OT: Laptop battery question

[pheasant]

Read in a NG that leaving them plugged into AC at all times will ruin them.
Dell's battery (Inspiron 3800) must be in the computer to operate. (from
what I understand) Bought one for kid to take to college, so won't be used
daily until next fall. Should I charge it up, then let it discahrge on it's
own from setting before recharging, or simply let it go dead until it's
needed and then charge. It's just a spare currently, so if we would need it
could just plug into AC.
Thanks

 

[philo]

Read in a NG that leaving them plugged into AC at all times will ruin them.
Dell's battery (Inspiron 3800) must be in the computer to operate. (from
what I understand) Bought one for kid to take to college, so won't be used
daily until next fall. Should I charge it up, then let it discahrge on it's
own from setting before recharging, or simply let it go dead until it's
needed and then charge. It's just a spare currently, so if we would need it
could just plug into AC.
Thanks

If it's a lead-acid type... charge your spare battery every 3 - 6 months
while not in use
and keep it in a cool place if possible.

 

[Tony A.]

Read in a NG that leaving them plugged into AC at all times will ruin them.
Dell's battery (Inspiron 3800) must be in the computer to operate. (from
what I understand) Bought one for kid to take to college, so won't be used
daily until next fall. Should I charge it up, then let it discahrge on it's
own from setting before recharging, or simply let it go dead until it's
needed and then charge. It's just a spare currently, so if we would need it
could just plug into AC.
Thanks

If it's a lithium-ion battery (it probably is, but check), then you should
keep it charged up - lithium-ion batteries get wrecked if you leave them
fully discharged.

Older battery technologies (NiCd, NiMh) suffered from a "memory effect",
whcih meant their capacity would be reduced if you don't let them discharge
fully before charging on a fairly regular basis. Li-Ion doesn't suffer from
that effect, so top-up charging is fine, and indeed recommended.

Tony

 

[Dick Sidbury]

Older battery technologies (NiCd, NiMh) suffered from a "memory effect",
whcih meant their capacity would be reduced if you don't let them discharge
fully before charging on a fairly regular basis.

Can you substantiate this claim? I know that NiCad has the memory
effect but I had heard that NiMH didn't.

dick

 

[ric]

Can you substantiate this claim? I know that NiCad has the memory
effect but I had heard that NiMH didn't.

NiMH suffers the "memory effect" on a much lessor basis than does NiCd.
All of my NiMH equipped devices recommend a complete discharge once a
month. I have been charging the NiMH AA batteries in my MX700 mouse nightly
for 6 months with no ill effect.

 

[pheasant]

Read in a NG that leaving them plugged into AC at all times will ruin them.
Dell's battery (Inspiron 3800) must be in the computer to operate. (from
what I understand) Bought one for kid to take to college, so won't be used
daily until next fall. Should I charge it up, then let it discahrge on it's
own from setting before recharging, or simply let it go dead until it's
needed and then charge. It's just a spare currently, so if we would need it
could just plug into AC.
Thanks

OK Guys;
It's a lithium ion type, and guess after following the thread, I still
ain't sure what to do. DOH!!!

 

[Tony A.]

Can you substantiate this claim? I know that NiCad has the memory
effect but I had heard that NiMH didn't.

NiMH does suffer a reduction in capacity if continually top-up charged, but
unlike NiCd the capacity can be fully restored over a number of conditioning
cycles, so it's probably wrong of me to link it to the memory effect
suffered by NiCd, so I guess you're right to call me on that one.

The following text I think came from a Duracell document, when I looked this
issue up for a friend a while back:

"A reversible drop in voltage and loss of capacity
may occur when a nickel-metal hydride battery is partially
discharged and recharged repetitively without the
benefit of a full discharge, as illustrated in Figure 5.9.1.
After an initial full discharge (Cycle #1) and charge, the
cell is partially discharged to 1.15 volts and recharged
for a number of cycles. During this cycling, the discharge
voltage and capacity drop gradually in very small
increments (Cycles #2 to #18). On a subsequent full
discharge (Cycle #19), the discharge voltage is
depressed compared to the original full discharge
(Cycle #1).
Because the cell appears to "remember" the
lower capacity, this voltage depression phenomenon is
often referred to as memory effect. However, the cell
can be quickly restored to full capacity with a few full
discharge/charge cycles, as indicated in Cycles #20
and #21."

Tony

 

[Dick Sidbury]

NiMH does suffer a reduction in capacity if continually top-up charged, but
unlike NiCd the capacity can be fully restored over a number of conditioning
cycles, so it's probably wrong of me to link it to the memory effect
suffered by NiCd, so I guess you're right to call me on that one.

The following text I think came from a Duracell document, when I looked this
issue up for a friend a while back:

"A reversible drop in voltage and loss of capacity
may occur when a nickel-metal hydride battery is partially
discharged and recharged repetitively without the
benefit of a full discharge, as illustrated in Figure 5.9.1.
After an initial full discharge (Cycle #1) and charge, the
cell is partially discharged to 1.15 volts and recharged
for a number of cycles. During this cycling, the discharge
voltage and capacity drop gradually in very small
increments (Cycles #2 to #18). On a subsequent full
discharge (Cycle #19), the discharge voltage is
depressed compared to the original full discharge
(Cycle #1).
Because the cell appears to "remember" the
lower capacity, this voltage depression phenomenon is
often referred to as memory effect. However, the cell
can be quickly restored to full capacity with a few full
discharge/charge cycles, as indicated in Cycles #20
and #21."

Tony

That's good to know. I have a 30 minute charger and have been topping
off my NiMH batteries for a while now. So I'll run all of them totally
down over the next few cycles to get them back up to original factory specs.

dick
--now if I just knew why my Gateway notebook's l-ion battery's full
charge has reduced to 1900 maHr from the original 4400.

 

[Tony A.]

[...]

OK Guys;
It's a lithium ion type, and guess after following the thread, I still
ain't sure what to do. DOH!!!

Just don't store it completely flat, that can damage it. If you're storing
it unused for a long period, most manufacturers seem to recommend storing it
at around 40% charge.

Tony