From Wikipedia, the free encyclopedia Battery charger
Battery charger
The charge current depends upon the technology and
capacity of the battery being charged. For example, the
current that should be applied to recharge a 12 V car bat-
tery will be very different from the current for a mobile
phone battery.
Types of battery chargers
Simple
A simple charger works by supplying a constant DC or
pulsed DC power source to a battery being charged. The
simple charger does not alter its output based on time
or the charge on the battery. This simplicity means that
a simple charger is inexpensive, but there is a tradeoff
in quality. Typically, a simple charger takes longer to
charge a battery to prevent severe over-charging. Even
so, a battery left in a simple charger for too long will
be weakened or destroyed due to over-charging. These
chargers can supply either a constant voltage or a con-
stant current to the battery.
Simple AC-powered battery chargers have much
higher ripple current and ripple voltage than other kinds
of battery supplies. When the ripple current is within
the battery-manufacturer-recommended level, the rip-
ple voltage will also be well within the recommended lev-
el. The maximum ripple current for a typical 12 V 100
Ah VRLA battery is 5 amps. As long as the ripple cur-
This unit charges the batteries until they reach a specific volt- rent is not excessive (more than 3 to 4 times the battery-
age and then it trickle charges the batteries until it is discon- manufacturer-recommended level), the expected life of a
nected. ripple-charged VRLA battery is within 3% of the life of a
constant DC-charged battery.[1]
Trickle
Main article: Trickle charging
A trickle charger is typically a low-current
(500–1,500 mA) battery charger. A trickle charger is gen-
erally used to charge small capacity batteries (2–30 Ah).
These types of battery chargers are also used to maintain
larger capacity batteries (> 30 Ah) that are typically
found on cars, boats, RVs and other related vehicles. In
larger applications, the current of the battery charger is
A simple charger equivalent to an AC/DC wall adapter. It ap- sufficient only to provide a maintenance or trickle cur-
plies 300mA to the battery at all times, which will damage the rent (trickle is commonly the last charging stage of most
battery if left connected too long. battery chargers). Depending on the technology of the
trickle charger, it can be left connected to the battery
A battery charger is a device used to put energy into a indefinitely. Some battery chargers that can be left con-
secondary cell or rechargeable battery by forcing an elec- nected to the battery without causing the battery dam-
tric current through it. age are also referred to as smart or intelligent chargers.
1
From Wikipedia, the free encyclopedia Battery charger
Timer-based instant. Charging is terminated when a combination of
the voltage, temperature and/or time indicates that the
The output of a timer charger is terminated after a pre-
battery is fully charged.
determined time. Timer chargers were the most common
For Ni-Cd and NiMH batteries, the voltage across the
type for high-capacity Ni-Cd cells in the late 1990s for ex-
battery increases slowly during the charging process, un-
ample (low-capacity consumer Ni-Cd cells were typically
til the battery is fully charged. After that, the voltage de-
charged with a simple charger).
creases, which indicates to an intelligent charger that the
Often a timer charger and set of batteries could be
battery is fully charged. Such chargers are often labeled
bought as a bundle and the charger time was set to suit
as a ΔV, "delta-V," or sometimes "delta peak", charger,
those batteries. If batteries of lower capacity were
indicating that they monitor the voltage change.
charged then they would be overcharged, and if batteries
The problem is, the magnitude of "delta-V" can be-
of higher capacity were charged they would be only part-
come very small or even non-existent if (very) high ca-
ly charged. With the trend for battery technology to in-
pacity rechargeable batteries are recharged.[citation needed]
crease capacity year on year, an old timer charger would
This can cause even an intelligent battery charger to not
only partly charge the newer batteries.
sense that the batteries are actually already fully
Timer based chargers also had the drawback that
charged, and continue charging. Overcharging of the bat-
charging batteries that were not fully discharged, even if
teries will result in some cases. However, many so called
those batteries were of the correct capacity for the par-
intelligent chargers employ a combination of cut off sys-
ticular timed charger, would result in over-charging.
tems, which should prevent overcharging in the vast ma-
jority of cases.
Intelligent A typical intelligent charger fast-charges a battery up
to about 85% of its maximum capacity in less than an
hour, then switches to trickle charging, which takes sev-
eral hours to top off the battery to its full capacity.[2]
Universal battery charger–analyzers
The most sophisticated types are used in critical applica-
tions e.g.: military or aviation batteries. These heavy-du-
ty automatic “intelligent charging” systems can be pro-
grammed with complex charging cycles specified by the
battery maker. The best are universal (i.e.: can charge
all battery types), and include automatic capacity testing
and analyzing functions too.
Fast
Example of a smart charger for AA and AAA batteries
Fast chargers make use of control circuitry in the batter-
A "smart charger" should not be confused with a "smart ies being charged to rapidly charge the batteries without
battery". A smart battery is generally defined as one con- damaging the cells’ elements. Most such chargers have a
taining some sort of electronic device or "chip" that can cooling fan to help keep the temperature of the cells un-
communicate with a smart charger about battery char- der control. Most are also capable of acting as standard
acteristics and condition. A smart battery generally re- overnight chargers if used with standard NiMH cells that
quires a smart charger it can communicate with (see do not have the special control circuitry.
Smart Battery Data). A smart charger is defined as a
charger that can respond to the condition of a battery, Pulse
and modify its charging actions accordingly. Some smart Some chargers use pulse technology in which a series of
chargers are designed to charge "smart" batteries. Some voltage or current pulses is fed to the battery. The DC
smart chargers are designed to charge "dumb" batteries, pulses have a strictly controlled rise time, pulse width,
which lack any internal electronic circuitry. The term pulse repetition rate (frequency) and amplitude. This
"smart battery charger" is thoroughly ambiguous, since technology is said to work with any size, voltage, capac-
it is not clear whether the adjective "smart" refers to the ity or chemistry of batteries, including automotive and
battery or only to the charger. valve-regulated batteries.[3] With pulse charging, high
The output current of a smart charger depends upon instantaneous voltages can be applied without overheat-
the battery’s state. An intelligent charger may monitor ing the battery. In a Lead–acid battery, this breaks down
the battery’s voltage, temperature and/or time under lead-sulfate crystals, thus greatly extending the battery
charge to determine the optimum charge current at that service life.[4]
2
From Wikipedia, the free encyclopedia Battery charger
Several kinds of pulse charging are patented.[5][6][7] Since the Universal Serial Bus specification provides for a
Others are open source hardware.[8] five-volt power supply, it is possible to use a USB cable as
Some chargers use pulses to check the current bat- a power source for recharging batteries. Products based
tery state when the charger is first connected, then use on this approach include chargers for cellular phones
constant current charging during fast charging, then use and portable digital audio players. They may be fully
pulse charging as a kind of trickle charging to maintain compliant USB peripheral devices adhering to USB power
the charge.[9] discipline, or uncontrolled in the manner of USB decora-
Some chargers use "negative pulse charging", also tions.
called "reflex charging" or "burp charging".[10] Such
chargers use both positive and brief negative current Solar chargers
pulses. There is no significant evidence, however, that Further information: Solar charger and energy harvest-
negative pulse charging is more effective than ordinary ing
pulse charging.[11][12] Solar chargers convert light energy into DC current. They
are generally portable, but can also be fixed mount. Fixed
Inductive mount solar chargers are also known as solar panels. So-
Main article: Inductive charging lar panels are often connected to the electrical grid,
Inductive battery chargers use electromagnetic induc- whereas portable solar chargers are used off-the-grid (i.e.
tion to charge batteries. A charging station sends electro- cars, boats, or RVs).
magnetic energy through inductive coupling to an elec- Although portable solar chargers obtain energy from
trical device, which stores the energy in the batteries. the sun only, they still can (depending on the technolo-
This is achieved without the need for metal contacts be- gy) be used in low light (i.e. cloudy) applications. Portable
tween the charger and the battery. It is commonly used solar chargers are typically used for trickle charging, al-
in electric toothbrushes and other devices used in bath- though some solar chargers (depending on the wattage),
rooms. Because there are no open electrical contacts, can completely recharge batteries. The Kinesis K3 is a
there is no risk of electrocution. handheld charger for charging small personal devices
like cellphones, gps’s, digital cameras, gaming devices,
USB-based etc. It contains a small wind generator, a small solar pan-
See also: USB#Power el and batteries. The batteries can be charged by the
panel, the wind generator or by connection to a power
source (120V, 12V, or USB). It can then be used to
recharge a small personal device.
Motion-powered charger
Several companies have begun making devices that
charge batteries based on regular human motion. One ex-
ample, made by Tremont Electric, consists of a magnet
held between two springs that can charge a battery as
the device is moved up and down, such as when walking.
Such products have not yet achieved significant commer-
cial success.[13]
Charge rate
Charge rate is often denoted as C or C-rate and signifies a
charge or discharge rate equal to the capacity of a battery
in one hour.[14] For a 1.6Ah battery, C = 1.6A. A charge
rate of C/2 = 0.8A would need two hours, and a charge
rate of 2C = 3.2A would need 30 minutes to fully charge
the battery from an empty state, if supported by the bat-
tery. This also assumes that the battery is 100% efficient
at absorbing the charge.
Pay-per-charge kiosk, illustrating the variety of mobile phone
charger connectors
3
From Wikipedia, the free encyclopedia Battery charger
Applications charging circuitry which is almost always contained
within the mobile phone.[15] They are notoriously di-
Since a battery charger is intended to be connected to a verse, having a wide variety of DC connector-styles and
battery, it may not have voltage regulation or filtering voltages, most of which are not compatible with other
of the DC voltage output. Battery chargers equipped with manufacturers’ phones or even different models of
both voltage regulation and filtering may be identified as phones from a single manufacturer. A way to charge all
battery eliminators. your electronic accessories is with a Chargebox.
Users of publicly accessible charging kiosks must be
Mobile phone charger able to cross-reference connectors with device brands/
See also: USB#Power models and individual charge parameters and thus en-
sure delivery of the correct charge for their mobile de-
vice. A database-driven system is one solution, and is be-
ing incorporated into some designs of charging kiosks.
Mobile phones can usually accept a relatively wide
range of voltages[citation needed], as long as it is sufficiently
above the phone battery’s voltage. However, if the volt-
age is too high, it can damage the phone. Mostly, the volt-
age is 5 volts or slightly higher, but it can sometimes vary
up to 12 volts when the power source is not loaded.
There are also human-powered chargers sold on the
market, which typically consists of a dynamo powered by
a hand crank and extension cords. There are also solar
chargers.
China, the European Commission and other countries
are making a national standard on mobile phone charg-
ers using the USB standard.[16] In June 2009, 10 of the
Micro USB mobile phone charger
world’s largest mobile phone manufacturers signed a Me-
morandum of Understanding to develop specifications
for and support a microUSB-equipped common External
Power Supply (EPS) for all data-enabled mobile phones
sold in the EU.[17][18] On October 22, 2009, the Interna-
tional Telecommunication Union announced a standard
for a universal charger for mobile handsets (Micro-
USB).[19]
Battery charger for vehicles
Further information: Charging station
There are two main types of charges for vehicles:
• To recharge a fuel vehicle’s starter battery, where a
modular charger is used.
• To recharge an electric vehicle (EV) battery pack.
Battery electric vehicle
These vehicles include a battery pack, so generally use
series charger.
EV converted electric vehicle battery chargers come
in a variety of brands and characteristics. Zivan, Man-
zanita Micro, Elcon, Quick Charge, Rossco, Brusa, Delta-Q,
Kelly, Lester and Soneil are the top 10 EV chargers in 2011
according to EVAlbum.com. These chargers vary from 1
KW to 7.5 KW maximum charge rate. Some use algorithm
A charging station for various brands of mobile phones. charge curves, others use constant voltage, constant cur-
rent. Some are programmable by the end user through
Most mobile phone chargers are not really chargers, only a CAN port, some have dials for maximum voltage and
power adapters that provide a power source for the amperage, some are preset to specified battery pack volt-
4
From Wikipedia, the free encyclopedia Battery charger
age, amp-hour and chemistry. Prices range from $400 to
$4500.[20].
A 10 Ampere-hour battery could take 15 hours to
reach a fully charged state from a fully discharged condi-
tion with a 1 Ampere charger as it would require roughly
1.5 times the battery’s capacity.
Public EV charging[21] heads (aka: stations) provide
6 kW (host power of 208 to 240 VAC off a 40 amp circuit).
6 kW will recharge an EV roughly 6 times faster than
1 kW overnight charging. Portable chargers comes in various capacities: 3400 – 11200
Rapid charging results in even faster recharge times mAh
and is limited only by available AC power and the type of
charging system.[22] Non-contact magnetic charging
On board EV chargers (change AC power to DC power Researchers at the Korea Advanced Institute of Science
to recharge the EV’s pack) can be: and Technology (KAIST) have developed an electric
• Isolated: they make no physical connection between transport system (called Online Electric Vehicle, OLEV)
the A/C electrical mains and the batteries being where the vehicles get their power needs from cables un-
charged. These typically employ some form of derneath the surface of the road via non-contact magnet-
Inductive charging. Some isolated chargers may be ic charging, (where a power source is placed underneath
used in parallel. This allows for an increased charge the road surface and power is wirelessly picked up on the
current and reduced charging times. The battery has vehicle itself. As a possible solution to traffic congestion
a maximum current rating that cannot be exceeded and to improve overall efficiency by minimizing air resis-
• Non-isolated: the battery charger has a direct tance and so reduce energy consumption, the test vehi-
electrical connection to the A/C outlet’s wiring. Non- cles followed the power track in a convoy formation[23]
isolated chargers cannot be used in parallel.
Power Factor Correction (PFC) chargers can more closely Use in experiments
approach the maximum current the plug can deliver,
A battery charger can work as a DC power adapter for ex-
shortening charging time.
perimentation. It may, however, require an external ca-
Charge stations
pacitor to be connected across its output terminals in or-
Main article: Charging station
der to "smooth" the voltage sufficiently, which may be
There is a list of public EV charging stations in the U.S.A.
thought of as a DC voltage plus a "ripple" voltage added
and worldwide[21]
to it. Note that there may be an internal resistance con-
Project Better Place is deploying a network of charg-
nected to limit the short circuit current, and the value of
ing stations and subsidizing vehicle battery costs
that internal resistance may have to be taken into con-
through leases and credits.
sideration in experiments.
Prolonging battery life
What practices are best depend on the type of battery.
Nickel-based cells, such as NiMH[citation needed] and NiCd,
need to be fully discharged occasionally, or else the bat-
tery loses capacity over time in a phenomenon known as
"memory effect". Once a month (once every 30 charges)
is sometimes recommended.[citation needed] This extends
the life of the battery since memory effect is prevented
while avoiding full charge cycles which are known to be
hard on all types of dry-cell batteries, eventually result-
ing in a permanent decrease in battery capacity.
Most modern cell phones, laptops, and most electric
Auxiliary charger designed to fit a variety of proprietary de- vehicles use Lithium-ion batteries. These batteries last
vices longest if the battery is frequently charged; fully dis-
charging them will degrade their capacity relatively
quickly.[24] When storing however, lithium batteries de-
grade more while fully charged than if they are only 40%
charged. Degradation also occurs faster at higher tem-
5
From Wikipedia, the free encyclopedia Battery charger
peratures. Degradation in lithium-ion batteries is caused web/20070402140958/http://www.dallas.net/
by an increased internal battery resistance due to cell ox- ~jvpoll/Battery/aaPictures.html.
idation. This decreases the efficiency of the battery, re- [5] ""fast pulse battery charger" patent". 2003.
sulting in less net current available to be drawn from the http://www.wipo.int/pctdb/en/
battery.[citation needed] wo.jsp?wo=2003088447.
Internal combustion engine vehicles, such as boats, [6] "Battery charger with current pulse regulation"
RVs, ATVs, motorcycles, cars, trucks, and more use patented 1981 United States Patent 4355275
lead–acid batteries. These batteries employ a sulfuric [7] "Pulse-charge battery charger" patented 1997
acid electrolyte and can generally be charged and dis- United States Patent 5633574
charged without exhibiting memory effect, though sulfa- [8] http://www.dallas.net/~jvpoll/Battery/
tion (a chemical reaction in the battery which deposits a aaPictures.html Pulse-charger/desulfator circuit
layer of sulfates on the lead) will occur over time. Keep- schematic
ing the electrolyte level in the recommended range is [9] "Pulse Maintenance charging."
necessary. When discharged, these batteries should be [10] "The pulse power(tm) battery charging system"
recharged immediately in order to prevent sulfation. Th- [11] "Negative Pulse Charge, or "Burp" Charging: Fact
ese sulfates are electrically insulating and therefore in- or Fiction?"
terfere with the transfer of charge from the sulfuric acid [12] Tech Brief: Negative Pulse Charging Myths and
to the lead, resulting in a lower maximum current than Facts and Negative Pulse Charging: Myths and
can be drawn from the battery. Sulfated lead acid batter- Facts
ies typically need replacing. [13] Martin LaMonica, CNET. "Motion-powered gadget
Lead–acid batteries will experience substantially charger back on track." Jul 1, 2011. Retrieved Jul 1,
longer life when a maintenance charger is used to "float 2011.
charge" the battery. This prevents the battery from ever [14] A Guide to Understanding Battery Specifications,
being below 100% charge, preventing sulfate from form- MIT Electric Vehicle Team, December 2008
ing. Proper temperature compensated float voltage [15] Mobile phone battery care
should be used to achieve the best results.[citation needed] [16] China to work out national standard for mobile
phone chargers. English.sina.com. Retrieved on
See also [17]
2011-11-11.
"Cellphone charger harmonization". ec.europa.eu.
• Battery eliminator http://ec.europa.eu/enterprise/sectors/rtte/
• Battery holder chargers/index_en.htm. Retrieved 2011-01-21.
• Battery management system [18] PC World:Universal Chargers are a Good Start Jan
• List of battery sizes 2009
• Charge controller [19] Oct 22, 2009, ITU press release Universal charger
• Lithium-ion battery for mobile phone handsets
• Recharging alkaline batteries [20] EV Lithium Battery Charger Options (2011-11-19)
• Solar energy [21] ^ Home. EV Charger News (2010-08-28). Retrieved
• Solar lamp on 2011-11-11.
• Underwriters Laboratories (UL) certification. [22] Fuji Heavy Speeds Up Recharging of R1e EV. Green
• Alternator – battery charging device in car Car Congress (2007-09-18). Retrieved on
2011-11-11.
References [23] Korean electric vehicle solution. Gizmag.com.
Retrieved on 2011-11-11.
[1] "Effects of AC Ripple Current on VRLA Battery Life" [24] "How to prolong lithium-based batteries".
by Emerson Network Power September 2006.
[2] Dave Etchells. "The Great Battery Shootout". http://www.batteryuniversity.com/
http://www.imaging-resource.com/ACCS/BATTS/ parttwo-34.htm. Retrieved November 21, 2009.
BATTS.HTM.
[3] "AN913: Switch-Mode, Linear, and Pulse Charging
Techniques for Li+ Battery in Mobile Phones and
PDAs". Maxim. 2001. http://www.maxim-ic.com/
appnotes.cfm/appnote_number/913/.
[4] "Lead–acid battery sulfation". Archived from the
original on 2007-04-02. http://web.archive.org/
Retrieved from "http://en.wikipedia.org/w/index.php?title=Battery_charger&oldid=466703078"
6
From Wikipedia, the free encyclopedia Battery charger
Categories:
• Energy conversion
• Battery chargers
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