AA Battery Booster

[Silverwing]

Verizon Motorola Droid AA Battery Booster : (5 Star Rating): Google Checkout available.

Anybody know anything about this site, or this product and how it is? It look's pretty useful, to say the least.

 

[raven1911]

Wondering if you have to use alkaline batteries with this as well? Would it be possible to use rechargeable batteries with this device??

 

[kilo]

cool beans

 

[ldimick]

Guys. Do the math. AA batteries have what, 1800 or 1900 mAh? Our Droid holds 1300 or 1400? There is no way that you can get 2.5 charges out of that thing. You can get 1.3 charges or so. But it is certainly a good option. Or you can wait for the Zagg device to come back on sale. 6000 mAh for $49 yesterday. And it is completely rechargeable. and can be used on any device that has a USB charger.

 

[ldimick]

Wondering if you have to use alkaline batteries with this as well? Would it be possible to use rechargeable batteries with this device??

Yes you can use rechargeable batteries. However, they typically have a lower mAh capacity and would not be as effective.

 

[Silverwing]

Guys. Do the math. AA batteries have what, 1800 or 1900 mAh? Our Droid holds 1300 or 1400? There is no way that you can get 2.5 charges out of that thing. You can get 1.3 charges or so. But it is certainly a good option. Or you can wait for the Zagg device to come back on sale. 6000 mAh for $49 yesterday. And it is completely rechargeable. and can be used on any device that has a USB charger.

How can 4 AA batteries not charge a device 2.5 times. I do not understand your math, at all.

Using Sanyo Eneloop:

http://www.amazon.com/SANYO-eneloop...2?ie=UTF8&s=electronics&qid=1260952499&sr=8-2

That is 8,000 mAh, at almost 5 volts. charging the droid's 1,400 mAh, which is 3.7 volts. So I am really confused by your math.

Anyway, with all that said, is that merchant reliable and is this device safe? Has anybody used it, read reviews or know anybody who has used it?

Are the batteries even replaceable in this device?

 

[TheOldFart]

Guys. Do the math. AA batteries have what, 1800 or 1900 mAh? Our Droid holds 1300 or 1400? There is no way that you can get 2.5 charges out of that thing. You can get 1.3 charges or so. But it is certainly a good option. Or you can wait for the Zagg device to come back on sale. 6000 mAh for $49 yesterday. And it is completely rechargeable. and can be used on any device that has a USB charger.

How can 4 AA batteries not charge a device 2.5 times. I do not understand your math, at all.

Using Sanyo Eneloop:

Amazon.com: SANYO eneloop 4 Pack AA NiMH Pre-Charged Rechargeable Batteries: Electronics

That is 8,000 mAh, at almost 5 volts. charging the droid's 1,400 mAh, which is 3.7 volts. So I am really confused by your math.

Anyway, with all that said, is that merchant reliable and is this device safe? Has anybody used it, read reviews or know anybody who has used it?

Are the batteries even replaceable in this device?

That is not 8000 mAh at 5 volts. It is 8000 mAh at 1.3 volts if the batteries are in parallel.. If the batteries are in series then it is only 2000 mAh at 4 x 1.3 = 5.2 volts. You can't multiple BOTH the charge level and the voltage by the number of batteries.

 

[Silverwing]

Can you multiply both by two then, so two in series, two in parallel: that is 2.6 volts and 4000 mAh?

 

[TheOldFart]

Can you multiply both by two then, so two in series, two in parallel: that is 2.6 volts and 4000 mAh?

Yes, that is correct.

 

[TheOldFart]

The charger that comes with the Droid is a 5.1 volt charger. The nominal voltage of a NiMH battery is 1.2 volts and is pretty constant throughout the discharge cycle. That would make 4 in series 4.8 volts. They are available in capacities up to about 2900 mAh. The Droid battery voltage is 3.7 volts. This would indicate to me that its 1400 mAh battery could be recharged twice from completely dead by 2900 mAh batteries. Even though there is more energy in the 4 NiMH batteries because of the higher voltage, there are losses in the charging circuit. I have no idea how much though. Since it is not a good idea to allow the Driod's battery to run completely down, you could probably get nearly 3 recharges if you recharge at say 25%. That would be 2900 / (0.75 x 1400) = 2.76 recharges. I would imagine it would be somewhat less than this though.

 

[Silverwing]

So, the only question that remains is.....is this device safe and reliable? I don't want to melt my Droid =)

 

[TheOldFart]

So, the only question that remains is.....is this device safe and reliable? I don't want to melt my Droid =)

I'm not qualified to give an absolute answer, but here are my thoughts. If you use NiMH batteries then the voltage would be 4.8 volts. I don't think this would cause any problem. However, if you were to use alkaline batteries, the initial voltage could be 6.0 volts. I would be concerned about this higher voltage, but I honestly don't know if it could damage the Droid.

I would also like to hear other people's thoughts or experiences on this.

 

[mbeatle]

OldFart has already explained things pretty well, but to directly compare the two batteries on equal terms, convert each to watt-hours

Droid:
1500mah x 3.7v = 5.55 watt-hours

Eneloops:
4 x 2000mah x 1.2v = 9.6 watt-hours

I'd say you could likely get 2 full charges out of a set of Eneloops without an issue. I'm not sure at what voltage the Droid shuts off the device, but you may not fully empty the battery before it reaches the low-voltage threshold.

I'll just wait for Seidio's extended battery.

 

[Silverwing]

So, if somebody would be using 2 D-cell, 1.2 volt and 12,000 mAh like this battery Titanium D Size 12000mAh NiMH Rechargeable Battery Button Top

That is:

2 x 12,000 mAh x 1.2 volts = 57.6 watts/hour - in other words around 10 full charges for the droid?

 

[TheOldFart]

So, if somebody would be using 2 D-cell, 1.2 volt and 12,000 mAh like this battery Titanium D Size 12000mAh NiMH Rechargeable Battery Button Top

That is:

2 x 12,000 mAh x 1.2 volts = 57.6 watts/hour - in other words around 10 full charges for the droid?

2 x 12 Ah x 1.2 v = 28.8 watt-hours, not 57.6. Besides, you would need 4 batteries to get enough voltage and then that would equal 57.6 watt-hours.