Powerbank that can continuously power an Android smartphone

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AC Question

I am building an asset tracking device based on an old Android smartphone and a power bank (i.e. a battery bank with a USB port). I want the phone to last for a week or two, sending GPS coordinates over mobile network. I want to leave the phone permanently plugged into the external power bank, hoping that the power bank would power the phone as long as it has charge, then the phone should revert to using its internal battery and last another two-three days.

I got a 20,000Mah power bank, but it has a feature that detects that the phone stops charging (i.e. stops drawing current from the bank and goes into trickle charge mode) and the power bank powers itself down. So, in effect, I am only getting one charge out of the power bank. To make it charge the phone again I would have to hit the power button on the power bank, but I can't do this since I want to leave the phone unattended.

Does anyone know whether all power banks have this "charge complete" detection electronics? Any ideas how I can do what I want to do?
 

Rukbat

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Feb 12, 2012
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I know for a fact that they don't - but the Coocheer that I reviewed (which can stay on indefinitely even after the phone is fully charged) is only 7500mAh.

You could butcher the one you have (figuring out the "charge complete" circuit and defeating it) or ask all the manufacturers of large enough power banks if theirs will stay on after the phone is completely charged. (If they won't answer your email to get you as a customer, they sure won't if you have a problem later. And if you're building more than one, they're being foolish if they lose your business.)
 

Rukbat

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I usually don't post reviews of things that are "like that", because the people asking me to do the review don't like what I write if they send me garbage. Like the Bluetooth speaker with a jack to plug directly into the phone if you want to use it wired. The first time I plugged in a patch cord, the jack came off the PC board. (It's an easy fix if you have a soldering pencil on your computer desk ... but few people do). You won't see a review of it here, and I won't mention the vendor. If I post a review, it's usually because I'm at least a little bit impressed by the product, and I'm not easy to impress. The Coocheer really impressed me - it feels like a brick. (I've been "wearing" it in my pocket for the past 3 weeks now, knocking into things, and the only thing that suffered was one pair of jeans - not the powerbank.)
 

Wingerr

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I am building an asset tracking device based on an old Android smartphone and a power bank (i.e. a battery bank with a USB port). I want the phone to last for a week or two, sending GPS coordinates over mobile network. I want to leave the phone permanently plugged into the external power bank, hoping that the power bank would power the phone as long as it has charge, then the phone should revert to using its internal battery and last another two-three days.

I got a 20,000Mah power bank, but it has a feature that detects that the phone stops charging (i.e. stops drawing current from the bank and goes into trickle charge mode) and the power bank powers itself down. So, in effect, I am only getting one charge out of the power bank. To make it charge the phone again I would have to hit the power button on the power bank, but I can't do this since I want to leave the phone unattended.

Does anyone know whether all power banks have this "charge complete" detection electronics? Any ideas how I can do what I want to do?
Is this being used in a vehicle with 12V power available or does it have to be battery powered only?
I bought an inexpensive battery bank that uses 18650 batteries that supplies power continuously without shutting down output; with four batteries, it would have over 12000 mAh capacity.
I use it to make use of old laptop battery pack cells and as a charger.
Thanks, I've orderd the Coocher 7500 bank. Should be good enough for a proof of concept. Good to know they are not all like that. :)
 

chanchan05

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Nov 22, 2014
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Bavin power banks automatically detect a phone that needs charging to. They stay on even when the phone is full, but it's not actively charging. They have an 18000mah, 12000mah, 10000mah, 9000mah, and some else.