Laptop batteries and storage

[VirtualLarry]

Why is it, that laptops, introduced last year, can sit in store inventories for months, and yet, when you buy them and plug them in, they still have charge left.

But, take them home, charge them, and then forget to charge them after a month or so, and then they are at 0% (or lower) to 2% charge, and sometimes, the battery dies because it wasn't charged in time.

Are the batteries put into some sort of "hibernation" state, from the factory, and the first time you plug the laptop in and charge it, it "wakes up" the battery?

I've heard that they have some sort of failsafe "sleep mode", that they go into, when they get too low, to prevent dangerous deep discharge.

 

[C1]

A guess is that it is because the systems are shipped with battery out of circuit.

Whenever I receive a newly ordered battery from Fujitsu, it arrives with about a 50% remaining charge. I find that storing a notebook battery (that is in good shape) out-of-circuit with about 50% charge, will retain its charge for many months (try it and see).

A battery kept in circuit leaks down. This is true now for automobiles since they have become so solid stated (ie, clocks, computer/ECU, emission and anti-theft, remote control systems).

 

[VirtualLarry]

A guess is that it is because the systems are shipped with battery out of circuit.

Whenever I receive a newly ordered battery from Fujitsu, it arrives with about a 50% remaining charge. I find that storing a notebook battery (that is in good shape) out-of-circuit with about 50% charge, will retain its charge for many months (try it and see).

A battery kept in circuit leaks down. This is true now for automobiles since they have become so solid stated (ie, clocks, computer/ECU, emission and anti-theft, remote control systems).

This laptop I purchased recently on clearance, had the battery already affixed. I think that there is more to this.

 

[heymrdj]

If the battery is affixed, that is where your battery leaked down. Batteries should not be attached already at the time of sale.

 

[VirtualLarry]

If the battery is affixed, that is where your battery leaked down. Batteries should not be attached already at the time of sale.

http://forums.anandtech.com/showthread.php?t=2435921

This laptop has the battery already affixed, in the factory packaging. As do all of the modern budget laptops with "integrated" batteries, that are non-user-removable.

I'm suggesting that they have some sort of "factory mode" in the battery-controller circuit, that prevents discharge before the laptop is purchased.

If there wasn't, I would expect to see buyers of laptops complaining more about dead batteries after purchase.

 

[inachu]

Not just batteries but capacitors also remain more fresh when under a charge.

Keeping your electronic all at 50% or more charge will mean longer over all life.

 

[heymrdj]

http://forums.anandtech.com/showthread.php?t=2435921

This laptop has the battery already affixed, in the factory packaging. As do all of the modern budget laptops with "integrated" batteries, that are non-user-removable.

I'm suggesting that they have some sort of "factory mode" in the battery-controller circuit, that prevents discharge before the laptop is purchased.

If there wasn't, I would expect to see buyers of laptops complaining more about dead batteries after purchase.

All the devices I've bought with integrated batteries were brand new, and dead. Sony Vaio Flip 13A was dead, had to charge for nearly 3 hours before it'd even boot. My HTC M8 For Windows was dead, needed to charge for a few hours to turn on. Samsung Galaxy SIII was at 15% when I go it. Asus Transformer Prime took 5 hours to turn on (I thought it was DOA, but it was just a super dead battery).

 

[VirtualLarry]

All the devices I've bought with integrated batteries were brand new, and dead. Sony Vaio Flip 13A was dead, had to charge for nearly 3 hours before it'd even boot. My HTC M8 For Windows was dead, needed to charge for a few hours to turn on. Samsung Galaxy SIII was at 15% when I go it. Asus Transformer Prime took 5 hours to turn on (I thought it was DOA, but it was just a super dead battery).

Interesting data point, thanks. Apparently, some devices sold new DO have "dead" batteries. (I put it in quotes, because they were discharged, but not actually DEAD. Meaning, cannot even be charged.)

So perhaps my theory isn't true.

It was based on information that I obtained from someone that did some research on laptop batteries, that evidently, the charge controller hooked up to the batteries, goes into a "sleep mode", once the cells are discharged too much, to prevent a deep discharge, which could affect battery chemistry, and be unsafe.

 

[heymrdj]

Interesting data point, thanks. Apparently, some devices sold new DO have "dead" batteries. (I put it in quotes, because they were discharged, but not actually DEAD. Meaning, cannot even be charged.)

So perhaps my theory isn't true.

It was based on information that I obtained from someone that did some research on laptop batteries, that evidently, the charge controller hooked up to the batteries, goes into a "sleep mode", once the cells are discharged too much, to prevent a deep discharge, which could affect battery chemistry, and be unsafe.

From what I understand the circuits simply disconnect completely when the voltage drops too much. That is still a state of deep discharge (the device won't power on) but keeps from damaging the battery. On that point, that's done by the controller chips and not something that could be changed by the user.

 

[mindless1]

Yes every Li-Ion battery powered device must have a protection circuit to prevent deep discharge damage, or use cells with the protection built into them. By "every" I'm excluding some of the cowboy penny pincher designs coming out of China because you can never say never with some of that junk where there's no accountability.

 

[grepawking]

I seem to remember that most laptop batteries come with some type of removeable plastic sticker type thing that is to be removed from the connection tabs once the unit is purchased. This essentially keeps the battery "out of contact" with the machine which allows it to last longer.

 

[imagoon]

This isn't new or "this year." When I was selling computers more than 17 years ago they would come installed and power up new on the desk without installing them or removing plastic. It is very simple, they fully shut the machine off. If the battery on a laptop is discharged while off in less than a month, it isn't being shutdown correctly or the battery is so old the charge in minimal. Random examples for today: walked in to the store room grabbed a random Dell Latitude with "wiped ready for use 2-15-15," booted it up to 85% battery. (Part of the storage process here is to fully charge the battery before putting it away.) 3 month old blackberry at 76% charge.

Battery being dead in a month while off is the exception, not the rule from my experience.

 

[Sabrewings]

Keeping your electronic all at 50% or more charge will mean longer over all life.

In the right direction, but not specific enough. Li-ion chemistry lasts the longest when stored at 80%. Being kept at full charge breaks down the chemistry, as does being below 80%. If a Li-ion battery powered device is to be stored, target 80% and remove the battery if possible or hard shut down if not.

 

[mindless1]

Multiple Li-Ion battery storage tests have determined that an optimal charge level for storage is around 40%, but with the burden that you never allow it to drop below 2V/cell to avoid damage, which obviously will happen sooner if you start with a lower voltage.

However, I don't expect laptop manufacturers to particularly care if you get the maximum lifepan out of your battery pack, rather that putting a higher charge % in at the factory allows them to sit longer before sale to a customer without self discharging to a critically low level.

 

[Sabrewings]

Multiple Li-Ion battery storage tests have determined that an optimal charge level for storage is around 40%,

Ack, wow thanks for the correction. I was thinking of LiFePO4 chemistry. I've used a few of those in 12v applications.

 

[imagoon]

In the right direction, but not specific enough. Li-ion chemistry lasts the longest when stored at 80%. Being kept at full charge breaks down the chemistry, as does being below 80%. If a Li-ion battery powered device is to be stored, target 80% and remove the battery if possible or hard shut down if not.

The charge % is often misrepresented by the devices. There is a lot of cells that use 80 to 85% of cell charge as 100% "Battery charged" so you need to be aware of that. The majority of LI-ON cells are never 100% or 0% no matter what the device claims.

 

[Sabrewings]

The charge % is often misrepresented by the devices. There is a lot of cells that use 80 to 85% of cell charge as 100% "Battery charged" so you need to be aware of that. The majority of LI-ON cells are never 100% or 0% no matter what the device claims.

Agreed. I use the info on the battery to figure out how many cells are in series and measure myself with a multimeter. :biggrin:

 

[mindless1]

nvm, necro due to a spammer something