Author Topic: How to prevent accu power banks from turning off on devices with low current?  (Read 31123 times)

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Offline RodastTopic starter

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Hello All,

I have several power banks and use them with a lot of different devices.

All of the ones I own from Anker and EasyAcc power off automatically when a connected device is fully charged and also when a connected device does not draw enough current.

This means I cannot charge my bluetooth headset or gps navigation system on the go and also can't power a bluetooth speaker I own.

With the larger power banks I found a workaround by plugging an usb stick into one of the additional ports.

Unfortunatly this does not work with power banks that only have one outlet.

I have a short USB extension cable lying around here which I could take apart and wonder if I could tune and use it for those devices that only draw less than 50mA when they are connected.

An idea how to do this without altering the voltage delivered by the power bank and without draining too much battery life over time?

Best regards

Rodast

 
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Offline Mr Smiley

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What is the minimum load that prevents the unit from switching off  :-//

 :)
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Offline RodastTopic starter

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It was a bit hidden in my previous text :-)

As the devices shut down with a load smaller than 50mA I have to get it above that.

So to be on the safe side create a 50mA load would keep the power packs from switching off as soon as I connect the device I want to use.

 

Offline kingofkya

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I remember something a while back i think adafruit but i don't remember where they had a micro periodically trigger a fet with a resistor to short the supply to get it register that a device is connected.

The other option at lest on the one i have is to tape the power button down:)
 

Offline NiHaoMike

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Large cap (1000uF or so), P channel MOSFET, and low frequency oscillator. Connect the large cap across the load, then have the MOSFET switching power such that the internal diode would conduct when the MOSFET is off.  Have the oscillator switch the MOSFET off for half a second or so every 30 seconds or so. Very little extra power use.
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Offline HKJ

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All of the ones I own from Anker and EasyAcc power off automatically when a connected device is fully charged and also when a connected device does not draw enough current.

Get one that does not power off at low load, you can always check http://www.lygte-info.dk/info/indexUSB%20UK.html for technical reviews, where this kind of information is present.
 


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