BU-802b: What does Elevated Self-discharge Do?
Learn about an often ignored characteristic of batteries
All batteries are affected by self-discharge. Self-discharge is not a manufacturing defect but a battery characteristic; although poor fabrication practices and improper handling can increase the problem. Self-discharge is permanent and cannot be reversed. Figure 1 illustrates self-discharge in the form of leaking fluid.
|
Figure 1: Effects of high self-discharge. Self-discharge increases with age, cycling and elevated temperature. Discard a battery if the self-discharge reaches 30 percent in 24 hours. Courtesy of Cadex |
The amount of electrical self-discharge varies with battery type and chemistry. Primary cells such as lithium-metal and alkaline retain the stored energy best, and can be kept in storage for several years. Among rechargeable batteries, lead acid has one of the lowest self-discharge rates and loses only about 5 percent per month. With usage and age, however, the flooded lead acid builds up sludge in the sediment trap, which causes a soft short when this semi-conductive substance reaches the plates. ( See BU-804a: Corrosion, shedding and Internal Short )
The energy loss is asymptotical, meaning that the self-discharge is highest right after charge and then tapers off. Nickel-based batteries lose 10–15 percent of their capacity in the first 24 hours after charge, then 10–15 percent per month. Figure 2 shows the typical loss of a nickel-based battery while in storage.
|
Figure 2: Self-discharge as a function of time. The discharge is highest right after charge and tapers off. The graph shows self-discharge of a nickel-based battery. Lead- and lithium-based systems have a lower self-discharge. Courtesy of Cadex |
NiMH and NiCd belong to rechargeable batteries that have the highest self-discharge; they need recharging before use when placed on a shelf for a few weeks. High-performance NiCd has a higher self-discharge than the standard versions. Furthermore, the self-discharge increases with use and age, of which crystalline formation (memory) is a contributing factor. Regular full discharge cycles keeps memory under control. ( See BU-807: How to restore Nickel-based Batteries )
Li-ion self-discharges about 5 percent in the first 24 hours and then loses 1–2 percent per month; the protection circuit adds another 3 percent per month. A faulty separator can lead to elevated self-discharge that could develop into a current path, generating heat and, in an extreme case, initiate a thermal breakdown. In terms of self-discharge, lead acid is similar to Li-ion. Table 3 summarizes the expected self-discharge of different battery systems.
Battery system |
Estimated self-discharge |
---|---|
Primary lithium-metal |
10% in 5 years |
Alkaline |
2–3% per year (7-10 years shelf life) |
Lead-acid |
5% per month |
Nickel-based |
10–15% in 24h, then 10-15% per month |
Lithium-ion |
5% in 24h, then 1–2% per month (plus 3% for safety circuit) |
Table 3: Percentage of self-discharge in years and months. Primary batteries have considerably less self-discharge than secondary (rechargeable) batteries.
The self-discharge of all battery chemistries increases at higher temperature, and the rate typically doubles with every 10°C (18°F). A noticeable energy loss occurs if a battery is left in a hot vehicle. High cycle count and aging also increase self-discharge of all systems. Nickel-metal-hydride is good for 300–400 cycles, whereas the standard nickel-cadmium lasts for over 1,000 cycles before elevated self-discharge starts interfering with performance. The self-discharge on an older nickel-based battery can get so high that the pack goes flat from leakage rather than normal use. (See BU-208: Cycling Performance demonstrating the relationship of capacity, internal resistance and self-discharge.)
Under normal circumstances the self-discharge of Li-ion is reasonably steady throughout its service life; however, full state-of-charge and elevated temperature cause an increase. These same factors also affect longevity. Furthermore, a fully charged Li-ion is more prone to failure than one that is partially charged. Table 4 shows the self-discharge per month of Li-ion at various temperatures and state-of-charge. The high self-discharge at full state-of-charge and high temperatures comes as a surprise. ( See also BU-808: How to Prolong Lithium-based Batteries )
State-of-charge |
0°C (32°F) |
25°C (77°F) |
60°C (140°F) |
Full charge 40–60% charge |
6% 2% |
20% 4% |
35% 15% |
Table 4: Self-discharge per month of Li-ion at various temperatures and state-of-charge
Self-discharge increases with rising temperature and higher SoC.
Lithium-ion should not be discharged below 2.50V/cell. The protection circuit turns off and most chargers will not charge the battery in that state. A “boost” program applying a gentle charge current to wake up the protection circuit often restores the battery to full capacity. ( See BU-803a: How to Awaken Sleeping Li-ion )
There are reasons why Li-ion is put to sleep when discharging below 2.50V/cell. Copper dendrites grow if the cell is allowed to dwell in a low-voltage state for longer than a week. This results in elevated self-discharge, which could compromise safety.
Self-discharge mechanisms must also be observed in manufacturing. They vary from corrosion to impurities in the electrodes that reflect in self-discharge variations not only from batch to batch but also form cell to cell. A quality manufacturer checks the self-discharge of each cell and rejects those that fall outside tolerances.
Figure 5 compares the self-discharge of a new Li-ion cell with a cell that underwent forced deep discharges and one that was fully discharged, shorted for 14 days and then recharged. The cell that was exposed to deep discharges beyond 2.50V/cell shows a slightly higher self-discharge than a new cell. The largest self-discharge is visible with the cell that was stored at zero volts.
Figure 5: Self-discharge of new and stressed Li-ion cells. Cells that had been stressed with deep discharges and kept at 0V show a higher self-discharge than a new cell.
Source: TU München
Figure 6 illustrates the self-discharge of a lead acid battery at different ambient temperatures At a room temperature of 20°C (68°F), the self-discharge is roughly 3% per month and the battery can theoretically be stored of 12 months without recharge. With a warm temperature of 30°C (86°F), the self-discharge increases and a recharge will be needed after 6 months. Letting the battery drop below 60 percent SoC for some time causes sulfation. (See also BU-702: How to Store Batteries.)
Figure 6: Self-discharge of lead acid as a function of temperature.
Lead acid should never drop below 60% SoC. Charge more often when warm.
Source: Power-Sonic
Last Updated 2017-04-04
*** Please Read Regarding Comments ***
Comments are intended for "commenting," an open discussion amongst site visitors. Battery University monitors the comments and understands the importance of expressing perspectives and opinions in a shared forum. However, all communication must be done with the use of appropriate language and the avoidance of spam and discrimination.
If you have a suggestion or would like to report an error, please use the "contact us" form or email us at: BatteryU@cadex.com. We like to hear from you but we cannot answer all inquiries. We recommend posting your question in the comment sections for the Battery University Group (BUG) to share.
Or Jump To A Different Article
- BU-001: Sharing Battery Knowledge
- BU-002: Introduction
- BU-003: Dedication
- BU-101: When Was the Battery Invented?
- BU-102: Early Innovators
- BU-103: Global Battery Markets
- BU-103a: Battery Breakthroughs: Myth or Fact?
- BU-104: Getting to Know the Battery
- BU-104a: Comparing the Battery with Other Power Sources
- BU-104b: Battery Building Blocks
- BU-104c: The Octagon Battery – What makes a Battery a Battery
- BU-105: Battery Definitions and what they mean
- BU-106: Advantages of Primary Batteries
- BU-106a: Choices of Primary Batteries
- BU-107: Comparison Table of Secondary Batteries
- BU-201: How does the Lead Acid Battery Work?
- BU-201a: Absorbent Glass Mat (AGM)
- BU-201b: Gel Lead Acid Battery
- BU-202: New Lead Acid Systems
- BU-203: Nickel-based Batteries
- BU-204: How do Lithium Batteries Work?
- BU-205: Types of Lithium-ion
- BU-206: Lithium-polymer: Substance or Hype?
- BU-206a: Finding the Optimal Runtime and Power Ratio of Li-ion
- BU-208: Cycling Performance
- BU-209: How does a Supercapacitor Work?
- BU-210: How does the Fuel Cell Work?
- BU-210a: Why does Sodium-sulfur need to be heated
- BU-210b: How does the Flow Battery Work?
- BU-211: Alternate Battery Systems
- BU-212: Future Batteries
- BU-213: Cycle Performance of NiCd, NiMH and Li-ion
- BU-214: Summary Table of Lead-based Batteries
- BU-215: Summary Table of Nickel-based Batteries
- BU-216: Summary Table of Lithium-based Batteries
- BU-217: Summary Table of Alternate Batteries
- BU-218: Summary Table of Future Batteries
- BU-301: A look at Old and New Battery Packaging
- BU-301a: Types of Battery Cells
- BU-302: Series and Parallel Battery Configurations
- BU-303: Confusion with Voltages
- BU-304: Why are Protection Circuits Needed?
- BU-304a: Safety Concerns with Li-ion
- BU-304b: Making Lithium-ion Safe
- BU-304c: Battery Safety in Public
- BU-305: Building a Lithium-ion Pack
- BU-306: What is the Function of the Separator?
- BU-307: How does Electrolyte Work?
- BU-308: Availability of Lithium
- BU-309: How does Graphite Work in Li-ion?
- BU-310: How does Cobalt Work in Li-ion?
- BU-311: Battery Raw Materials
- BU-401: How do Battery Chargers Work?
- BU-401a: Fast and Ultra-fast Chargers
- BU-402: What Is C-rate?
- BU-403: Charging Lead Acid
- BU-404: What is Equalizing Charge?
- BU-405: Charging with a Power Supply
- BU-406: Battery as a Buffer
- BU-407: Charging Nickel-cadmium
- BU-408: Charging Nickel-metal-hydride
- BU-409: Charging Lithium-ion
- BU-409a: Why do Old Li-ion Batteries Take Long to Charge?
- BU-410: Charging at High and Low Temperatures
- BU-411: Charging from a USB Port
- BU-412: Charging without Wires
- BU-413: Charging with Solar, Turbine
- BU-413a: How to Store Renewable Energy in a Battery
- BU-414: How do Charger Chips Work?
- BU-415: How to Charge and When to Charge?
- BU-501: Basics about Discharging
- BU-501a: Discharge Characteristics of Li-ion
- BU-502: Discharging at High and Low Temperatures
- BU-503: How to Calculate Battery Runtime
- BU-504: How to Verify Sufficient Battery Capacity
- BU-601: How does a Smart Battery Work?
- BU-602: How does a Battery Fuel Gauge Work?
- BU-603: How to Calibrate a “Smart” Battery
- BU-604: How to Process Data from a “Smart” Battery
- Close Part One Menu
Introduction
Crash Course on Batteries
Battery Types
Packaging and Safety
Charge Methods
Discharge Methods
"Smart" Battery
- BU-701: How to Prime Batteries
- BU-702: How to Store Batteries
- BU-703: Health Concerns with Batteries
- BU-704: How to Transport Batteries
- BU-704a: Shipping Lithium-based Batteries by Air
- BU-704b: CAUTION & Overpack Labels
- BU-704c: Class 9 Label
- BU-705: How to Recycle Batteries
- BU-705a: Battery Recycling as a Business
- BU-706: Summary of Do’s and Don’ts
- BU-801: Setting Battery Performance Standards
- BU-801a: How to Rate Battery Runtime
- BU-801b: How to Define Battery Life
- BU-802: What Causes Capacity Loss?
- BU-802a: How does Rising Internal Resistance affect Performance?
- BU-802b: What does Elevated Self-discharge Do?
- BU-802c: How Low can a Battery be Discharged?
- BU-803: Can Batteries Be Restored?
- BU-803a: Cell Matching and Balancing
- BU-803b: What causes Cells to Short?
- BU-803c: Loss of Electrolyte
- BU-804: How to Prolong Lead-acid Batteries
- BU-804a: Corrosion, Shedding and Internal Short
- BU-804b: Sulfation and How to Prevent it
- BU-804c: Acid Stratification and Surface Charge
- BU-805: Additives to Boost Flooded Lead Acid
- BU-806: Tracking Battery Capacity and Resistance as part of Aging
- BU-806a: How Heat and Loading affect Battery Life
- BU-807: How to Restore Nickel-based Batteries
- BU-807a: Effect of Zapping
- BU-808: How to Prolong Lithium-based Batteries
- BU-808a: How to Awaken a Sleeping Li-ion
- BU-808b: What Causes Li-ion to Die?
- BU-808c: Coulombic and Energy Efficiency with the Battery
- BU-809: How to Maximize Runtime
- BU-810: What Everyone Should Know About Aftermarket Batteries
- BU-901: Fundamentals in Battery Testing
- BU-902: How to Measure Internal Resistance
- BU-902a: How to Measure CCA
- BU-903: How to Measure State-of-charge
- BU-904: How to Measure Capacity
- BU-905: Testing Lead Acid Batteries
- BU-905a: Testing Starter Batteries in Vehicles
- BU-906: Testing Nickel-based Batteries
- BU-907: Testing Lithium-based Batteries
- BU-907a: Battery Rapid-test Methods
- BU-908: Battery Management System (BMS)
- BU-909: Battery Test Equipment
- BU-910: How to Repair a Battery Pack
- BU-911: How to Repair a Laptop Battery
- BU-912: How to Test Mobile Phone Batteries
- BU-913: How to Maintain Fleet Batteries
- BU-914: Battery Test Summary Table
- Close Part Two Menu
From Birth to Retirement
How to Prolong Battery Life
Battery Testing and Monitoring
- BU-1001: Batteries in Industries
- BU-1002: Electric Powertrain, then and now
- BU-1002a: Hybrid Electric Vehicles and the Battery
- BU-1003: Electric Vehicle (EV)
- BU-1004: Charging an Electric Vehicle
- BU-1005: Does the Fuel Cell-powered Vehicle have a Future?
- BU-1006: Cost of Mobile and Renewable Power
- BU-1007: Net Calorific Value
- BU-1008: Working towards Sustainability
- BU-1009: Battery Paradox - Afterword
- BU-1101: Glossary
- BU-1102: Abbreviations
- BU-1103: Bibliography
- BU-1104: About the Author
- BU-1105: About Cadex
- BU-1403: Author’s Creed
- BU-1501 Battery History
- BU-1502 Basics about Batteries
- BU-1503 How to Maintain Batteries
- BU-1504 Battery Test & Analyzing Devices
- BU-1505 Short History of Cadex
- Why Mobile Phone Batteries do not last as long as an EV Battery
- Battery Rapid-test Methods
- How to Charge Li-ion with a Parasitic Load
- Ultra-fast Charging
- Assuring Safety of Lithium-ion in the Workforce
- Diagnostic Battery Management
- Tweaking the Mobile Phone Battery
- Battery Test Methods
- Battery Testing and Safety
- How to Make Battery Performance Transparent
- Battery Diagnostics On-the-fly
- Making Battery State-of-health Transparent
- Batteries will eventually die, but when and how?
- Why does Pokémon Go rob so much Battery Power?
- How to Care for the Battery
- How to Rate Battery Runtime
- Tesla’s iPhone Moment — How the Powerwall will Change Global Energy Use
- Painting the Battery Green by giving it a Second Life
- Charging without Wires — A Solution or Laziness
- What everyone should know about Battery Chargers
- A Look at Cell Formats and how to Build a good Battery
- Battery Breakthroughs — Myth or Fact?
- Rapid-test Methods that No Longer Work
- Shipping Lithium-based Batteries by Air
- How to make Batteries more Reliable and Longer Lasting
- What causes Lithium-ion to die?
- Safety of Lithium-ion Batteries
- Recognizing Battery Capacity as the Missing Link
- Managing Batteries for Warehouse Logistics
- Caring for your Starter Battery
- Giving Batteries a Second Life
- How to Make Batteries in Medical Devices More Reliable
- Possible Solutions for the Battery Problem on the Boeing 787
- Impedance Spectroscopy Checks Battery Capacity in 15 Seconds
- How to Improve the Battery Fuel Gauge
- Examining Loading Characteristics on Primary and Secondary Batteries
- BU-001: Compartir conocimiento sobre baterías
- BU-002: Introducción
- BU-003: Dedicatoria
- BU-104: Conociendo la Batería
- BU-302: Configuraciones de Baterías en Serie y Paralelo
- Change-log of “Batteries in a Portable World,” 4th edition: Chapters 1 - 3
- Change-log of “Batteries in a Portable World,” 4th edition: Chapters 4 - 10
- Close Part Three Menu
Amazing Value of a Battery
Information
Learning Tools
Battery Pool
Language Pool
Batteries in a Portable World
Comments
This is the best website on batteries, thank you so much..
I have been wondering what the difference is between “precharged”
NIMH vs standard NIMH batteries.
What are the pros and cons of these 2 types??
Thanks
So, do you charge your phone to 100percent or charge it only to 80 percent and use it down to 20 percent and recharge again ?
Comment 1 -John Fetter - So what is that suitable chemical substance then ?
Tom Tercek- I notice precharged is marked on more recent rechargeables because the have lower self discharge . Standard rechargeables seem to be flat in 1 to 3 months max. The precharged seem to last many months of non use before needing recharge.
tytower: The source and preparation of this material was revealed on, “How to Prolong Lead-acid Batteries”, Dec 8, 2011 at 3:12 am, (a parallel page on this website). You can find more info. scattered about on various pages.
Thanks for the wealth of Info on self discherge od secondary batteries. Much of it, I’ve not seen before, and I’ve been working with batteries about 65 years.
I would like to find a very low self discharge battery, 6 volt, Group 1 for use in antique cars dating back to the teens. Often they sit unused for years. They should also have a long useful life (eg. 10 to 30 years). Use of a trickle charger is no problem.
Thanks for all the infos.
I am facing a big problem of Self-Discharge in a CR2 (Lithium Prinary) battery : When I use it for 75% of its capacity, in less than a day, the 25% left disapear by Self-Discharge.
Does anyone knows about this problem?
Thanks
I am curious how the chip inside the battery pack of a laptop accounts for self discharge. For instance if you leave the laptop off for long periods of time unplugged and off (weeks) or leave the battery out of the laptop for weeks or months. When you start up the laptop again and pop in the battery I think it’s smart enough to immediately give the updated, perhaps semi-accurate charge % so it accounts for the self discharge somehow? It can looks at instantaneous voltage readings and changes with load.
Does the chip log history so it knows the behavior of the battery so it doesn’t need to be calibrated when you let the battery self discharge, looking at voltage and maybe resistance and it knows immediately?
Thanks
Good day,
I have n lithium polymer battery that discharge in 2 days.
I do laser alignment. So I have 2 components. One is n receiver and the other one n laser.
I have to charge to laser every time before I go and work. Say I did not work for 2 days. The laser discharge by it self. But the receiver sits on 90%.
Whats wrong with the laser battery? Why is it losing its charge?
Is there any possiblity to reduce self discharge of Lead acid batteries.
Madhav - Yes, there is. Please refer to my posts on Additives to Boost Flooded Lead Acid, dated Jan 8, Jan 13 and May 25, 2014.
John Fetter— are you the Lead-Acid experter???
Edward - Are you Swedish?
John Fetter—No i am a ni battery engineer from China, my email is zzrm316@163.com . keep in touch please
great battery site
Edward - You might like to explain why.
Hello, I just found this excellent website.
Question re. self discharge (particularly Li-Ion). I presume that the specified discharge rates are based on cells which are not connected / on the shelf. And wonder if/how taking a small amount of current from the cell (c. 50-100 uA) would effect the self discharge characteristics.
The reason for asking this is that I recall a supplier comment some time ago regarding Li-SOCl2 primary cells, which suggested that a small continuous current excited the chemistry sufficiently to reduce the effects of self discharge.
Hi John ,Do you mean you want to charge the Li-SOCI2 primary cells at very small current??
Hi Edward.
No, we currently use Li-SOCI2 primary cells in an application which has a small continuous current drain, and are lead to believe that this can improve the life (as it excites the chemistry).
What I was asking was if a similar continuous current would have any positive effect on Lithium-Ion battery’s and possibly help the comparatively poor self discharge characteristics. My understanding following the post yesterday is probably not :-(
keep in charging the Lithium-ion battery at small current long time? the over-charge to Lithium-ion battery will damage it
This is a great site, and this topic a real eye opener. When I first discovered LiPO cells I was ecstatic about their energy capacity, but soon came to realize how much extra care they needed. My latest concern was in a project involving a 200maH LiPo. I had a good charging circuit, but not such good protection against over discharge. In trying to solve that with a home brewed protection circuit, i realized that you can not make a low voltage cut off circuit that draws zero current, a paradox since a LiPO is easily ruined by over discharge. At least this page helped me put it in perspective. seems if I can get my protection circuit to contribute less than 3% of the self discharge, I’m already doing better than a lot of the built in protection circuits.
Hi, dear all.
I want to find chart of battery dischart, battery capacity after a period of using. Who do you have? Please give me
Thank you very much
I have required a low self discharge battery for remote location area without any charging.
Application…...gsm based data transmitters
Volt ...9-12vdc
Load…..50ma constantly and 1A for 1 minutes twice in per day
Required life ...minimum 5 year
Please suggest which should I use
If my new battery from my phone arrived in a 1% state and it was left in the warehouse for 3 months according to this article the self discharge would be greater esp if it’s been in a low voltage state less than 2.5V. I understand the protection circuit switches the battery off so it doesn’t fall below this low level but if it is at a 2.5V state in storage for 2-3 months the self discharge is how bad you reckon?
Gajender,
If “no charge” then Alkaline 2-3% per year (7-10 years shelf life, according to the article.
Capacity
5 years x 356 days x 2 minutes / 60 minutes = 61 Ah (transmit)
+ 5 years x 365 days x 24 hours x 0.05A = 2190 Ah (standby)
You would need 2650 Ah (!!) battery pack assuming 15% self discharge. You need 1.25 Ah daily. Why don’t you use a small solar powered charger with 6Ah rechargeable system?
Gajender, Robert - There is no commercial battery that will reliably deliver 50 mA constantly and 1 A for one minute twice a day, for five years. There may be an exotic battery costing a very large sum of money that will work. Solar is obvious, evidently not considered. Which means the objective is for the equipment to remain “invisible”.
For anyone interested, I have a small (3 component ) circuit you can build for cutting off the current flow from a single lithium-ion (or LiPO) cell to prevent overdischarge. Unlike most circuits that are built into higher priced cells, this one is designed to cut off at about 3.0V instead of the more typical 2.5, which IMHO sacrifices very little usable charge and better protects a cell. I’ve included a link to my site where I wrote the article, which actually uses this page as a reference at one point. I hope this is OK with the moderators.
http://elfintechnologies.com/liIonProtect.html
Incidentally, a not to Mr. Gajende’. You might want to touch base with me using the CONTACT from on that same website I linked, and explain more about your project. I tend to agree with the comments of others, that some backup solar charging might make for a smaller power pack for the longevity you need, but I may be able to help you think out a solution.
i would like to know for how longcan i store the battery without losing its efficiency.
I mean if i had to to store 2V batteries in awarehouse without charging them, for how long do these battereis maintain their efficiency in this case?
Ahmad - Depends entirely on temperature. If it gets very hot, you will begin to damage the cells within a few months. I suspect the reason why you ask is because your warehouse gets very hot. The only way to store batteries is to keep them cold. As cold as possible. Charging batteries that are being kept in a hot warehouse is not a good way to solve the problem.
I have a Roadtrek RV that uses a Tripplite inverter charger.
Overnight the battery voltage will drop from 12.6 to 11.1 with no known loads, the charger may have a few 10’s of MA idle current.
Plug in shore power and it will charge for about five minutes, the charger will cut off, and then be back at 12.6.
It has no capacity, a 10 amp load will drop to 11.1 in a few minutes.
It is a brand new USBattery sealed AGM 100 amp hour.
Dealer has removed and recharged battery and says it is fine.
Can any body tell me what is going on here?
Wayne—-If you Google up “Li-Ion discharge curves”, and look at a few of the graphs you find, you’ll quickly discover that the normal discharge of any Li_ION type battery includes a fairly rapid decline from the max of 4.2V/ cell, to about 3.8. At that point the discharge curve is a near flat slow decline until you get to around 3.5V, and then it drops very quickly. So a freshly charged 3 cell Li-ION battery should indeed be about 4.2 x 3, or 12.6v. But it doesn’t take much to make it drop to 3.8 x 3, or 11.4V. Self discharge can be part of it, and the self protection circuitry built into most quality cells these days can actually contribute a little more. I’d suggest you consider it normal for the load you described to drop the amount you described. if the battery is indeed good, even though it seemed to lose over a volt in 10 minutes, you SHOULD find that the same load will take another 10 hours or more to drop another volt, because that is the nature of the way these batteries discharge. On the other hand if you find it declines much faster then that, you’ll need to demand your money back. :-
It sounds like a bad battery. I may have been overcharged and lost some electrolyte. AGM batteries do not have excessive electrolyte and long term floating at too high a voltage can ruin them. A good load test should reveal the health of the battery.
The fact that it charges to good open circuit cell voltages may be what the dealer used as a criteria for battery condition.
I would insist the dealer load test the battery and compare the load test results with a new battery. I would guess that would show quite difference and you would have a case for a new battery. I am curious now so let me know what happens.
My previous comment was directed to the Roadterk RV owner about the AGM battery. BTW Cadex makes some really good battery load testers etc.
Hi,
do you have chart or graft for self discharge in 24 hours VS battery life time
to be more clear i want to test few tablet batteries, i want to measure self discharge and by that estimate battery condition.
I have battery thats come from my old laptop. I try to recover it and re use the battery but when a single cell well charge it from 0 volts to 3.5v, but after 10 hours the voltage drops without load. What is suggestion its ok to used or not? Thanks for helping me.
Mark - Based on your description, that cell sounds useless. Old laptop batteries are often not worth salvaging, for the very behavior you mentioned.
Hi. I’m a little uncertain on the definition of self discharge.
When a 1000 mA-h battery specs “1%/month self discharge” for example (at our operating temp, and assuming a well-treated happy battery), I understand that there is an initial drop off that looks somewhat exponential (which is new, interesting info—Thanks for this great site!).
But after that point, will the battery essentially drain at an average of 10 mA-h/month until it is nearly drained?
Or will it initially self discharge at 10 mA-h/month, and when it’s down to 500 mA-h left, it’ll drain 5 mA-h/month, and when it’s at 250 mA-h, self discharge will drop to 2.5 mA-h/month?
Please advice-
What is the self discharge pattern for automotive lead-acid battery?
What will the discharge voltage in a month time for a fully charge 60Ah lead-acid battery?
For a Li-ion cell the self discharge is given as initial 5% and then 1-2% per month.
The datasheet for a Li ion cell from Samsung (ICR18650-30B) states a capacity of better than 80% after a month.
Wouldn’t you think they rather use 90-93% if those types of cells would be able to do that?
TLDR: I’m questioning the low self discharge for Li-Ion cells given in the article up there.
*) http://gamma.spb.ru/media/pdf/liion-lipolymer-lifepo4-akkumulyatory/ICR18650-30B.pdf
The self discharge graph shows a loss of 7mV/day for a new Li cell. Why is the graph showing voltage instead of amp-hour (Ah) loss?
In self discharge, isn’t the issue amp-hours being lost?
I ‘m using a netbook with Li-ion battery packs and I can only charge them ONCE every 7 days.
My “empty” packs still hold 10-20 % of charge and are sitting on the shelf at room temperature for several days before being fully recharged.
Will this practice reduce the lifespan of my battery packs ?
Hello. Interesting read…I have an Acer Switch 11V convertible laptop that is “self draining” at the rate of 5-7% per day of being “off”. If I leave it off for several weeks (which happens since I travel quite frequently), I’ll come home to a dead laptop. Acer is aware of the issue, but says that 5-7% per day is “normal” and quite acceptable. After reading your discussion of Li-ion self drain, I’m am convinced that they have either “bad cells” or “bad design” in this device. Would anyone care to comment on this to assist? My email: necostanzo@gmai.com Much thanks, Nick
Can anyone answer my question from earlier please:
If my new battery from my phone arrived in a 1% state and it was left in the warehouse for 3 months according to this article the self discharge would be greater esp if it’s been in a low voltage state less than 2.5V. I understand the protection circuit switches the battery off so it doesn’t fall below this low level but if it is at a 2.5V state in storage for 2-3 months the self discharge is how bad you reckon?
Further to this i dont know how long it was left in warehouse for but i got a new samsung phone with a 3000mah batttery as a new replacement and it came shipped again with 0% battery and wouldn’t turn on and was made in dec 2015 meaning it could have been lying on the shelf for nearly a year.
When i checked the voltage after it charged to 3% it said 3500mv so 3.5v is it possible the elevated discharge would be greater because it was left at less than 3500mv for nearly a year?
Stupid samsung factory dont charge the phones up i have had 3 replacements the original camd with 0% and this 1 did too. The 2 aftef the first one came with 60% already charged. Rather annoyed ebcause thr battery cant be replaced by myself easily without it being opened up.
Is there anyway to tell whether my battery is faulty? It’s saying 80% left but the voltage is only 4000mv on my previous replacement i would take it off the charger at 61% because the voltage would say 3920mv (the ideal voltage) by the looks of things by the time i get down to 61% it will be much less than the 3920mv. I know it could just be a calibration issue but i dont feel confident that a samsung 3000mah battery left on a shelf at 0% which turned off by itself with protection circuit activated is not damaged somehow
Is there any negative effect if say it was protected at 3500mv? Maybe samsungs cut off protection level is higher than the standarf 2.9v for this very reason.
Is there anyway for me to tell if the capacity is affected? The 4200mv or 4.2v should show at 100% correct?
I honestly dont know how to figure it out.. i have a tablet by samsubg with a 8000mah battery and i have to charge to 72% to get a 3920mv reading but my othet tablet which is 4000mah reaches 3920mv at only 58%. And previous phones with 3000mah battery 67% was 3920mv it’s very confusing can anyone explain to me how the capacity of the battery ie the mah affects what % it reaches 3920mv.. surely it should all be the same?
sir we have a battery 2c where it was not charging for more time and i want to know how can we know the battery capasity
Hi john please tell me is the self discharge same for the lead acid if the batteries are connected in series?
The rate of self-discharge of a single battery or many batteries connected in series is the same. They are open circuit, hence do not affect each other.
Anyone have an idea what the self discharge rate is for silver oxide? More or less than alkaline? I’ve searched the web, and the only possible hit I found was for a paper that required purchase.
We produce an electric toothbrush using a rechargeable Nickel–metal hydride battery. According to the manufacturer the performance of the speed /power of the battery should will not diminish with time and thus the performance of the electric should be at full over the the 50 minutes operation time. However, we have noticed a reduced effect already after 4 minutes of use after fully charged and I understand this is due to self-discharge! It´s less than optimal to have a electric toothbrush operating at 50 % of full speed after 25-30 minuter of operational time.
Which kind of battery is most suitable for an electric tooth brush? Should we rather go with a Lithium-Ion battery?
My battery gone deep discharge so how can I charge ?
Does keeping a set of batteries connected in-series to a device (such as a breast pump) causes them to drain faster?
thanks lot
why self discharging in the rest step?
do you know?
What type of battery should be selected ...?
We designed an iot. cow tracking system. It will be put to the cow’s stomach. The battery needs to work for 7-8 years. No chance of battery change. Operating voltage from 1.8 to 3.6 volts.
we have a NCA/MCMB li ion battery. this battery Cycles but in the rest step, the voltage drop sharply. What do you think is the cause?
Is there any information about SilverOxide battery?
Hi,
very good post! However, i was wondering:
- What is the typical discharge curve (Voltage(time)) of alkaline AA with very low discharge currents (20uA)? is it going to stay around 1.5V until it is really dead? (so not like the typical s curves that i find for mA currents)
Context:
I am operating a sensor device with an AA 1.5 V battery. My device only draws 17uA constant (peak consumption when sensing is high but only 9ms, flattened by decoupling capacitors). The problem is that I need 1.5V for the microcontroller, and seeing typical discharge curves i thought i would need a DCDC step-up to ensure constant 1.5V. But if at very low currents, the voltage stays close to 1.5V until death, this would not be necessary.
@Ender vural. You need to calculate the current needed from the battery. It is not just the self discharge, but you need to consider how much juice you will be needen from the battery over these 7-8 years. Coin cells are the best ones regarding the self discharge, but they are only arated like 240mAh. Besides no battery company will give you green light to use their battery in an animal stomach
I have an AGM 12volt deep cycle battery less than 2 years old. The percent charge according to my charger drops from 100% to 10% when sitting for a month or so. Is the battery faulty. It will charge back to 100% in 30 min. at 15 amps. Thanks for any advice.
Self discharge is generally caused by impurities. In the case of lead-acid, it is feasible to keep impurities from causing excessive self discharge. This is done by using a suitable chemical substance that prevents the impurities, that inevitably migrate via the electrolyte, reaching the negative plates.
Impurities are present in the negative plates at the time of manufacture, however, they get buried in the negative active mass over time. The impurities in the positives and that are put in the electrolyte with the filling water just keep electroplating out onto the negatives.
These “electroplating” impurities can be stopped by that chemical substance. After about three months in service, the battery ends up with near-zero self discharge.