| 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) |
0°C
- 45°C (32°F - 113°F)
5°C - 45°C (41°F - 113°F)
Charging a hot battery decreases the charge time. The
battery may not fully charge.
|
0°C
- 45°C (32°F - 113°F) 5C° - 45°C
(41°F - 113°F)
Temperature sensor may prevent charge or cut off the
charge prematurely.
|
0°C
- 45°C (32°F - 113°F)
5C° - 45°C (41°F - 113°F)
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. |
