## Lead acid max discharge rate explained,my toshiba laptop battery is plugged in but not charging,best battery for yamaha fz16 quito,car batteries direct jobs - PDF Books

02.06.2015
The battery capacity, or the amount of energy a battery can hold, can be measured with a battery analyzer.
When discharging a battery with a battery analyzer capable of applying different C rates, a higher C rate will produce a lower capacity reading and vice versa. To obtain a reasonably good capacity reading, manufacturers commonly rate alkaline and lead acid batteries at a very low 0.05C, or a 20-hour discharge. While lead- and nickel-based batteries can be discharged at a high rate, the protection circuit prevents the Li-ion Energy Cell from discharging above 1C.
Standard charge = ” Standard charge ” means charging the cell with charge current 1075 mA and costant voltage 4.2 V.
You mean to say that we have to select the charging current such that it can full charge (100% capacity) the battery in 20 hr. You may again find it will take 30hrs, yet better that going full and charging in 10hrs and slamming the battery with too much. Initial charge of something I just built, personally, I’d have a hard time going over 50% of what I believe it will do. If you just run cyclic voltammetry (potentiostat) you do not need any capacity value, you get it from this experiment.
When you run cyclically (potentiostat), I assume you then get the capacity related to the current over time?
Do you know how this compares to a “typical” charging profile where you hold the current (then the voltage) constant?
If we use our new device we get a diagram in which the time is the x-axis, one y-axis is capacity and the other one is the voltage. Right now I can not tell you more, I do not really know what this fig.1 in the link is (but I work not Li-ion batteries). Can any body share the the probability of lead acid automotive battery being exploded dusting cracking of an engine ? Can any body share the probability of lead acid automotive battery being exploded durting cracking of an engine ? I have been busy working over the past few months, if you still check this site i would be happy to try and get a discussion going on. In follow up I have some questions about the voltammetry; I plan on using the technique myself XD but in my initial learning I didnt see how it could be applied to a theoretical capacity. When you send me a mail I will reply with some images, this makes discussion easier (and I can not add pictures here, so mail is the best).
C therefore, in this context, represents a way to describe current, not capacity of a battery, although it is particularly related to its capacity. It is useful to describe a regimen in which the battery is being used regardless of its capacity, so two batteries of different capacities but of the same type can be, current wise, described in mutually comparable terms. Of course, different types of battery chemistry have different requirements, or rather interpretations. Therefore, you will only need to know a universal, C-rate based characteristics of a given battery type (chemistry) and will be able to convert this to actual current values depending on the battery’s capacity.
In the late 1700s, Charles-Augustin de Coulomb ruled that a battery receiving a charge current of one ampere (1A) passes one coulomb (1C) of charge per second. But that is all very theorical; is the battery really charge to full capacity (is your charger calibrate?), C is from what is written on battery or measured? Accidentally removed myself from the comments recipients list, as I had commented on this article previously and have been receiving notifications.
I accidentally removed myself from the comments recipients list, as I had commented on this article previously and have been receiving notifications. In conclusion, the battery whose (incomplete) rating you provided would, if it were a 12 V battery, have a C100 capacity of 20 kAh and a C100 charge rate of 200 A. Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts.
I am building a flashlight using a large(ish) 35W HID headlamp from a car, and I'm having troubles choosing a good battery technology.
Not the answer you're looking for?Browse other questions tagged battery-operated discharge lead-acid maximum-ratings battery-chemistry or ask your own question. What is the effect of pulsed discharge on watt hour (Wh) efficiency of lead-acid batteries? During a normal discharge cycle, lead-acid batteries form a layer of amorphous lead sulfate on their plates.
When I first started this job, I would often go to the deployment sites to investigate reports of customers receiving dead batteries.
Equation 1 tells us that increasing temperature produces an exponential increase in reaction rate.
A battery at a temperature of T+10 °C self-discharges twice as fast as the same battery at a temperature of T. I am not an electrochemist and I will not discuss all the details of Equation 1, but we can learn some things from a qualitative examination of Figure 1.
The chart shows that you do not want to let a battery discharge below 60% of its full capacity.
A lead-acid battery can be stored for about a year at room temperature before it needs a recharge.
I would not want to explain to my boss that I screwed up by not following the directions included with every battery.
Alternative energy sources deliver small amounts of power intermittently, and at times power levels may not match the needs of the applications that depend on them. Just as semiconductor buffers smooth the flow of data between a processor and memory, some form of buffering is needed between energy harvesting sources and their associated applications. On the supply side there is a great deal of variability in the amount of power available from different energy harvesting sources (see Table 1). In many cases, you can increase the amount of energy harvested by utilizing a variety of sources. Wireless sensor nodes highlight the need for energy buffering, since the current demand during transmit is often 10 to 100 times that required while the MCU is in a sleep state. Since the output voltage of a lead-acid battery varies with the state of charge (see Figure 1), both charge control circuitry and voltage regulation between the battery and the application are necessary. Lead-acid batteries are inexpensive and well-suited to outdoor applications that may be subject to extreme temperature. Small lithium-ion coin cells are not rechargeable, but they still have a place in low-power devices that harvest ambient energy sources. In contrast to lead-acid batteries, lithium-ion coin cells have an extremely flat discharge curve (see Figure 2) thanks to a very low self-discharge rate.
Figure 3: Discharge characteristics of the Panasonic ML-1220 manganese-lithium battery (Courtesy of Panasonic).
Coin cell batteries, whether rechargeable or not, are a natural fit for many, if not most energy harvesting-based applications.
When an application requires more power than a standard Li-Ion coin cell can deliver for sufficient amount of time, designers should consider rechargeable manganese lithium coin cells such as the ML-1220 in conjunction with energy harvesting sources of power.
For ultra-low-power devices that need to operate indefinitely, thin-film batteries are a natural storage choice to use with energy harvesting sources.
EnerChip CC devices contain a built-in power manager, temperature compensated charge control, and built-in energy storage protection.
The EnerChip CC’s discharge characteristics (see Figure 4) closely resemble those for Li-Ion coin cells, with the output voltage remaining largely flat before eventually falling off a cliff.
Infinite Power Solutions (IPS) offers a line of rechargeable THINERGY™ micro-energy cells (MECs), solid-state batteries targeting energy harvesting applications. Figure 5: Typical discharge curves at 250C for THINERGY MEC225 (Courtesy of Infinite Power Solutions).
IPS makes the Infinite Power Solutions Energy Harvesting Evaluation Board that includes a four volt 0.7 mAh THINERGY MEC, a small solar cell, and associated circuitry to enable you to experiment with a solar powered energy harvesting application.
Supercapacitors tend to suffer from internal leakage, resulting in a much faster self discharge rate than batteries or capacitors. While acknowledging the advantages of coin cell batteries (rechargeable and not) and supercapacitors in various applications, Infinite Power Solutions stresses the advantages of thin-film batteries in energy harvesting applications. Table 2: Storage choices for energy harvesting applications (Courtesy of Infinite Energy Systems). Traditional rechargeable batteries are a good choice when AC power is available; lead-acid batteries are the least expensive and most durable, though they have a higher self discharge rate, lower energy density, and shorter cycle life than lithium-based rechargeable cells. Thin-film batteries have numerous advantages in small battery-powered devices, including high energy density, small size, minimal charging requirements, voltage stability during discharge, and low self-discharge rate. There are numerous storage devices available for energy harvesting applications, including miniature lead-acid batteries, lithium-ion coin cells, supercapacitors, and thin-film batteries. Okay, like the title suggests, I need a method of calculating self discharge rates of Lead-Acid batteries. Standard lead-acid cells have a low self-discharge, about 5% per month, so continuously monitoring makes little sense.
Anyway, self-discharge is exponential, so that the largest change will be right after the cell is charged.

Asking people about fine details of cell performance tends to legitimatise and hide the fact that a process of no real certainty is being investigated. Until the underlying issues have been at least lightly investigatred the question is premature and ill advised.
In the absence of a good grasp of the chemistry there is no certainty that extrapolated results will be in any way accurate.
A "certain" method, for at least the current cycle, is to use a number of cells of each type and discharge them to endpoint after selected periods.
For example, a total of 7 batteries would allow all periods of 1 to 12 months to be checked.
The new large result per month starts to go wrong as 6+3+2+1 6 months result until after a year.
A key issue is, are the cells going to have increasing capacity over the first few cycles (as eg NimH do) or will they fall progressively with cycles?
There is no doubt that you will get some sort of battery in each case, but as the capacity you achieve will be lower at best and probably much lower, then a long self discharge life may not return a better net capacity that a standard lead acid battery for at least 12 months. Determination of battery state of charge from loaded or open circuit voltage is notionally possible, but depends on many factors - with major ones being temperature & specific gravity of electrolyte. The above diagram is a rearrangement of the diagram on page 68 from the excellent Lead Acid battery state of charge versus voltage - Home power #36, Aug-Sep 1993. I think you would have to take regular readings of the voltage, using a setup that has less current draw than normal expected self discharge rate, so as not to skew the result. I guess, the self discharge has a function similar to the discharge of a capacitor+resistor circuit (but of course with much larger time constants).
I Mean we do not know how much capacity it can store, in this case how we can choose the C rates.
Once we do this we will find out the full capacity of battery and according to this full capacity we have to select the C-rates.
That is why I am getting these silly questions and I am learning slowly and after that only I will start making the battery. Since we do not know the capacity of the test cell, do we first have to measure CV on our old device to know the highest achievable capacity, so that we can calculate e.g.
In the first tests with the new one we noticed that the time for one cycle depends on the capacity of the cell (so a short cycle shows less capacity in the capacity-cycle-diagram). 1 C is indeed the standard abbreviation for the SI unit 1 coulomb, but in this article, the notation 1C is used to mean a totally different thing! If you use a battery cycler you need a C-rate (so: yes, using different C values is possible, most people does). If we run cyclic voltammetry in our old device we just have to add the parameters voltage range, scan number, Esteps and scanrate. And also the same battery being used for DG starting with permanent float cum boost charger connected ? I am somewhat hesitant to put my skype name or email up on a permanent online post, but I think there could be a way to get in contact at least through an email. Wont the measurement only tell you the potentials at which reactions inside the cell are occurring? As I wrote we have two different ones, so it depends a bit if its more of a battery cycler or a potentiostat (at least in this way we name or two ones). Therefore C-rate is a good way to really get a grasp on the load placed upon a battery, regardless of whether it is during the charging or discharging process. Is C rate defined by the specific mah capacity of each cell in a pack, or is it defined by the aH rating of the pack as a whole? Our products generally ship with an Uninterruptible Power Supply (UPS) that contains a 7.2 A-hr Sealed Lead-Acid (SLA) battery. They are murdered by owners that charge them improperly, cycle them too deeply, let them sit discharged for too long, or store them at too high a temperature. Let's examine how this reaction rate affects a battery that appears to just be sitting there -- it actually is experiencing an internal chemical reaction that is discharging the battery. If it is true, the customer that I mentioned earlier who stored his batteries at 50 °C would see his batteries discharged in his warehouse within about two and half months.
Each battery vendor's products have different self-discharge rates because the rates are a function of how the plates are constructed (i.e. At one deployment site, I saw that the customer had over 900 batteries reported as failures. Replacing a battery is not cheap, and paying for a service call to install the battery is not cheap either. In Figure 1, we see that as the battery temperature raises from 30 °C to 40 °C, the self-discharge time reduces from 8 months to about 5 months, which is less than half. The derivation in Figure 2 shows that the rule of thumb is only true for a limited range of values. I too have had some batteries that have lasted very long in float applications and under the same operating conditions that you list. The owner of this blog makes no representations as to the accuracy or completeness of any information on this site or found by following any link on this site. The owner will not be liable for any losses, injuries, or damages from the display or use of this information. Some form of energy storage is needed, though the solution will vary with the demands of the application. The amount of buffering needed increases in proportion to the mismatch between supply and demand. With the exception of the ambient RF, typical energy harvesting devices can supply anywhere from 10 µW to 1 mW, though rarely on a steady basis. Looking again at Table 1, there is often a few orders of magnitude difference between the theoretically available source power and the actual power you can harvest using currently available devices. For example, a remote wireless strain sensor on a building might combine a small solar cell with a TEG; on a bridge roadbed, a similar device might combine a TEG with a vibration sensor. If over time, the energy requirement of your device is equal to or less than what your energy harvesting sources can supply, then the device should be able to operate independently for an indefinite period of time. To minimize power consumption, they typically power down the microcontroller as far and as frequently as possible, only waking up to check for beacons and to quickly burst out data for a few microseconds every second.
In these applications, capacitors or even supercapacitors are often placed in the supply line to be able to handle the sudden surge in current.
The EnerSys Cyclon 0810-0004 2 V thin-plate, sealed-lead battery, delivers 2.5 Ah at 260 mA. Overcharging or repeatedly fully discharging these batteries can markedly shorten their life expectancy. Since even the CR2032 can last up to ten years if your application is sufficiently low powered, the ability to recharge may not be an issue. They also offer a Product Training Module (PTM) on Digi-Key’s site, Energy Processing and Solid State Batteries for Energy Harvesting. They have a rated cycle life of 100,000 charge discharge cycles from a ten percent depth of discharge with a typical application load; they can be recharged to 90 percent state of charge in 15 to 20 minutes. Their high density is a direct result of the extremely close proximity of the conductive layers, which also results in a very low breakdown voltage. The curves highlight some of the advantages as well as disadvantages of super caps in energy harvesting applications. As a result, they are usually used in conjunction with batteries to buffer the load for the power source and provide peak power when needed. However, they also have a number of disadvantages, including high cost, limited storage capacity, limited surge capability, and some fragility regarding the minimum and maximum voltage levels they can tolerate – though the latter is generally handled by an accompanying power management IC (PMIC).
Over the last 25 years John has published two books, dozens of manuals, and hundreds of technical articles. Here's the catch: I varied the electrolyte which the batteries were using, replacing sulphuric acid with hydrochloric acid, another one with nitric, and another one with phosphorous acid. To measure this I would take a reading with a DMM every few days, and you may need to take readings over a period of more than a month to get a decent graph.
Materials and construction of lead accus have been optimized long ago now, and have proven their worth.
Take measurements at a few hours interval, and decide if one measurement every few days is still sufficient. This led to my writing this series of articles on the various battery technologies available to us. 1), I decide on primary or secondary types and then calculate the energy my load will need over the desired run time. Answers to these questions can be found at the website of the Car Charging Group, the largest electric-vehicle charging service provider.
This is a secondary battery that provides a very low energy-to-weight ratio and a low energy-to-volume ratio, but it compensates for this by supplying high surge currents at low cost.

These are collectively known as valve-regulated lead-acid (VRLA) or sealed lead-acid batteries. With higher charge currents and multi-stage charge methods, the charge time can be reduced to 10 hours or less. The constant-current charge applies the bulk of the charge and takes roughly half the required charge time. A very useful resource for the use and recycling of lead-acid batteries is the Battery Council International organization.
Others modify the plates to alter the ion density, to slow the movement of the heavier lead-sulfur crystals so it cannot stick. The sum should be the same since the identical amount of energy is dispensed over a shorter time.
Manufacturers provide capacity offsets to adjust for the discrepancies if discharged at a higher C rate than specified.
However, all communication must be done with the use of appropriate language and the avoidance of spam and discrimination. Neither can we take responsibility for any damages or injuries that may result as a consequence of the information provided. Initially I thought that we need to select the C-rates according to the theoretical capacity of anode and cathode (combined capacity) do we select C-rates according to theory?.
Does this mean that the new device notices when all active material has reacted and automatically starts the charging process, or what else can be the reason? What is the acceptable charge range for it (Im expecting to end up with a disharge rate of around 14 hours in my application, should that matter)?
This is, of course, implying that during such discharge, the rated voltage will remain just that - (practically) the same. I have looked at purchasing a small 4Ah 12V Pb battery, but I am hesitant, because I am unsure of what currents the battery may be able to supply. Unfortunately, when a discharged battery is stored for a long period of time (usually weeks or months), the amorphous lead sulfate changes into a crystalline form that cannot be converted back to lead through normal charging. Since our UPS units have built-in controllers and the units are rarely deeply discharged, the primary battery killer is heat. Chemical reactions exist within a battery that cause them to discharge while just sitting in storage. Every failed battery had been stored improperly and then installed in a private residence when fiber service was installed at that home. There were many tens thousands of dollars worth of avoidable problems at this one customer site alone.
Excerpts and links may be used, provided that full and clear credit is given to Mark Biegert and Math Encounters with appropriate and specific direction to the original content. This article will examine various energy buffering solutions, including small form-factor batteries, thin-film batteries, and supercapacitors, highlighting both their specifications and the applications to which they are best suited. This problem can be addressed by adding more solar cells or TEGs in parallel, for example, if your application will allow it. If your application can combine light, vibration, and thermal energy sources, it may be able to operate indefinitely by just harvesting these energy sources.
If supply falls short of demand, then you have to consider whether the time your device can operate before needing attention is adequate under the circumstances; if not, then energy harvesting sources may not be part of the solution. The cycle life of a lead-acid cell is a function of depth of discharge (DOD), temperature, and charging rate. For example, the coin cell that is maintaining the BIOS configuration data in the computer on which you are reading this article should be good for up to ten years.
When the primary power supply dips below a user-defined threshold voltage, the EnerChip CC signals this event and routes the EnerChip voltage to VOUT in order to maintain continuous power to the MCU or other circuitry. The smallest device in the THINERGY MEC family of products, the MEC-225, can accommodate a discharge rate of up to 7 mA and an ultra-low self-discharge rate of one percent per year at 25°C. Supercapacitors have a lower energy density than batteries, but a far higher power density, since, unlike batteries, they can be discharged almost instantaneously.
On the plus side, they have very fast charge and discharge rates, the latter being a key advantage in applications that occasionally require high peak power delivery.
Unless you have worked though the chemistry it is not certain that there will be a satisfactory outcome.
Note the shape of the curve is not a concave exponential one, as might be expected, but a convex curve - ie voltage change per % of capacity change increases with increasing discharge (and doesn't decrease as in a normal exponential decay). In addition to the nitty-gritty technology details, I'm including tips and tricks for selecting the most appropriate battery technology for your application (the first two tips appeared in my previous column), along with tidbits of trivia and nuggets of knowledge, as Max would say.
A rough estimate is the average load voltage multiplied by the average load current multiplied by the required number of run time hours. In my next column, we'll look at some more tips and tricks, and we will consider another battery technology. Smart Carbon is a proprietary Trojan formula which provides improved performance when the batteries operate in PSOC, enhancing overall battery life in off-grid and unstable grid applications where the batteries are under charged on a regular basis. Another clever approach (specialty battery) is a mechanical structure that monitors the specific gravity and adds a buffer from a reservoir, which reverses at full charge. Losses at fast discharges reduce the discharge time and these losses also affect charge times. If a 1Ah battery provides 1A for one hour, an analyzer displaying the results in percentage of the nominal rating will show 100 percent.
In reality, internal losses turn some of the energy into heat and lower the resulting capacity to about 95 percent or less.
Please accept our advice as a free public support rather than an engineering or professional service. I would expect an influx of 0.8 V from solar energy that contributes to slow down the discharge rate to show a higher SoC. Than you just have to calculate the area under the redox-peaks and with this (and the active mass) calculate the specific capacity.
I know the battery is small, but I have a small budget (Got the HID bulbs for free off a friend), and I am OK with a 30 minute battery life, as that is the max time I will be using it. Since we charge the batteries just before shipment, I know the batteries left our facility functional and with a full charge.
The UPS did a battery load test every ten days, so the battery would be reported as failed 10 days after it was installed, which means a technician had to physically go out to a person's home and replace the failed battery (often with another failed battery).
Still, you are dealing with micropower sources and there is a limit to what you can do with them. The chance of the average person not replacing their computer within ten years is close to zero. These are obviously quite small batteries, so they are targeted at ultra-low-power applications such as wireless sensors, RFID tags, and standby supply for NV-SRAM in real-time clocks.
Of particular interest is their ability to accept charge currents along 1 µA, well within the range of all but the smallest micro-power source. On the downside, their output voltage drops quickly as they discharge, generally requiring a buck boost voltage regulator to assure constant output from the supply to which they are attached. You would probably have to lightly load the battery during measurement as Voc will probably be less representative of the real state of charge. Keep in mind that loads may be constant power, constant current, constant resistance, or a mix (including pulses).
Sealed lead-acid technology is sluggish and cannot be charged as quickly as other battery systems. Along with increased life in a partial state of charge, Trojan's Smart Carbon proprietary formula also provides improved charge acceptance and faster recharge in PSOC applications.
If the discharge lasts 30 minutes before reaching the end-of-discharge cut-off voltage, then the battery has a capacity of 50 percent.
Discharging the same battery at 0.5C, or 500mA over 2 hours, will likely increase the capacity to above 100 percent. I think that you would need some sort of time scale to know the amount of charge you are putting into the batter? I read that resistance increases with higher C-rate but can i have detail explanation on the chemistry part and in electrical part too? In every single case, the customer had not properly handled the batteries -- the batteries had become fully discharged because they had been stored for too long between charging cycles. Both of these reactions are accelerated by temperature according to the Arrhenius equation, which I state in Equation 1. With a voltage regulator between the energy scavenging sources and the battery, that should be a fairly easy target for such micropower sources to hit. The CBC3112 comes in a 20-pin, 7 mm x 7 mm square dual flat no-lead (DFN) package that is only 0.9 mm thick.
A new battery is sometimes overrated and can produce more than 100 percent capacity; others are underrated and never reach 100 percent, even after priming.
A discharged lead-acid battery will eventually become sulfated -- a state where the battery plates are coated with a crystalline layer of lead sulfate and lead oxide. He is a member the Association for Computing Machinery (ACM) and a Senior Member of the IEEE. Next time, I will show how to estimate all the losses and temperature derating to arrive at the minimum Watt-hours rating of the battery. Some people refer to this layer as a "varnish" because sulfated plates look like they are coated with wood varnish.
The UPS units and their batteries were stored in the loft of the barn at a temperature of about 50°C (122 °F). I told my customer that the batteries were not being stored according to the vendor's battery storage requirements.
He said that no one ever told him what the battery handling requirements were and I needed to pay to replace every one of his failing batteries (including service call). I then reached into a UPS box and pulled out the battery handling specification that ships with every UPS. He seemed pretty sheepish after seeing that he had received thousands of battery handling instruction sheets.