Laptop Batteries

Hi Everybody!

I would like to know the truth, once and for all, about laptop battery care.

I was issued a refurbished laptop at my job that had a brand new battery. I wanted to maintain that battery to use it to it's full potential. I treated it like a NiCd battery, I fully charged it then fully drained it, and made sure not to break the cycle. However, in my field, I have to use the laptop all day, so I keep it plugged in. I was told by the IT dept that "memory effect" isn't an issue with NiMh batteries, and that I really should USE the battery, because not using the battery is also bad. Well, now my laptop will only run for 15 mins. on battery power, where it used to last 1hr 15mins. under full load. I have read online that "memory effect" IS an issue with laptop batteries too.confused

The same thing with the laptop I bought for my wife. After all of this battery care confusion, I just let her just charge and discharge the battery at any rate-- now her laptop will live for about 7 mins on the battery.

I have seen instructions for both kinds of rechargeable batteries say totally different methods for charging, and my question is... How IS a laptop battery supposed to be charged and used properly to maintain it's length of charge? Also, if you unplug a laptop, and plug it right back in 3mins later, is that bad?

Thank You.

 

There is much confusion about batteries it is true.

The memory effect is peculiar to Nickel - Cadmium cells. It does not affect Nickel -Metal Hydride or Lithium ION cells or the Lead Acid batteries used in vehicles and some UPS units.

That said all batteries become partially exhausted as they approach the end of their lives. This process is often mistaken for the 'memory effect'. It is also hastened by battery abuse. Constant trickle charging is one form of battery abuse, overheavy discharge is another, charging from a true dc supply is yet another.

So your IT department are correct to say use the battery. Any submariner will tell you od the strict charge / discharge regime they keep. Of course their lives depend on maintaining their batteries well.

Hope this helps

Studio T

 

If the battery is always fitted into the laptop, isn't it getting a trickle charge?
confusedconfused Bazza

===

 

Yes indeed.
You may remember when rechargable calculators first came out, people had them plugged in on their desk all day and wondered why , one day the battery was dead.

So what the IT dept mean is to charge unplug use plugin charge........

Modern batteries will take more abuse you can leave them on charge and use them some of the time, so long as every now and then (say 1 in 10) you take the battery down to full a discharge/ charge cycle.

Studio T

 

Thank You Studio T for that detailed explaination... it makes sense to me. I am afraid that the damage might already be done. I am in a tough position because I need to use the laptop all day, but at times I need to move it, or take it on the road. About the only way I can do this is to remove the fully charged battery, then shut it down and install the battery when I need to take it on the road... if a laptop will even RUN with the battery removed-- I don't know, never tried it.

 

What kind of batt do you have? If it's nicad.. you have the memory effect.. but not many nicad batts still in use... most laptops batts are now lithium ion. They have a shelf life if in the notebook... they will "cycle' if they're in the notebook and you're running on ac adapter power. so, with li-ion batts you should use them and don't worry about memory effect, but if you have the notebook on ac power for longe perioeds (days) take the batt out and it will last longer. Most laptops will not require the batt to run while on ac (wall ooutlet) power.

 

The memory effect is mostly a myth,I agree with studio T on most points,I disagree with not trickle charging the battery leaving it for a few days without a charge as it is bad,most damage is caused by overcharging,heat is the enemy if the battery is warm to the touch its charged under normal charge rates,as studio said you dont need to discharge the battery every time you use it your just shortening the lifespan of the battery if its a nicad or nimh

It sounds like the battery is a lipo battery though as tchansen said,totally discharging will kill it,if it isnt there are ways of bringing nicad and nimh batteries back to life by sending a short burst of high current through the battery to break up the crystals between the plates but I'd just take it back

 

I didn't actually say trickle charging I said constant trickle charging.

That means don't go to work every day, plug the thing into the mains a 0900, leave it on until 1700 when you unplug it and take it home or what ever.

At least once a week, run it on its battery supply alone until the battery needs recharging. Ask you IT dept I expect they will confirm this.

Studio T

 

Thanks studiot. :cool Bazza