Popular Post Garry Posted June 28, 2006 Popular Post Share Posted June 28, 2006 Here is a guide for all your questions you have to do with the electric side of R/C cars. This guide is written by Garry, Nick, doom56 and c0sie of the MSUK forum, and is NOT to be reproduced in any way, shape or form without expressed written consent from the author. To find what you are looking for easily, use Ctrl+F and type the word, phrase or number in the box that pops us. =====[Table of Contents]===== A. Basic information. - (A01) What is a battery pack? - (A02) What is a motor? B. Brushed Motors - (B01) What is a brushed motor? - (B02) What is a Turn/Wind? - (B03) What is a Stock/Super Stock motor? - (B04) What is a Modified motor? - (B05) Why is there difference in prices of motors? - (B06) What's a 'skim', and how often should I do it? - (B07) How do I tune a motor? - (B08) What are 'caps'? C. Brushless motors - (C01) What's a brushless motor? - (C02) What does 'Kv' mean? - (C03) How do I maintain one? - (C04) What is 'cogging'? D. Batteries - (D01) Whats the difference between NiCD, NiMH, LiPO etc? - (D02) What what do the numbers on a battery mean? - (D03) What is a 'matched' battery? - (D04) Does more cells equal more power? - (D05) What's the difference in pricing mean? - (D06) What's the deal with LiPo? E. Charging and Chargers - (E01) Do all chargers charge any battery? - (E02) What charge rate should I use? - (E03) Why is the battery warm/hot during a charge? - (E04) What is 'discharging/equalizing/cycling'? - (E05) How do I look after my new battery? - (E06) How do I look after a LiPo pack? F. Radio Equipment - (F01) What does the radio equipment consist of? - (F02) Which is better, sticks or wheels? - (F03) What are 'crystals'? - (F04) Is any frequency available? - (F05) What is 'interference'? - (F06) Which servo is best for me? G. Electronic Speed Controllers - (G01) What is an Electronic Speed Control? - (G02) Why are some more expensive than others? - (G03) Should I buy one with reverse? - (G04) Are brushed and brushless ESC's the same? - (G05) What does the 'turn limit' mean? - (G06) What is a 'power cap'? H. Update notes - Created July 1st 2006. - Made available 4/6/2006. - Added to 'Useful Links' 6/6/2006 - LiPo informationa dn charging guidelines added 11/01/2007 - BRCA 4200mah guidelines added 26/02/2008 - Updated with latest technology, ideas and guides 04/05/2009 ======================================================== A. Basic information. - (A01) What is a battery pack? A battery pack is several individual cells soldered together to create a pack. The most common type and form are six 1.2v sub-C sized Nickel Metal Hydride cells soldered together to create what is known as a 'Stickpack', as it resembles a stick: [][] [][] [][] There are other styles of battery though, which include side-by-side: [][][][][][] and the 5-cell hump pack (used as reciever batteries in nitro cars): [][] [][][] Depending on the application, battery packs can consist of anywhere between 2 and 14 cells, with some custom cars and trucks using even more. - (A02) What is a motor? A motor can best be described as a mechanical device used to move the car under an electrical current. In the past 10 years, the technology used to create them is astounding, and you can make an car very quick, fairly simply. Most motors used in RC share the same basic idea as motors found in real cars (Starter motors), or PC's (disk drives etc). There are two specific types of RC motors used today, which we will go into further detail about below. B. Brushed Motors - (B01) What is a brushed motor? A brushed motor is exactly that - a motor using rectangular faced brushes, but not the kind you sweep the floor with. They are a metal mixture of compounds that wear out, but can be replaced to alter performance. It is a fairly complicated thing, but can be easily understood with practice. In general, a motor consists of the following components: Armature (with 3 stacks of windings) Can (with either 2 or 4 magnets) Endbell with brush hoods and timing ring Brushes Springs Ball bearings/bronze bushings Each of these combine to make the motor rotate the armature, which turns the pinion. The power from the ESC goes into the positive side of the endbell, through the brush hoods and brushes, and into one side of the armature stack, via the copper commutator. The magnet repels that side and turns the armature round, whilst the power does the same to the next stack. This happens thousands of times a minute! On a lot of motors, the timing can be changed to increase performance, but also the wear. In addition to this, there are 4 main types of brush design, what give difference perfomance and lifespan characteristics. 'Laydown' brushes are where the longest edge of the brush face is 'laid down' across the width of the commutator, these are usually found on 27t motors. 'Standup' brushes are where the longest edge of the brush face is 'stood up' along the length of the commutator, these are usually found in 19t and modifited motors. 'Checkpoint' brushes are a round or octagonal faced brush screwed into the brush hood and gives the best characteristics of both laydown and standup brushes. They are found in the Checkpoint range of 19t and modified motors. 'V2' are similar to Checkpoint brushes, but have an oval face, and are inserted at a 45deg angle to the commutator. These are similar in perforamce to standup brushes, but much less wear, and are found in Peak and Orion 19t amd modified motors. - (B02) What is a Turn/Wind? Turns are the number of times wire is wrapped around each armature stack. Less turn means a faster motor and more means slower. But thats not all of it. Motors are classified in a certain number order. For example: 19x1 This means that the motor in question a 19 turn single. The second number is the power delivery of the motor. This usually ranges from 1 to 6 (single, double, triple, quad, quint, hex). With this number, lower means more punchy, higher means smoother. You will see motors with as few as 6 turns and as many as 35 or more. - (B03) What is a Stock/Super Stock motor? In the UK (touring cars especially), there are 3 classes of racing. Stock, Super Stock and Modified. Mod will be discussed below. Stock racing is simple. The motors have to be rebuildable 27t's, with fixed timing and bushings. Super Stock is similar, but are rebuildable 19t's, with fixed timings and ball bearings. Both can be tuned for give lots more power than factory, and companies such as Demon, Team Br00d, EA Motorsports etc offer ready to use tuned motors. - (B04) What is a Modified motor Modified is another class of racing. The basic motor is similar to Super Stock, but has adjustable timing and any armature turn can be used. At nationals, you can regularly see 7t or 8 turn motors. Thus, this is the quickest class of UK racing. However, any motor that has adjustable timing is usually classed as a modified motor, so you can 13t, 16t, 20t modifieds etc. - (B05) Why is there difference in prices of motors? As with many things, you get what you pay for. If you don't spend a lot on a motor, you won't get much in the way of performance. For example, you could buy a modified motor with bushings, low power/long life brushes and £20 RRP, it won't perform as well as a £60 ballraced high power race modified. In the UK, the BRCA governs the price limits of motors. 27t: £30 19t: £34 Modified: £59 95% of racing bred motors will be right on these price limits, so assume that any which are below these prices are sport-spec motors. The main differences between sport and race spec motors are that sport motors are designed for a longer life at a lower performance level than race motors. Sport motors usually have bushings than bearings, but there are some exceptions. In almost every race, as race motor will be quicker than sport motor. For example, a race 19t will be faster than a sport 13t modfied. - (B06) What's a 'skim', and how often should I do it? In the process of the motor running the brushes contact the commutator, and small sparks occur where the contact is made. This is a tiny carbon deposit on both the comm and the brush. After a while you will find the speed of the car isn't what it was when the motor was new, and will probably be the time you need to skim the armature. Skimming itself is where you take apart the motor and put the armature onto a dedicated motor lathe, to 'skim' the carbon layer off of the comm. Lathes vary in price, and generally are £100+ new, so if you race a lot, or use lots of motors, it may be a good idea to invest in one. Otherwise, your local model shop should provide a service for maintaing motors. Here is a guide on how to actually skim the comm: http://www.petitrc.c...ews.php?id=4223 Don't be tempted to use Brasso, or sandpaper on the comm though. They are very delicate, and can easily break up the surface. To work at its best, you need to have the comm being mirror smooth. If you take off the carbon deposts with a method other than a comm lathe, you'll cause the edges of the brushes to break apart and cause premature wear (as the comm and the brush surfaces aren't a match anymore). - (B07) How do I tune a motor? Tuning motors are definitely a black art, and few know how to do it effectively. In general, to make a motor go faster, you would increase the timing (where possible), and change to harder brush springs with softer, silver content brushes. However, you'll probably have to skim the motor every 2 or 3 times, so unless you race, stick with the motor as it comes, or if you use a 27t or 19t, try a 'tuned' factory motor from one of the dedicated companies, like Demon, Team Br00d, EA Motorsports etc - (B08) What are 'caps'? Suppressor caps (capacitors (usually small, normally yellow/green in size - need to use 3 ideally)) reduce/eliminate electrical 'noise'. 'Noise' can cause interference, create 'arcing' etc etc...not good. They are soldered accross the motor, from Pos+ to can, can to Neg-, and Neg- to Pos+. Some 27t and 19t motors come with caps pre-installed in the form of a PCB on the endbell, these don't need any more caps to be added. C. Brushless motors - (C01) What's a brushless motor? A motor that uses no brushes. It reduces friction resulting in improved efficency. With this limitation removed, brushless motors can be alot more powerful and efficent. Essentially, the design is an inside-out brushed motor. It has the magnets mounted onto the armature with the windings mounted into the can. They are usually rated in two types of terms, the Kv rating, and the Point scale. - (C02) What do the ratings mean? When looking at brushless motors, you'll see that there are two types of ratings. The "Kv" rating is how many RPM per Volt. For example, if a motor was rated at 5900kv, then at 7.2v (6 cells), it would theoretically rev to 42,480rpm. These are useful for working out which motor will rev higher on a given amount of voltage. Lower Kv's can take more voltage, so are better for bigger and heavier models, such as 1/8th buggy kits. The Point scale is more recent, and is mostly just for racing motors. Its generally accepted in the UK that 13.5 motors are similar in terms of performance to 27t brushed, and 10.5 to 19t brushed. Other motors are essentially ''Modified'' motors. To roughly work out a Point to brushed rating, take the brushless turn, and double it to make the brushed turn. For example, 6.0 brushless is similar to a 12t brushed, 3.5 brushless is similar to a 7t brushed. Brushless motor design means that the brushless versions are more torquey though, so can pull a higher gear ratio. - (C03) How do I maintain one? There is little that needs maintaining with brushless motors. Depending on the can used, openings, normally near the wiring and base of the motor should be covered with electrical tape. To reduce dirt getting inside the motor. Bearings should be oiled every couple of months, but other than that, they are 'fit-and-forget' motors. With some makes, a "clamp" is required because of the pressure inside, the end cap can pop off the motor. A clamp, holds this together. This is mostly common with the sensorless motors, such as Feigao and BK. If the end cap is screwed in, a clamp is not required. - (C04) What is 'cogging'? Cogging is seen in sensorless systems. However this term is becoming less frequent, as the systems on the market are becoming increasingly advanced. When the ESC sends a signal to the motor, its a pre-set signal that tells the motor whichs windings to turn on and off. When the armature position is 'caught' between two winding signals, it causes the armature to electronically 'bounce' off of each signal, casuing the stutter. This can be due to high gearing, a poor power source or the quality of the motor. D. Batteries - (D01) Whats the difference between NiCD, NiMH, LiPO etc? These terms descirbe the chemical make-up of the cell. NiCD means Nickel Cadnium, NiMH means Nickel Metal Hydride and LiPO means Lithium Polymer. NiCDs are dangerous to recycle, so they are being phased out. - (D02) What what do the numbers on a battery mean? This is the capacity. 1Ah = 1000mAh. The larger the number, the more energy the battery holds. More energy = longer runtimes. In terms of sub-C size, NiCDs begin around 1400mAh and go up to 2800mAh. NiMH's begin around 3000mAh and go up to 5200mAh currently. LiPO start around 600mAh and go up to 10,000mAh! The most common capacities are around 3300-4600mAh. - (D03) What is a 'matched' battery? When a battery pack is picked, you cannot have any 2 cells indentical. Therefore, companies offfer 'matching' services. Basically, you have a pack where each cell is matched on a computer to have the highest overall voltage, or the longest runtime. Depending on whether you race, or just drive for fun will dictate whether you need or want matched cells. - (D04) Does more cells equal more power? Yes and no. If you were to have a 6 cell battery pack in a car, and added an extra cell, you'll see a performance increase as you'll now be running on 8.4v as opposed to 7.2v. But, the extra cell you add needs to be the same brand, spec and condition as the others in the pack, or the pack will be become unbalanced and start to damage the others in the pack. If you do go for more cells, do so whilst buying a new pack. - (D05) What's the difference in pricing mean? As with motors, you tend to get what you pay for. If you can, buy the most expensive cells you can afford. Matched batteries (as mentioned above), tend to come in different levels of matchedness, where compnaies will offer 'club' spec cells at a lower price than 'team' spec or even 'worlds' spec cells. Generally the more you pay, the better the pack you will get. - (D06) What's the deal with LiPo? LiPo are a fairly recent technology in RC cars. Using a different chemical make-up to our more familiar cells, they offer huge runtime, no memory effect and higher voltage. For car use, the majority of packs are 7.4v, 2 cell. There are 2 varients of packs, cased and uncased. 'Cased' are where the cells are housed a hard plastic, foam lined case to help protect the cells in an impact. 'Uncased' are where the cells are are just heatshrunk, and shouldn't be used for racing, or in other situations where you're driving with another car. A hard impact with a LiPo can cause an irreversable chemical reaction inside the battery that can result in a fire, so caution MUST be taken. LiPo are not suitable for electric newcomers! As with any rechargeable battery, damage can be cuased though mistreatment, misuse or carelessness. Always follow the reccomended guidelines when using LiPo batteries. E. Charging and Chargers - (E01) Do all chargers charge any battery? No. There are several limitations among chargers. Capacity, voltage, amps and type. Check your manual before trying to charge any batteries to see if it is compatible. Generally, most new chargers will do both NiCD and NiMH, but LiPO's require specialized chargers. - (E02) What charge rate should I use? Generally, the higher amps you charge at, the more 'punch' the pack has, but the downside is the overall lifespan of the pack drops. It doesn't matter too much whether you fast charge or trickle charge. Sub-C battery packs used to work best with a 6amp charge rate and a delta peak threshold of 3 mv/cell. However, recent well publicised failiures of IB (Intellect) cells means that the BRCA have issued a safety guideline for all 4200+ mah cells. http://www.brca.org/BRCA/elecboard/news/20...%20Practice.htm Micro and receiver packs should be charged at 1.4 - 2amps with a delta peak threshold of 3 mv/cell. - (E03) Why is the battery warm/hot during a charge? It is down to the chemical recation taking place inside each cell. Don't worry about it, unless the pack becomes too hot to touch for more than 10 seconds. - (E04) What is 'discharging/equalizing/cycling'? Even if you drive your car until it stops dead, there will still be some life left inside the pack. To get this out, you need to discharge the pack. If you don't the pack won't get a full charge the next time you charge it, and over a period of time, the pack will become useless. To discharge a pack, you can make your own discharger out of a 10a car lightbulb (10a is the typical load a motor puts a battery pack under), or buy one of the dedicated dischargers companies like LRP do for around £20 Either of these is fine for stickpacks, but for side-by-side saddle packs, you'll need to equalize the cells. When a pack is charged and discharged over a couple of months, the performance of cells changes greatly. Each cell charges and discharges at its own rate, and have their own capacity. Therefore, every once in a while you need bring them back up to freshness with an equalizing tray. Essentially, its 6 small dischargers in one, used to equalize each indiviual cell. LRP, Nosram, Robitronic and Novak all do equalizing trays, from £15 to £75. Cycling is where you either charge and discharge twice, or charge and equalize twice. Both are recommended every 3 or 4 months, or when you buy a brand new pack. - (E05) How do I look after my new battery? When new, NiMH's should be cycled 3 times, then ran. After that, charge up to half capacity, then store until next use. When you are ready to use, discharge what's left, then recharge. Treatment for regular (weekly) use should be discharge and/or equalise, then recharge to 50% to store. When needed next, discharge, then charge. - (E06) How do I look after a LiPo pack? LiPo is fairly simple to look after, if you know what you are doing. All LiPo packs need to be charged at 1C (0.1a for every 100mah. For example, a 4800mah pack is 4.8a, 3200mah is 3.2 etc). The charge rate changes throughout the charge when set to 1C. Between 10% and 80% charged, the rate will be exactly 1C, but as the pack gets more and more charged, the optimum voltage is reached, and the charger will start to lower the amperage until the pack is full. Once the pack is being charged below 1a, you can take it off the charger and use it, but capacity won't be as much as it could be. Although some packs can take a higher charge rate, the lifespan is shortened considerably! You shouldn't discharge a LiPo pack. the cutoff voltage is 3v, go below that and an irreversable chemical reaction takes place, causing permenant damage. As the design of LiPo packs have such a flat discharge curve, its easy to see when the pack is low on capacity. If you are driving and the car starts to slow down, then stop immediately, and remove the pack from the car. To be extra safe, some ESC's some with a LVP (Low Voltage Protection), which will stop the car when the pack reaches 6v. Novak, amongst others make plug-in LVP's for ESCs without them. LiPo's have no memory effect, so you can store the pack part charged for days, weeks or even months. When you come back to use it again, it'll still have the same voltage as what you left in it. F. Radio Equipment - (F01) What does the radio equipment consist of? For the typical electric touring car or buggy, the radio equipment consists of the following items: Transmitter Reciever Crystals Servo Electronic Speed Control The transmitter is the control unit you hold, and will be either a 2 stick transmitter, or one with a trigger and wheel. This basically sends the steering or throttle inputs you are making through radiowaves which are picked up by your car. Whichever you have, it'll be known as either a 2channel or 3channel transmitter, as steering will be on channel 1, and throttle/brakes on channel 2. If it has a third channel, this can be used for the gearshift, or a second steering servo, it really depends on the car you have. In addition to the 2 main types of transmitter, there's also computerized units. These have a small microprocessor and LCD screen that allow you to digitally change features on the radio, such as the sharpness and overall travel of the steering or throttle, or even ABS and laptiming! Generally, the more expensive the transmitter, the more features and functions you have to play with, but if you mess around in a carpark or field, you could get away with a more basic unit. The reciever is the item which picks up the signal that the transmitter makes. It is the 'hub' of the car, in which the Electronic Speed Control and Servo are plugged in to know what they need to do to operate correctly. Finally, the servo is the steering unit of the car. It is a small box containing a circuit board, micro motor, and several reduction gears connecting the motor to the output spline. The gears are usually replaceable whent hey wear out or break, and some plastic ones can be replaced with metal gears. It is fully proportional, meaning if you turn the stick only a little bit, the steering will turn only a little bit. - (F02) Which is better, sticks or wheels? Not one is better than the other. It really depends on what you learnt to drive with. In general, there are more people using stick transmitters than wheel transmitters in the UK, as the first RC cars wre controlled by Plane radios. However, there are more and more Ready to Run cars coming onto the market with a wheel radio, so try both types if you can and stick with the more comfortable one. - (F03) What are 'crystals'? The crystals are the most important things in the radio equipment. They are a pair of tiny quartz 'chips' that define what frequency and band yuor car transmits on. In the UK, it'll either be 27or 40mhz, and either of these frequencies are split into separate 'bands'. There are 12 bands on 27mhz, and 34 on 40mhz, meaning that more people can run on 40mhz together without interference. Also, there's AM and FM. This is the type of frequency used in radios. FM gives a cleaner, stronger signal than AM. If your radio is AM, then you have to use AM crystals. If its FM, then you have to use FM crystals. However, on 27mhz, any brand 27mhz crystals should work (keeping to AM or FM), whereas on 40FM, you have to generally use the same brand crystals as your radio. - (F04) Is any frequency available? Nope. In the UK, you are only allowed to use 27mhz, and 40mhz for land based vehicles (cars and boats). 35mhz is for aircraft only. In 27mhz, the following bands (known as colours) are legal: 26.975 Grey/Brown 26.995 Brown 27.025 Brown/Red 27.045 Red 27.075 Red/Orange 27.095 Orange 27.125 Orange/Yellow 27.145 Yellow 27.175 Yellow/Green 27.195 Green 27.225 Green/Blue 27.245 or 27.255 Blue For 40mhz, the following are legal: 40.665 40.675 40.685 40.695 40.705 40.715 40.725 40.735 40.745 40.755 40.765 40.775 40.785 40.795 40.805 40.815 40.825 40.835 40.845 40.855 40.865 40.875 40.885 40.895 40.905 40.915 40.925 40.935 40.945 40.955 40.965 40.975 40.985 40.995 Note: you can buy 40mhz crystals in Hong Kong and Japan with the number ending in '0'. These are NOT legal for UK use! 2.4ghz is a relatively new frequency that was made legal for use in late 2005. It uses a frequency range way above both 27 and 40mhz, and has 79 bands for use. It is a great new system, one you should consider. - (F05) What is 'interference'? Interference is where the car doesn't do exactly what you tell it to do. This can be in the form of glitching, or total loss of control. The moment this happens, stop what you are doing and find out the cause. The first cause will be other people on the same frequency as you. Check to make sure there is no-one on your crystal, or anything nearby than can cause interference, such as telegraph poles, pylons, garage dorrs etc. If you car still having problems, check your motor. Remember above? In the process of the motor running the brushes contact the commutator, and small sparks occur where the contact is made. This is a tiny carbon deposit on both the comm and the brush. This sparking is also a form of electrical interference, and this can be stopped by adding a couple of noise supressing capacitors and a schottky diode on the motor wires (do not use if you have a reversing ESC!) The last form of interference can be found in your equipment itself. Check for any battery or motor leads going over the reciever ariel. The ariel itself should be unbroken, and original length. If you still have problems after all these checks, replace each component in line, from crystals, reciever, to transmitter. - (F06) Which servo is best for me? There are hundreds of different servos on the market. Some have plastic gears, some metal. Some are high speed, others high torque. The right one for you depends what car you are going to put it in. If you car going to be bashing off road, a metal geared high torque servo would be good as the power and reliability is needed to turn large wheels. However, a plastic geared high torque servo would suit a racing touring car, where the loads the wheels are put under are not as high as in off-road. As with most things, buy the most expensive you can afford. G. Electronic Speed Controllers - (G01) What is an Electronic Speed Control? Put simply, an Electronic Speed Control (also known as a Speedo, or ESC) is the electronic brain of your setup. It takes the power from the batteries, and converts it into a pulse-width modulated signal from an R/C receiver and then converts it to an amount of power delivered to an electric motor. As ESC generally is a small unit, with a servo lead and connection (to be plugged into the reciever), and 4 4 control wires - a pair of motor wires and a pair of battery wires. You may find ESC's with only 3 control wires, this is there the positive motor wire goes to the battery too. - (G02) Why are some more expensive than others? Every ESC on the market contains MOSFETS, tiny computer chips that handle the current and creates the signal to the motor. Some are better than others, and can handle a higher current and withstand a higher amp draw. Reversing ESC's are more expenive than theor forward only counterparts because they contain more FETS. In most cases, the more expensive the ESC, the better it is. - (G03) Should I buy one with reverse? It depends what you plan to do. If you want to just bash around, then yes, go for a reversing ESC. it'll get you out of tight situations without you having to walk over to the car to move it free. However for racing, reversing ESC's are banned as they pose a safety risk for marshals rescuing a crashed car. You can buy some ESC's that the reverse can be disabled if you want to take it racing. - (G04) Are brushed and brushless ESC's the same? Nope, the requirements for a brushless motor means that most of the design is different. However, a few ESC's such as the Novak GTB, and LRP Sphere are both bushed and brushless compatable. - (G05) What does the 'turn limit' mean? The turn limit is the limit the ESC can cope with that turn of motor. For example, if you bought a Novak XRS ESC, which as a 15t limit, the fastest motor you could fit would be a 15t. Fit a 13t or 12t, and the motor will pull more amps than the MOSFETS can cope with, and will catch fire! - (G06)What is a 'power cap'? A power cap (capacitor) stores a small amount of electrical power inside itself. It is normally soldered directly to the ESC, either to the battery cables or the circuit board. When you punch the throttle, the power cap discharges itself. If your motor is drawing alot of current, that the cells cant give, the cap will help with that initial punch. This gennerally happens coming out of slow corners, or from a standing start. Motor Turn - KV Estimate Chart Please note this varies between manufacturers. 4 Quote Link to comment Share on other sites More sharing options...
DataMatrix Posted July 9, 2008 Share Posted July 9, 2008 (edited) Just to say: A brushless motor is a motor that is electronically controlled not mechanically. Instead of using connection wires to change polarities inside the motor, a circuit board does it instead, this allows for the motor to spin at much higher speeds and save power. Edited July 9, 2008 by DataMatrix Quote Link to comment Share on other sites More sharing options...
Garry Posted December 26, 2008 Author Share Posted December 26, 2008 General guide for charging rates of cells Remember, these are guidelines only, and although certain brands of cells can take higher rates, the risk associated with it increases too. The author of this guide takes no responsibilty for the consequences following this advice. If in doubt, get a second or third opinion. A couple of pointers first though, if you haven't got a delta peak charger that you can adjust the amperage in individual amounts (like 0.1A increments), save up and get one as soon as you can. And when the term '1C' is mentioned, it means the the capacity of the pack as the charge rate (4200mah = 4.2A, 3600mah = 3.6A etc). Basics: In general, the higher the charge rate, the faster the pack charge. BUT, the charging process will heat the cells up. Up to a point, this is a good thing, but beyond that, the cells will start to leak/vent, and possibly explode. Too hot to touch is deffo a problem.... With 'normal' cells (i.e Nickel based), then the process is called Constant Current (CC), where the the amperage remains constant throughout the whole charge process. With a delta peak charger, the voltage rises and rises, and when it 'peaks', the charger terminates the charge. With LiPo cells, the process is a mixture of constant current and constant voltage (CC/CV), where the amperage is constant while the voltage is brought up to 4.2v per cell, then the charger holds the pack at that voltage and lowers the amps until the pack is charged. So: Sub C cells (car packs) NiCD: - For bashing use, 3A. - For racing use, 4-5A, 10mv cutoff. NiMH: - For bashing/general driving use, charge at 1C. - For racing use, charge around 5A, no more than 10mv cutoff. Exceptions being IB4200 cells, don't charge these above 1C. 2/3A cells (Micro packs, reciever packs) NiMH: - For micro packs, 1-2A, but keep a check on the temperatures. - For reciever packs, 1C. LiPo packs (all applications and sizes) For all packs and applications, 1C. Double and triple check all charger settings (cell type, capacity and voltage) before starting the charge. -------------------------------------------------------------------------- Discharging cells In general, there is no performance benefit to discharging cells at a higher rate, only that the pack is discharged quicker. Most discharger units will discharge at 1A, some that are built into chargers can do up to 10A. LiPo packs do not need to be discharged at all, and must never be allowed to drop below 3v per cell. -------------------------------------------------------------------------- Summary Make sure you check all settings before starting a charge, and with NiMH cells, keep an eye on the temps - if you can't touch the cells for longer than 10 secs, then the pack is too hot. Take it off charge and allow it to cool before recharging at a lower rate. 3 Quote Link to comment Share on other sites More sharing options...
HappyLad Posted December 26, 2008 Share Posted December 26, 2008 (edited) Nice one Garry - seen a couple of Q's on charging recently. Just one (constructive) criticism, and I hope its not one you find too pedantic.... The symbol for the ampere is 'A', not 'a' Edited December 26, 2008 by HappyLad Quote Link to comment Share on other sites More sharing options...
Garry Posted December 26, 2008 Author Share Posted December 26, 2008 All fixed now. Quote Link to comment Share on other sites More sharing options...
ta05 Posted January 9, 2009 Share Posted January 9, 2009 Another small note to add is, the higher your charge rate, the more power the batteries (or cells some refer to them as) will give to your motor, but will have a shorter run time. If you charge your cells at a lower amperage, you wont feel the motor being quite as powerful, but the cells will last a bit longer. If you are charging your cells at a high amperage (5A or more) I would strongly suggest you use either deans or corally type connectors, as tamiya connectors cannot carry large amounts of current very well at all.... and will more than likely melt! Quote Link to comment Share on other sites More sharing options...
nitrorhys Posted January 9, 2009 Share Posted January 9, 2009 Good guide garry Quote Link to comment Share on other sites More sharing options...
TiM! Posted January 10, 2009 Share Posted January 10, 2009 yeah nice one. some really good info there Quote Link to comment Share on other sites More sharing options...
RogerRally Posted January 10, 2009 Share Posted January 10, 2009 Ref Lipos, you state 1c, so to a novice, does this mean on a 3600 mah battery, you should charge at 3.6a, and should take about an hour to charge up?. My badly written charger instructions suggests charging at half c ,(trying at 1.6a, but it takes over an hour to recharge a pack, not so good on a raceday!) amny help appreciated Quote Link to comment Share on other sites More sharing options...
JamesChatz Posted January 10, 2009 Share Posted January 10, 2009 Ref Lipos, you state 1c, so to a novice, does this mean on a 3600 mah battery, you should charge at 3.6a, and should take about an hour to charge up?. Yes Charging at 1.6A will take approx 2 hours, depending on how full the battery is. Quote Link to comment Share on other sites More sharing options...
Perko Posted January 14, 2009 Share Posted January 14, 2009 Fantastic summary and very informative to a newbie like me. Thanks very much!! Quote Link to comment Share on other sites More sharing options...
Goldenballs Posted January 23, 2009 Share Posted January 23, 2009 i have a 7.2volt 150mah battery and acharger with 1,2,4 amp charging what is best Quote Link to comment Share on other sites More sharing options...
Garry Posted January 24, 2009 Author Share Posted January 24, 2009 Do you mean 150mah or 1500mah? Quote Link to comment Share on other sites More sharing options...
madmarder Posted January 24, 2009 Share Posted January 24, 2009 i have a 7.2volt 150mah battery and acharger with 1,2,4 amp charging what is best 1500mah at 1amp will take about 1 1/2 hrs matey Quote Link to comment Share on other sites More sharing options...
bbdave Posted February 12, 2009 Share Posted February 12, 2009 I've been told nimhs over 4500mah need to be charged differently or is it ok to charge a 5100mah at 1c? Quote Link to comment Share on other sites More sharing options...
Garry Posted February 13, 2009 Author Share Posted February 13, 2009 Nope, just charge 4500's at 4.5A, and 5100's at 5.1A (if possible). 1 Quote Link to comment Share on other sites More sharing options...
TerrorTrooper Posted February 17, 2009 Share Posted February 17, 2009 (edited) i dont know if this information is relevant.. But if you have a more basic NiMh charger, for example, it may have switchable charging at 1A, 2A, and 4A. As a rule of thumb, as you cant increase/decrease in 0.1A increments, Go to the next one down from your pack rate. For example, i charge my 4200Mah and 4500MaH packs at 4A, But i charge my 3000MaH and 3600MaH packs at the 2A setting. My reciever Packs are 1200MaH and 1600MaH and i charge them at 1A. So in theory, im never going above the 1C rating. Its good for the packs, and its good for me.. Edited February 17, 2009 by TerrorTrooper 1 Quote Link to comment Share on other sites More sharing options...
C3PO Posted April 5, 2009 Share Posted April 5, 2009 Superb summary, really, really good. Quote Link to comment Share on other sites More sharing options...
danhodge3820 Posted April 19, 2009 Share Posted April 19, 2009 Ok so heres a question, i have an annsman ac30 fast charger and use 3300 mAh batteries, so im gettin half and hour charge at 2.3A then it switches to a trickle, but how do i know when the battery is full? is it maths meaning half an hour at 2.3A means ive got 1.15A in my batt but i can hold 3300mAH so do i need a longer main charge? trying to get my head round this stuff!! Quote Link to comment Share on other sites More sharing options...
TiM! Posted April 19, 2009 Share Posted April 19, 2009 It goes to trickle because it is done charging. Quote Link to comment Share on other sites More sharing options...
danhodge3820 Posted April 19, 2009 Share Posted April 19, 2009 It goes to trickle because it is done charging. Sorry it goes to trickle after half an hour timer sorry should have made that clearer, so say 1500 batteries got warm but my 3300's dont so i was wondering how you know when all types are fully charged as im gonna get some larger cap batts, thanks Quote Link to comment Share on other sites More sharing options...
TiM! Posted April 19, 2009 Share Posted April 19, 2009 Sorry it goes to trickle after half an hour timer sorry should have made that clearer, so say 1500 batteries got warm but my 3300's dont so i was wondering how you know when all types are fully charged as im gonna get some larger cap batts, thanks Yeah I just had a look at the charger on fusion hobbies. It says it can only charge up too 1500mah packs. Quote Link to comment Share on other sites More sharing options...
danhodge3820 Posted April 19, 2009 Share Posted April 19, 2009 Yeah I just had a look at the charger on fusion hobbies. It says it can only charge up too 1500mah packs. Oh right, ive been lookin in other places, fusion eh, thanks very much you're being most helpfull today! Quote Link to comment Share on other sites More sharing options...
Garry Posted April 26, 2009 Author Share Posted April 26, 2009 At some point this week, the guide will get updated and adjusted in line with recent tech advances. Anything you'd like to see added or clarified? Post below. Quote Link to comment Share on other sites More sharing options...
TiM! Posted April 28, 2009 Share Posted April 28, 2009 (edited) At some point this week, the guide will get updated and adjusted in line with recent tech advances. Anything you'd like to see added or clarified? Post below. Could sort this out...... - (E04) What is 'discharging/equalizing/cycling'? Even if you drive your car until it stops dead, there will still be some life left inside the pack. To get this out, you need to discharge the pack. If you don't the pack won't get a fll charge the next time you charge it, and over a period of time, the pack will become useless. All I can think of at the mo. Edited April 28, 2009 by TiM! Quote Link to comment Share on other sites More sharing options...
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