Monthly Archives: January 2016

The Experience about Parallel Charging My LiPo Batteries

What is parallel charging?

In a nutshell parallel charging allows for multiple same cell count batteries to be connected in parallel to create a single larger logical battery that can then be charged. The following is my experience about lipo battery parallel charging.

With cells in series, and no balance lead, your charger has no idea how much voltage is in an individual cell; it only knows the total voltage. If it reads 7.4V, that might be cell 1 with 4.2V and cell 2 with 3.2V, or it might be cell 1 with 3.7V and cell 2 with 3.7V, or it might be something else. Unless the charger connects to the balance lead, it just doesn’t know. So, let’s imagine it’s the first case. You start charging, with cell 1 at 4.2V and cell 2 at 3.2V, and the charger says, “ok, I need to see 8.4V before I stop, so I’ve got a long ways to go,” when in actuality it is going to overcharge cell 1 and possibly blow it up or catch it on fire, and definitely it is going to ruin or at least damage cell 1 at a bare minimum. That’s where active balancing comes in. Cells in series must be *actively* balance by a smart charger, to get them to be equal.

gens ace lipoHowever, here’s what you’re missing still: cells in parallel do *not* need active balancing by a smart charger. Rather, they naturally, by the laws of physics, will perform passive balancing. Cells in parallel automatically, passively, due to voltage gradients (differences), self-balance until they are equal. If you take 2 individual LiPo cells, and place them in parallel, and wait long enough, no matter what voltages they *were*, they will equalize, automatically, to become *equal* voltages over time. One will discharge into the other, until they are equal.

So, in your case of 11.1v 2200mah lipo, when you place the whole packs in parallel, and the balance leads in parallel too, cell 1 of pack 1 is placed in parallel with cell 1 of pack 2, so both cell 1′s will automatically, by the laws of physics, passively balance until they are equal. Both cell 2′s will also passively balance until they are equal, since cell 2 of pack 1 is also in parallel with cell 2 of pack 2. However, both cell 1s (as if a large single cell) are still in series with both cell 2s (as if a large single cell), so *active* balancing is still required here, to get the cells in *series* actively balanced, and that’s where the smart charger does its job.

Therefore, when charging in parallel, you are still getting all 4 cells to be balanced, just as if you were not charging in parallel.

What are some specific uses of parallel charging?

450 sized heli:
Many times people start with a 450 sized heli and in the beginning they can not get enough flight time. This is what we call the “Welcome to your new addiction” stage. Parallel charging can be a great aid to the new pilot. For example with a 350W charger a 6x parallel lead set, a new pilot could charge 6 450 packs in 30min.

700 sized heli:
Larger electric helis are becoming very popular and they come with large needs in terms of power. A common battery pack for a 700 is a 12s 5000mAh made up of (2) 11.1 v 3s lipo battery wired in series. Due to the lack of 12s chargers available, a need for charging pairs of large 6s packs has arisen. Of course you could use 2 chargers, or a dual port charger, but there is another solution, a solution that really brings out the best on the new powerful chargers offering 1000W or more of output. By using one of these new 1000W chargers and parallel charging, you can charge a pair of 6s 5000mAh packs in 25min or less.

Remember to be careful about large voltage gradients (differences), however, as the passive balancing can be quite fierce (and potentially damaging or even dangerous), if cell voltage differences are too great before being placed in parallel–refer back to my article for warnings & recommendations on this.

How to Tell If Your Lipo Battery Is Bad or Good

A good RC lipo battery is one that will accept and hold a charge, and is capable of producing close to its rated amperage output. A bad battery is one that will NOT accept or hold a charge, or cannot produce adequate cranking amps. Buy high quality lipo battery, we can recommend you Gens ace lipo, they are the best brand of RC lipo battery supplier. A GOOD RC battery can be recharged and returned to service but a BAD battery needs to be replaced. Most RC batteries only last about 3 to 5 years, so if your Lipo battery is 4 or more years older and is not holding a charge (keeps running down), or it does not seem to crank your engine a normal speed, you probably need a new battery.

A low or dead Lipo battery does not mean your battery has failed, or that it needs to be replaced. A good Lipo battery can run down for any number of reasons: somebody left the lights on, you haven’t been driving your vehicle enough to keep the lipo battery fully charged, your vehicle has been sitting for a long period of time without being started, there is a problem with the charging system or alternator, or an electrical problem is draining power from the battery when your RC car is off.

gens ace

Good RC Battery Recommedation

The 5000mah 30C gens ace batteries are designed for use with small scale RC helicopters such as Blade mCPX and are the original batteries made by E-fliete for that particular model, though they are also compatible with other similar models such as WLtoys v922 or Gens ACE lipo and others. And while these RC lipo batteries are quite Ok for stock batteries for these RC helicopters the question is if they are able to meet their specifications and that is exactly what we are going to check now.

Here are some ways to test your battery at home, and determine if it’s bad

1) Inspect the Battery

Sometimes you can tell if your 5000mah lipo 2s is bad by simply taking a good look. There are a few things to inspect, such as: a broken terminal, bulge or bump in the case, crack or rupture of the plastic, excessive leaking, and discoloration. Broken or loose terminals are dangerous, and can cause a short circuit. If a short did occur, there would be some indication of burning or melting. When a battery short circuits, all of the power is unloaded in an instant. That produces a lot of heat, and sometimes even causes the battery to explode (no joke). If the battery is still intact, but there is a bulge in the case, this is usually a result of being overcharged. Others signs such as physical openings in the case are often caused by mishandling. Cracks, splits, and holes will not cause a battery to stop working, but for safety reasons the battery should be labeled unsafe to use.

2) Take a Voltage Reading

If your Lipo battery is reading 0 volts, chances are the battery experienced a short circuit. If the lipo battery cannot reach higher than 10.5 volts when being charged, then the liop battery has a dead cell. If the battery is fully charged (according to the battery charger) but the voltage is 12.4 or less, the battery is sulfated. As we know, lipo battery voltage comes from 3.7v to 22.2v, you often see many online store, write 1s lipo, 2s lipo, 3s lipo, it is equal to 3.7v. For example, 3.7v lipo battery also can read to 1s lipo battery. Naturally, re-charging the lipo battery will reverse the sulfation crystals and turn it back into electrolyte, ready to produce power again. But if a battery sat, uncharged, severely discharged, and/or drained for extended periods of time, the sulfation will increase in size and harden onto the plates. This covers the surface area of the plates, removing the chemicals needed to produce power. Sulfation decreases the potential to reach a full charge, and it self-discharges the battery quicker than normal. Charging a sulfated battery is like trying to wash your hands while wearing gloves. At this point, charging alone will not restore the battery to a healthy condition. The majority of replacement battery purchases occur when the original battery has reached this point.

3) Load Test the Battery

Your local automotive shop is more than able to load test your lipo battery for you. But it’s quite easy to do at home. All you need is a digital voltmeter. For any load test to be accurate, the battery must be fully charged. Let’s use a motorcycle battery for an example. Remove the seat and expose the battery in your bike so that you have access to the terminals. Do not disconnect the lipo battery because you will attempt to start the bike. Hold the prongs of your voltmeter to the correct terminals on the lipo battery. Now push the starter button and watch what the voltage drops to. It doesn’t matter if the bike starts or not, what you’re looking for is a voltage reading.

Battery Testing

Many auto parts stores will test your lipo battery for free. If your vehicle is drivable or you can get it going with a jump start, drive to a nearby auto parts store that offers free testing and have them test your lipo battery and charging system. If you can’t get your car started, remove the lipo battery and get a friend to give you a ride to the auto parts store so you can have the lipo battery tested. Many repair shops will also test your lipo battery and charging system, but they usually charge a fee for this service (some will test your battery for free or offer to apply their diagnostic fee towards the cost of repair).

How to Test LiPo Battery Packs

Lithium Polymer Batteries (LiPo’s) have now been with us for many years and have become an essential part of this hobby. Their low discharge rate is perfect for devices that don’t draw considerable current, and the cell’s compact footprint makes them easy to squeeze into tiny devices. The challenge with LiPo batteries lies in their charge and discharge profile because unlike nickel or lead-based batteries, LiPo cell voltage is not self-limiting. Without a specifically designed charger, the battery voltage would continually increase until it bursts into flames (a generally frowned upon outcome in electrical design). Discharging LiPo batteries without proper protection is only marginally better, and will result in cell damage without restricting the operating voltage to a very specific range. If you want to test the condition of your 3s 1300mah lipo pack then use a multimeter and you can test the voltage and mAh.

Look on the label on the LiPo battery pack. You need to find out the output voltage and mAh rating. The voltage figure is always a multiple of 3.7 and the mAh always a multiple of 2,100. For example, a LiPo battery pack using three cells has a voltage of 11.1 and mAh of 6,300, it is 2200mah 3s lipo battery. The figures on the label are the figures you can expect to get when you test the battery using the multimeter.

gens ace lipo from Genstattu.com

Measuring Voltage

To start, let’s measure voltage on a AA battery: Plug the black probe into COM and the red probe into mAVΩ. Set the multimeter to “2V” in the DC (direct current) range. Almost all portable electronics use direct current), not alternating current. Connect the black probe to the battery’s ground or ‘-’ and the red probe to power or ‘+’. Squeeze the probes with a little pressure against the positive and negative terminals of the AA battery. If you’ve got a fresh battery, you should see around 1.5V on the display (this battery is brand new, so its voltage is slightly higher than 1.5V).

If you’re measuring DC voltage (such as a battery or a sensor hooked up to an Arduino) you want to set the knob where the V has a straight line. AC voltage (like what comes out of the wall) can be dangerous, so we rarely need to use the AC voltage setting (the V with a wavy line next to it). If you’re messing with AC, we recommend you get a non-contact tester rather than use a digital multimeter.

Set the multimeter to read voltage. Check the two terminals on the battery pack to determine which is positive and which is negative. They are labeled “+” and “-” respectively.

Read the voltage output on the multimeter display. It reads the same as on the battery pack label. If the voltage is more than five percent less then it’s likely the battery is losing charge quickly as you have only just charged it.

Set the multimeter to measure mAh. Place the two sensors on the battery terminals as before. Read the mAh on the multimeter display. It is the same as the label on the LiPo battery. If the mAh is more than five percent below the figure on the label it’s likely you have a problem with your battery pack as it should not lose energy after just getting charged.

Leave the LiPo battery overnight. Do not use it as you need to see if it loses charge while not in use. A good battery pack has the same readings the next day.

How to test for aging lipos

As a possible rule of thumb, you might find that if a 3s has an IR more than around 50-60 milliohms, it is probably past its best. Based on my experience with 6s lipos, they seem to show other signs of aging before getting up to around 20 milliohms per cell (like the 3s), so perhaps around the same value 50-60 milliohms for the 6s pack as well.

The overall % of capacity seemingly dropping (ie. the charger will tell you that you pack has, say 20% left when you put it on charge, and yet you only took out 62% based on mAh put back in compared with rated mAh, so it only adds up to 82%)

You can’t measure the battery voltage without taking the battery packs apart because the voltage converter in the battery pack will provide a constant voltage (5.0V for USB, etc.) regardless of the battery voltage. However, you can estimate the battery voltage by determining when the power packs shut off. Lipo and li-ion cells are considered depleted when then fall below 3.3-3.5V, so the circuitry inside the battery pack should shut off then.

If you have direct access to the cells, you can also rely on the voltage info given by your hobby charger. When discharging, the Accucel displays the voltage, and that’s the battery voltage under load.

Charging Multiple LiPo Batteries With One Charger

In this tutorial, I’ll be going over everything you need to know in order to charge multiple lipo batteries. by basically using just one part that you don’t already have called a parallel charging board, you’ll be able to charge up to 6 gens ace lipo batteries all at the same time.

How It Works

Here’s a detailed schematic of a harness used to charge two 3s lipos in series. In series, the positive of the bottom battery is connected to the negative of the upper battery. Notice how this connection is made twice, through both the power harness and the balance harness. More on this later.

How To Para Charge

First you will need to build or purchase a parallel charge plug or board that the charge leads from each lipo 5000mah battery will be plugged into. The positive from each plug is hooked to positive and the negative of each plug is hooked to negative (parallel circuit). To keep things in reason, most will only build a plug or board that will support up to 5 or 6 batts maximum.

rcheli-diagram-charger_setup_2x_3s

Things start to become a little congested as you can see with that amount of wiring and batteries, especially if you still want to use a fire safe charge container or bag.

My general rule is it’s better to charge in parallel. With parallel charging, the batteries must have the same number of cells and a similar state of discharge. The same number of cells rule is easy for me because I keep all of my battery pairs permanently connected. For example in my Revo, my 2s batteries are wired together in series all the time. My ESC only has one plug for the batteries. Same thing goes for a pair of my 4s batteries. They are permanently wired together in parallel. So regardless of the single pack configuration, all of my battery pairs are 4s before they hit an ESC or a charger. Makes life easier.

Here’s an example of two of my 4s lipos “permanently” wired together. The stay connected to this harness all the time. In these pictures, I have a protective cap installed on the balance plug. This keeps that connector clear while I’m driving.

gens ace 3000mah lipo

Requirements and recommendations for serial charging

  • Serial wiring adapter for the main leads that matches your charger’s output capabilities. Because serial charging effectively creates a larger cell count pack, the capabilities of the charger will limit the number of packs that can be charged in series. For example a 6s capable charger can charge 2x 3s pack in series. Charging 2x 4s packs in series would require an 8s capable charger.
  • A wiring adapter for the balance leads is basically required and needs to have the same number of connections as the main leads adapter.
  • All the packs you charge in series must be the same capacity. For example you could charge a 3s 2200mAh lipo, a 2s 2200mAh lipo and a 4s 2200 mAh lipo in series together, but you can not charge a 3s 2200mAh lipo in series with a 3s 3200mAh lipo.
  • All the packs to be charged in series together need to be very close to the same voltage per cell. If I had to put a number on it I would say within .05V per cell.
  • Serial charging is best suited for someone looking to charge flight packs made up of pairs of packs like 2x 3s 2200mAh packs used in a 500 sized heli.

Things You Should Not Do

1. Because the lipo cells are connected to each other throughout multiple batteries, you should never plug in a fully or half charged battery with a battery that’s dead. Basically, the farther apart the voltages are, the hotter the wires will get. So all of the batteries should be hovering around the same voltage.
2. Another important thing to remember, is that you can’t charge two completely different batteries with each other. You can mix lipo packs from different brand names, but the cell count needs to be the same, and the battery capacity needs to be the same.

if i understand this right a 3s 2000mAh 10c 12.4 battery contains inside it 3x 1 cells 2000mAh 10c ~4.15v packs (safe recommended charging voltage). So with those Lipo batterys that are now showing up i could take apart a larger pack like a Gens 500mAh 2s 7.4v 65c – 130c to get 2x 500mAh 65c – 130c ~4.35v (can be safely charged to 4.35v per cell) for a single cell rc model and say run in a hubsan quadcopter as a example provided it fits. This would be a massive improvment over the stock batterys of most single cell quads right? slightly higher volts with high discharge giving way more power at a cost of weight.

That’s it!

Hopefully this short guide gave you some idea what multiple charging is, and how to do it on your own in a safe fashion.

Lithium polymer vs lithium ion battery which is better

A lithium polymer battery is rectangular in shape and is very thin. These batteries are used in a variety of devices from laptop computers, cell phones, and other electronic devices. Other names for lithium polymer batteries are “LiPo” and “LiPoly.” If a person had to choose which is safer, a lithium polymer or a lithium ion battery, most would say the polymer based battery is safer. The commone Lipo batteries, we can see that is RC lipo battery. Any 5000mah lipo 3s can explode if over charged but the polymer battery is not as likely to burst into flames like the ion based battery. The lithium polymer battery is what many call a pouch cell design battery. This is what makes it lighter than the lithium ion battery. The lithium polymer battery is designed where the electrode sheet and its separator are laminated onto each other. This eliminates the metal needed in the ion batteries. Another benefit of the lithium polymer battery is that manufactures can shape the cell into any form that is needed for any type of device.

Application of lithium polymer battery

LiPo cells provide manufacturers with compelling advantages. They can easily produce batteries of almost any desired shape. For example, the space and weight requirements of mobile phones and notebook computers can be completely satisfied. Also, they have low-self discharge rate, which is about 1%.

Radio controlled equipment and Airsoft

LiPo batteries have just about taken over in the world of radio-controlled aircraft, radio-controlled cars and large scale model trains, where the advantages of lower weight and increased capacity and power delivery justify the price.

As of the beginning of 2013, LiPo packs of 1.3 Ah exist, providing 45C continuous discharge, and short-time 90C bursts. Bigger packs of 4.5 Ah may feature discharge rates of 70C, with 140C bursts.

Much More have introduced a completely new line of Impact LiPo batteries called FD or Flat Discharge. The new configuration gives a flatter discharge curve meaning you get more voltage for longer instead of a steady drop in voltage as in regular packs. Available in 7200mAh 80C & 6000mAh 80C stick packs, 6000mAh 80C & 5000mAh 50 (low height) saddle packs, 4600mAh 80C shorty pack, 6400mAh 70C 1S & 3000mAh 2 cell lipo battery packs and a 4200mAh 50C (low height) stick pack.

Lithium ion batteries use carbon anode and lithium cobalt oxide cathode and an electrolyte gel. Chemistry of lithium polymer is much similar to Li-ions but it also uses a porous separator which converts into gel on exposure to electrolyte. Also Li-polymers employ different architecture. These batteries do not use metal shell like Li-ion batteries. Li-polymer battery is in next level of development and replaces liquid electrolyte with a plastic or polymer electrolyte thus allows these batteries to be molded in various shapes and sizes. The chemical construction of Li-ion battery restricts it to only rectangular shape.

 

Selecting the right battery for a specific task can become quite a technical challenge which is why retail battery packaging sometimes lists the kind of device they are best suited for. An example of the problems with selecting the best battery technology for a specific task might be the new Boeing Dreamliner. The entire fleet was grounded for several weeks because of a battery catching fire.

We are the number one manufacturer of custom LiPo batteries for RC hobby and commercial grade quadcopters and rc vehicles. Gens Lipo batteries are the best way to upgrade your DJI and Traxxas batteries. We can custom build with any voltage or capacity you require.

The Characteristics of Li-Ion/Polymer Battery

The nominal voltage of a Li-Po battery cell is 3.7V (about 4.23 V when fully charged). Two and three cell batteries are available giving us a choice of 7.4 or 11.1 volts. Li-Po batteries can provide substantial current, 6A continuously and 12A for short (30-second) bursts. lipo battery 3s have a flexible, foil-type (polymer laminate) case. Since no metal battery cell casing is required, Li-Po batteries are very light. Because of the absence of metal casing and less space utilized in intercell spacing, the energy density of Li-Po batteries is over 20% higher than that of a classical Li-ion battery and store more energy than nickel-cadmium (NiCd) and nickel metal hydride (NiMH) batteries of the same volume.

Care must be drawn in using Li-Po batteries. Their capability to provide high burst currents, lack of a rigid case, and overcharging sensitivity presents both electrical and thermal hazards. Intelligent chargers designed specifically for Li-Po batteries must be used to recharge these batteries. Overcharging a 2200mah 3s 11.1v 30c lipo will likely lead to explosion and/or fire. Li-Po cells must not be discharged below 2.75V per cell, or else the battery will subsequently no longer accept a full charge and may experience problems holding voltage under load.

Very little battery performance data seems to exist regarding the current generation of low-cost Li-Po batteries. Since we were unable to locate discharge or charge rate charts for the batteries, we decided to perform our own characterization.

Since lithium polymer (and lithium ion) are so sensitive to overcharging, the individual cells that make up the battery pack are charged independently. With NiCad and NiMH packs, the standard charging method is to apply a voltage and current across the series-connected cells so that the same current passes through each cell. The voltage across the entire pack is the sum of the individual cells voltages, but the cell voltages are not necessarily all equal. In fact, it is almost certain that they are not. Since nickel-based cells are relatively tolerant of some overcharging, there is usually no danger. It is not uncommon for one cell in a NiCad or NiMH battery pack to be dead, and yet the rest of the cells charge normally. What that means is in the case of an 8-cell pack, with the nominal voltage of each cell being 1.2 V (9.6 V total), if a charging voltage of 10.4 V is present, each cell would ideally receive 10.4 / 8 V = 1.3 V. If one cell is dead, however, the voltage across each cell would be 10.4 / 7 V = 1.5 V. That 15% increase can be handled by most NiCad and NiMH cells, but a 15% overvoltage applied to a lithium cells would eventually result in a failure, and likely a fire. Li-Po batteries are also intolerant of over discharging, and tend to die if discharged below around 2.5 V. In operation, controller circuitry should prevent the cell voltage from dropping below 3.0 V. Cell temperature should never exceed 90 °C in order to prevent the internal separator polymers from melting and allowing plate shorting through physical contact.

To the left is my Mini Pulse XT aerobatic airplane. It uses the 450 motor and a 3 cell , 11.1 V, 2100 mAh, Li-Po battery. Futaba 4-channel radio.

Early lithium batteries had a rather high internal resistance, and had rather low discharge rates. As with all technology that is doggedly pursued, significant improvements have been made to the point that the contemporary Li-Po batteries may be substituted in most systems for the original NiCad or NiMH batteries. Discharge rates of 20C or 25C are commonly available on the commercial market. You can find 20C on google, there are Gens ace 20C 2000mah lipo, Gens 25C lipo battery in the market. In battery discharge terminology, each “C” is a discharge current equivalent to the value of the energy capacity of the cell (it is not the abbreviation for the Celsius degree unit). In the case of a 1,200 mAh rating, 1C is equal to a discharge current of 1,200 mA, or 1.2 amps. A 10C cell can deliver a continuous current to a load of 10 x 1.2 A = 12 A during its discharge cycle. The E-flight 450 motor shown to the right would require atleast a 12C battery to deliver full rated power. This motor, by the way, is the one I use in my electric-powered sailplane (2-meter wingspan) and in my 4-channel aerobatic airplane (an E-flight Mini Pulse XT).

In my opinion, Lipo batteries are grossly overpriced, given the huge production volumes in effect. When you consider that almost every mobile electronic device and cordless power tool uses these batteries, the cost should be a lot lower. Maybe it is partially product liability insurance that manufacturers have to purchase that keeps the prices high, but I just paid $50 each for two 3-cell (11.1 V), 2,100 mAh packs. That is at least 2x to 3x what is should be costing at this point in the lithium cell evolution.

The Lipo Battery Management

Understanding the condition of the batteries powering the various systems of an unmanned aircraft and ground station is essential to safe and reliable flight. Their condition should be methodically monitored by charging and discharging on a regular schedule to detect degrading performance or imminent failure. An 80 percent reduction in capacity below rated, puffing of the battery pack, a distinct chemical odor, or any observed physical damage is cause to discard the pack. Of all the battery types available, the lithium polymer battery has the most demanding service requirements and dangerous failure modes. The charger for a lithium polymer (lipo) battery must be designed and rated specifically for the charging and discharging of this type of battery. Preferably, the charger will have a built in balancing circuit with a connector to the specific lipo pack being charged. Typically a lipo is charged at IC, meaing 1 times the packs rated capacity. As an example, a gens ace lipo pack would be safely charged at 2.4 amps. The discharged capacity of lipo batteries varies from 15C to over 100C with the high discharge rates bein more costly and better suited for extreme amperage discharge installations without overheating and damage.

schematic

The lipo battery may ignite and burn rapidly, or explode if mishandled. The charging and inspection precautions listed above should prove adequate to keep this from ocuurring. As a precuation, never leave lipo batteries charging or discharging unattended. There are fire proof charging bunkers and bags designed specifically to contain the flames of an ignited lipo. They are only designed to be used while personnel stand ready to react to a battery emergency. Lipo battery storage for an extended period of time should be done with the battery at 40%-50% capacity and in a stable temperature environment near 70 degrees F.

How the 3.3V step down voltage converter fits into the system:

The 3.3V regulator will supply regulated voltage to the LiPo fuel gauge and the control board (including an STM32 micro and wireless chips (WiFi and Bluetooth) from two series LiPo cells (2200mah 3s 11.1v 30c lipo)

Design Considerations:

The current draw from the LiPo fuel gauge and control board is estimated to be no more than 500mA. The chip has been configured for the following:

3.3V, 0.5A output
6.3V-8.4V input (limited to 6.3V as draining the LiPo cells too much will greatly reduce life)
50KHz

Important factors:

Efficiency: A switching regulator was chosen as it has a high efficiency. As the batteries are required to supply around 1.5A for a while. Once this circuit is implemented, tests for efficiency will need to be carried out (measuring input power/output power)
Switching frequency: A low switching frequency (50kHz) was chosen for this design. The benefits of a low switching frequency compared to a high switching frequency (such as 100MHz) means higher efficiency (less switching, less heat dissipated). However, the drawbacks are that larger chips and components are required. Efficiency has a higher priority than size of components for this project, so the lower frequency is justified.

A lithium polymer battery, or more correctly lithium-ion polymer battery (abbreviated variously as LiPo, LIP, Li-poly and others), is a rechargeable battery of lithium-ion technology in a pouch format. Gens Ace provides various types of Lipo batteries including RC lipo battery, UAV battery and RC car battery, ect. For most of the RC Lipo battery, the 2s Lipo battery, 3s Lipo battery, 4s lipo battery, 5s lipo battery, 6s lipo batttery are all available. In additon, we also have 5000mah lipo, 6000mah lipo in stock.

LiPo batteries swelling questions

A puffed LiPo battery is a sign of damage from a few causes such as over-capacity discharging (flying the battery for too long), over-current discharging (drawing too much current from the battery – unlikely in your case since you’re flying with the motor/propeller it was intended for) or simply many cycles and it’s naturally nearing the end of its life cycle.

lipo battery swelling

I have done this quite a few times with my 3S and 4S 4000 and 7.4v lipo battery 5000mah with excellent results. I use a good sized metal T pin to do the deed but am very careful not to go deep.

You can expect to store a LiPo battery fully charged for as long as you’d like. It’ll self-discharge of course. But it won’t puff up in the process. Storage at high charge levels does cause the cell to permanently lose capacity with the duration of the storage. Numbers most often quoted are on the order of a few percent of capacity per month. If you put your 2000mAh packs away fully charged, after 6 months you’re only going to have about 1800mAh of usable capacity even after fully recharging the pack. That’s why you put them away on a storage charge. The rate at which the degradation occurs is slower (much) at a lower state of charge.

LiPo battery puff because they get hot. High ambient storage temps, over charging, charging/discharging at too high a rate, deep discharges, will get the cell hot and cause the electrolyte to outgas and puff the envelope. Deep discharge can also generate gas at (I think) the Cathode. There’s supposed to be only one other process in a LiPo battery that’ll make gas, and for that you need the anode and cathode to short out, and the gas is usually accompanied by fire.

There’s no question, in my experience and from what I’ve read, anyway, that a few days storage at nominal ambient conditions in a fully charged state won’t puff the pack. I’ve left fully charged packs sitting for weeks (yeah, stupid) and only realized it when I went to recharge them and they were already at >90%. None of those packs have puffed. And I’ve been flying LiPo battery for close to 10 years now. Something else is the cause, not the charge level in storage.

Here I recommend Gens Ace Lipo battery

Gens Ace 11.1 v 3s lipo battery Pack. These new packs have a 100C constant 200C burst rate! With a rated 6000 mah of discharge capacity. The cells are Ω matched (1.8 milliohms per cell on average) and can be charged at up to 3C. These packs are really gaining popularity in the 1/8th Scale 4wd BUGGY class! They make your car easier to control with very little loss in speed due to the lighter weight of the pack. These packs come hardwired with 10 gauge wire, XH style balance plug, and your choice of power plug. We strongly urge you to select the EC5 plug as the other plugs may eventually fail under the high current demands of 1/8th scale vehicles. Add to this a free 1 year replacement warranty and our dedication to customer satisfaction and your choice becomes crystal clear.

Benefits of Lithium Polymer Batteries

The Li-polymer batteries differentiate themselves from other battery systems in the type of electrolyte used. The original design, dating back to the 1970s, uses a dry solid polymer electrolyte only. This electrolyte resembles a plastic-like film that does not conduct electricity but allows an exchange of ions (electrically charged atoms or groups of atoms). The polymer electrolyte replaces the traditional porous separator, which is soaked with electrolyte.

Like any other technology, Lithium Polymer or Lipo battery cells and batteries have their advantages and disadvantages. While there are many different types of lithium polymer cell, it is possible to describe some of the generic advantages and disadvantages. It is then possible to look at the different variants to see their own advantages and disadvantages.

Obviously the choice of whether to sue a lithium ion battery or cell is dependent upon analysing and weighing up the different advantages and disadvantages to see whether they give a real benefit. A decision can then be made about the correct type or format to use.

According to Lipo voltage, Lipo battery include 1s lipo battery, 2s lipo battery, 11.1v lipo, 4s lipo battery, 5s lipo battery, 6s lipo battery. The nominal voltage of each cell is 3.7 volts (4.2v fully-charged), so the total pack voltage is: 4 cells x 3.7v = 14.8v.

According to Lipo 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). 2200mah lipo battery 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 “energy.” Because the battery shown has a 1P arrangement, each cell has a capacity of 2600mAh.

Lithium Polymer battery advantages

One of the first advantages of lithium batteries is their small size. You can fit a lot of lithium on a bicycle frame. This alone can give your ebike some seriously impressive range. Two or three mid to large capacity lithium batteries could easily fit on one ebike, giving potential ranges of 100 miles (160 km) or more. I guess this would be great for people that don’t mind sitting on their bike for three to five hours at a time, or that for some reason don’t want to charge up for weeks (hey, when riding your ebike through a zombie apocalypse, the last thing you want to be doing is searching for an outlet).

Lithium Polymer batteries made specially for ebikes often come with specific bicycle mounting points making them easy to bolt to the bike frame, seat post or rear rack. If you go with a different type of lithium battery without ebike specific mounts, you’ll likely have to put it in a bag on the bike, which is still a good option, and one that I even prefer sometimes. (Link to blog post of mine about center frame triangle batteries).

Lithium Polymer batteries are also small enough to allow you to place your batteries pretty much anywhere on your bike. This is especially true for people who want to assemble their own pack or use heat shrink wrapped lithium batteries instead of hard case lithium batteries with prefabricated bicycle frame mounts. This can help spread the weight around or hide the batteries to make a stealthier bike.

Proper Way to Disposal of Lithium Polymer Battery

To begin with, damaged lithium polymer batteries (and even undamaged ones) can be extremely dangerous. The horror stories are very well-known, but new RC hobbist typically don’t come across good info on proper handling, storage, and disposal of lipos until well after they’ve begun their journey into the hobby. Usually, it takes a search for “why is my lipo so swollen?” before people get the spiel about the dangers of lipos. The scary part is that most people would have squeezed and poked at the RC car lipo lipo before they ever do the research. And typically, if you’re new, you’re doing some crashing and hard landings that bang the battery up even more.

The most important part of lipo disposal is to make the lipo safe, safe to be crushed in a garbage truck or safe when tossed in the recycle bin. We do not want to pass off a potentially dangerous lipo to people that do not understand what it is or how to handle it. As such I believe we have a responsibility to make them safe before they leave our care.

So, what is the safest way to dispose of LiPos? Enter the humble incandescent 12 volt automobile taillight bulb. If you have any skill at all at soldering (and you’ll need it anyway if you do anything with electric RC) it’s very easy to solder some wire to the contacts of a 12 volt automobile taillight, add whatever your battery connector of choice is to the other end and insulate it with electric tape or heat shrink. To dispose of your battery, just plug the battery into the taillight, put it somewhere where it’s safe (I use the holes in a cinderblock with a plastic baggie full of sand above – if the battery blows the baggie will melt and the sand will pour over the battery) and leave it until the bulb goes out. Then leave it for some hours more, check the voltage to make sure the battery is completely discharged, cut of the battery connector, strip the wires and twist them together. Then dispose or recycle the now completely safe battery. A single taillight bulb will work for up to a 3s 11.1v lipo battery pack of any size, use two taillights in series for 4S lipo battery or more.

Here recommend Brand Lipo battery for you

Trust the battery that consistently delivers peak performances even through the roughest conditions. The Gens Ace 40C 4S 5000mAh 14.8V LiPo Hard Case battery pack has a high-capacity, high-discharge rate that gives you the power and run-time you expect from all Gens Ace batteries. This battery includes not only plug adaptors to fit Deans, Traxxas, Tamiya and EC3 plug types, but also heavy-duty features like 12 AWG soft silicone wire leads and our patented High Current Universal Plug System.

Gens Ace warrants this product to be free of material and workmanship defects when new. This product has been checked for proper functionality and inspected before leaving the factory. All Gens Ace batteries are warranted against the following: DOA (Dead on Arrival) cell or pack, swollen or puffed pack upon arrival, loose or broken solder joints, and wires or plugs on arrival.

Home made battery disposal

The first task is to drain the battery to 0V as Lithium polymer batteries are safe if carrying no voltage then you need to ensure no more charge can build up, the following will guide you through it.

  • Grab a bucket of sand and place it outside with the battery inside.
  • Connect an led or small lamp to the battery and drain it completely, leave connected for 1 day after the led stops glowing.
  • Cut the connectors off the battery.
  • Strip the wires
  • Join the red and black wires to create a short circuit and prevent any build up of voltage.
  • LiPo Battery successfully stabilised and you can safely dispose in the regular trash.

A slow discharge produces less heat and is much more safer then draining the battery fast with a motor or high load connection.

Hopefully I have dispelled the myth of salt water LiPo disposal, and I hope that this helps people who are looking for a safe way to dispose of their LiPos.

This article source comes from: http://rclipobatteries.blogspot.com/2016/01/how-to-choose-and-where-to-buy-lipo.html