Samsung Moment

Sarah - how's yours doing?

Seems odd that charging off a USB port in the computer would give better battery life, unless it's because it's a slower charge.  Most PC usb ports only provide 500ma, while the charger is 800ma.

@latinmaxima - does your battery appear to report correctly?  I've noticed my battery life has significantly increased since i first got the phone, but the reporting is sporadic at best.  I hold for 4-5 hours at 15% - and tonight it hovered between3-5% for about 5 hours (2 x 20 minute phone calls and medium use during that time).

I ran it dead and i'll try the trickle charge method tonight.  We'll see what happens.

Thank you for your post. We just purchased 3 moment's and have had them 2 days. We had read about the battery life and were hoping there is a way to improve it because we too like the phones. I am hopeful that the charger is the solution to the problem. I may have sent my phone back without having found your post. I have mine plugged into the USB right now, so wish us  luck!

Charging with the USB did it for me. My phone lasted from 8am yesterday to 9pm tonight with pretty good usage, and even though the battery said 15% at 6pm it still made it through an hour on the phone from 8-9 (being used as a baby monitor). Great phone. I hope that it improves a little more, but it's enough for me to keep it.

Charging through USB should make zero difference.  Putting the battery through a few full cycles should help the phone calibrate the battery meter so it is a bit more accurate.  The capacity of a lithium ion battery will be at it's max right when it leaves the factory and shortly after.  Pretty much the second it leaves the factory, it begins losing capacity, which is roughly 20% per year.  This is the reason lithium ion batteries generally only have a usable life cycle of a couple years.

Heat is your main enemy with charging batteries.. The hotter the battery gets, the less actual amperage it is able to hold...

To dumb down the reasoning.. Think of V = IR where V is the target voltage of the battery pack that the phone is charging at... Resistance(R) is a constant so the only unknown is current (I)...  V/R = I.. if resistance is held at a constant then the way the battery charges is V = I so when the voltage hits the target you know you have the correct current (amps) in the battery...

BUT when a battery or any other cell heats up.. R = R(o)*(1+alpha(T-T(0)) meaning Resistance is temperature dependent.. the higher T gets from original temperature (T(0)) the larger the resistance gets

Since Resistance is indirectly proportionate to current (I) the larger R gets the small I gets... If you go back to V(Target) = I(1) and V(Target) = I(2)R you will notice that V(1) (target voltage) remains teh same

so I(1) = I(2)R... I(1)/R = I(2)... if resistance increases the current that the phone thinks is full actually decreases...

One thing you have to know is the battery meter is actually determining the voltage of the cell.. Not the current in the cell (since current meters need to be installed in series and have to have a theoretical resistance close to 0 which is near impossible).. So what you see in the meter is a representation on what the voltage of the battery is

Basically all i proved and demonstrated is that if temperature increases, the battery will absorb less actual current and still think the battery is full based upon the Voltage it reads.. When the battery cools this voltage decreases as resistance decreases

When you use a rapid charger, it heats up the battery because it is pumping more current through the battery faster... when you use a slower trickle charge it keeps temperature more stable as it charges...

Message was edited by: numus

Most USB wall chargers can charge at 1 A, whereas your standard USB port will only allow a max of 500 mA, so charging via a USB port on your computer should be slower.  Without looking at the charger, I would assume it's a 1 amp charger like most others.