First charge

[Guest Pulse]

How long should I charge my o2 Exec for the first time for? ;) I was thinking of leaving it overnight.

[Guest Tech]

for any phone really:

keep it on charge until it shows fully charged. then take out the plug, wait a few seconds, put it back in and let it charge again until its "green"

then use the phone and flatten the battery until completly dead

then recharge again fully and that should do it ;)

[Guest Jasonkruys]

for any phone really:

keep it on charge until it shows fully charged. then take out the plug, wait a few seconds, put it back in and let it charge again until its "green"

then use the phone and flatten the battery until completly dead

then recharge again fully and that should do it ;)

<{POST_SNAPBACK}>

Assuming your phone has a lithium ion battery (which most do), you should NEVER run such a battery completely dead :exclaim:

"Other than higher power and lower weight, li-ion batteries are user friendly as well. Unlike its predecessor, the nickel-cadmium, lithium-ion batteries do not suffer from the “memory effect.” That is, the battery does not have to be fully discharged before being recharged. On the other hand, earlier nickel-cadmium batteries would “remember” where they were recharged, leading them to charge only to that point again. Later developed nickel-metal-hydride batteries also solved this problem.

Though the batteries do not suffer from the memory effect, it is just the opposite that users should be wary of. Lithium ion batteries shouldn’t be run all the way down before charging; they respond much better with constant recharges. Battery gauges, on the other hand, are often impacted and display incorrect readings from this practice. This leads some people to believe a memory effect exists, when in fact it’s the meter that needs to be reset. Draining the battery all the way down every 30 charges or so can recalibrate the gauge"

[Guest dazza12]

The bit that you added doesn't say never completely discharge, it says to do it every 30 charges or so to recalibrate the battery meter.

It doesn't actually damage the battery, but it's true that it can have an impact on the efficiency of the battery. If it's done occasionally it's not a problem, but constant draining would be an issue.

[Guest Metoo]

It doesn't actually damage the battery, but it's true that it can have an impact on the efficiency of the battery. If it's done occasionally it's not a problem, but constant draining would be an issue.

This is factually incorrect and is bad advice. The only real enemies of Lithium batteries are low voltage and heat[2]. Letting the voltage get too low outside of its design limits WILL permanently damage the internal structure of the cells.

That's why modern phone batteries have an internal controller on a chip, to prevent abuse, limit charging currents if the voltage goes below approx. 2.5V, and to disconnect it forever if any cell gets too low. [1]

So you should only ever run the battery down until you see the low voltage warning message. The discharge curve after this is very steep, so charging from this point is perfectly sufficient to recalibrate a software "gauge" (as you would from new).

If you try to run it down further, you certainly run the risk of

a) doing long term damage to the battery cell structure, and

;) triggering the internal protection circuitry, rendering normal charging inoperative, or worse, the battery permanently out of action.

[1] This is done for safety reasons. If a cell goes below 1.5V, it is considered to be faulty and well outside normal operating limits. Attempting to charge a faulty Lithium cell is potentially explosive, so the controller permanently disables the whole battery as a precaution.

[2] Which is why if you are storing a battery for a long time, you should keep it topped up, or give it a full charge and keep it in the 'fridge!

Edited January 2, 2006 by Metoo

[Guest Jasonkruys]

[2] Which is why if you are storing a battery for a long time, you should keep it topped up, or give it a full charge and keep it in the 'fridge!

<{POST_SNAPBACK}>

The only bit I would disagree with, slightly.

The discharge curve from a 40% charge is less, particularly when stored at 25C (most people won't bother putting it in a fridge, as they should)

If stored at 100%, after 1 year at 0C it will be at 94% of original charge

If stored at 40%, after 1 year at 0C it will be at 98% of original charge

If stored at 100%, after 1 year at 25C it will be at 80% of original charge

If stored at 40%, after 1 year at 25C it willl be at 96% of original charge

So for long-term storage, you are best doing storing it at 40% charge to protect the cells from rapid discharge.

[Guest Metoo]

The only bit I would disagree with, slightly.

The discharge curve from a 40% charge is less, particularly when stored at 25C (most people won't bother putting it in a fridge, as they should)

If stored at 100%, after 1 year at 0C it will be at 94% of original charge

If stored at 40%, after 1 year at 0C it will be at 98% of original charge

If stored at 100%, after 1 year at 25C it will be at 80% of original charge

If stored at 40%, after 1 year at 25C it willl be at 96% of original charge

So for long-term storage, you are best doing storing it at 40% charge to protect the cells from rapid discharge.

<{POST_SNAPBACK}>

Interesting figures, and appreciate what you are saying about the discharge rate.

But unless I've misunderstood, I think you're confusing "original charge" with "fully charged". The second battery in your example can never be above 40% of capacity, so it is already much further down the road to going flat.

So surely a fully charged battery has the longer shelf life, as it will take much longer to reach a critical low voltage, than one which starts off at 40%?

E.g., using your example, after 12 months stored at 0C:-

A fully charged battery would be at 94% of the original 100% charge = 94% of total capacity.

A 40% charged battery would be at 98% of the original 40% charge = 39.2% of total capacity.

Therefore, even if we assume critical voltage is something like 20%, it's going to take the fully charged battery a lot longer to get there than the one thats already down at 39%.

Especially when you consider that the discharge rate of the first battery is going to slow down even further when it eventually gets down to your quoted 40% "start point".

Edited January 2, 2006 by Metoo