My laptop (a relatively new Gateway, purchased for my use on business) is also my desktop when I’m not traveling. On travel, I usually make do with battery power on the plane, but in meetings I leave the laptop plugged in if I can.
At work, I also leave it plugged in, and run it as though it were a desktop machine. What I’ve noticed is that the power LED on the front glows green once the system gets charged to 100%, but then over the next week or two, the light stays green and I lose a few percent of power. In six days, the battery was down to 96% (with the power LED still green). When it’s unplugged and turned off at night, it loses about 2%.
If I pull the plug (after it’s been running for a while, and is down to 95% for example) and then re-insert it, the computer switches briefly to battery power, and when the wall power is re-introduced, it begins to charge the battery again, “topping off” my battery in about a half hour.
Is this “leakage” normal? Is my meddling (to keep the battery as full as possible all the time) having any ill effects on the battery? Would it be better to let the laptop run down to nearly no charge and then fill it all the way up, or is it better to try to keep it full?
Do *not[/] let a latop battery get trickle charged past fully charged. Either run the laptop off the battery, or run off the adaptor (possibly with the battery inserted if it really needs charging).
Old NiCads should be cycled from fully charged to drained all the time. NiMhs can be kept fully charged for longer, but still need to be cycled every now and then. Newer LIons get harmed by continous charging. They’re really quite fragile in this regard.
Your laptop maker will suggest that you keep your battery trickle charged. This is for their monetary advantage, not yours. Scumbags.
(Note: if you have a charging choice between “slow” and “fast”, always use “slow”.)
This is a very complex question, which I guess is why nobody has answered it yet. I’ll state what I do know:
[ul]
[li]If a battery is disconnected and stored, it slowly loses charge. This is normal.[/li][li]If a battery is installed in a laptop and the power is connected, usually the laptop keeps the battery fully charged. Apparently yours does not, but it may be normal for that model.[/li][li]There should be no harm in letting the battery run down due to natural (self-) discharge. [/li][li]Running the battery down by using the battery can result in damage, but all laptops should have a cutoff circuit which cuts off the battery before any harm is done.[/li][li]If the charging circuit is designed properly, there is no harm in “topping off” a battery. You may have heard that charging a partially used battery results in “memory effect”, but this is a myth. What happens is that with poorly designed charging circuits, charging a partially used battery results in over-charging, which causes the battery to degrade. With modern laptops, this isn’t a concern.[/li][/ul]
And how can one “trickle charge” past fully charged? My battery meter goes up to 100%, are you saying it can go past 100%? How would I know if I were trickle charging past fully charged? I keep my laptop plugged in most of the time, in case I need to use it from the battery for an hour or two. Am I doing damage by keeping it plugged in and charging all the time?
Trickle charging is charging usiong a very low current. Typically, trickle charging takes overnight to charge a battery fully. Once a battery is fully charged, a dumb charger will continue to pus current through it, causing heating and electrolysis of the electrolyte, which eventually lead to failure.
The charging circuitry itself sets the charging current. If the package it comes in says it will charge the battery in several hours, it’s considered a trickle charger. Most rapid chargers will state specifically that the will charge the battery quickly. This is bad. You want a charger that will recharge your battery slowly, like overnight.
OK, I see now. My Laptop battery didn’t come in a package, it came in my laptop. I’ve never even taken it out of the laptop. Is there any way to tell if it is a trickle charger? Sorry for all the questions, I often wonder if leaving my laptop plugged in all the time is bad for it. I don’t use it everyday, but when I need it, I need it to be charged.