AA battery holder to recharge smartphone?
#1
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[SOLVED] AA battery holder to recharge smartphone?
Hello,
To tour, I have a 20000mAh Aukey powerbank.
But since I picked up camping, it's possible I might not be able to recharge the powerbank often enough, especially since it takes several hours to fill it when it's empty.
As a backup, I was thinking of simple battery holders so I can just buy 3-4 AA batteries that can be found anywhere.
Problem is, the smartphone expects 5V, so neither 3*1.5 nor 4*1.5 will do.
Are there battery holders that can up/reduce the voltage to match what the phone expects? And how much mAh does each AA battery contain? The battery in my smartphone holds 2,200mAh.
Thank you.
To tour, I have a 20000mAh Aukey powerbank.
But since I picked up camping, it's possible I might not be able to recharge the powerbank often enough, especially since it takes several hours to fill it when it's empty.
As a backup, I was thinking of simple battery holders so I can just buy 3-4 AA batteries that can be found anywhere.
Problem is, the smartphone expects 5V, so neither 3*1.5 nor 4*1.5 will do.
Are there battery holders that can up/reduce the voltage to match what the phone expects? And how much mAh does each AA battery contain? The battery in my smartphone holds 2,200mAh.
Thank you.
Last edited by Winfried; 06-10-17 at 03:34 PM.
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Thanks. Apparently the Goal Zero Guide 10 Plus Recharger can be used with regular batteries:
"Yes it can. I just tested it with Kirkland AA's and a Motorola Moto X. The phone reported charging. Don't try to charge the Alkaline batteries with the charger though. Alkaline batteries and NiMH battery chargers don't mix. Also keep in mind some phones are picky about their chargers, so while I just tested it with my phone, it may not work for another phone or brand."
Before ordering, I'm interested in any real life feedback.
"Yes it can. I just tested it with Kirkland AA's and a Motorola Moto X. The phone reported charging. Don't try to charge the Alkaline batteries with the charger though. Alkaline batteries and NiMH battery chargers don't mix. Also keep in mind some phones are picky about their chargers, so while I just tested it with my phone, it may not work for another phone or brand."
Before ordering, I'm interested in any real life feedback.
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Christopher Bennett, an endurance cyclist, uses the goal zero.
https://triduffer.wordpress.com/2016...durance-races/
https://triduffer.wordpress.com/2016...durance-races/
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Those of us who toy with DIY LED projects and need to achieve a specific voltage to match the LEDs are very familiar with what you want. It is called a DC-DC step down transformer and they are dirt cheap from overseas sources. DC-DC Buck Voltage Converter 4.5-40V 12V to 5V/2A Step-down Volt Transformer*1 | eBay
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Heck I've picked them up off eBay for like $2.
This exact one in fact. I have several. They work fine. 3 weeks shipping from Hong Kong of course.
Portable AA Battery Emergency Travel USB Charger Cell Phone Power Bank Case | eBay
This exact one in fact. I have several. They work fine. 3 weeks shipping from Hong Kong of course.
Portable AA Battery Emergency Travel USB Charger Cell Phone Power Bank Case | eBay
__________________
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Work: the 8 hours that separates bike rides.
#11
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Typically AA batteries have ~1.5V * 2000mAh = 3 Wh, a typical smart phone has a 3.7V * 2000 mAh = 7.4 Wh.
An even bigger issue is that standard alakaline batteries have a linear voltage drop, so they may only discharge ~30% before cutting off, leaving you with getting maybe 25% charge. Lithium based AA batteries are significantly better but more expensive.
The best solution is using AA sized 18650 cells. Each cell is 3.7V*2500mAH so enough to fully charge a phone. This is what's used in most power banks. The solution is to buy a bigger power bank.
The only advantage that AA cells have is that they're readily available at stores. However, if you're at a place with stores then you can re-charge a phone and power bank.
An even bigger issue is that standard alakaline batteries have a linear voltage drop, so they may only discharge ~30% before cutting off, leaving you with getting maybe 25% charge. Lithium based AA batteries are significantly better but more expensive.
The best solution is using AA sized 18650 cells. Each cell is 3.7V*2500mAH so enough to fully charge a phone. This is what's used in most power banks. The solution is to buy a bigger power bank.
The only advantage that AA cells have is that they're readily available at stores. However, if you're at a place with stores then you can re-charge a phone and power bank.
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Thanks for the infos.
I already have a 20,000mAh powerbank, and it takes over 12hrs to fill it from empty. In case I can't and am stuck with an empty phone when I get to a camp site, I was looking for a solution to simply recharge my phone with off-the-shelf AA batteries that can be found everywhere.
Looks like it's just no feasible. I'll get a lighter, single-charge powerbank: [strike]Are there powerbanks that use a higher voltage than 5V for faster recharging?[/strike] Yes, although they seem to be big, heavy powerbanks.
I already have a 20,000mAh powerbank, and it takes over 12hrs to fill it from empty. In case I can't and am stuck with an empty phone when I get to a camp site, I was looking for a solution to simply recharge my phone with off-the-shelf AA batteries that can be found everywhere.
Looks like it's just no feasible. I'll get a lighter, single-charge powerbank: [strike]Are there powerbanks that use a higher voltage than 5V for faster recharging?[/strike] Yes, although they seem to be big, heavy powerbanks.
Last edited by Winfried; 06-09-17 at 04:02 AM.
#14
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Why not a folding solar charger? They work pretty well. Of course, you need to be in daylight, but they even work on cloudy days.
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But then, if the AA batteries stop at 1/3 of a total charge when I wake up the next morning, it's not what I had in mind.
As for solar panels, I was told they're more of a gadget than a real solution. Besides, they're a lot less pratical than an empty charger with AA batteries.
As for solar panels, I was told they're more of a gadget than a real solution. Besides, they're a lot less pratical than an empty charger with AA batteries.
#17
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But then, if the AA batteries stop at 1/3 of a total charge when I wake up the next morning, it's not what I had in mind.
As for solar panels, I was told they're more of a gadget than a real solution. Besides, they're a lot less pratical than an empty charger with AA batteries.
As for solar panels, I was told they're more of a gadget than a real solution. Besides, they're a lot less pratical than an empty charger with AA batteries.
There are others like this with even more power. It still isn't practical on a bike as you'd need to have a way to mount it, I guess on the rear rack and open since I'm assuming this would only be used on long touring rides.
All that said, I've never tried one myself as overnight touring/camping isn't my thing. I prefer a hotel, bed and shower.
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Thanks. A solar panel is too big/heavy for my folding bike. A second external battery would be lighter and simpler.
I'm new to camping. I also used to only consider hotels, but camping makes it possible to plan tours that would otherwise not be possible, or require detours/longer days. Besides, campsites do provide showers, and sometimes power as well.
Conclusion: I'll have to either add more stops at hotels so I can charge the Aukey overnight (about 10hrs @ 2A), or pack a second, smaller external battery as backup. Or consider adding a Shimano dynohub.
I'm new to camping. I also used to only consider hotels, but camping makes it possible to plan tours that would otherwise not be possible, or require detours/longer days. Besides, campsites do provide showers, and sometimes power as well.
Conclusion: I'll have to either add more stops at hotels so I can charge the Aukey overnight (about 10hrs @ 2A), or pack a second, smaller external battery as backup. Or consider adding a Shimano dynohub.
Last edited by Winfried; 06-10-17 at 07:32 AM.
#19
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Typically AA batteries have ~1.5V * 2000mAh = 3 Wh, a typical smart phone has a 3.7V * 2000 mAh = 7.4 Wh.
An even bigger issue is that standard alakaline batteries have a linear voltage drop, so they may only discharge ~30% before cutting off, leaving you with getting maybe 25% charge. Lithium based AA batteries are significantly better but more expensive.
The best solution is using AA sized 18650 cells. Each cell is 3.7V*2500mAH so enough to fully charge a phone. This is what's used in most power banks. The solution is to buy a bigger power bank.
The only advantage that AA cells have is that they're readily available at stores. However, if you're at a place with stores then you can re-charge a phone and power bank.
An even bigger issue is that standard alakaline batteries have a linear voltage drop, so they may only discharge ~30% before cutting off, leaving you with getting maybe 25% charge. Lithium based AA batteries are significantly better but more expensive.
The best solution is using AA sized 18650 cells. Each cell is 3.7V*2500mAH so enough to fully charge a phone. This is what's used in most power banks. The solution is to buy a bigger power bank.
The only advantage that AA cells have is that they're readily available at stores. However, if you're at a place with stores then you can re-charge a phone and power bank.
You also want to pay attention to the ( output ) charge rate of the power bank. Keep in mind that you are probably only going to get maybe 500ma ( output ) out of anything using AA cells. Compared to a standard 18650 power bank ( 1000-2000ma ) that is a very slow charge rate. If you find one using 6-8 AA cells and it charges at 1000ma. I'd go with that. Sadly, after doing a quick search, I'm not seeing any AA power banks using more than 4-cells.
Now as for replacement AA's...you can buy standard Lithium ( non-rechargeables ) AA cells but generally I don't see these being sold in typical stores like CVS, 7-11, etc. The lithiums would give you more watt-hours but cost a whole lot more.
Last edited by 01 CAt Man Do; 06-10-17 at 11:21 AM.
#20
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External battery things made for extending run time and recharging phones have gotten pretty cheap of late.
look around. they're USB powered, a mains to usb plug is cheap too..
top up your phone during lunch .
look around. they're USB powered, a mains to usb plug is cheap too..
top up your phone during lunch .
#21
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Indeed, lithium batteries are harder to find, and more expensive (€ = euro).
So, for the time being, I'll just stick to my 20,000mAh Aukey powerbank, and plan stops accordingly.
Thanks everyone for the input.
So, for the time being, I'll just stick to my 20,000mAh Aukey powerbank, and plan stops accordingly.
Thanks everyone for the input.
#22
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Like you said, best to try to use the good Li-ion power bank you have as much as possible. If you get in a situation where your phone is down to say 20% power and you don't know when you might get access to line voltage and your Li-ion bank is almost dead, that would be the time to use the AA bank. Turn the phone off and plug in the AA charger. Keep in mind it will take a very long time to charge a phone with only a 500ma input current. During that time try not to use the phone if you can. Once you get access to line voltage hopefully you can charge both the phone and Li-ion bank at the same time.
#23
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Having more precautionary mindset, perhaps the safe Haz-Mat disposal costs are built into the sales price..
#24
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One option is using a small solar panel to re-charge a USB pack. They have limited charging capability, but it's very easy if you have a fixed camp site.
#25
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I recently bought an external battery from Amazon:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
With this thing I can fully recharge a smartphone 4 times. The battery itself can take as much as 12 hours to recharge.