C
1C*1.8Ah = 1.8A charge current
2S*3.7V = 7.4V charge voltage
1.8A*8.4V (fully charged voltage) = 15.12W power draw

5000mAh 2S LiPo charged at 1C
1C*5.0Ah = 5.0A charge current
2S*3.7V = 7.4V charge voltage
5.0A*8.4V (fully charged voltage) = 42.00W power draw

All these charges of their respective batteries are very safe and within the realm of the charger's capability.  Additionally, each of these charges, because they are being performed at a 1C charge rate, theoretically take 1 hour to charge each battery from 3.00V per cell "dead" to 4.20V per cell "full."  In real life, charge time varies depending on the degree of discharge of the battery (most of the time you'll stop using the battery before it hits 3.00V/cell) and the degree of imbalance between the cells (the more imbalanced they are, the longer it takes the charger to balance them).

Just for further illustration, let's take a look at the same batteries, but this time charged at 2C:

2600mAh 3S LiPo charged at 2C
2C*2.6Ah = 5.2A charge current
3S*3.7V = 11.1V charge voltage
5.2A*12.6V (fully charged voltage) = 65.52W power draw

1800mAh 2S LiPo charged at 2C
2C*1.8Ah = 3.6A charge current
2S*3.7V = 7.4V charge voltage
3.6A*8.4V (fully charged voltage) = 30.24W power draw

5000mAh 2S LiPo charged at 2C
2C*5.0Ah = 10.0A charge current
2S*3.7V = 7.4V charge voltage
10.0A*8.4V (fully charged voltage) = 84.00W power draw

We can see that the chargers I own are incapable of charging the 2600mAh 3S battery and the 5000mAh 2S battery at 2C, but there are plenty of other chargers that are.  Charging at 2C means that each charge would theoretically take just 30 minutes.  Never charge your battery at a rate higher than is intended. Even then, I still don't recommend charging any battery above 1C, whether it's rated for it or not.  You can do it if your battery is capable and you're in a time crunch, but repeated charges at higher C rates wear down your battery quicker than charges at lower C rates do.

Step 6: Balance Charging

Picture of Balance Charging

After you've set up your charger for the LiPo you're going to charge, it's time to plug in all the cables on the battery side of things.  Plug the balance adapter into the charger, and your battery's balance leads into the appropriate slot on the balance adapter (it'll only fit in the one made for its cell count).  Then plug the charger's charge leads into the discharge leads of your battery.  Depending on your charger and its accessories it may plug into your battery in different ways.  In my case, the charger came with a variety of banana plug leads.  I conveniently misplaced the leads that connect to my battery's plug (called a Deans Ultra plug), so I had to use a different plug on the charger's lead and run an adapter between that and my battery...

Once everything's plugged in, go ahead and start balance charging your LiPo.  Like I said, after I tell my charger to start, it checks the battery's cells and asks me to confirm my settings before it starts charging, so yours may do the same.

LiPo chargers follow a 2-part process, using a "constant current" technique first and a "constant voltage" technique second.  During the "constant current" portion of the process, the charger ramps up to its specified amperage output and keeps that amperage constant as cell voltage rises.  When the cells hit a certain threshold, the charger switches over to "constant voltage." During this portion, the charger varies current output to keep all the cells of the battery at the same voltage.  Balancing occurs in this part of the charging process.  As the charger nears completion, current drops off significantly until the battery is fully charged at 4.20V per cell, at which point the charger stops.

While your LiPo is charging, watch out for temperatures (I told you I'd come back to it!).  A properly functioning LiPo shouldn't exceed 90-100 degrees F while charging.  If it does seem to be getting hotter than that (you can feel it with your hand, read it with the temp sensor for the charger, or use an IR thermometer), stop charging immediately.  Within my chargers, I can set the charger to cut power to the battery at a temperature threshold.

Step 7: Storage

Picture of Storage

If you don't plan on using your LiPo for an extended period of time (a few weeks to a month or more), it's a very good idea to store it properly.  The first step to LiPo storage is to charge/discharge it to proper storage voltage.  LiPos, like all other battery chemistries, do self-discharge, but at a very low rate.  If left discharged, a LiPo can discharge further below its safe voltage range rendering it useless and dangerous the next time you want to charge it.  If left fully charged, the cells in a LiPo will unbalance quickly.  Proper storage voltage for a LiPo is 3.85V per cell.  Most LiPo chargers have a storage function that will either charge or discharge your battery until it hits 3.85V per cell.  

As my chargers have a discharge range of 0.1-1.0A, the max storage charge rate is 1.0A, so I set it as close to 1C as I can (usually the full 1.0A) and set the voltage in accordance to the battery I want to store.

After your LiPo is at a proper 3.85V per cell for storage, you can find a good place for it to stay.  LiPos are best stored in relatively low temperatures (40-45 degrees F), so a refrigerator is an excellent place for them.  It's a good idea to still protect the stored batteries in case of fire, so I recommend placing the LiPos in a LiPo bag and putting the LiPo bag in the fridge.  The fridge is not the only place for LiPos, though.  Anywhere with low humidity and reasonable temperatures will suffice.

Step 8: Discharging

Picture of Discharging

In some instances, you will need to completely discharge your LiPo.  The most likely reason for this is to measure capacity, because charging from 3.0V per cell to 4.2V per cell (or discharging from 4.2V per cell to 3.0V per cell) is the only way to accurately judge capacity.  As I said in the last step, my chargers have a max discharge current of 1.0A, so that's what I use when discharging most of my LiPos unless they're really small (the RC cars I use my LiPos in consistently draw 25-75A, so 1A is not a problem for my batteries).  Think back to the constant C rating for discharge of your battery, and get as close to its max constant discharge current as you can.

For reasons mentioned in the last step, don't leave your LiPos full discharged for long or you risk not being able to charge them again.

Step 9: Usage

Picture of Usage

If you take care of your LiPo battery, it will take care of you.  Or not burn your house to the ground at the very least.  Here are some guidelines to follow for safe usage of LiPos:

-don't poke it or puncture it. fire will happen

-don't drop it. fire will happen

-don't short it out. fire will happen

-don't overcharge it. fire will happen

-don't let it overheat. fire will happen

-don't throw it in a fire. more fire will happen

All jokes aside, follow the instructions that come with your equipment and you should be fine, but always stay alert.  Avoid walking away from your charger while it's working on your LiPo, because if something goes wrong it's good to be around to make it go right... or at least less wrong.

One of the most important guidelines for a good experience with these batteries is to always work within the electrical capabilities of your LiPo by doing the following:

-constantly monitor the voltage of each cell either manually or, better yet, automatically with an LVC or something similar

-match the components in your project to ensure you never draw too much current from your LiPo


I plan on updating this Instructable throughout the future with added information and answers to people's questions.  In the meantime, please rate and comment on this Instructable.  I hope it provided some helpful insight into the realm of Lithium Polymer!

Comments

LabRatMatt (author)2017-10-01

I have to charge a pretty beefy 10Ah 6-cell battery. Do the same rules apply for batteries of that size?

RedSuner (author)2017-04-10

This is a very useful Lipo battery Comprehensive Guide, especial for newbie to Lipo battery. Teach you know the capacity, voltage and discharge rate basic knowledge. I have bought a Gens Ace 5000mAh 2S 50C Lipo battery from GensTattu, my battery is the same to yours, and after read your guide, I have knew more about Lipo battery.

Discharge,

Charge,


Storage,

Good article.

dunk8888young (author)2017-01-18

Having said all that i have a feeling my battery charger is a fault,it never charges lipos verry long,and the charger never wants to charge at what i set it.ive a imax b6 clone and if i set to 4amps for 4000mah battery it charges at about 300mah and gradualy go to 0 then cut off,it does it with all batterys exept the rc lipo,infact probly just the 1s lipo only.

graphixv (author)dunk8888young2017-02-20

It's possibly the knockoff charger because most of them have inferior components. I have a real B6 (verified via sticker on their website) and it charges anything I have thrown at it. You can get a real B6 cheaply enough (I did anyway) that it doesn't make sense to buy a knockoff. You're probably only talking a $15 to $20 difference, I mean, why bother?

The other possibility is that It has something to do with your PS to the B6. If the PS can't handle the amps/volts asked of it, the unit will shut down. 4 amps for a 7.2 volt battery is something like 32 watts! My little 17 watt PS I use couldn't handle that either.

PeterC201 (author)2015-12-20

Why are most LiPo charger/balancer/dischargers limited to 1.0 Amp. max discharge rate? When I want to discharge a 5000mAh battery to storage levels, it takes forever. What do other people do so that their expensive LiPos are safe and balanced for storage?

graphixv (author)PeterC2012017-02-20

Why don't you just run it down a little with whatever uses it? Frankly my situation is different because I'm not using batteries as expensive as those but I don't even bother running mine down. I figure since they are off charge, the voltage is going to start dropping down off peak anyway.

rgarand (author)2016-11-18

hi, very well done article ! 1 question arises about the necessity to wait for the battery to cool down before charging it. I came to this question because my copter came with the charger, i stop using the copter as soon as the warning low-battery light come on, even then, batteries don't work fot long...am i on the right track ?

graphixv (author)rgarand2017-02-20

The chargers that come with copters are not really smart chargers. A smart charger will decrease the amps when the battery gets closer to being fully charged so it doesn't overshoot the upper voltage limit. I wouldn't mess with charging it inside the copter. if you plan on getting something else in the future I'd just buy a hobby charger like a real B6 (not a knockoff). With one of those and a pigtail, you can charge more than one battery at once and who wants to charge these batteries one at a time?

dunk8888young (author)2017-01-18

Hi,does this apply to any lipo battery? even the ones inside gadgets and tablets etc

I ask as ive a lipo from a tablet and it says its 4000 mah now it wont take a charge any more than 3 or 400 mah,ive never been able to give a charge to a lipo at what its rated at,i have with the rc lipo batterys,the tablets charger was rated at 500mah with a 4000 mah battery in it!.this is why i ask if none rc battaries should be charged at the mah it says on it.

oldaudio (author)2016-11-01

I'm not making the connection (no pun intended) between the "peak" or "boost" output of LiPo cells and a constant load rate. It seems to me that if the power is in the LiPo cell, it would let me have it at a nominal rate, say 200ma for a long period of time. No? I'm mainly talking about these 12V LiPo "battery boost" types sold thru Radio Shack and auto parts stores. What am I missing?

You can draw current at whatever rate you'd like, up to the burst rate.

GotTraxxasMan (author)2016-09-02

I've been storing my 3s 5000mah Traxxas power cell batteries for about 2 weeks now and I was wandering if I needed to charge them fully before using??? Plz help

MarkT201 (author)2016-08-22

Hi there, I have what I believe to be a lipo 11.1v 1500mah battery. It's kinda dead(ish) so I need a replacement. However it only has 2 wires coming out from it. Obviously it must be safe but I'm really struggling to find a replacement.

Any help would be much appreciated
JY 754060-1500mah 11.1v 121112

CraigN15 (author)MarkT2012016-08-25

When I said they (lion) fully charged I meant it could be & stored safely fully charged, unlike lipo's that will puff & ruin being stored fully charged.

CraigN15 (author)MarkT2012016-08-25

Chances are its not a 3s 11.1v lipo. Or it would have 2 leads & 3 more small ones for a balance lead with plug. Its more than likely a lithium ion battery or similar chemistry with similar voltage to the 3s lipo. 3.3v x 3 is 9.9v fully charged its 10.9v & the 3.6v x 3 is 10.8v so 11.8v fully charged, so that is probably what it is. They typically have less voltage than lipo batteries (3.3v - 3.6v instead of lipo at 3.7v) & can be stored fully charged & fully discharged unlike lipo's & are more user friendly. So if you can find a lion battery around the same voltage you should be good using it & charging it the same way it was charged before.

ukocad (author)2016-07-20

Great guide, thank you.
Two question from a newbie.
Is it faster to do a normal charge over a balanced charge?
And how often is balanced charging needed?

Weanuts (author)2016-05-24

Battery topping off at 11.30 volts.

Both of these are high discharge 3s1p 25c-3000mah lipo batteries by 2 different manufactures. 2 Imax B6 Lipo chargers same model. Both these chargers were used in most if not all configerations

First battery will start recharge at or about 10 volts and stop at 12.60 volts by way of meter on Imax, and takes 119.59 to complete charge. All of these readings are backed up by a multimeter to

confirm readings on charger.

Second battery (in question) will start charge at or about 10 volts and complete its run at or about 11.30 volts, in about 5 minutes or or less and about at this point Immediately jumps to 12.60 volts on both chargers with either charger saying Full. Without disconnecting, battery voltage is checked on both balance line, 3.766 volts and 11.30 on Deans connector.

Both chargers have had several wall warts used to power them up, any where from 1.5, to 3 amp, 12 volt output.

I have been able to charge second battery by leaving balance line disconnected, with charger going from 2.0 amp output, and slowly drops down to 0.00 volts output and shortly thereafter Imax

charger stops charging, with meter saying 12.60 This takes about 45 minutes. A check with a multimeter says approximately 4.2 volts volts, on each cell. Temperature of battery number 2 does not

rise, everthing seems normal.

2 questions.

1/ Why is this happening?

2/ can I hurt either charger and or number 2 battery as it stands now?

thanks

adamb202 (author)2016-04-18

Hi so im having a problem i have a drone the battery it came with only shows 7.4v 1300mAh but dont show the c value how can i find this out as i wand to run a 7.4v 2800mAh 20c or is that to much or to little plz help thanks

MattiaM12 (author)adamb2022016-05-02

Hi adamb202, c rating can never be too high. If you have 20c pack and drone requires 10c to fly then it is fine. If drone requires 30c the battery gets too hot and it might catch fire. Better safe than sorry, look at other drones of similar size and weight and see what is their recommended battery pack c rating.

aviatorex1 (author)2016-03-16

I have a 7.4V 500 mah, 602540-25 used to charge a battery for an H8C quadcopter. while charging it blew up and then caught on fire. I am 82 years young and need some help. Thanks,George Clark. my e-mail is aviatorex1@gmail.com

symabingbing (author)2016-02-21

I recommend gens ace 5000mah lipo here, click this link

http://www.genstattu.com/gens-ace-5000mah-7-4v-50c-2s1p-hardcase-lipo-battery-659.html

Fragesteller (author)2016-02-07

Excellent guide, Radioactive_Legos! You qualify your opening remark (in Step 2: The Battery) with a (should); 'All LiPo batteries (should) have 2 sets of wires coming out of them: discharge leads and balance leads (sometimes called balance taps).

I have 8 batteries that have just 1 set of wires, which are for the JJRC H8C Quadcopter. The Quadcopter came with 1 of these batteries, plus a charger, which can only charge one battery at a time.

Are these batteries LiPo batteries, or another type of battery? In my present state of ignorance, I have a multi-charging cable, hoping to be able to charge 5 batteries at once, and a Accucel-6 50W 6A balancer/charger.

I've noticed that, although my batteries by themselves have no balancing cable, the multi-charge cable (DYX-009 Cable for JJRC H8C RC) does have what seems to be a balancing cable, and I would appreciate it if you could confirm this for me.

If I am correct in this, would I, with a modification to (DYX-009 Cable for JJRC H8C RC) the multi-cable charger input connectors, be able to charge these batteries whilst also balancing them?

Thank you in advance

mumbles_mcboomboom (author)2016-02-06

I am using a 3S 5800 mAh 60C LiPo for my senior project. This guide is SO HELPFUL! THANK YOU SO MUCH for writing it.

This battery scares the hell out of me and we've set a requirement of having a battery recharge circuit as part of our project.

Srijal97 (author)2016-02-06

Nice, detailed explaination. Thank you for this.

I remember while replacing the battery connectors on my first LiPo battery, I used bare metal scissors to cut both the wires in a single cut, which shorted them...luckily there was no fire, only a spark and the battery died. Never be in a hurry with LiPo batteries!

CliffU (author)2016-01-31

My oldest set of four battery's have a flight time of 5mins, 3.7v. 720 mAh. My new set (same size) have a flight time of 8.5mins. Can my old set be revived?. Cliff.

KofiA5 (author)2015-12-11

please i have a tablet battery (4800mAh 3.7v 3082150) which had two red wires and two black wires. can i replace it with one which has the same specs but single red wire and a single black wire?

Radioactive_Legos (author)KofiA52015-12-13

Ehhh, I wouldn't recommend it. It's probably a 1S2P pack, so there are two cells in there. The tablet could be reading voltages from both cells while in use, so dropping in a single cell LiPo could confuse and/or damage it. Unless it's an OEM part or you've read of other people doing this for your particular device, I wouldn't risk it.

I'm highly doubtful that it's a 1S2P pack, and if it were by some freak occurrence a parallel pack - it would not require the cells to be balanced. Parallel packs do not require the cells to be balanced, as current is divided evenly for the most part between all of the cells in the parallel circuit. Whereas in a series pack, the cell with the lower voltage (or higher internal resistance) will be the "weak link in the chain" and will have a chance of either over-discharging or over-charging if not balanced. I know these things, being that I'm an electrician as well as being really into electronics and quadrotors as hobbies - I live and breathe this stuff ;) Plus a simple googling will tell you that most cell phone batteries either have a thermistor or will have protection circuits that communicate with the device over a single conductor in the case of a 3-pin battery. You could probably trick the device into thinking it has a temperature probe by using a resistor, but without knowing the device or the information on the original battery there's no way to know for sure as these things vary between manufacturers.

Great, so it sounds like we're in agreement that KofiA5 should stick with OEM batteries :)

MatthiasA3 (author)2015-12-30

Thank you very much for one of the best descriptions avail! Unless we have a more comprehensive system of LiPo charging and maintenance (which is up to those crazy manufacturers, imagine you had to go through all this to charge your cell phone!) this is outstanding.

tkendrick (author)2015-12-30

Incredibly useful! Thank you for taking the time to provide information like this, and the best part it it's free.

GolsO (author)2015-10-15

do i need to charge it again after i put in storage fuction..?

JerryB37 (author)GolsO2015-11-13

That $9 deal blossoms into a $20 deal when they ship it to you. It's a great deal if you can go to the store in Miami and pick it up.

amoljoshi_bangalore (author)2015-06-03

Can anyone please tell me the function of each wire in the battery (Image attached). It's a tablet battery.

Or can anyone direct to a resource that illustrates the wiring of a Lipo battery.

I'd be grateful!

Thanks

~amol

Actually, that's a 1S2P battery, the pinout is:

2 red = 1 (+) from each cell

2 black = 1 (-) from each cell

Yellow, brown, green = balance leads. 1 (+) from each cell and 1 (-) connected to both cells. You can determine the specific function of each of these 3 wires with a DVOM; you will have 3.7v positive on 2 of the balance wires when measured with the 3rd balance wire as negative. If one pair of balance wires give you -3.7 volts, then the wire connected to your DVOM (+) is the negative balance wire for both cells, if one pair of the balance wires reads 0v, they are the (+) balance wires from each of the 2 cells, and the one you are not connected to is the (-) balance wire. It should take you less than a minute to determine the function of these 3 wires.

This is a common battery pack configuration for high continuous current draw items such as the tablet that this battery is designed for.

Hi there, your battery is a single cell Lipo with a capacity of 3.7 amp hours.

when fully charged it should show 4.2 volts.

when half charged it should show 3.7 volts.

and when fully discharged it should show 3 volts.

the wires most likely are the two black will be the negative and the two red will be the positive and the other wires will be for sensing the temp and charge state of the battery to prevent you from over charging or discharging and to prevent it getting to hot, also on most laptop and tablet battery's they store how many times you have charged and discharged the battery and at a certain number it will stop allowing you to charge it which is done to help prevent it from bursting into fire (and also to make you to buy a new one)

On most Lipo's that people use for RC models you get two plugs one with the main wires for discharging and charging the battery and the second for checking the charge of each separate cell and to allow you to balance all the cells so they are all at the same voltage.

So on a 2s battery the second connector will have 3 wires one negative one from the positive of the first cell and one from the positive of the second cell.

On a 3s battery the second connector will have 4 wires one negative, one from the positive of the first cell and one from the positive of the second cell and one from the positive of the third cell and so on.

I hope this may help you understand Lipo's

Regards Poppy Ann.

It is Li-ion battery, not LiPo...

TristanL2 (author)ddeshmukh22015-06-28

It says Li-Polymer right on the label. That is indeed a LiPo battery.

filthyPhil (author)2015-10-19

Hi, I bought one of these.

http://www.amazon.com/6800mAh-13000mAh-Super-Li-io...

It came with a charger but no instructions.

I don't want to over charge it or damage it but have no idea how long it should take to charge.

Do you think there would be any kind of charge protection?

Thanks.

patrick1118 made it! (author)2015-10-15

hi ,A good new for you. gens ace lipo local in USA now! 25c-2200-3s1p promo price is only $8.99 but Maximum 5 Qty Allowed in Shopping Cart !

http://www.genstattu.com/ga-b-25c-2200-3s1p.html

heathbruce (author)2015-08-01

The charger is a Walkera GA005 balance charger

heathbruce (author)2015-08-01

The charger is a Walkera GA005 balance charger

heathbruce (author)2015-08-01

The charger is a Walkera GA005 balance charger

heathbruce (author)2015-08-01

The charger is a Walkera GA005 balance charger

heathbruce (author)2015-08-01

11.67v

heathbruce (author)2015-08-01

11.67v

heathbruce (author)2015-08-01

I got my walkers runner 250 yesterday, so I charged my 3s 25c 11.1v 2200mah battery and flew the drone and charged it a couple more times etc.. So I made this thing with pins and headers so I could charge the battery and check each cell to see if they were charging and not over charged and I accidentally put the battery balance pins in reverse onto the thing I made and smoke came out the vents of the charger and I immediately disconnected the battery. The red light flashes to say its charging but it doesn't even charge the battery, it just stays at its discharged voltage after flying(shown). I opened the charger up and there is 4 relays that obviously turn the charger on when the battery is detected and I cant here them click as they switch over, so there's either a transistor mangled inside is this fixable? Or do I have to buy a charger that has a screen and heaps of functions?
Much appreciated if someone could help Me :)

ColinM1 (author)2015-05-27

ColinM1 (author)ColinM12015-05-27

sorry my question didnt show up , so trying again,.

My question is do you ever discharge and charge singularly or a series of cycles after normal use of a Lipo. I`m also dont understand disharging/charging to measure capacity , could you please explain how and why?

Poppy Ann (author)ColinM12015-07-15

Hi Colin,

I am not sure what you are asking where you have put "do you ever discharge and charge singularly or a series of cycles after normal use"

most people recharge their Lipo's after each use depending on how much use they have made of them, if you have only run it for a couple of minutes and it is still above half charge then you may use it again for a short time.

it really depends on the person and on what you are using it for if it is below 3.7 volts (half discharged) and you want to go for a long flight in a high prices model then you are taking a chance of loosing control of your model so unless you want to chance the loss of the model then either do not fly or replace the battery, when I am going to go flying I check all my battery's the night before and any that are below 4 volts get recharged and then when I am about to fly the first thing I check is the voltage of the battery then the controls of the aircraft if there is a problem with either then I do not fly it is better to wast a trip to the flying site than to loose the model.

A battery is made up of a number of separate cells and depending on how it is wired up it will give out a certain voltage at a certain Ah (Amps per hour).

On Lipo's each cell will give out when charged 4.2 volts and depending on how they are built each cell will have a certain capacity which for most depends on the physical size of the cell.

so if you have a battery with 6 cells of 1Ah it could be wired up as either:-

6s1p which is all six cells in series which will give 6x4.2 volts=25.2 volts @ 1Ah volts.

3s2p which is 3 cells in series twice which will give 3x4.2 volts=12.6 volts @ 2Ah.

2s3p (which is unusual) which is 2 cells in series 3 times which will give 2x4.2 volts=8.4 volts @ 3Ah.

as always I have gone on a little to much but I hope it helps you.

Regards Poppy Ann.

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Bio: A Bay Area native interested in electronics, mechanics, and robotics, and automobiles. Formerly the electronics captain of Team 100 in the FIRST Robotics Competition, I ... More »
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