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Posts: 2,050 | Thanked: 1,425 times | Joined on Dec 2009 @ Bucharest
#32
Originally Posted by shadowjk View Post
I'd like to see some references for your claim that a partial cycle equals a full cycle.

Considering that what the N900 (and almost everything else) does once the battery reaches full is let it discharge 2-5% and then top it up again, it should be burning through a large amount of "cycles" once it reaches full. (And the green light comes on independent of whether the battery is actually full at that time or not, and stays green until charger is disconnected)
And that's why I said half charge. Small cycles don't count almost at all. Also, N900 charges to about 98 then doesn't charge until approx 86. Standby and self-discharge doesn't take that much overnight in normal circumstances. So, actually, N900 only chages one cycle overnight. Should it take longer, it tops it off again. My phone still says battery full if standby overnight.

And yes, battery does go away if phone is left plugged in for extended periods.

As for how much a cycle counts for a chemistry, I already linked battery university.

Originally Posted by Estel View Post
but I think that shadowjk got a point here. If you let the phone charge overnight, in fact it is just charged to full in few hours, then discharged to 95%, then charged again to 100, etc...
He does, just not under normal circumstances.

Originally Posted by Estel View Post
power is cut off until battery drop to 95% or so.
We already went through this in another thread. Also, if you decide to use a different metric, the battery module versus Nokia's, the we can't talk numbers, now can we? The module you use does not make the charge decision, bme does.

Originally Posted by Estel View Post
So, that would mean You got 10-20 cycles every night...
And that's why we don't use that module for reference. If bme says 90 percent and you plug it in, N900 says "battery full" and doesn't charge. If you want to see how bme works, ask bme via lshal.

Originally Posted by Estel View Post
Look ndi. N900 battery rounded up got 5Wh - You're right at that. It's capable to safe deliver for our needs 1315 mA constant current @ 3.8V (rounded from 3.3V-4.2V, doesn't matter for our calculations) for time of 1 hour. Also, it can deliver 657 mA constant current for 2 hours, etc. Every fluctuation of current change total time, but after C (current)*V (voltage)=5W or higher, battery is already at 3.3V and is discharged, aka "dead".
You have long lost me. In my post I said that IF IT REALLY ATE 10 PERCENT in a few seconds, dissipated power would be in the order of 100s watts. Nothing above has anything to do with my post. You seem to be on about what it really eats, my post was about what it would eat if.

If you still think I'm off, please quote the segment so we are on the same page.

[QUOTE=Estel;1004643]Then, if we want to calculate how much power could be drained if powercycle would use 3% of battery capacity, we need to keep in mind that Wh = Ch*V, so (Wh = Ch*V) / h -> W=C*V - we need to divide by h, not multiply by h as you did.[QUOTE]

Power multiplied by time is capacity/energy. If capacity is the same, small time equals big power. If you used C as discharge factored as capacity per hour, then the equation is:

Capacity = power multiplied by time.
Capacity = volt times ampere times time.

if you factor hour, you get WATT equals Amp times Volt. Which is what we already know. You substituted C oddly. There is no Ch. C is an abstract-ish concept, in which a battery is drained in one hour, so A equals Ah. No operations using h is allowed.

Wh = W * h
Wh= V * A * h
5 Wh = 3.8V * 1.3A * 1h

If you make 1 to be 0.1, or 6 minutes, and volts is the same, then Amp jumps tenfold.

5 Wh = 3.8V * 13A * 0.1h

Same bucket spilled in half the time means twice the intensity.

So, if instead of 3600s you do 36 seconds, that's 100 times current, and 1.3 A becomes 130 amps, so, you know, some 500W.

Originally Posted by Estel View Post
Also, if we treat serious Your calculations about 10% beign 180W, that would mean we got 1800W at 100% - real beast. That would allow us for powering up high-power driller for an hour, just using our little battery, no need for wall plug I got nothing against that idea, but for now we must be happy with 5W thing...
You missted the h again. 5 Wh is 5 * 3600 watts second. That's 18 kWs. Notice the s, it's not plural. Same battery can power a high power drill for a second not for an hour.

1 Ws is 1 watt for a second, 1 kW for a miliwecond or a wris****ch for a year.

Assuming zero internal resistance.

ETA: Haha, forum censored wris****ch. Wrist Watch. Timepiece. Portable clock. Heh.
__________________
N900 dead and Nokia no longer replaces them. Thanks for all the fish.

Keep the forums clean: use "Thanks" button instead of the thank you post.

Last edited by ndi; 2011-05-12 at 09:39.
 

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