x |
Nickel-based (NiCd and NiMH) |
Lithium-ion (Li-ion) |
Lead-acid (Sealed or flooded) |
Should I use up all battery energy before charging? |
Yes,
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,
it is better to recharge more often; avoid frequent full
discharges.
Yes, on batteries with a fuel gauge, allow a full discharge once
a month to enable reset |
No,
it is better to recharge more often; avoid frequent full
discharges. Deep cycles wear down the battery. Use a larger
battery if full cycles are required. |
Should I charge my battery partially or fully? |
Allow full charge without interruptions. Repeated partial charge
can cause heat buildup. (Many chargers terminate charge by heat.
A fully charged battery will re-heat, causing overcharge.)
|
Does
not matter. Charging 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. |
Does
not matter. Charging 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 the battery be kept charged when not in use? |
Not
critical. Manufacturers recommend a 40% charge for long storage.
(Open terminal voltage cannot determine state-of-charge.) Store
in a cool place. Battery can be fully depleted and recharged.
Priming may be needed. |
Best
to store at 40% charge or 3.75-3.80V/cell open terminal. Cool
storage is more important than state-of-charge. Do not fully
deplete battery because Li-ion may turn off its protection
circuit. |
IMPORTANT: always keep battery fully charged. A discharged
battery causes sulfation (insulating layer in the cell). This
condition is often irreversible. |
Will
the battery heat up during charge? |
Yes,
towards full charge. The battery must cool down when ready.
Discontinue using a charger that keeps the battery warm on
standby. |
No,
little heating is generated during charge. A large laptop
battery may get lukewarm. Do not allow the battery to heat
during charge. |
No,
the battery should remain cool or lukewarm to the touch. The
battery must remain cold on maintenance charge. |
What
are the allowable charging temperatures? |
Important: Rechargeable batteries can be used under a wide
temperature range.
This does not automatically permit charging at these extreme
conditions.
The maximum allowable charge temperatures are shown below: |
Slow
charge (0.1)
Fast charge (0.5-1C) |
0ºC
- 45ºC
5ºC - 45ºC
Charging a hot battery decreases the charge time. The battery
may not fully charge. |
0ºC
- 45ºC, 5ºC- 45ºC
Temperature sensor may prevent charge or cut off the charge
prematurely. |
0ºC
- 45ºC
5ºC- 45ºC
Warm temperature lowers the battery voltage. Serious overcharge
occurs if the cut-off voltage is not reached. |
What
should I know about chargers? |
Best
results are achieved with a fast-charger that terminates the
charge by other than temperature alone. Fastest full-charge
time: Slightly over 1 hour. |
Charger should apply full charge. Avoid economy chargers that
advertise one-hours charge. Fastest full-charge time: 2-3 hours. |
Multi-level charges shorten charge time. Charge must be fully
saturated. Failing to do so will gradually decrease the
capacity. Fastest full-charge time: 8-14 hours. |