Found Two Batteries For Pandora?

[borgqueenx]

I have searched for some backup batteries for pandora and my other gadgets and found this:
http://www.dealextreme.com/search.dx/search.20000mah

Click the link and you'l see two 20.000mah batteries. I dont know if they are any good, like true mAh capacity and if they will be capeable of charging my pandora and iphone 3gs.
One batterie even states 6000mah and 20.000mah so im really confused.

I want to buy a good backup battery for not more then 140 dollars, with a large capacity and capable of charging both my iphone and my pandora for when im wildcamping

 

[Dead1nside]

I think 4400Mah will do me fine. Nice that you can get large batteries like that though.

 

[borgqueenx]

with wildcamping you dont have any power around. and playing some pandora/iphone games and taking pictures and notes on the go is nice.
20.000mah would be nice. it thats a true capacity i can charge my iphone 3gs 16 times with that. and charge pandora 5 times.

 

[Consequence_9]

none of those are really the mah they claim to be, trust me, i've looked thru all the ones on dx. There is a real 18,000 mah one available from energizer here. it is pretty expensive ($179 usd) but at least you're getting what you pay for.

 

[Tor]

When I'm wildcamping the only electrons nearby will be an emergency flashlight. Everything else done by passive hardware, clothing and a magnetic needle.

 

[Gary13579]

they're all fake hun

if you'er truly wildcamping you won't want any electronics with you, ut if you have to bring it are you best off with a solar charger or a harger that hooks up with your car battery.

 

[borgqueenx]

none of those are really the mah they claim to be, trust me, i've looked thru all the ones on dx. There is a real 18,000 mah one available from energizer here. it is pretty expensive ($179 usd) but at least you're getting what you pay for.

i have the experience with DX that they sell alot overrated batteries, but also the experience you get what you pay for.
20.000mah is 140 dollar. that sounds it could be genuine.

but did you test any of those 2 batteries?

 

[Consequence_9]

none of those are really the mah they claim to be, trust me, i've looked thru all the ones on dx. There is a real 18,000 mah one available from energizer here. it is pretty expensive ($179 usd) but at least you're getting what you pay for.

i have the experience with DX that they sell alot overrated batteries, but also the experience you get what you pay for.
20.000mah is 140 dollar. that sounds it could be genuine.

but did you test any of those 2 batteries?

No, but it's common-sense when dealing with chinese electronics. Fake SD cards (among other things) are often sold at full-price nowadays. These things are easily faked, and even if they aren't the build quality is often sub-par. Batteries are an especially big gamble; cells are often recycled & thus have a short life-span and a much greater chance of being faulty. Li-Po is especially nothing to mess around with; if faulty there can be explosive results. IMHO you'd be better off just paying the premium to guarantee you're getting a high-quality product with a substantial life-span.

 

[borgqueenx]

none of those are really the mah they claim to be, trust me, i've looked thru all the ones on dx. There is a real 18,000 mah one available from energizer here. it is pretty expensive ($179 usd) but at least you're getting what you pay for.

i have the experience with DX that they sell alot overrated batteries, but also the experience you get what you pay for.
20.000mah is 140 dollar. that sounds it could be genuine.

but did you test any of those 2 batteries?

No, but it's common-sense when dealing with chinese electronics. Fake SD cards (among other things) are often sold at full-price nowadays. These things are easily faked, and even if they aren't the build quality is often sub-par. Batteries are an especially big gamble; cells are often recycled & thus have a short life-span and a much greater chance of being faulty. Li-Po is especially nothing to mess around with; if faulty there can be explosive results. IMHO you'd be better off just paying the premium to guarantee you're getting a high-quality product with a substantial life-span.

the weight of the battery also seems to be genuine. but il keep your advice back in my mind, thanks will look futher.

 

[Squidge]

Note that it says the battery is 20,000mAh (20Ah), but doesn't state voltage. That means the mAh figure is useless.

Amps is useless on its own to calculate energy. So is voltage. You need Wattage, which is Volts*Amps.

Amps will always increase as voltage decreases.

 

[cbox]

I got some 2800 mah rechargeable AA's on ebay, they turned out to be 800 mah, so buyer beware with any of these Chinese companies.

 

[laurencevde]

Those batteries have a variable output-voltage, but don't specify at which voltage they provide the specified mAh... Rating the capacity in Wh (watt-hour, energy) is much more useful (remember, Wh=Ah*V)
Without a voltage, it can just as well be the amount of mAh at 0,1V...

For the first one, let's assume the 20000mAh is for its lowest voltage, 4,2V. It should then have 84 Wh. That'd be 16800 mAh at 5V. Other stores (it's back-label says it's an apc-20000)tell me it's only 74Wh...

The second one's specs also don't add up: it specifies 66,6Wh, which equals 13320mAh at 5V, 4162,5mAh at 16V, or 3505mAh at 19V, its 3 supported voltages. Now how did they ever come up with 20000mAh or 6000mAh??? ...

 

[dflemstr]

ignore me...

 

[Trevsweb]

if you want to buy something that blows up when you turn it on buy from buyextreme... seriously only dodgy crap from there... funny but crap

 

[Tokiopop]

There are some good things (DS Lite replacement cases, for example), but the batteries are probably some of the worst things you're going to find on there. Trust me.

 

[Yoyobuae]

For the second battery I think it's like this:

• The per-cell nominal voltage is 3.3V
• The rated capacity is calculated using the cell nominal voltage: 66.6Wh / 3.3V = ~20000mAh
• Three cells are chained in series in the actual battery assembly
• The capacity measured from the three in-series cells would be: 66.6Wh / 9.9V = ~67000mAh

Differences in voltage change the meaning of the mAh. Also its necessary to add the limited efficiency of the power supplies involved in the process. Also lithium batteries have a 80-90% charge/discharge efficiency. Pandora's battery has a nominal voltage of 3.7V.

Putting it all together:

• Assuming the backup battery can output 66.6Wh in total into the Pandora
• Ignoring the unknown potential losses from power supplies at the backup battery and Pandora
• Assuming the Pandora battery recieves 66.6Wh at the nominal average voltage of 3.7V: 66.6Wh / 3.7V = 18000mAh
• Assuming worst case losses during the charging process: 18000mAh * 80% = 14400mAh

So thats around 3 and a third times that the Pandora battery could be fully charged with this backup battery. If the losses in the power supplies are significant, that might reduce to 3 times flat instead.

Hmmm, at least the Energizer guys are a bit more honest about their mAh ratings:

Specifications
[*]Battery Cell: Lithium Polymer
[*]Power Capacity: 18000 mAh @ 5v
[*]...

I just wonder if that is measured from the output of the 5V port? (ie. including the losses due to power supply).

 

[Consequence_9]

I just wonder if that is measured from the output of the 5V port? (ie. including the losses due to power supply).

I'm sure it is. I mean it's energizer, not some shady chinese no-brand.

 

[metallurge]

As far as a reasonably-priced general-purpose portable power source, I have one of these, and I have been pretty happy with it. And, of course, it has other functionality as a bonus. It's pretty well made for what it is.

 

[Trevsweb]

As far as a reasonably-priced general-purpose portable power source, I have one of these, and I have been pretty happy with it. And, of course, it has other functionality as a bonus. It's pretty well made for what it is.

lol nice and portable. but no ammount of duct tape will stick that to the back of my pandora

 

[metallurge]

lol nice and portable. but no ammount of duct tape will stick that to the back of my pandora

True, that. I figured that, for the price, if you need truly portable, you just buy some extra internal batteries, however many you need. They are not unreasonably priced.