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A Guide to Lithium Polymer Batteries Before using this battery- the following MUST be read. Lithium cell technology, both lithium polymer (Li-poly or LiPo) and lithium ion (Li-ion), is quite different from the more commonly used NiCd and NiMH. There are many things to consider before using lithium cells for e-flight. But none is more important than safety. While all cells must be treated with respect due to the energy they contain when fully charged, lithium cells have the highest energy density. They also have some unique qualities that require special safety considerations. Before discussing other aspects of lithium cells, it's important to first understand these special safety considerations.
Charging – Safety IMPORTANT DO NOT use lithium polymer batteries Unless you are willing to learn about them prior to use: Read on to find out why. Lithium cells must be charged very differently than NiCad or NiMH. They require a special charger specifically designed to charge lithium cells.
Make sure your charger is designed to be used with Lithium Polymer batteries before going any further. In general any charger that can charge lithium ion can charge lithium Polymer assuming that the cell count is correct. You must NEVER charge lithium cells with a NiCad or NiMH only battery charger. This is dangerous. Charging cells is the most hazardous part of using lithium batteries. EXTREME care must be taken when charging them. It is important to set your charger to the correct voltage or cell count. Failure to do this can cause the battery to spew violent flames. There have been many fires directly caused by lithium batteries. PLEASE BE RESPONSIBLE when charging lithium batteries.
Here are a few MANDATORY guidelines for charging /using LiPos. 1. Use only a charger approved for lithium batteries. The charger may be designed for Li-Ion or Li-Poly. The both batteries are charged in exactly the same. 2. Make certain that the correct cell count is set on your charger. If you don't know how to do that, ask your local hobby shop or get a charger that is fully automatic - like the” CellPro” brand of new computer controlled chargers that are able to sense the correct cell count. 3. Before you charge a new Lithium pack, check the voltage of each cell individually. I do this after every tenth cycle there after. This is absolutely critical- in that an unbalanced pack can explode while charging even if the correct cell count is chosen. If the cells are not within 0.1 volts of each other then charge each cell individually to 4.2 volts so that they are all equal. If after every discharge the pack is unbalanced you have a faulty cell and that pack must be replaced. Again the CellPro charger does this automatically. 4. NEVER charge the batteries unattended. This is the number one reason for houses and cars being burned to a crisp by lithium fires. 5. Use a safe surface to charge your batteries on so that if they burst into flame no damage will occur. Vented fire safes, pyrex dishes with sand in the bottom, fireplaces are all good options. 6. DO NOT CHARGE AT MORE THAN 1C.( ie. minimum charge time is 1 hour) Unless you are using a quality high rate battery and a CellPro charger that is designed to charge at the higher rate. 7. If a cell balloons while charging DO NOT puncture the cell while it is still hot. Discharge the cell first, then put the cell/pack in salt water and wait until the cell has cooled and is completely discharged. Once it is cool gently puncture the pack's outer casing and put it back in the salt water. After this the cell is safe to throw in the garbage. If the outer cover is punctured and left open to the air it WILL EXPLODE . 8. VERY IMPORTANT: If you crash with your lithium cells they may be damaged such that they are shorted inside. The cells may look just fine. If you crash in ANY way carefully remove the battery pack from the airplane and watch it carefully for at least the next 20 min. Several fires have been caused by damaged cells being thrown in the car and then the cells catch fire later and burns the car completely. 9. Charge your batteries in an open ventilated area. If a battery does rupture or explode hazardous fumes and material will spew from the battery. 10. Keep a bucket of sand nearby when you are flying or charging batteries. This is a cost effective way to extinguish fires. 11.Realize that these batteries are dangerous, do not think to yourself that “it won't happen to me” as soon as you do that it will happen to you and you'll be trying to rescue your kids from your burning house or car.
Now that we have covered that important topic let's move on to lighter matters: Lithium What? Lithium Polymer batteries are used in many electronic devices. Cell Phone, Laptops, PDA's, Hearing Aids just to name a few. Most, if not all, lithium polymer batteries are not designed for RC use, we use them in different applications than they were designed for. They are similar to Lithium Ion batteries in that they each have a nominal voltage of 3.6 volts, but dissimilar in that they do not have a hard metal casing but rather a flexible material encloses the chemicals inside. The "normal" lithium polymer batteries are thin rectangle shapes with two tabs on the top one positive one negative. The reason we use Lithium cells is that they are significantly lighter than comparable NiCad or NiMH batteries, which makes our planes fly longer and better. Voltage and Cell Count: LiPolys act differently than NiCad or NiMH batteries do when charging and discharging. Lithium batteries are fully charged when each cell has a
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voltage of 4.2 volts. They are fully discharged when each cell has a voltage of 3.0 volts. It is important not to exceed both the high voltage of 4.2 volts and the low voltage of 3.0 resting volts or 2.5 during discharge. Exceeding these limits can harm the battery. The way to ensure that you do not go below 2.5 volts while flying is to set the low voltage cutoff (LVC) of your electronic speed control (ESC). It important to use a programmable ESC since the correct voltage cutoff is critical to the life of your batteries. Use the ESC's programming mode to set the LVC to 2.5 volts per cell with a hard cutoff, or 3.0 volts per cell with a soft cutoff. If your ESC does not have hard or soft cutoff, use 3.0 volts per cell. You will know when flying that it is time to land when you experience a sudden drop in power caused by the LVC. If you have previously been flying with NiCad or NiMH batteries, switching over to lithium polymer will result in a different number of cells being used. If you had 6 to 7 cells of round cells then 2 lithium polymer cells will correctly duplicate the voltage of those cells. If you had 10-11 cells then 3 lithium polymer cells would be right for you. There are a lot of 8 cell flyer's out there that are stuck between 2 and 3 cells. In my experience the best option is to determine how many watts you were using before and duplicate that with your Lithium Polymers, Motor, and Prop. For example. If you were running 8 cells (9.6volts) at 10 amps on a speed 400 airplane, then you have 9.6 x10, 96 watts. So if you went with 2 lithium polymer cells (7.2 volts nominal) then you'd need to change your prop such that you used 13 amps. If you went to 3 LiPoly's (10.8 volts nominal) then you'd need to reduce the amperage to 8.9 amps. These estimates are approximate, and some experimentation is required for best results but conserving Watts is a good way to start. 10C from 3S4P? How fast a battery can discharge is it's maximum current capacity. Current is generally rated in C's for the battery. C is how long it takes to discharge the battery in fractions of an hour. For instance 1 C discharges the battery in 1/1 hours or 1 hour. 2 C discharges the battery in ½ or half an hour. All RC batteries are rated in Milliamp hours. If a battery is rated at 2000 Mah and you discharge it at 2000mA (or 2 amps, 1 amp = 1000mA) it will be completely discharged in one hour. The “C” rating of the battery is thus based on its capacity. A 2000mAh cell discharged a 2 amps is being discharged at 1C (2000mA x 1), a 2000mAh cell discharged at 6 amps is being discharged at 3C ( 2000mA x 3). Currently LiPoly technology does not allow currents as high as NiCad or NiMH batteries do. Because of this many LiPoly batteries are put in parallel to increase the current capacity of the battery pack. When 2 batteries are wired positive to positive and negative to negative they become like one battery with double the capacity. If you have 2 - 2000mAh cells and you wire them in parallel then the result is the same as 1 - 4000mAh cell. This 4000mAh cell has the same C rating as the original 2000mAh cells did. Thus if the 2000mAh cells could discharge at a maximum of 5C, or 10 amps then the new 4000mAh cell can also discharge at 5C or (4000mA x 5) 20 amps. This method of battery pack building allows us to use LiPoly batteries at higher currents than single cells could produce. The naming convention that allows you to decipher how many cells are in parallel and how many are in series is the XSXP method. The number in front of the S represents the number of series cells in the pack so 3S means it's a 3 cell pack. The number in front of P means the number of cells in parallel. So a 3S4P pack of 2100mAh cells has a total of 12 cells inside. It will have the voltage of any other 3S pack since the number of cells in series determines the voltage. It will have the current handling of 4 times the maximum C rating of the 12 individual cells. So say our 3S4P pack had a maximum discharge of 6C. That means that it has a nominal voltage of 10.8 volts (3x3.6) and a maximum discharge rate of 50.4 amps (2100mAh x 6Cx4P ).
General usage tips. 1. Lithium batteries don't work well in cold air. If you are flying in the winter keep the batteries in your car for best performance. 2. Don't let the batteries overheat. Try and keep them under 140-160 degrees F. This will prolong your battery life. Use a heat sensitive stick on label to keep a check on this. They change colour if the Temp. goes too high during a flight at any time – they are cheap and worth using. 3. Don't push the batteries past their rated maximum C rating. This will damage the battery and the apparent capacity of the batteries will drop. If when you recharge you are only putting ½ to ¾ of the rated capacity back into the batteries you are probably pushing them too hard. 4. Occasionally a cell will “puff” up a little when first used – This is normal , and will NOT reduce the performance of the battery- However as always, keep an eye on the battery for any obvious deformation.
LITHIUM POLYMER BATTERY PACK SAFETY INSTRUCTIONS General charging and discharging guidelines. Lithium polymer batteries are charged using the constant voltage/constant current charging method. Charge Voltage The batteries should be charged at no more than 4.2V per cell. e.g. 2 cell pack – 2 x 4.2V = 8.4V charge voltage. Charge Current The recommended charge current is 0.7C – 1C. e.g. 1000 MAH battery pack should be charged in the range of 700 MAH to 1000 MAH ie. 1 hour charge time. Only use a faster charge rate if you have good quality cells and a smart charger like the CellPro. Ambient Temperature of Battery Pack During Charging 0 ºC – 45 ºC Charging of Low-Voltage Battery Packs When the voltage per cell is 2.9V or less, the charge current should be 0.1 CA or less. Termination of Charging The charger will determine when the battery is fully charged by detecting a change in current. Stop charging once the current has reached a point between 0.1 CA and 0.07 CA Discharge End Voltage Avoid discharging cells under 3.0V per cell . Excess discharge may result in deterioration in the battery’s performance and if discharged lower , the battery will be useless / or dead !. In other words, try not to discharge the battery to less than 3.0 Volts per cell.
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SAFETY PRECAUTIONS • • • • • • • • • • • • • • • • • •
Only charge lithium polymer batteries using chargers specifically designed for Lithium Polymer batteries. Do not leave your battery connected to any device like a Voltage Regulator, as these can slowly flatten the cells and will permanently destroy the battery ! Never leave Lithium Polymer batteries unattended whilst charging. Never charge Lithium Polymer batteries inside a model; hot batteries can cause fires. Never charge Lithium Polymer batteries inside a motor vehicle. Never charge Lithium Polymer batteries on any surface which can catch fire e.g. wooden benches. Do not dispose of batteries in a fire. Do not allow batteries to get wet. Do not use the batteries with positive and negative terminals reversed. Do not short circuit the battery. Do not pierce the battery or subject it to heavy knocks or impacts. Do not directly solder to the battery. Do not use or store the battery inside motor vehicles during hot weather. Doing so may cause the battery to overheat, risking fire or explosion. Never charge the battery with more than 6 volts per cell. Doing so may cause the battery to overheat and ignite. Do NOT add additional cells to your pre-built packs unless battery voltage within.01Vper cell .Do NOT parallel partially charged packs together with fully charged packs. Always store cells or battery packs in a secure location where they cannot be shorted or handled by children. Do not store fully charged nor fully empty battery packs.
FIRE WARNING: If your battery balloons in size, is punctured or is malformed, take precautions to get the battery to a non-flammable area for at least one hour IN CASE OF FIRE. After several hours place the battery in salt water for 24 hours – then throw out it out.
Battery DISCHARGE or “C” Rating Limits and Specifications. Discharge limit is : battery capacity in Mah. multiplied by the “C” rating. Eg. 2000 mah pack @ 15C Maximum discharge rate is :2000 x 15 = 30,000 mah or 30 Amps. continuous per battery. If more current is required – add more batteries in parallel to double up output. These limits must NOT be exceeded or permanent damage will occur. Use of an Amp -Meter to measure discharge rate is essential. It is highly recommended to use a cell balancer device to charge LiPo batteries if supported by your battery pack. This device will balance out the voltage of each cell within the battery, which avoids over charging of an individual cell and the resulting damage to that cell. Discharge should only be via the “power” lead from the battery – not the balance lead. ………………………………………………………………………………………………. The proceeding information is a guide only. Tates Performance Hobbies is not the author of this information. Specifications and methods may change any time without notice. It is your responsibility to operate these batteries in a safe manner. If you are not sure how to use this battery, call for instructions or return for a refund, Battery must be new and unused, and proof of purchase must be provided.
WARRANTY Due to the complexity and special procedures required while using LiPo batteries it is impossible to provide a product warranty on LiPo cells. All batteries are tested, and leave the factory in working order, but due to the high performance nature and special handling required, it is impossible to ascertain if a battery has been correctly handled during use. All Li Po battery cells are therefore sold only as is – and Do NOT have any implied WARRANTY. Distributed By :
135 Shannon Ave Geelong West VIC 3218
Ph 03 52224201 Fax 03 52231257 ABN 0007437523 E Mail ;
[email protected] Web : www.tates.com.au + www.magnumengines.com.au Importers and Distributors of Quality Radio 3 Control Hobby Products
CellPro – Fully Automatic 2 to 4 Cell LiPo Charger The Cellpro balancing charger is an new innovative design for charging LiPo and A123 battery packs at up to 4 Amps. Fully AUTOMATIC - this feature allows you to simply Plug-and-Play and Walk Away! Super FAST Charge rates - The proprietary algorithms, and its ability to individually monitor each cell, allow higher charge rates of up to 3.0C with the “Revolution” and other high quality brand LiPo’s. Super SAFE- Automatic full protection from all connection errors. Easy to use features and menu simplify operation and help eliminate operator errors. Fuel Gauge reading - Displays the remaining capacity of the battery as a percentage Added Features – Displays individual cell voltage, Charge Current, Supply Voltage and amount of charge added (mAh). Automatically determines pack capacity and sets optimum charge rate, dynamically updates charge rate to suit. Manual Charge rates of – 0.25A to 4A in 0.25 A increments Cold weather cycle - Reduces damage in cold weather, limits cell voltage to 4.10 Vlts. Cell recovery cycle – restores cells after over discharging. Adapters available separately to interface with various manufacturers batteries.
Revolectrix CellPro- 10 Fully Automatic 1 to 10 Cell LiPo Balance Charger Up to 10A Charge Current – Continuous Power 300W (estimate) Displays Individual Cell Internal Resistance to 0.1 mohm Resolution (Battery Quality Indicator), a feature exclusive to the Cellpro 10s charger. Charges Lithium Polymer or A123 Cells (variable charge rates for both Lipo and A123 cells). Charges 1 Pack of 1s-10s or 2 Packs of 1s-5s Simultaneously Includes Start/Stop Button Backlit Liquid Crystal Display Supports 2-way P.C. Interface - Drive the Charger from the P.C. Access Advanced Features from the P.C. (Setup Custom Presets, Adjust Speaker Volume, LCD Contrast, and More) Internet Up gradability (IU) Feature -- No need to send the charger to the factory for firmware upgrades again. Do it over the internet. The Cellpro Node Connector is a key part of the system. It enables the charger to monitor individual cells and independently charge each cell to its optimum level. The Cellpro 10s charger may be used to charge any brand of Lithium pack using either the Cellpro adapters or pigtails. The charger includes two 5s output connectors and includes two simple 5s-to-4s adapters. This enables automatic support for any current Cellpro 2s4s battery sold in the past. These extra accessories also enable you to connect any of the existing Cellpro 4s adapters for other brand batteries with the Cellpro 10s charger. Using the Cellpro 10s Charge Control Software, the charger can be set to work with virtually any good, regulated power supply, even if the power supply is not designed for high power. By entering current capability; e.g., 1-25A, the charger will automatically adjust the maximum charge current to protect the programmed power supply. There is also a simple procedure that can be performed at the field to reset the input power supply to the factory default (25A) if a PC is not available. You might need to do this, if for example, you use a small AC power supply at home, but you want full charge current from your car battery at the field. This powerful feature allows you to decide how much money to spend on your power supply. Faster Auto Charge rates (1.0C, 2.0C, and 3.0C), permit safe charging Lipo batteries at up to a 3C charge rate. This is only possible with Direct cell-balancing technology which incorporates integrated, highly-accurate cell monitoring and balancing during charge. Unprecedented Accuracy - Fuel Gauge Readout - Simple, easy to use one button user interface Unparalleled Safety - Self Diagnostics - Storage Charge Mode - Safety Charge Mode Support for long battery extensions - Cold Weather Mode Accessory Items: For PC Interface, the Cellpro 10s charger requires the new FUIM2, 2 way, P.C. USB Interface Module. The charger will not operate with the older FUIM1 device which is designed for 1 way communication only. The Cellpro charger is designed to charge Revolution battery packs directly. Adapters are available separately to interface with various manufacturer's battery packs up to 4s configurations. These adapters are used with the Cellpro 4s charger and may be used with the new 10s charger for packs up to 4s. Users of the 10s charger may also adapt to larger battery packs using the 6 pin Cellpro balancing connectors (CPBP6P-10) or a combination of the 5 pin Cellpro balancing connector (CPBP7) and the CPBP6P-10. All current and future Revolution branded battery packs will adhere to the following conventions for the above connectors. We recommend that customers adhere to the standards we have defined when re-wiring battery packs using the Cellpro battery pigtails.
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