Where do you put the 4xAA's ?
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Somebody put up the wrong photo...
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Somebody else posted obvious comments on theDailyWTF.
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TRWTFis that a really good alkaline AA battery has a little less than 2.5 watt-hours of juice. 4 of them means 10 watts. A PSP battery contains 6.5 watt-hours of power. Assuming 100% energy transfer (LOL! Not a chance in hell) you could charge your PSP 1 time fully, and another time somewhat. Four times? Not a chance in hell.
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@shepd said:
TRWTFis that a really good alkaline AA battery has a little less than 2.5 watt-hours of juice. 4 of them means 10 watts. A PSP battery contains 6.5 watt-hours of power. Assuming 100% energy transfer (LOL! Not a chance in hell) you could charge your PSP 1 time fully, and another time somewhat. Four times? Not a chance in hell.
No, a typical alkaline AA has 2.5 AMP-hours of charge at 1.5V. That's 15 watt-hours in 4 batteries. I don't know anything about the PSP battery, though.
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@Anon Ymous said:
@shepd said:
TRWTFis that a really good alkaline AA battery has a little less than 2.5 watt-hours of juice. 4 of them means 10 watts. A PSP battery contains 6.5 watt-hours of power. Assuming 100% energy transfer (LOL! Not a chance in hell) you could charge your PSP 1 time fully, and another time somewhat. Four times? Not a chance in hell.
No, a typical alkaline AA has 2.5 AMP-hours of charge at 1.5V. That's 15 watt-hours in 4 batteries. I don't know anything about the PSP battery, though.
real-world performance (tm) would be about 12watt hours for 4xtypical Alkaline AA
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@shepd said:
TRWTFis that a really good alkaline AA battery has a little less than 2.5 watt-hours of juice. 4 of them means 10 watts. A PSP battery contains 6.5 watt-hours of power. Assuming 100% energy transfer (LOL! Not a chance in hell) you could charge your PSP 1 time fully, and another time somewhat. Four times? Not a chance in hell.
Even with Anon Ymous' correction (15 watt-hours), that's still only enough juice to charge the batteries from completely flat to completely charged a little over twice, or (yay 1.2V lithium batteries, thanks Helix!) a little less than twice. However, you forget that the PSP has a relatively narrow operating range when it comes to voltage, and can only use (out-my-ass-number) 4 watt-hours out of the battery per charge. So you could in theory recharge your PSP from so-called "fully discharged" to fully charged 4 times on those 4 batteries.
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@Helix said:
real-world performance (tm) would be about 12watt hours for 4xtypical Alkaline AA
Depends on the device and battery. When a battery says it has a 2500 mAh charge, that means it maintains a voltage high enough to power typical devices for 2500 mAh. By the time a battery stops working in a high drain device its voltage might be around 1.3V. At this point you may still be able to get a few hundred more mAh in a remote control or other low drain device.
If the PSP battery is less than 6V (according to google it's 3.6V), you may actually be able to get more than 15Wh out of the batteries. Even with premium batteries I still wouldn't expect more than 2 and a half charges though.
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@Anon Ymous said:
@Helix said:
real-world performance (tm) would be about 12watt hours for 4xtypical Alkaline AA
Depends on the device and battery. When a battery says it has a 2500 mAh charge, that means it maintains a voltage high enough to power typical devices for 2500 mAh. By the time a battery stops working in a high drain device its voltage might be around 1.3V. At this point you may still be able to get a few hundred more mAh in a remote control or other low drain device.
If the PSP battery is less than 6V (according to google it's 3.6V), you may actually be able to get more than 15Wh out of the batteries. Even with premium batteries I still wouldn't expect more than 2 and a half charges though.
I didn't say anything about the device. I was talking about the average AA alkaline cells that 'Joe the Gamer' might buy. They have variance in charge from cell to cell depending on manufacture tolerance and also variance in manufactures specifications. Also to note here we are looking at typical (most popular) price point, we know cells go from a fraction of a dollar to multi-dollar. Please also note that the battery pack will work at the performance of the worst cell in the pack.
The device might be good at converting the 12watts or very wasteful. It is clear that even 100% conversion with typical alkaline cells will not achieve the manufacturer claims.
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We know that 4xAA's (non-rechargable) is 6V, we know the PSP expects 5.2V, and that the battery inside the PSP expects 4.2V.
If we assume theres a diode (such as a 1N4001), we can lose 0.7V straight away to give us 5.3V, suitable for the PSP. But, a fully (re)charged set of batteries is about 1.4V (5.6V) which would give us 4.9V, so the PSP would only be able to charge its internal battery to 70%.
So there has to be something more intelligent in there. If they use a vreg, there will be heat (and thus efficiency loses).
Since theres no way we can measure battery voltage from the outside of the PSP, I find the "overcharge protection" claim a bit WTFy - the PSP does that itself (It has to).
Ah sod it, lets just say the claim is bogus :)
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@Anon Ymous said:
@shepd said:
TRWTFis that a really good alkaline AA battery has a little less than 2.5 watt-hours of juice. 4 of them means 10 watts. A PSP battery contains 6.5 watt-hours of power. Assuming 100% energy transfer (LOL! Not a chance in hell) you could charge your PSP 1 time fully, and another time somewhat. Four times? Not a chance in hell.
No, a typical alkaline AA has 2.5 AMP-hours of charge at 1.5V. That's 15 watt-hours in 4 batteries. I don't know anything about the PSP battery, though.
Just to make this debate about 10 or 15 watts hours in 4xAA batteries, here you go:
Battery life. Duracell Ultra Alkaline 2.31 watt hours. You can get more watt hours in some batteries, but not by much if you stick to alkaline like the ad suggested. You'll never recharge the PSP battery 3, never mind 4 times with 4xAA batteries, trust me. 1 charge will drain them completely due to ineffeciencies. The old PSP batteries were 1800 mAh @ 3.6 volts (6.48 w/h). They have only increased the storage capacity of the PSP batteries since then. I was trying to give them a fighting chance. :-)
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@Mole said:
We know that 4xAA's (non-rechargable) is 6V, we know the PSP expects 5.2V, and that the battery inside the PSP expects 4.2V.
If we assume theres a diode (such as a 1N4001), we can lose 0.7V straight away to give us 5.3V, suitable for the PSP. But, a fully (re)charged set of batteries is about 1.4V (5.6V) which would give us 4.9V, so the PSP would only be able to charge its internal battery to 70%.
You don't need a 6 V source to [re]charge a 6 V cell. Ever heard of a capacitor?
The people using mAh for their calculations are correct. You aren't.
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@Aaron said:
You don't need a 6 V source to [re]charge a 6 V cell. Ever heard of a capacitor?
What? We are not charging a 6V cell, we are powering a device which expects 5.2V DC. The device itself decides whether to use that to power the device or charge its internal battery.Putting between 6.0-6.4V into a device expecting 5V is just asking for trouble. It may take it, but over time, it may damage it as well. Thats why they say 5.2V, not "Roughly 5V".
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@Mole said:
@Aaron said:
You don't need a 6 V source to [re]charge a 6 V cell. Ever heard of a capacitor?
What? We are not charging a 6V cell, we are powering a device which expects 5.2V DC. The device itself decides whether to use that to power the device or charge its internal battery.Putting between 6.0-6.4V into a device expecting 5V is just asking for trouble. It may take it, but over time, it may damage it as well. Thats why they say 5.2V, not "Roughly 5V".
hahahaha, thats right, it decides if to charge or not depending on it's mood. Every now and then it will decide to make a cup of tea instead.
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and you can change its mood by using something called an power switch - you should look those up. It lets you choose between using the device and charging the battery.
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@Mole said:
and you can change its mood by using something called an power switch - you should look those up. It lets you choose between using the device and charging the battery.
No it doesn't
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It does on my unit. It doesn't charge unless the device itself is switched off.
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@Mole said:
It does on my unit. It doesn't charge unless the device itself is switched off.
Battery cannot be charged when the unit is on AND WLAN feature is used. Nothing here to say the power switch will not make it charge.
If it is not charging when on this suggest the Power supply does not deliver enough power(below spec on output watts) or the input power protection/converter is faulty.
