Post by navlem on Jan 11, 2007 22:31:14 GMT 7
I have decided to start a thread on batteries and please ask me any questions on batteries that i have not written inside this guide, I will update this guide accordingly.
Contents :
-----------------------------
Part 1 : Basic Info
Part 2 : Who would win the war?
Part 3 : Charging your batteries
Part 4 : Battery FAQs
Part 5 : Priming new batteries
Coming up :
-----------------------------
Discharging your batteries
Tips to prolonging your battery's life
How to store battery
More to come.
Battery Part 1 : Basic info
-----------------------------
There are many kinds of batteries out there on the market, but many people ask, what is the best battery? Here i will explain the different kinds of batteries and their characteristics.
1) Nickel-cadmium(Ni-CD) - mature but has moderate energy density. Nickel-cadmium is used where long life, high discharge rate and extended temperature range is important. Main applications are two-way radios, biomedical equipment and power tools. Nickel-cadmium contains toxic metals.
2) Nickel-metal-hydride(Ni-MH) - has a higher energy density compared to nickel-cadmium at the expense of reduced cycle life. There are no toxic metals. Applications include mobile phones, laptops and of course R/C cars. NiMH is viewed as steppingstone to lithium-based systems.
3) Lead-acid(Pb) - most economical for larger power applications where weight is of little concern. Lead-acid is the preferred choice for hospital equipment, wheelchairs, emergency lighting and UPS systems. Lead acid is inexpensive and rugged. It serves a unique niche that would be hard to replace with other systems. So far i have not yet seen any Lead-Acid batteries for R/C yet.
4) Lithium-ion(Li-On) - fastest growing battery system; offers high-energy density and low weight. Protection circuit are needed to limit voltage and current for safety reasons. Applications include notebook computers and cell phones. High current versions are available for power tools and medical devices.
5) Lithium-Polymer(Li-Po) - Latest battery technology to date, its based on lithium, which is also the same for Li-On, thus having similar characteristics. It is currently being used in the world of R/C as a professional battery.
================================================
Battery Part 2 : Who would win the war?
-----------------------------
There has been a controversy over the type of batteries used for Drifting. Though mainly Ni-MH batteries have been used by drifters throughout Singapore, there are some who prefers the best, willing to pay must more for lithium based batteries. Why would they want to do that? Is there really a big difference? Lets compare.
Nickel Based Batteries
*****************
Ni-CD
........................
Advantages
* Fast and simple charge, even after prolonged storage.
* High number of charge/discharge cycles - if properly maintained, nickel-cadmium provides over 1000 charge/discharge cycles.
* Good load performance - nickel-cadmium allows recharging at low temperatures.
* Long shelf life - five-year storage is possible. Some priming prior to use will be required.
* Simple storage and transportation - most airfreight companies accept nickel-cadmium without special conditions.
* Good low temperature performance.
* Forgiving if abused - nickel-cadmium is one of the most rugged rechargeable batteries.
* Economically priced - nickel-cadmium is lowest in terms of cost per cycle.
* Available in a wide range of sizes and performance options - most nickel-cadmium cells are cylindrical.
Disadvantages
* Relatively low energy density.
* Memory effect - nickel-cadmium must periodically be exercised (discharge/charge) to prevent memory.
* Environmentally unfriendly - nickel-cadmium contains toxic metals. Some countries restrict its use.
* Relatively high self-discharge - needs recharging after storage
Ni-MH
........................
Advantages
* 30-40% higher capacity than standard nickel-cadmium. Nickel-metal-hydride has potential for yet higher energy densities.
* Less prone to memory than nickel-cadmium - fewer exercise cycles are required.
* Simple storage and transportation - transport is not subject to regulatory control.
* Environmentally friendly - contains only mild toxins; profitable for recycling.
Disadvantages
* Limited service life - the performance starts to deteriorate after 200-300 cycles if repeatedly deeply cycled.
* Relatively short storage of three years. Cool temperature and a partial charge slows aging.
* Limited discharge current - although nickel-metal-hydride is capable of delivering high discharge currents, heavy load reduces the battery's cycle life.
* More complex charge algorithm needed - nickel-metal-hydride generates more heat during charge and requires slightly longer charge times than nickel-cadmium. Trickle charge settings are critical because the battery cannot absorb overcharge.
* High self-discharge - typically 50% higher than nickel-cadmium.
* Performance degrades if stored at elevated temperatures - nickel-metal-hydride should be stored in a cool place at 40% state-of-charge.
* High maintenance - nickel-metal hydride requires regular full discharge to prevent crystalline formation. nickel-cadmium should be exercised once a month, nickel-metal-hydride once in every 3 months.
Lithium Based Batteries
*****************
Li-ON
........................
Advantages
* High energy density - potential for yet higher capacities.
* Does not need prolonged priming when new. One regular charge is all that's needed.
* Relatively low self-discharge - self-discharge is less than half that of nickel-based batteries.
* Low Maintenance - no periodic discharge is needed; there is no memory.
* Specialty cells can provide very high current to applications such as power tools.
Disadvantages
* Requires protection circuit to maintain voltage and current within safe limits.
* Subject to aging, even if not in use - storage in a cool place at 40% charge reduces the aging effect.
* Transportation restrictions - shipment of larger quantities may be subject to regulatory control. This restriction does not apply to personal carry-on batteries.
* Expensive to manufacture - about 40 percent higher in cost than nickel-cadmium.
* Not fully mature - metals and chemicals are changing on a continuing basis.
Li-Po
........................
Advantages
* Very low profile - batteries resembling the profile of a credit card are feasible.
* Flexible form factor - manufacturers are not bound by standard cell formats. With high volume, any reasonable size can be produced economically.
* Lightweight - gelled electrolytes enable simplified packaging by eliminating the metal shell.
* Improved safety - more resistant to overcharge; less chance for electrolyte leakage.
Disadvantages
* Lower energy density and decreased cycle count compared to lithium-ion.
* Expensive to manufacture.
* No standard sizes. Most cells are produced for high volume consumer markets.
* Higher cost-to-energy ratio than lithium-ion
================================================
Battery Part 3 : Charging your batteries
-----------------------------
Knowing your battery is one thing, knowing how to charge them is a different thing, you will either make or break them. Read on .
- Slow Charger - Also known as 'overnight charger', the slow charger applies a fixed charge of about 0.1C* (one-tenth of the rated capacity) for as long as the battery is connected. Charge time is 14-16 hours. Slow chargers are found in cord-less phones, portable CD players and other consumer goods.
- Quick Charger - Also knows as rapid charger, this charger serves the middle range, both in terms of charging time and price. Charging time is 3-6 hours. The charger switches the battery to trickle charge when ready. Quick-chargers are used for cell phones, laptops and camcorders.
- Fast Charger - Designed for nickel-based battery, the fast charger fills a pack in about one hour. Fast charging is preferred because of reduced crystalline formation (memory). Accurate full-charge detection is important. When full, the charger switches to topping and then trickle charge. Fast chargers are used for industrial devices such as two-way radios, medical devices and power tools.
*Note*
New nickel-based batteries should be trickle-charged for 24 hours prior to use. Trickle charge brings all cells to equal charge level because each cell self-discharges at a different rate. Trickle charge also redistributes the electrolyte to remedy dry spots on the separator brought on by gravitation of the electrolyte during long storage.
Points to take note of:
........................
* Avoid high temperature during charging. Discontinue the use of chargers that cook batteries.
* A charger for nickel-metal-hydride can also accommodate nickel-cadmium, but not the other way around. A charger designed for nickel-cadmium would overcharge the nickel-metal-hydride battery.
* nickel-based batteries prefer fast-charge. Lingering slow charges cause crystalline formation (memory).
* nickel- and lithium-based batteries require different charge algorithms. The two chemistries can normally not be interchanged in the same charger.
* If not used immediately, remove the battery from the charger and apply a topping-charge before use. Do not leave nickel-based battery in the charger for more than a few days, even if on trickle charge.
A well-designed charger is a reasonably complex device. Taking short cuts will cost the user in the long run. Choosing a well-engineered charger will return the investment in longer lasting and better performing batteries.
================================================
Battery Part 4 : Battery FAQs
-----------------------------
This section will include a FAQ on how to start using your battery, maintain it, and what you should take note.
Categorized by Nickel-based and Lithium-based
........................
How to prepare my battery?
Nickel-based batteries come partially charged. Prime new battery by putting on a 14-16h charge.
Li-ion comes partially charged. You can use the battery right away and charge it when needed.
Can I damage my battery if incorrectly prepared?
No; For Nickel-Based batteries, without priming, the performance will be low at first, then gradually improve with use.
No; Li-ion is forgiving to partial and full charge. No priming is needed when new.
Should I use up all battery energy before charging?
Yes, for Nickel-Based batteries, fully discharge once every 1-3 months to prevent memory. It is not necessary to deplete the battery before each charge. Over cycling wears down NiMH.
No, for Lithium-Based, it is better to recharge more often; avoid frequent full discharges.
Should I charge my battery partially or fully?
Allow Nickel-Based batteries to full charge without interruptions. Repeated partial charge can cause heat buildup.
Does not matter. Charging Lithium-based batteries in stages is acceptable. Full charge termination occurs by reading the voltage level and charge current. Charging a full battery is safe and does not cause harm.
Should I remove the battery from the charger when full?
Yes, for Nickel-Based batteries, it is best to remove the pack from the charger when full. A prolonged trickle charge to a fully charged battery can be harmful.
It does not matter. For Lithium-Based, the charger automatically cuts the charge current when the battery is full.
Should the battery be kept charged when not in use?
Not critical. For Nickel-Based batteries, manufacturers recommend a 40% charge for long storage.
For Lithium-Based batteres, best to store at 40% charge. Cool storage is more important than state-of-charge. Do not fully deplete battery.
What happens when my battery is hot during charging?
It is normal for Nickel-Based batteries, just remember to let it cool down once the battery is ready.
As for Lithium-based batteries, heating is dangerous, stop charging when you realised your battery is overheating, or face dire consequences.(Explosion etc.)
What kind of charger?
Best results are achieved with a fast-charger that terminates the charge by other than temperature alone.
Lithium-Based chargers should be able to charge at 1C. Avoid economy chargers.
Anyone knows abt cells balancer?? Wat does it do to the batts or how can it help??
Li-Po needs a cell balancer because it cannot take heavy cycles as Nickel-Based batteries do, so a balancer will actually balance the voltage of the Li-Po batteries.
As for Nickel-Based batteries, a balancer is not required as they are balanced if you would just set it on trickle charge for around 24 hour
================================================
Battery Part 5 : Priming new batteries
-----------------------------
Using a battery is easy, keeping them in top shape is not. Lets find out how to keep them in good condition.
Nickel-Based Batteries
........................
Manufacturers recommend to trickle charge a nickel-based battery for 24 hours when new and after long storage. This service brings all cells to equal charge level and redistributes the electrolyte to remedy dry spots on the separator brought on by gravitation of the electrolyte. It is advisable to verify the capacity with a battery analyzer before use. This is especially important in critical applications.
Cycling (priming) is recommended to regain lost capacity after a nickel-based battery has been stored for 6 months or longer. A slow charge followed by one or several discharge/charge cycles will do this. The recovery rate is governed by the condition under which the battery was stored. The longer and warmer the storage temperature, the more cycles will be required. The Prime program of the battery analyzers automatically applies the number of cycles needed to regain full capacity.
Nickel-based batteries are not always fully formed when leaving the factory. Applying several charge/ discharge cycles through normal use or with a battery analyzer completes the forming. The number of cycles needed to attain full capacity differs between cell manufacturers. Quality cells perform to specification after 5-7 cycles. Those lacking formation may need 50 or more cycles to reach acceptable capacity levels.
What is the difference between priming and forming? For the user, both symptoms manifest themselves as insufficient capacity. The difference may be explained in that forming needs to be done only once when the battery is new, while priming must be repeated after each prolonged storage.
Lithium-Based Batteries
........................
Lithium-ion batteries deliver full power after the initial charge. Manufacturers of lithium-ion cells insist that no priming is required. However, priming is beneficial as an initial start and to verify battery performance. Excessive cycling should be avoided because of wear-down effect.
The internal protection circuit of lithium-based batteries is known to cause some problems after a long storage. If the battery is left discharged after use, the self-discharge will further drain the pack and eventually drip the protection circuit at about 2.5 volts per cell. At this point, the charger will no longer recognize the battery and the pack appears dead.
To reduce the self-discharge on newly manufactured batteries, advanced lithium-based packs feature a sleep mode that keeps the protection circuit off until activated by a brief charge. Once engaged, the battery remains operational and the advantage of the sleep mode no longer applies.
To Be Continued...
Contents :
-----------------------------
Part 1 : Basic Info
Part 2 : Who would win the war?
Part 3 : Charging your batteries
Part 4 : Battery FAQs
Part 5 : Priming new batteries
Coming up :
-----------------------------
Discharging your batteries
Tips to prolonging your battery's life
How to store battery
More to come.
Battery Part 1 : Basic info
-----------------------------
There are many kinds of batteries out there on the market, but many people ask, what is the best battery? Here i will explain the different kinds of batteries and their characteristics.
1) Nickel-cadmium(Ni-CD) - mature but has moderate energy density. Nickel-cadmium is used where long life, high discharge rate and extended temperature range is important. Main applications are two-way radios, biomedical equipment and power tools. Nickel-cadmium contains toxic metals.
2) Nickel-metal-hydride(Ni-MH) - has a higher energy density compared to nickel-cadmium at the expense of reduced cycle life. There are no toxic metals. Applications include mobile phones, laptops and of course R/C cars. NiMH is viewed as steppingstone to lithium-based systems.
3) Lead-acid(Pb) - most economical for larger power applications where weight is of little concern. Lead-acid is the preferred choice for hospital equipment, wheelchairs, emergency lighting and UPS systems. Lead acid is inexpensive and rugged. It serves a unique niche that would be hard to replace with other systems. So far i have not yet seen any Lead-Acid batteries for R/C yet.
4) Lithium-ion(Li-On) - fastest growing battery system; offers high-energy density and low weight. Protection circuit are needed to limit voltage and current for safety reasons. Applications include notebook computers and cell phones. High current versions are available for power tools and medical devices.
5) Lithium-Polymer(Li-Po) - Latest battery technology to date, its based on lithium, which is also the same for Li-On, thus having similar characteristics. It is currently being used in the world of R/C as a professional battery.
================================================
Battery Part 2 : Who would win the war?
-----------------------------
There has been a controversy over the type of batteries used for Drifting. Though mainly Ni-MH batteries have been used by drifters throughout Singapore, there are some who prefers the best, willing to pay must more for lithium based batteries. Why would they want to do that? Is there really a big difference? Lets compare.
Nickel Based Batteries
*****************
Ni-CD
........................
Advantages
* Fast and simple charge, even after prolonged storage.
* High number of charge/discharge cycles - if properly maintained, nickel-cadmium provides over 1000 charge/discharge cycles.
* Good load performance - nickel-cadmium allows recharging at low temperatures.
* Long shelf life - five-year storage is possible. Some priming prior to use will be required.
* Simple storage and transportation - most airfreight companies accept nickel-cadmium without special conditions.
* Good low temperature performance.
* Forgiving if abused - nickel-cadmium is one of the most rugged rechargeable batteries.
* Economically priced - nickel-cadmium is lowest in terms of cost per cycle.
* Available in a wide range of sizes and performance options - most nickel-cadmium cells are cylindrical.
Disadvantages
* Relatively low energy density.
* Memory effect - nickel-cadmium must periodically be exercised (discharge/charge) to prevent memory.
* Environmentally unfriendly - nickel-cadmium contains toxic metals. Some countries restrict its use.
* Relatively high self-discharge - needs recharging after storage
Ni-MH
........................
Advantages
* 30-40% higher capacity than standard nickel-cadmium. Nickel-metal-hydride has potential for yet higher energy densities.
* Less prone to memory than nickel-cadmium - fewer exercise cycles are required.
* Simple storage and transportation - transport is not subject to regulatory control.
* Environmentally friendly - contains only mild toxins; profitable for recycling.
Disadvantages
* Limited service life - the performance starts to deteriorate after 200-300 cycles if repeatedly deeply cycled.
* Relatively short storage of three years. Cool temperature and a partial charge slows aging.
* Limited discharge current - although nickel-metal-hydride is capable of delivering high discharge currents, heavy load reduces the battery's cycle life.
* More complex charge algorithm needed - nickel-metal-hydride generates more heat during charge and requires slightly longer charge times than nickel-cadmium. Trickle charge settings are critical because the battery cannot absorb overcharge.
* High self-discharge - typically 50% higher than nickel-cadmium.
* Performance degrades if stored at elevated temperatures - nickel-metal-hydride should be stored in a cool place at 40% state-of-charge.
* High maintenance - nickel-metal hydride requires regular full discharge to prevent crystalline formation. nickel-cadmium should be exercised once a month, nickel-metal-hydride once in every 3 months.
Lithium Based Batteries
*****************
Li-ON
........................
Advantages
* High energy density - potential for yet higher capacities.
* Does not need prolonged priming when new. One regular charge is all that's needed.
* Relatively low self-discharge - self-discharge is less than half that of nickel-based batteries.
* Low Maintenance - no periodic discharge is needed; there is no memory.
* Specialty cells can provide very high current to applications such as power tools.
Disadvantages
* Requires protection circuit to maintain voltage and current within safe limits.
* Subject to aging, even if not in use - storage in a cool place at 40% charge reduces the aging effect.
* Transportation restrictions - shipment of larger quantities may be subject to regulatory control. This restriction does not apply to personal carry-on batteries.
* Expensive to manufacture - about 40 percent higher in cost than nickel-cadmium.
* Not fully mature - metals and chemicals are changing on a continuing basis.
Li-Po
........................
Advantages
* Very low profile - batteries resembling the profile of a credit card are feasible.
* Flexible form factor - manufacturers are not bound by standard cell formats. With high volume, any reasonable size can be produced economically.
* Lightweight - gelled electrolytes enable simplified packaging by eliminating the metal shell.
* Improved safety - more resistant to overcharge; less chance for electrolyte leakage.
Disadvantages
* Lower energy density and decreased cycle count compared to lithium-ion.
* Expensive to manufacture.
* No standard sizes. Most cells are produced for high volume consumer markets.
* Higher cost-to-energy ratio than lithium-ion
================================================
Battery Part 3 : Charging your batteries
-----------------------------
Knowing your battery is one thing, knowing how to charge them is a different thing, you will either make or break them. Read on .
- Slow Charger - Also known as 'overnight charger', the slow charger applies a fixed charge of about 0.1C* (one-tenth of the rated capacity) for as long as the battery is connected. Charge time is 14-16 hours. Slow chargers are found in cord-less phones, portable CD players and other consumer goods.
- Quick Charger - Also knows as rapid charger, this charger serves the middle range, both in terms of charging time and price. Charging time is 3-6 hours. The charger switches the battery to trickle charge when ready. Quick-chargers are used for cell phones, laptops and camcorders.
- Fast Charger - Designed for nickel-based battery, the fast charger fills a pack in about one hour. Fast charging is preferred because of reduced crystalline formation (memory). Accurate full-charge detection is important. When full, the charger switches to topping and then trickle charge. Fast chargers are used for industrial devices such as two-way radios, medical devices and power tools.
*Note*
New nickel-based batteries should be trickle-charged for 24 hours prior to use. Trickle charge brings all cells to equal charge level because each cell self-discharges at a different rate. Trickle charge also redistributes the electrolyte to remedy dry spots on the separator brought on by gravitation of the electrolyte during long storage.
Points to take note of:
........................
* Avoid high temperature during charging. Discontinue the use of chargers that cook batteries.
* A charger for nickel-metal-hydride can also accommodate nickel-cadmium, but not the other way around. A charger designed for nickel-cadmium would overcharge the nickel-metal-hydride battery.
* nickel-based batteries prefer fast-charge. Lingering slow charges cause crystalline formation (memory).
* nickel- and lithium-based batteries require different charge algorithms. The two chemistries can normally not be interchanged in the same charger.
* If not used immediately, remove the battery from the charger and apply a topping-charge before use. Do not leave nickel-based battery in the charger for more than a few days, even if on trickle charge.
A well-designed charger is a reasonably complex device. Taking short cuts will cost the user in the long run. Choosing a well-engineered charger will return the investment in longer lasting and better performing batteries.
================================================
Battery Part 4 : Battery FAQs
-----------------------------
This section will include a FAQ on how to start using your battery, maintain it, and what you should take note.
Categorized by Nickel-based and Lithium-based
........................
How to prepare my battery?
Nickel-based batteries come partially charged. Prime new battery by putting on a 14-16h charge.
Li-ion comes partially charged. You can use the battery right away and charge it when needed.
Can I damage my battery if incorrectly prepared?
No; For Nickel-Based batteries, without priming, the performance will be low at first, then gradually improve with use.
No; Li-ion is forgiving to partial and full charge. No priming is needed when new.
Should I use up all battery energy before charging?
Yes, for Nickel-Based batteries, fully discharge once every 1-3 months to prevent memory. It is not necessary to deplete the battery before each charge. Over cycling wears down NiMH.
No, for Lithium-Based, it is better to recharge more often; avoid frequent full discharges.
Should I charge my battery partially or fully?
Allow Nickel-Based batteries to full charge without interruptions. Repeated partial charge can cause heat buildup.
Does not matter. Charging Lithium-based batteries in stages is acceptable. Full charge termination occurs by reading the voltage level and charge current. Charging a full battery is safe and does not cause harm.
Should I remove the battery from the charger when full?
Yes, for Nickel-Based batteries, it is best to remove the pack from the charger when full. A prolonged trickle charge to a fully charged battery can be harmful.
It does not matter. For Lithium-Based, the charger automatically cuts the charge current when the battery is full.
Should the battery be kept charged when not in use?
Not critical. For Nickel-Based batteries, manufacturers recommend a 40% charge for long storage.
For Lithium-Based batteres, best to store at 40% charge. Cool storage is more important than state-of-charge. Do not fully deplete battery.
What happens when my battery is hot during charging?
It is normal for Nickel-Based batteries, just remember to let it cool down once the battery is ready.
As for Lithium-based batteries, heating is dangerous, stop charging when you realised your battery is overheating, or face dire consequences.(Explosion etc.)
What kind of charger?
Best results are achieved with a fast-charger that terminates the charge by other than temperature alone.
Lithium-Based chargers should be able to charge at 1C. Avoid economy chargers.
Anyone knows abt cells balancer?? Wat does it do to the batts or how can it help??
Li-Po needs a cell balancer because it cannot take heavy cycles as Nickel-Based batteries do, so a balancer will actually balance the voltage of the Li-Po batteries.
As for Nickel-Based batteries, a balancer is not required as they are balanced if you would just set it on trickle charge for around 24 hour
================================================
Battery Part 5 : Priming new batteries
-----------------------------
Using a battery is easy, keeping them in top shape is not. Lets find out how to keep them in good condition.
Nickel-Based Batteries
........................
Manufacturers recommend to trickle charge a nickel-based battery for 24 hours when new and after long storage. This service brings all cells to equal charge level and redistributes the electrolyte to remedy dry spots on the separator brought on by gravitation of the electrolyte. It is advisable to verify the capacity with a battery analyzer before use. This is especially important in critical applications.
Cycling (priming) is recommended to regain lost capacity after a nickel-based battery has been stored for 6 months or longer. A slow charge followed by one or several discharge/charge cycles will do this. The recovery rate is governed by the condition under which the battery was stored. The longer and warmer the storage temperature, the more cycles will be required. The Prime program of the battery analyzers automatically applies the number of cycles needed to regain full capacity.
Nickel-based batteries are not always fully formed when leaving the factory. Applying several charge/ discharge cycles through normal use or with a battery analyzer completes the forming. The number of cycles needed to attain full capacity differs between cell manufacturers. Quality cells perform to specification after 5-7 cycles. Those lacking formation may need 50 or more cycles to reach acceptable capacity levels.
What is the difference between priming and forming? For the user, both symptoms manifest themselves as insufficient capacity. The difference may be explained in that forming needs to be done only once when the battery is new, while priming must be repeated after each prolonged storage.
Lithium-Based Batteries
........................
Lithium-ion batteries deliver full power after the initial charge. Manufacturers of lithium-ion cells insist that no priming is required. However, priming is beneficial as an initial start and to verify battery performance. Excessive cycling should be avoided because of wear-down effect.
The internal protection circuit of lithium-based batteries is known to cause some problems after a long storage. If the battery is left discharged after use, the self-discharge will further drain the pack and eventually drip the protection circuit at about 2.5 volts per cell. At this point, the charger will no longer recognize the battery and the pack appears dead.
To reduce the self-discharge on newly manufactured batteries, advanced lithium-based packs feature a sleep mode that keeps the protection circuit off until activated by a brief charge. Once engaged, the battery remains operational and the advantage of the sleep mode no longer applies.
To Be Continued...
