I have registered here just because I have read all the post till here and I see that A LOT of people are speaking NON - SENSE and NONE said anything about having an multimeter to verify voltage, or no one said about the charge rate.
Sorry for my english is not my native language, I understand but it is harder to express myself. I sometimes use google translate.
Answering to the question:
- First, make a question the the manufacturer, read the device manual.
- If the phone IS LITHIUM ION / LITHIUM BATTERY you can LET the phone to be recharged over night but I do not recommend it ! It is usually not happening but there is a minor posibility to caugh fire and burn house.
The BIG QUESTION IS, IF HAVING THE BATTERY Li-Ion OVERNIGHT OR NON-STOP WILL IT get MORE or LESS LIFE CYCLES?
- The "tricky part" of leaving Li-Ion/Li-Po in the cellphone, and the cellphone plugged into the charger over night is on what I have read here on the forum, so you have two options each one with advantages and disavantages:
I ) "A portable device should be turned off while charging. This allows the battery to reach the threshold voltage unhindered and reflects the correct saturation current responsible to terminate the charge. A parasitic load confuses the charger."
So, I assume that if the phone is not turned off or if the phone is having a buggy software, or if the "stop charging control" will rely only on pcb, or there will be "micro-recharge-cycles" like a "loop", so the phone&battery will "LOOP FOREVER" when leaved @ charging overnight somewhere between 98 or 99-100%, that woud be like......uhm 4.18 Volt and 4.20 Volt. Because of this loop MAYBE the phone battery life cycle will decrease.
Some Laptop batterys are designed to stop charging/discharging after an XXXXXX number of charge-discharge cycles.
On the other hand
II) "If you take it out immediately after it's charged then you'll have to charge it sooner, getting closer to your rated limit of charges. Laptops that mostly run off of wall power usually have batteries that last longer because they are not continuously drained and recharged."
So, MAYBE in this scenario will lower the life cycle.
Explication:
- Usually a Lithium Phone Cell BATTERY will have A BUILD IN a Protection Circuit which cut the current at 4.2 V, if the voltage go more to that limit the battery WILL REACT WITH A VIOLENT FIRE FLAME or EXPLODE and is possibily to BURN the house. The Phone manufacturers had taken measures for this to NOT happen as many people will sue them in court for burning the houses down.
- I assume that NOT every phone will cut the power off (from the software) and some of them are relying only on the battery protection circuit.
- The CHARGER is NOT STOPING the charing when the battery is full, it is a simple transformer from 12V/110V/220V etc. to 5-6 Volt ! ! !
So, the charger or the laptop USB is fowarding the current non-stop to the device! ! ! And depends on the protection circuit which is build in into the phone battery to keep the battery in the safe volage limit and by the device itself (software).
- There are some "SMART" Li-Ion/Li-Po that have build in protection circuit BUT not in the case of a regular phone charger or the original phone charger that come with your phone.
Keep your battery above 75% procent charged if it is possible,
GET A MULTIMETER AND TEST THE BATTERY VOLTAGE
OVERDISCHARGE VOLTAGE LI-ION / LI-PO:
Aproximate Estimated Remaning Capacity of Li-Ion Li-Po,
as there are various mAh Li-Ion/Po cells
4.2 V ..... 100%
4.1 V ..... 85-94%
4.0 V .....75-85%
3.9V ......60%
3.8V.....60%
3.7V.....20%
3.6 V .... 0-15% (empty for practical propourses, but oky to power up a led small led for a small time period for example, and if you have a protection circuit between the battery and the led, when will reach 3.0 V the led will stop to burn, if not then the battery will drain to zero and get damaged)
or
" 4.0 under load just fully charged
3.6 under load for eons
3.0 under load Fricking dead "
"if device will drain to zero volts and could then explode if you attempt to recharge it. If you find the battery and it tests over 3 volts (entirely possible in a one-year time frame, it's still perfectly good and you can charge/use it normally. If it's under ~2.7 volts, toss it."
____ Other stuff expained ____
We have OVERCHARGE And OVERDISCHARGE.
We have VOLTAGE AND AMPERAGE, where Volt means "tension" like in a water tube and Amperage means "how much water is left to flow"
We have WATT (power) which is an relation Watts = Amps x Volts, more watt, more power. More Voltage require Less Amp, More Amp require More Voltage, for example
an Regular 100 Watt Bulb will "suck" more current in the USA at 110 Volt and a Regular 100 Watt Bulb will "suck" less in Europe at 220 Volt.
Usually the phone charger (and usb devices) are with a range of 5-6.8 Volt and with a charging rate of 320mAh, 500mAh, 550mAh, 850mAh, 1 A (1000 mAh), and a maximum of 2 A (2000 mAh).
The 320 mAh will require more time, the 2000 mAh will require less time to charge the same phone/battery.
For a 1000 mAh a good charging rate will be like ~5-6V and 500-550 mAh
For a 1700 mAh a good charging rate will be like ~5-6V and 800 mAh
Sadly I DID PUT the multimeter on a LOT of power supply or "chargers" and they don't "throw" the exact voltage and the current (mah) that they claim to do, and the claimed nominal values are ony on a few, and quality chargers, with a LOAD and without a LOAD on them.
There was TWO types of batteries on the cellphone:
A) Some old phones used NiCd or NiMH, they are similar with some slightly - tiny difference
B) New phones uses Li-Ion or Li-Po, they are similar with some tiny difference.
Note: Altrouh NiMh/NiCd is the "old cellphone technology" it really have some advantages over Lithium ones. They are JUST PERFECT for the DSLR FOTO FLASH which DRAINS and REQUIRE a battery that can Give Big Power once, a li-ion or li-po can be Damaged if you use it to very a high discharge rate, but NiCd will tolerate high discharge rate better. And, now sanyo makes eneloops which are LSD - Low Self Discharge, and hold the charge better, like 90% in a year, they do not explode, and NiMh don't suffer from the "memory effect" like the NiCd, they are just PERFECT for SMALL Solar devices like garden led, motion detection sensor with led light. But when FAST chargig is required, high enery density, lightweight, Lithium are the king / rules but saftley measures need to be take care of.
Now.... BE WARNED, LITHIUM BATTERIES ARE HIGHT EXPLOSIVE AND THEY DO CAUGHT FIRE IF NOT HANDLED PROPRETLY !
VOLTAGE RANGE:
One standard CELL OF Ni-Cd/Ni Mh is rated at 1.2 V NOT at 1.5 V like an "single use alkaline battery"
So, we can say that a 1.2V niMh.niCd will have about 0.7 Volts when discharged and approximate 1.4 Volts when is full right out of the charger.
I repeat,
ONE CELL OF NI-CD / NI-MH will have about 0.7 V - 1.4 V RANGE,
The Cellphone, mp3 player, flashlight etc. Lithium based battery is rated at 3.7 Volt
BUT
Usually the Li-Ion and LiPo have an protection circuit which will cut the current in a voltage range! There are Lithium based battery with NO circuit protection, for example some of laptop battery cell 18650, comes in variat WITH and WITHOUT PCB. Electronic ciggars, flaslights included!
So....
Home stuff or Cell Phone Lithium battery will have a range of aproximate 2.8 or 3 to 4.2 Volt.
The pcb usually is from 3.0 V and from 4.2 V for HOME applications.
FOR MILITARY APLICATION USUALLY IS LIKE 3.2-4.0 Volt.
Now, how is the battery charging controled:
A) Ni-Cd, Ni-Mh ===>>> THE VOLTAGE OF THE NICD and NIMH IT IS NOT RELEVANT FOR CONTROLING THE CHARGING ! <<<===
1) Time based (for example an empty battery of 1.2 Volts and 1000 mAh will recharge fully in an approximate time range of ~ 10-16 Hours at a rate of 2-3 Volts and 120 mAh)
2) Delta V protection (the circuit from a "smart" charger will terminate the charging by measuring a little drop of Voltage, for example from 1.45 Volt, the voltage will make a tiny drop to 1.42 Volt, and will stop the charging. The "drop" range will a little different far as I know depending by "brand"/manufacuturer and if it is nicd or nimh)
3) Trickle charging, that means that the battery will be charged / topped with only few Amps (so if you have a small solar panel for example which have good Voltage but low amps will fully charge an NiMh/NiCd battery in a long time like a week, and will NOT damage the cell if it is being left to charging for 6 months)
Note: A "safe" discharge Voltage for NiMh will be about 0.7-0.9 Volt, while as far as I know a "safe" discharge ofr NiCd COULD be 0.5 or 0.1 Volt as NiCd is more tolerating to the over-discharge.
The only danger that you can get with Nichel battery if it is overdischarge is the "reverse polarity", so the cell will be damaged but will not explode, eventually will vent if the cell get damaged.
I REPEAT THE VOLTAGE ON NIMH TECH IS NOT RELEVANT TO FINISH A CHARGING, SO IS HARDER TO FINISH THE CHARGING CORECTLY.
B) For the Lithium based battery the VOLTAGE IS VERY RELEVANT !
1) When the Li-Ion is FULL will have 4.2 Volt and NOT 3.7 Volt ! ! !
So, IF the battery/cell/special charger IS having an PCB will cut the current/power off!
When, the Voltage (tension) will DROP the Chargeing will start again, and when it will reach 4.2 will stop and so on.
IF A CELL IS REACHING OVER 4.2 VOLT WILL EXPLODE, CAUGH FIRE, BURN HOSE, DAMAGE YOUR SKING, EYES, LEGS ETC. ! ! !
PLEASE DO NOT PLAY WITH LITHIUM ION AND HANDLE THEM WITH CARE ! IF NOT HANDLED PROPLRETLY IT WILL REACT VIOLENTLY!
Note: A minimum "safe" voltage for Lithium Ion / Polimer is at about 2.8 or 3.0 V. Going more down than that IT WILL DAMAGE THE CELL, and when charged again can EXPODE, Caugh FIRE etc. If the Cell is NOT having a protection circuit and the Voltage Drops above 2.8V the cell will be damaged with no returing back, like forever.