- General battery information
- General battery information links
- General charging circuits
- Battery chargers for NiCd batteries
- Li-ion battery chargers
- Lead-acid battery cargers
- Combined power supplies and battery chargers
- Battery discharging circuits
- Battery backup circuits
- Battery protection
- Battery status sensors
- Normal battery chargers
- Portable equipment power
- Related pages
Battery Power Supply Page
Battery information and circuits
- IEEE 1189-1996, IEEE Guide for Selection of Valve-Regulated Lead Acid (VRLA) Batteries for Stationary Applications
- IEEE 1187-1996, IEEE Recommended Practice for Installation Design and Installation of Valve Regulated Lead -Acid Storage Batteries for Stationary Applications
- IEEE Std 450-1995, how to maintain batteries
- IEEE Std 485-1997, reference how to size batteries
- Lead Acid: most economical for larger power applications where weight is of little concern (cars, boats, wheelchairs, emergency lighting, UPS systems), low energy density (30-50 Wh/kg), available in low cost versions, cell voltage 2V, voltage limiting rather than current limiting is used for charging
- Sealed lead acid (SLA,Gelcell): maintenance-free lead acid battery with electrolyte in moistened separators, enclosure is sealed, used for wheeled mobility, typical charge times are 8 to 16 hours, must always be stored in a charged state, 200 to 300 discharge/charge cycles
- Nickel Cadmium (NiCd): mature and well understood technoogy used in chargeable batteries used in many applications (power tools, two-way radios, video cameras), standard against which other batteries are usually compared, not very good energy density (45-80 Wh/kg), cell voltage 1.25V, life cycle 1000-1500 charges
- Nickel-Metal Hydride (NiMH): higher energy density (60-120Wh/kg) compared to the NiCd at the expense of reduced cycle life, no toxic metals, used in mobile phones and laptop computers, cell voltage 1.25V, life cycle 300-500 charges
- Lithium Ion (Li-ion): fastest growing battery system, high-energy density (110-160 Wh/kg) and lightweight, technology is fragile and a protection circuit is required to assure safety, applications in notebook computers and cellular phones, cell voltage 3.6V, life cycle 500-1000 charges
- Lithium Polymer (Li-polymer): uses a dry solid polymer electrolyte, cell thickness measuring as little as one millimeter, suffers from poor conductivity (high internal resistance)
- Lithium Ion Polymer (Li-ion polymer): uses a combination of dry polymer electrolyte combined with some gelled electrolyte, ultra-slim geometry, high energy density (100-130 Wh/kg), used in mobile phones, cell voltage 3.6V, life cycle 300-500 charges, promotional reasons most battery manufacturers mark this kind of battery simply as Li-polymer
- Reuasable Alkaline: Special alkalinen battry which can be charged few times (energy density 80 Wh/kg), cell voltage 1.5V, life cyle around 50 cyled of 50% charge/recharge
Batteries are all over the place: in our cars, our PCs, laptops, portable MP3 players and cell phones. A battery is essentially a can full of chemicals that produce electrons. Chemical reactions that produce electrons are called electrochemical reactions.
If you look at any battery, you'll notice that it has two terminals. Electrons collect on the negative terminal of the battery. If you connect a wire between the negative and positive terminals, the electrons will flow from the negative to the positive terminal as fast as they can. Normally, you connect some type of load to the battery using the wire. Inside the battery itself, a chemical reaction produces the electrons. The speed of electron production by this chemical reaction (the battery's internal resistance) controls how many electrons can flow between the terminals. Normal batteries have generally 1.5V per cell voltage (except some Lithium cells which have 3V voltage). The batteries which have higher voltage output are built genrally from many 1.5V cells in series all put inside same "case". Since there are no real industry standards, many terms used by battery manufacturers have become misleading marketing hype.
Although the terms battery and cell are often used interchangeably cells are the building blocks of which batteries are constructed. Batteries consist of one or more cells that are electrically connected.The world of batteries divides into two major classes: primary and secondary batteries. Primary batteries such as the common flashlight battery are used once and replaced. The chemical reactions that supply current in them are irreversible. Secondary batteries (for example, car batteries) can be recharged and reused. They use reversible chemical reactions. By reversing the flow of electricity i.e. putting current in rather than taking it out, the chemical reactions are reversed to restore active material that had been depleted. Secondary batteries are also known as rechargeable batteries, storage batteries or accumulators.
As a battery is used, the amperage is consumed and the voltage drops. There is a formula for a ballpark estimate for battery life:
Estimated total battery life = (Ib / Id) x 0.7
Where: Ib = Total Capacity Rating of battery (mAh) and Id = Current Consumption of the device in milliamps (mA)
Use of this formula does not guarantee that you will get the determined battery life. Other factors such as weather condition (temperature, humidity, etc.), and battery condition can extend/shorten the battery life. This formula cannot be used to calculate battery life for alkalines. Battery state can be somewhat determined with the battery voltage. Please note that batteries do not show their correct voltage unless under a load. Battery testers are designed to provide this load; however, when testing batteries with a multimeter, you must have the meter set to measure DC voltage and place the battery under load by using a resistor in parallel with the test leads of the meter. How the battery voltage drops during the use varies from battery type to another.
Carbon Zinc based single-use batteries are those "regular" batteries you get from a normal shop. Those are cheap batteries. Typical cell voltage is 1.5 volts. This kind of batteries are available in conventional form factors like AA, AAA, C, D and 9-volt. Carbon Zinc batteries are usually the cheapest battery type you can find (cheapers per battery unit, propably not cheapest per capacity unit). The term Heavy Duty battery was used to refer to Zinc chloride batteries which had about 50% more capacity than traditional carbon zinc batteries (that was tens of years years ago). Calling zinc chloride batteries heavy duty became misleading once alkaline batteries (with 300% more capacity than zinc chloride batteries) became available.
Alkaline batteries are single-use batteries, but provide a higher start voltage and longer life than many other single use batteries. The capacity rating for alkaline batteries is not a fixed number on alkaline batteries, although it can be safely assumed that an alkaline battery will last significantly longer (2-3 times as long) as a same-size rechargeable under the same conditions. Alkalines do not have a fixed capacity rating because where the discharge rate of rechargeable batteries is a straight line, the discharge rate for alkalines slopes depending on the current drain. The higher the current drain, the faster the battery discharges. In alkaline batteries, the sloping discharge curve makes it impossible to accurately provide a mAh rating; the rating would vary depending on discharge rate and temperature. Alkaline batteries are significantly heavier than many other battery types for the same size, but they can store lots of energy (few times more than "regular" batteries). Alkaline batteries can take storage nicely when not used. Alkaline batteries stored at "room temperature" self discharge at a rate of less than two percent per year. However, if alkaline batteries are stored at higher temperatures they will start to lose capacity much quicker. At 85 degrees F they only lose about 5% per year, but at 100 degrees they lose 25% per year.
There is a variation of alkaline cell that can be charged with a limited number of times: Rayovac sells rechargable akaline batteries. Rechargeable alkalines are really just normal alkalines with a beefy casing to reduce leakage, but the full charge drops off significantly even after the first recharge cycle and gets worse from there.
There are also other single-use batteries. Lithium Manganese Dioxide (Li/MnO2) is used in some high capacity single use batteries (for example some camera batteries). Silver Oxide Zinc is used in some small batteries used to power watches and tiny electronics gadgets like digital thermometers. Silver Oxide technology features one of the greatest capacities to store electricity for a certain volume. Silver Oxide technology also provides a near constant voltage over the entire life of the battery. This is essential to ensure watch accuracy, and could not be attained easily with alkaline battery technology.
Rechargeable batteries tend to have a lower start voltage and shorter usage cycle; however, they make up the difference by being reusable. They are lighter in weight than alkaline batteries.Normal alkalines are 1.5V each, but Ni-Cd batts are only about 1.2V each. If you use four of them for instance, you only get 4.8V instead of 6V. By standard, the NiCad battery type nominal voltage is 1.25 V. This has to do with the chemistry of the battery. When shopping around, take care that many dealers will call the standard 1.25 V batteries a 1.5 V battery type, because people generally use them as 1.5 V batteries. If you have a consumer device that was made to use rechargeable batteries, it would be designed to use the standard 1.25 V rechargeable battery. The voltage difference is that's probably why some equipment instructions don't allow them. Another reason could be that NiCd batteries have enormous short-circuit current capability (easily tens of ampreres or more) compared to many traditional batteries (causes greater risk of fire in case of short circuit). On some applications the small internal resistance is a benefit. That high resistance combined with high current load causes voltage drop and this power lost in voltage drop causes the batteries to heat quickly, and because resistance increases with heat, it gets worse the longer you use the device. The voltage drop across the resistance causes the output voltage to drop, and before long it can drop below a useful voltage. In high-current devices, NiMH and NiCd batteries work much longer than alkaline batteries, in part because they don't heat as much. Ni-Cd batteries are the most popular type of rechargeable battery. They are quick to charge and work well in extreme temperatures. They will last up to 500-700 charge/discharge cycles. NiCd batteries are easy to charge at slow charge mode. Just applya charging current, typically around 50 mA for 500mah cells, for 12-14hours to change them. It does not hurt the batteries if you charge thebatteries at the current with somewhat longer times (even few times longer)than needed. When batteries are are charged after they are full,the applied power is converted to heat, so NiCd batteries should start to become warm then. Some will say sinking C/10 (50mA for500 mAh battery) indefinately into NiCd is acceptable but thisis not a recommended practice. NiCd batteries can also be charged faster with special"smart chargers" which use controlled higher current to the batteriesuntil they are charged and stop this current when batteries are full(the charger has special sense circuitry for this). You want the -deltaV controlled, which monitor the voltage on the battery to sense when they're fully charged. The timer controlled chargers, will overcharge the battery, and nothing kills batteries like overcharging. Ni-Cd batteries can suffer from what is called the "memory effect", although some people cailm this effect is just a myth. If a Ni-Cd battery is recharged before it is fully discharged, the recharge process can create a layer of bubbles in the battery which will eventually prevent the battery from discharging beyond that point. To avoid this problem, we recommend that Ni-Cd batteries be fully discharged before recharging. If they are only partially discharged and then recharged, then after several such recharge cycles, the batteries may not be able to recharge to full capacity. Exercise extreme precaution when handling and testing NiCd batteries.NiCd batteries include some amount of cadmium (Cd), which is dangerousmaterial for enviroment. Do not throw NiCd batteries away with your trash.You should bring those batteries to recycling. When discharging NiCd battery packs be cautious about over-discharge. Individual NiCd cells can go to zero volts but in a battery pack letting them drop below 1V each may reverse and ruin a weak cell since they are in series. Rechargeable batteries might not be right solution for all battery applications, for example in applications where normal batteries last many months. The rechargeable battery will loose its charge more quickly than a standard alkaline battery. You will find that after a month or two, you may have to recharge the batteries. When on the shelf, rechargeable batteries will loose their first 10% of charge within the first 24 hours. After that they will self discharge at a rate of about 5% for the next 24 hours. After about 24 to 48 hours, the rate of loss would be about 1% per day. If you were to charge a NiCad battery and put it on the shelf, you would have to re-charge the battery before use, if you let it sit for about a week, and want to have optimum performance.
In many modern applications NiCd batteries are replaced with higher capacity NiMH batteries. Those batteries have pretty much similar characteristics to NiCd (except that they need somewhat different charger).NiCad and NiMh cell voltages are identical. I like NiMH as it is relatively easy (and safe) to recycle. NiMH batteries are great but they have the downside of losing charge very quickly "on the shelf". A NiMH battery can lose up to 2% of its charge per day sitting on the shelf. So it is not a good choice for that emergency flashlight application. NiMh are sensitive to overcharge. NiMh should be preferably be always charged with "smart chargers" designed to charge NiMh batteries. There is some difference at end of charge and used by sophisticated chargers compared to NiCd, that's why an intelligent NiCd charger does not work with NiMH battery. NiMh batteries can also be charged with constant currentC/10 (50mA for 500 mAH cell) current, but you should avoidexcessive overcharge because this will shorten battery life. Compared to Nicad NiMh are nearly twice the capacity, can berecharged from any level, selfdischarge more tha twice as fast,have about half the full cycle number life, and are not as robust when charging. Some sources say that charging NiMH batteries will reduce their life, but for practical purposes with batteries that are designed to be quick charged, for example, Sanyo, GP, POWERhaus, that is not true. It is important to use a battery charger that has been specifically designed to rapid charge NiMH cells. Actually there is a much greater likely hood of reducing the life of a NiMH battery by using an "overnight" charger than by using a smart fast charger. Overnight chargers rely on the fact that you will unplug them after a number of hours. If you forget to unplug them they can continue to charge the batteries longer than they should. Overcharging WILL reduce the life of batteries.
NiMH is a superior battery compared to NiCd in many situations - just to inject a note of realism and take care of differences. A great deal of the raw materials for NiMH batteries comes from China (and Russia), regardless of what the "made in ..." sticker says. NiMH and NiCd batteries self discharge at a MUCH faster rate than alkaline batteries. In fact, at "room temperature" (about 70 degrees F) NiMH and NiCD batteries will self discharge a few percent PER DAY. Storing them at lower temperatures will slow their self discharge rate dramatically. NiMH batteries stored at freezing will retain over 90% of their charge for full month (so it might make sense to store them in a freezer in some applications). If you store you batteries in very cold place, it's best to bring them back to room temperature before using them (cold batteries perform poorly). Even if you don't freeze your NiMH batteries after charging them, you should store them in a cool place to minimize their self discharge.
By standard, the NiCad and NiMH battery type nominal voltage is 1.25 V. This has to do with the chemistry of the battery. The lower voltage cna be problem sometimes and that's why there are also battery types that give 1.5V out. There are some expensive industrial type chargeable batteries that are 1.5 V. These are not made the same way as the reasonable cost consumer batteries. For consumer markets Rayovac makes a rechargable alkaline that is the usual 1.5V (there could be also other makers). They like to be re-charged often and seem to have about the capacity of regular alkalines, perhaps a little less. They can take only about 50 charges to a set before they started to degrade, and ff you deep discharge them, they die. Those rechargeable alkaline batteries need a special charger (sold by battery manufacturer).
Lithium-ion batteries are the latest technology for portable use. Many new small gadgets like cellular phones use Li-ion batteries.Li-ion batteries have a high energy density. Compared with a Ni-Cd battery, these batteries will deliver twice the runtime on each charge. It is available only in a limited number of sizes and models. They have a life expectancy of 300-400 charge/discharge cycles. Generally, lithium batteries are designed to be recharged in the device rather than in an external charger. Exercise extreme precaution when handling and testing Li-ion batteries.Do not short circuit, overcharge, crush, drop, mutilate, penetrate,apply reverse polarity, expose to high temperature or disassemble them. Only use the Li-ion battery with the designated protection circuit(cellular phone batteries usually have this). Abuse of Li-ion can cause "explosion" like happening, because in short circuitthe case temperature can get very high and the electrolyte insideLi-ion battery is highly flammable. Lithium-ion Polymer battery is a special way built Lithium-ion battery. There are three main advantages to a lithium-ion polymer battery -- lighter weight, a wide range of possible shapes and greater performance at high and low temperatures. A lithium-ion polymer is lighter than a standard lithium-ion battery because it uses a plastic electrolyte instead of an electrolyte solution, as is used by lithium-ion batteries.
Lead-acid batteries are used for a vast number of purposes, but all batteries provide either starting or deep cycle power. The only difference is how much power is delivered and how long it needs to be delivered. When people think about lead-acid batteries, they usually think about batteries that start their cars. These are starting batteries. They deliver a short burst of high power to start the engine. Car batteries are built using lead acid cells. They have a cell voltageof around 2 volts (means 6 cells in series makes 12V battery). Normal 12V car battery is designed to be quite robust. It canbe carged with almost any reasonably current limited constantvoltage source of around the nominal voltage of the battery(for example 13.5V for 12V car battery). It supplies power to the starter and ignition system to start the engine, supplies the extra power necessary when the vehicle's electrical load exceeds the supply from the charging system and acts as a voltage stabilizer in the electrical system. Car batteries are built for heavy currents but DO NOT deep discharge them, only shallow discharge. If you repeatedly run a car battery down tomuch below 50% of capacity you will seriously shorten its life. Warnings on car batteries: Car batteries contain dangerous acid hare heavy, so handle carefully.Charging car batteries can generate highly flammabble hydrogen,so it is best to charge those only in well ventilated spaces. Car batteries have very large short circuit current (hundreds of amperes), so do not short circuit them (a fuse near battery terminal is essential for safety to avoid wire fires in short circuithappens).
There are also other types of lead acid cells than car batteries. Some are designed for deep discharge use and some for some otherapplications. Generally lead acid batteries don't like to be discharged below 1.67 volts per cell (10V for a 12V battery) and their full capacity can only be extracted if the load current is something like C/10 or C/20 (where C is the barrery capacity in Ah and resulting current is in A). There also are deep-cycle batteries. You'd find these on boats or campers, where they're used to power accessories like trolling motors, winches or lights. They deliver a lower, steady level of power for a much longer time than a starting battery. There are very many applications that use lead-acid batteries for stationary applications. Here is a list of some standards relevant to this application area:
Short list of most common battery characteristics:
Name Size Alkaline NiCd Ni-MH WeightThe data for battery rating is mostly based on infromation at http://electronicsusa.com/batteryinfo.html. The alkaline battery data is based on Duracell Battery Data, NiCd data is from Eveready and Ni-MH data is based in Radio Shack Ni-MH Battery data. LR batery types data is from maxel battery data at Batteryforce.com. The ratings of the bateries can vary somewhat from manufacturer to manufacturer. The battery size data is from http://www.powerstream.com/Size.htm. Diameter can vary as much as 1 mm between different manufacturers.Many battery types are known with many codes. Unfortunately, battery manufacturers have never agreed one standard convention for battery labels (there are few hundred different commonly used codes to identify a battery type). Here are some code names for different battery types:
(dia x len mm) (V / mAH) (V /mAH) (V / mAH) (alkaline/NiMH g)
AA 14.2 x 50 1.5 / 2100 1.2 / 500 1.2 / 1250 24 / 27
AAA 10.5 x 44.5 1.5 / 1000 1.2 / 180 1.2 / 550 12 / 13
N 11.5 x 28 1.5 / 700 6.6 / 11
C 26 x 46 1.5 / 7000 1.2 / 1200 65 / 80
D 33 x 58 1.5 / 14000 1.2 / 1200 135 / 105-160
9V 48.5x26.2x17mm 9.0 / 550 7.2 / 80 8.4 / 130 44
LR44 11.6 x 5.4 1.5 / 105 2
- 9V Alkaline Battery: 6LR61, 1604A, 1604AC, MN1604, 9V, 4022, 522, K9V, A1604, 6AM6, BLOC, ND65V, 1604, KA9, PP3, CLR6, 6F22, 9VOLT
- LR44: LR44, 5244, A76, A76LR44, 1166A, V13GA, KA76, RW82, FM28F, AG13, L1154, A200, GP76A, KA, A01, G13A, WL14, LR44H, G13-A
- LR54: L1131, LR54, 189, LR1130, V10GA, AG10, A120, GP89A, A05, RW49, 10L/122, WL10, G10, G10A, GP189
- CR2032 Lithium Button Cell (3V cell): CR2032, DL2032, L2032, BR2332, ECR2032, 2032, EA2032C, LF1/2V, L14, BR2032, 2332, SB-T15
- D: D, KD, MN1300, LR20, E95, 4050, AM1, MONO
- C: C, MN1400, KC, LR14, E93, 4014, AM2, BABY, AM-2, R14
- AA: AA, 15A, 15AC, MN1500, 4006, E91, KAA, 815, AM3, MIGNON, ND62S, LR6
- AAA: AAA, LR03, 24A, 24AC, MN2400, 4003, E92, K3A, 824, AM4, MICRO, ND61R
- 4LR61 Alkaline Battery: 4LR61, 539, KJ, 4AM6, 4018, 1412AP, J, 7K67
- CRV3 Lithium Battery: KCRV3, CRV3, CR-V3, LB-O1, LB-01, LBO1, LB01
- E10A 9V Alkaline Battery: L1021, GP-10A, GP10A, E10A, 10A
- 27A 12V Alkaline Battery: 27A, GP27A
When selecting a battery for a certain application many things needs to be considered. You just should not be looking at the voltage, capacity and price only. Many sources say that NiMh will last longer than alkalines in high power equipment. The capacity of an alkaline is maybe twice that of the NiMh, but the alkaline must be discharged much slower than the rechargeable in order to obtain more total energy. So, fo a low power device like a transistor radio, alkalines should last longer, but for higher power devices like digital cameras and flashlights, you are probably better off with the NiMh. But the shelf life of alkalines is much longer than NiMh since the rechargeable battery will self discharge just sitting on the shelf for a few months. So, for a flashlight that is seldom used, alkalines should be better. When powering high drain electronic devices like digital cameras, computer peripherals, or portable music players, an alkaline battery will only deliver a small fraction of its rated capacity. A NiMH or NiCd battery is likely to deliver much closer to its rated capacity when it's powering high drain devices. This means that a NiMH battery with a rated capacity of 1800 mAh can take many more photos than an alkaline battery with a rated capacity of 2,800 mAh.
Most equipment manufacturers recommend removing batteries from the equipment if it's not to be used for a while, so as to reduce the risk of equipment damage from leakage. There are many electronic devices that have been damaged by leaked and rusted batteries. Battery leaking is quite rare occurence when you use good quality batteries and do not leave them to the devices for long time you have used them. Modern "alkaline" batteries use a liquid electrolyte which incorporates a good deal of potassium hydroxide ("lye"), a corrosive alkaline material. Over time, the electrolyte can attack the metal shell of the battery, or the seals around the upper (positive) electrode, and leak out. This corrosive action is relatively small if the battery is in its "as new" condition and has not been partially discharged, and that the electrochemical processes which occur when you draw charge out of the battery have the effect of starting or speeding up the corrosion of the shell. To clean alkaline corrosion,use ordinary household vinegar to neutralize the alkalinity,then rinse and dry.
If you really do need to have the equipment available "on standby" for rapid use - then it's probably a good idea to swap out the batteries for fresh ones any time you've used it significantly. There are various recommendations which batteries you should use. There are some suggestions flowing around that battery-powered equipment which is used only occasionally, should be powered by "heavy duty" carbon/zinc batteries rather than by alkaline batteries. Carbon/zinc batteries have less power per cell (roughly half as much for the "heavy duty" types), but they're less expensive, and they use a chemistry with a near-neutral electrolyte pH (actually they use acidic electrolyte). If they "die of old age" it usually seems to be due to the electrolyte drying out, rather than chewing its way out of its cage and attacking innocent bystanders. Those carbon/zinc batteries are cheap too. Please also note that cheap carbon zinc (all made in China nowdays) tend to leak out much more often than "quality batteries" because they have typically vety thin casing. Heavy duty carbon zinc have somwhat better capacity than the cheap standard carbon zinc, and more importantly, are steel jacketed. Many people remember carbon-zinc cells leaking,and that's why manufacturers brought out their policies against leakage. Many manufacturers claim to replace damaged equipment. Alkalines will last in standby far longer than carbon-zinc cells. Alkaline batteries are nowadays the main product of most battery companies, leaving the carbon-zinc cells as the loss leaders. This means that they will be made as cheaply as possible. No matter how cheaply you can buy carbon-zinc cells, I'd strongly recommend that you not leave them in any device for long unless that device really had to value to you.
- 10 things to know about batteries - mostly about video camera batteries Rate this link
- Deep Cycle Battery FAQ Rate this link
- Batteries & Chargers Answers from Radio Shack Rate this link
- Battery Backup Applications Handbook Rate this link
- Battery Council International Rate this link
- Battery Life Information - Comparison charts for the various batteries available. Rate this link
- Car Battery and Deep Cycle Battery FAQ - This web site contains the free consumer information about car and deep cycle storage batteries. Rate this link
- Car and Deep Cycle lead-acid batteries - Car and Deep Cycle lead-acid battery answers to Frequently Asked Questions (FAQs), tips, information, references and hyperlinks are contained on this consumer oriented Web site about car, motorcycle, truck, marine, recreational vehicle starting and deep cycle applications. Rate this link
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- Proper handling helps make the most of Li-ion batteries - Li-ion batteries pack the most power per unit volume, but excessive charging or discharging can damage or destroy the battery and its surroundings, carefully designed circuits help you avoid such dire outcomes Rate this link
- Sizing Up The Benefits Of Integrated Battery Electronics Rate this link
- Smart-battery technology: power management's missing link - you no longer need to view a battery as a power-generating element whose characteristics are beyond your knowledge and controla Rate this link
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- Sealed Lead Acid Battery Size Chart - Most manufacturers have similar battery sizes. This chart was created to be a quick reference to the most common ones. Not every manufacturer makes every size. Rate this link
- Standard Cylindrical Battery Sizes Rate this link
- Testing batteries: The more things change, the more they stay the same - Despite new chemistries, improved manufacturing methods, "smart"-battery technologies, and a host of Information Age uses, batteries for consumer applications continue to rely heavily on functional testing for characterization and evaluation. Rate this link
- The Great Battery Shootout! - which batteries are best, many NiMH batteries tested Rate this link
- Typical voltage Tolerances for Dry Cell Batteries Rate this link
- What is the perfect battery? - We often get puzzled by announcements of new batteries that are said to offer very high energy densities, deliver 1000 charge/discharge cycle and are paper-thin. Are they real? Perhaps - but not in one and the same battery. Rate this link
- NIOSH Pocket Guide to Chemical Hazards: Battery acid Rate this link
- Batterylogic FAQ - a nice FAQ that contains useful information on rechargeable batteries Rate this link
- Battery myths Rate this link
- 6 volt lead acid battery chargerkit - lead acid charger that uses the uc3906 chip Rate this link
- Build A Smart Battery Charger Using A Single-Transistor Circuit - This automatic battery-charger design is created with a circuit that could qualify as the simplest window comparator ever built around a single transistor. It starts charging when the battery voltage drops beyond a preset value, and it stops when an upper preset voltage is attained. This circuit is designed for 12V battery. Rate this link
- Charger delivers 2.5A with 96% efficiency Rate this link
- Constant Current Battery Charger Rate this link
- Optimizing high-frequency battery-charger performance for worldwide applications - providing power for electric vehicles for worldwide use requires knowledge of energy-conserving and high-efficiency technologies Rate this link
- Remote charging circuit uses three-wire sensing - remote voltage sensing usually uses a four-wire sensing system, this system works with three wires Rate this link
- Sealed Lead-Acid Battery Charger Circuit - A very effective and simple sealed lead acid battery charger based on L200 IC Rate this link
- Shunt battery charger provides 1A continuous current - a shunt method is preferable than series regulation in solar-powered systems Rate this link
- Solar Panel Charge Controller / Low Voltage Disconnect Circuit - Lead acid charger, with battery voltage monitor, power comes from solar panels Rate this link
- Solar charger for lead-acid batteries - Solar lead acid charger, with battery voltage monitor, for 12V battery Rate this link
- Step-up/step-down current source charges batteries Rate this link
- Trickle Charging - Explains what trickle charging is Rate this link
- VK3EM Sealed Lead Acid Battery Charger MK II - A high-tech lead acid charger, uses the uc3906 chip Rate this link
- Electric Toothbrush with Inductively Coupled Charger - This was found in an Interplak Model PB-12 electric toothbrush but similar designs are used in other appliances that need to be as tightly sealed as possible. A coil in the charging base (always plugged in and on) couples to a mating coil in the hand unit to form a step down transformer. The battery is on constant trickle charge as long as the hand unit is set in the base. The battery pack is a pair of AA NiCd cells, probably about 500 mA-h. Rate this link
- Battery charger indicates rate of charge - a single LED indicates whether the battery charger s delivering a trickle charge or a fast charge, cricuit designed to charge 2-14 cells Rate this link
- Constant Current Nicad Charger - The schematic for this charger is pretty simple. You can charge from 1 to 20 +/- nicads at a constant current of from 20 to 200 ma +/-. Rate this link
- Make Your Own Simple Rx/Tx Battery Charger with Peak Detect - This circuit is designed to peak charge Rx and Tx batteries. It's programmed for a C/2 charge rate for 250mAh and 500mAh batteries (charge currents of 125mA or 250mA). It'll charge Rx from 12V at the field, Tx from a 15V supply (like a car w/engine running). Use a 15-18V supply to charge at home (you should be able to find wall cubes with this rating). It is based on a Maxim IC, the MAX713. Rate this link
- Nicad Battery Charger - uses a single transistor as a constant current source Rate this link
- Intelligent NiCd/NiMH Battery Charger Construction Project - This cheap and easy to build NiCd/NiMH Battery Charger is suitable for automatically charging a wide range of batteries for many applications. This charger can be used for cordless tool battery charging. Rate this link
- NICD / NIMH charger based on MAX 713 / MAX 712 Rate this link
- Temperature Controlled NICD Charger - This circuit prevent battery overcharging and electrolyte loss by stopping charging when the cells warm up. Rate this link
- Add current boost to a USB charger - This battery charger delivers 100 or 500 mA (selectable) to a single lithium cell when USB power is connected and charges at 1100 mA when ac power is present. Rate this link
- Charge Li-ion batteries from ac line voltage - converts energy from 120V ac to a regulated voltage or current as necessary to charge two Li-ion cells in series Rate this link
- Supply derives 5 and 3.3V from USB port - This circuit derives its power from a USB port and produces 5 and 3.3V supply rails for portable devices, such as digital cameras, MP3 players, and PDAs. The circuit allows the port to maintain communications while, for example, charging a lithium-ion battery. IC2 boosts the battery voltage, VBATT, to 5V, and IC3 buck-regulates that 5V output down to 3.3V. Rate this link
Lithium ion batteries (sometimes abbreviated Li-Ion) are a type of rechargeable battery commonly used in consumer electronics. They are currently one of the most popular types of battery, with one of the best energy-to-weight ratios, no memory effect and a slow loss of charge when not in use. They can be dangerous if mistreated.
WARNING: Exercise extreme precaution when handling and testing Li-ion batteries. Do not short circuit, overcharge, crush, drop, mutilate, penetrate,apply reverse polarity, expose to high temperature or disassemble them. Only use the Li-ion battery with the designated protection circuit(cellular phone batteries usually have this). Abuse of Li-ion can cause "explosion" like happening, because in short circuit the case temperature can get very high and the electrolyte insideLi-ion battery is highly flammable.
Li-Ion batteries can burn, explode, and spread toxic material that inflicts human injury and damages equipment if they are overcharged. Most commercial Li-Ion batteries have several automatic protection devices built-in, because of that danger. Generally charging current is interrupted if the voltage across any cell exceeds the safe limits (4.30 volts on some types), internal pressure exceeds a preset threshold, or internal temperature rises to an unsafe level. Li-Ion batteries usually are left in an unusable state after any of those things occur. Never defeat any of the internal protection devices or otherwise try to charge a lithium-ion battery that has become unchargeable. Despite these safety features, Li-ion batteries are subject of frequent recalls. During the past decade there have been numerous recalls of lithium-ion batteries in cellular phones and laptops owing to overheating problems.
Lithium-ion batteries can easily rupture, ignite, or explode when exposed to high temperatures, or direct sunlight. Short-circuiting a Li-ion battery can cause it to ignite or explode. Never open a Li-ion battery's casing. Li-ion batteries contain safety devices that protect the cells inside from abuse. In some cases internal contaminants inside the cells can defeat these safety devices (this was reason for millions of Laptop battery recalls in 2006).
A unique drawback of the Li-ion battery is that its life span is dependent upon aging from time of manufacturing (shelf life) regardless of whether it was charged, and not just on the number of charge/discharge cycles. At a 100% charge level, a typical Li-ion laptop battery will irreversibly lose approximately 20% capacity per year at normal room temperature (and much faster inside hot laptop). The capacity loss begins from the time the battery was manufactured, and occurs even when the battery is unused.
A stand-alone Li-Ion cell must never be discharged below a certain voltage to avoid irreversible damage. Therefore all systems involving Li-Ion batteries are equipped with a circuit that shuts down the system when the battery is discharged below the predefined threshold.
Li-ion batteries are not as durable as nickel metal hydride or nickel-cadmium designs and can be extremely dangerous if mistreated. A more advanced lithium-ion battery design is the lithium polymer cell.
- Lead-acid charger signals end of charge - lead-acid battery charger that works with either gel- or wet-cell, lead-acid, 12V batteries Rate this link
- Sealed Lead-Acid Battery Charger Circuit Rate this link
- Sealed Lead Acid Battery Charger Design Documentation - based on the UniTrode UC3906 Integrated Circuit Rate this link
- VK3EM Sealed Lead Acid Battery Charger Mk II Rate this link
- Battery-protection circuit allows surges - circuit monitors two lithium-ion batteries and protects both of them against overcharging, overdischarging, and undervoltage Rate this link
- Circuit prevents deep discharge of batteries - to avoid the deep discharge that can destroy or shorten the life of a rechargeable battery, you must disconnect its load before the discharge is complete Rate this link
- Circuit protects battery from overdischarge - In some applications, it is undesirable to overdischarge the battery, because it could irreversibly reduce the battery's capacity and the number of discharge/charge cycles. This circuit protects a single NiMH (nickel-metal-hydride) cell by disconnecting the load from the battery when it getting discharged enough. Rate this link
- Overload and reverse-current circuitry protects battery and load - there are numerous circuits can protect against backward installation of batteries and other overcurrent-causing conditions Rate this link
- LED flasher indicates low-battery condition Rate this link
- Phantom power battery test circuit - LED will light when battery is over 42 volts Rate this link
- Simple circuit monitors battery voltage - monitors four NiCd rechargeable batteries and causes the LED to flash if the voltage of the batteries goes lower than 4V Rate this link
- Test batteries without a voltmeter - This circuit an easy approach to testing batteries without exiting the voltmeter. The battery holders in sizes AAA, AA, C, and D make this tester so much faster than a voltmeter. Rate this link
- Test batteries without a voltmeter, part 2 Rate this link
Bascially all types of alkaline cells can be recharged, although the battery manufacturers discourage this (dangers of overcharging and battery leaking).You will need a special charger for charging alkaline cells (normal NiCd chagers are not suitable for this). There are some special alkaline cells nowadays which chan be charged better than normal alkaline cells. The best practice is not to discharge completely the cell or battery but rather to give a short charge often. Do not attempt to recharge a totally discharged cell or a cell showing even the slightest sign of damage.
- An Almost-Ideal Low-Battery Cut-Off Circuit Draws Only 1.2 ?A - this power-control circuit consumes no power when off, and no voltage drop occurs when the power is on Rate this link
- Choosing a power supply, automatically - Smart power switches provide a way for low-power devices to intelligently switch between power supplies and save power at the same time. Rate this link
- Circuit trade-offs minimize noise in battery-input power supplies - analyzing noise from the perspective of portable-system design will help you make appropriate power-supply design trade-offs Rate this link
- Dynamic voltage scaling conserves portable power - With portable applications on the rise, designers are turning to dynamic power-conservation techniques to delay the inevitable dead battery. Rate this link
- Energy Management for Small Portable Systems - Numerous diverse and conflicting constraints burden the designer of small hand-held products Rate this link
- Live long and prosper: juggling performance and battery life in handheld systems - Look beyond data sheets and examine your hardware design and software environment to ensure optimal performance and power consumption. Rate this link
- Mobile phones put the squeeze on battery power - powering mobile phones from fewer cells focuses attention on every aspect of battery discharge Rate this link
- Portable systems demand vigilant overcurrent protection - modern portable systems require protection from an arsenal of potential overcurrent problems Rate this link
- Power down for portables - A big battery can mean small market share. Reducing power consumption in your portable digital device is the "green" thing to do, as in money. Rate this link
- Pushbutton switch controls power supply and ?C - switching handheld units on and off with a pushbutton switch is a desirable feature but needs some thinking Rate this link
- Remote control turns battery on and off - circuit acts like a latching solid-state relay Rate this link
- Simple regulator monitors its input voltage - portable systems usually monitor their battery input to obtain an early warning of a loss of battery voltage Rate this link
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