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How to Charge - When to Charge Table

http://batteryuniversity.com/learn/article/how_to_charge_when_to_charge_table

Batteries have unique needs and Table 1 explains how to satisfy these desires based of common batteries. Because

of similarities within the battery family, we only list lead, nickel and lithium systems. Although each chemistry has itsown requirements, there are common denominators that affect the life of all batteries. These are:

Keep a moderate temperature. As food stays fresher when refrigerated, so also does cool temperature

retard battery corrosion, a life-robbing adversary of any battery.

Control discharge. Each cycle wears the battery down by a small amount. A partial discharge before charge

is better than a full discharge. Apply a deliberate full discharge only to calibrate a smart battery and to prevent

memory on a nickel-based pack.

Avoid abuse. Like a machine that is exposed to strenuous work, a battery wears down more quickly if

discharged harshly and if force-charged with high currents. Strenuous demands cannot always be prevented,

but the user has the choice of selecting the right battery size, keeping the temperature moderate and following

life-extending service guidelines.

Batteries for the electric powertrain have changed the philosophy of battery manufacturers from designing packs for

maximum energy density, as demanded by the consumer market, to focusing on optimal safety and longevity.

Batteries on the road are exposed to extreme environmental hazards; they must perform at maximum duty under

severe heat, cold, shock and vibration. Storing energy of several kilowatts, batteries for the electric powertrain can

be dangerous if stressed beyond normal conditions. Furthermore, vehicular batteries are expensive and must last for

the life of the car.

Pampering a battery to achieve an extended service life, as is sometimes possible with a laptop or cell phone pack,

is more difficult with a large battery in a vehicle that must deliver high load currents on command and is exposed to

freezing temperatures in the winter and blistering summer conditions. The user has limited control as to the care and

attention of the battery. This task is passed over to an intelligent battery management system (BMS), which takes

over the command and does the supervising. The BMS assumes the duty of a lead commander who must make sure

that the troops in a large army are well organized and that all soldiers are marching in the same direction.

While a battery in a portable device can have its own personality and occasionally slack off, this liberty does not exist

in a large battery system where all members must be of equal strength. Managing fading and failing cells as the

battery ages is a complex issue that the BMS must address effectively. Monitoring and eventual replacing the cells or

battery groups is far more complex than getting a new pack for a portable device when the old one becomes a

nuisance.

Frequently

asked question

Lead acid

(Sealed, flooded)

ickel-based

(iCd and iMH)

Lithium-ion

(Li-ion, polymer)

How should Iprepare a new

battery?

Battery comes fully

charged. Apply

topping charge

Charge 1416h.

Priming may be

needed

Apply a topping

before use. No

priming needed

Can I damage

a battery with

incorrect use?

Yes, do not store

partially charged,

keep fully charged

Battery is robust and

the performance will

improve with use

Keep some charge.

Low charge can turn

off protection circuit

Do I need to apply

a full charge?

Yes, partial charge

causes sulfation,Partial charge is fine

Partial charge better

than a full charge

Can I disrupt acharge cycle?

Yes, partial chargecauses no harm

Interruptions cancause heat buildup

Partial chargecauses no harm

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Should I use upall battery energy

before charging?

No, deep discharge

wears battery down.

Charge more often

Apply scheduled

discharges only to

prevent memory

Deep discharge

wears the battery

down

Do I have to worry

about memory?

No, there is no

memory

Discharge NiCd

every 13 monthsNo memory

How do I calibrate

a smart battery? Not applicable

Apply discharge/charge when the fuel

gauge gets inaccurate. Repeat every 13months

Can I charge with

the device on?

Some UPS systems

simultaneous charge

and deliver current.

It's best to turn the device off during

charge; parasitic load can alter full-charge

detection and overcharge battery or cause

mini-cycles

Must I remove the

battery when full?

Depends on charger;

needs correct float V

Remove after a few

days in charger

Not necessary;

charger turns off

How do I store

my battery?

Keep cells above

2.10V, charge

every 6 months

Store in cool place;

a total discharge

causes no harm

Store in cool place

partially charged, do

not fully drain

Is the battery

allowed to heat up

during charge?

Battery may get

lukewarm towards

the end of charge

Battery gets warm

but must cool down

on ready

Battery may get

lukewarm towards

the end of charge

How do I charge

when cold?

Slow charge (0.1): 045C (32113F)

Fast charge (0.51C): 545C (41113F)

Do not charge

below freezing

Can I charge at hot

temperatures?

Above 25C, lower

threshold by

3mV/C

Battery will not fully

charge when hot

Do not charge

above 50C (122F)

What should I

know about

chargers?

Charger should float

at 2.252.30V/cell

when ready

Battery should not

get too hot; should

include temp sensor

Battery must stay

cool; no trickle

charge when ready

Table 1: Best charging methods. Strenuous demands cannot always be prevented.

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