Why do manufacturers recommend min X hour charge before use on new devices?

I've noticed that on almost all new devices with a rechargeable battery the manufacturer says to chargne non-stop for at least X hours before using it for the first time.

I've also noticed that the device generally indicates that it is fully charged before said time has elapsed. Why do the manufacturers say to charge for this long? Do the batteries have some kind of 'memory'? Will they not last as long if you don't?

Anyone know about this?

Some batteries do have a memory. The first few times you use them you want to fully charge then discharge the batteries so that it always uses the full battery capacity.

I'm not sure if this applies to all batteries.

All rechargable batteries will develope a memory, they say Lithium Ion Batteries will not but they do from my experience they just seem to last a lot longer before they do.

this will work for pretty much any type of rechargable batteries, cell phones, AA, AAA etc.

Fully charge them if new, use them till they get low then totally drain them, AA, AAA or whatever type of round batteries are easily done using flash lights or even some kids toys just leave them on till it dies then swap the batteries and leave it on again till it won't do anything. Cell phones can be a bit tougher as most people need their phones but try and plan draining the cell battery around times where you won't need it as much.

Then once discharged, recharge them...

I usually totally discharge my cell phone battery once a month.

other batteries once they die I drain them complete with a flashlight & then recharge them and my batteries always last longer then the ones my wife use by a few months.

Wolverine690 said:

All rechargable batteries will develope a memory, they say Lithium Ion Batteries will not but they do from my experience they just seem to last a lot longer before they do.

this will work for pretty much any type of rechargable batteries, cell phones, AA, AAA etc.

Fully charge them if new, use them till they get low then totally drain them, AA, AAA or whatever type of round batteries are easily done using flash lights or even some kids toys just leave them on till it dies then swap the batteries and leave it on again till it won't do anything. Cell phones can be a bit tougher as most people need their phones but try and plan draining the cell battery around times where you won't need it as much.

Then once discharged, recharge them...

I usually totally discharge my cell phone battery once a month.

other batteries once they die I drain them complete with a flashlight & then recharge them and my batteries always last longer then the ones my wife use by a few months.

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You can read about the "memory effect" here: http://en.wikipedia.org/wiki/Memory_effect

The reason you have to charge new batteries is that while they sit on the shelf, they slowly discharge. If you start using the battery without first charging it, the "memory effect" can take over and cause the battery to have reduced capacity.

Im to impatient, i never do that

Memory effect is only apparent in NiCd batteries. NiCd's are really only used anymore in an electronic device that needs high surge currents. However, NiMH and now even Lithium Ion batteries are able to supply large surge currents (www.A123systems.com if you are interested, 100A surge, 60A continious). The memory effect was used to describe how the NiCd crystal, when only discharged partially, would not ionize completely, so when it was recharged the crystal structure became larger and surface area was lost. Hence "cell memory" was born.

When charging batteries for the first time they have to account for self discharge during storage time. NiCd/NiMH self discharge rates are approximately 5% during the first week and about 5% for every month thereafter. Lithium Ion is about 5% the first month and 2% for every month after. So OEM's must account for this when charging the battery the first time. Also, because that term is only given for batteries without a smart charger or charging circuitry time is their only way of telling when the battery is fully charged.

Wolverine690 - When you fully discharge your batteries then recharge them fully, thats essentially a "recondition" cycle which should restore much of its lost capacity.

Also don't attribute loss of capacity with memory effect, rechargable batteries do age. NiCd and NiMH usually do about 500+ cycles with good matenance. But will loose about 10%+ of their capacity over that lifetime. Another effect is that with chargers without control circuitry or smart charging capabilities they just pour current into the battery and that results in heat lost when the battery is fully charged, this increase in storage temperature can cause the battery to wear at much faster rates.

Partial discharge before recharging is not only not harmful for NiMH and LiIon batteries, it actually helps the batteries. As for LiIon batteries wanting to be fully charged before first use, my theory is that the first time you use it, the charge meter is collaborated based on the first time it is charged/discharged, and as such you should run it a full cycle the first time to ensure it gets a correct reading on the battery.

What can I say Roofles, you know a hell of a lot about batteries...

My questions are more than answered, and thanks to everyone else too.

I'm working with them at my internship =) I had to learn a lot in the first few weeks!

Roofles said:

I'm working with them at my internship =) I had to learn a lot in the first few weeks!

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I also used to work with them for 3-4 years when I sold Cell phones & pages so I delt a lot with batteries and problems with them.

Wolverine690 said:

I also used to work with them for 3-4 years when I sold Cell phones & pages so I delt a lot with batteries and problems with them.

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Cool. I'm doing battery design and such, charging circuits and performance testing and the like. I'm doing the power requirements design for the stuff we are working on. I must admit I <3 R&D.