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External charger for mobile phone batteries

sacentre

Sep 27, 2014
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Sep 27, 2014
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Hi newbie here

I would like to build an external charger for my mobile phone batteries. My wife and I use Samsung Galaxy J4 and J7 Duo models both of which use the same Li-ion battery

Nominal voltage 3.85V = / 11.55 Wh
Charge Voltage 4.4V = / 3000mAh.

My J7 Duo came with a spare battery so it would be very convenient to have the means of charging one while using the other. Can anyone point me to a circuit or ready made module I could make or buy that would do the job without damaging or shortening the life? I would have just bought a charger but can't find anything suitable for this size and spec of battery.

TIA
Trevor
 

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Bluejets

Oct 5, 2014
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Lithium charger modules available from Ebay for around $3.00. Run on a wide range of input voltages and 3 pot adjustment facility for max voltage, max current and trip level( latter usually does not need adjustment)
How are you with basic electronics, have a multimeter???
Difficult part might be an adaptor to suit the battery.
 

sacentre

Sep 27, 2014
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Sep 27, 2014
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Thanks Bluejets
I see those but am confused as to which one would be the appropriate one. I am confident with an MM but better with mechanical stuff than with electronics. If it's not too much to ask, could you point me to the 3-pot one you have in mind.
Trevor
 

Bluejets

Oct 5, 2014
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Only have my phone at the momentbut will send details a bit later.
 

Bluejets

Oct 5, 2014
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First is the one I referred to....details are further down the Ebay page

https://www.ebay.com.au/itm/LM2596-DC-DC-Step-down-Adjustable-CC-CV-Power-Supply-Module-Converter-LED-Driver/123288297784?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

There is also one i remember I used to build a usb charger for a small portable scope.......might be easier for you to use.........actually probably better for you

https://www.ebay.com.au/itm/2PCS-5V...2406231161?epid=595263530&hash=item212812a479

As with the one above, there are some user details further down the Ebay page.
Usually find some useful info on youtube as well.


 
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sacentre

Sep 27, 2014
29
Joined
Sep 27, 2014
Messages
29
Thank you Bluejets. Much obliged for the helpful info. I'll try to do some studying up to learn how to use these modules. They're certainly cheap enough if I accidentally fry them!
Trevor
 

bushtech

Sep 13, 2016
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Just a caveat emptor.

I am using one of those TP4056 boards.
TP4056 1.jpg

I find that they take a long time to charge a 18650 battery. Might check the charging current some time to see what it actually puts out
 
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