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Using a LiPo battery from sparkfun is easy as it comes with a molex connector on it. enter image description here

But how to conveniently connect to a LiPo battery taken from a cellphone? enter image description here

Soldering doesn't work on the exposed terminals of the battery.
I've tried to tie up with sticky tape and thread and glue, but its very unstable/unusable, a slight vibration ruins the connection.

Does anyone here know a better/convenient/stable way of connecting such battery to a circuit?

INFO: I wish to use this battery to power up my breadboard circuits.

vyi
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    Mill-Max 821-22-003-10-002-101 and a box made of PCB. – Ignacio Vazquez-Abrams Jan 01 '15 at 12:20
  • @IgnacioVazquez-Abrams That would make a clean and simple connection, the same way they are used inside the cellphone. It should be available at the cellphone spare shop. I'll try it. – vyi Jan 01 '15 at 12:35
  • Why doesn't soldering work to the battery terminals work? I've done it a bunch of times when I needed to hook up cell phone batteries to my test board. You have to be quick so you don't damage the terminals and protection circuit behind there. – Vince Patron Apr 25 '16 at 19:23
  • You will also need the protection circuitry. Doesn't look as if the second battery, the one you wish to use, has that, I guess it relies on the phone to do that? – Alex Jul 29 '16 at 09:34

7 Answers7

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The only way to connect those batteries properly is using spring loaded contacts, because you have to apply steady force to maintain low contact resistance.

There are manufacturers out there, who make such contacts like Kitagawa. But to make it work instantly you can make a spring contact yourself. For me it works properly. My Phone's USB-connector is wrecked, so I have to load it this way:

My loading setup

My battery

Connector detail

You may add something to align battery and contacts better. A handfull of nails or screws will do fine.

Ariser
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  • (+1) Your approach is pretty doable at home. I am trying to make a bit more mobile arrangement. – vyi Jan 03 '15 at 12:53
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What has worked very well for me is to buy a cheap universal cell phone battery charger, then gut it to use the case and connector. They are very cheap on eBay, Amazon etc. For example, below is a photo of one that costs $1.69 on eBay (including shipping). Browsing the various commercial products also gives ideas if you wish to build your own. Searching on "Universal Cell Phone Battery Charger" will find many different designs, most quite inexpensive.

Note: Be careful if you decide to use the cheap CC/CV Li-ion chargers in such units. I've seen some terminate the charge at too high voltage.

enter image description here

Bill Dubuque
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Adding to other answers:

You can make spring loaded contacts using "pogo pins" - test pins made for bed of nails testing. These have contacts which come in various styles including needle point and wider flat circular contacts and these push into a spring loaded base which can be soldered into a carrier of your choice (Vero board or PCB or ...).

Many examples of pogo pins in use with some good (and bad) DIY examples.

Wikipedia - pogo pin

Probe and spring alternative

Rather nice (looking) low profile versions. Source unknown (so far).
From here

http://i01.i.aliimg.com/photo/v0/152605471/pogo_pin.jpg

Typical DIY use](http://www.makerdyne.com/blog/wp-content/uploads/2013/06/Pogo-[Pin_Breakout_Board_Tester_08.jpg)

Stack Exchange related Q&A with some good examples of pp styles & use

For sale fom ADAFruit

Various styles with video related to that image.

enter image description here

Some very nice3 looking low profile examples from here.
Expect to pay as a factor of niceness^n.

enter image description here

Community
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Russell McMahon
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A much simpler version would be right angle headers on a pcb. They used a female header as a back stop. So these are friction fit.

enter image description here

If you don't have right angle headers, you could bend some regular ones.

Passerby
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There are a whole load of connectors for sale on AliExpress: http://www.aliexpress.com/cp/phone-battery-connectors-online-shopping.html

Otherwise I think a couple of protuberances made of solder on a small piece of stripboard might be held in place with an elastic band. I might do this soon and take a picture to illustrate what I'm trying to convey (or I might forget about it altogether).

Edit: Okay, the protuberances of solder didn't work but I made some contacts out of bent wire (e.g. from electronics component legs or sewing pins with the ends clipped off) which I soldered onto the stripboard and held on with an elastic band. I can shake it around pretty vigorously without the contacts breaking but if anything were to physically nudge the contacts then they might separate.

Metal wire in stripboard creates contacts for mobile phone battery Metal wire in stripboard creates contacts for mobile phone battery

user20221
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dyi spring loaded connector

This is my version of the spring loaded connector. The cables are from jst connector. I bend the pin to make it just like the connector inside the phone.

The battery is from a camera and I just need to charge it then put it back to the camera, so I cannot solder it.

After the connector firmly held by the clamp, I charge it with my b6ac charger.

Donny Kurnia
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Ok, here's my offering. The "basic" version is made from the 2 solid cores from a 20cm piece of "twin solid core" cable. I used wires with a cross-sectional area of 2.5mm² (approx 1.8mm diameter or 14 AWG) because it is a "standard" domestic cable size in the UK, but I'm sure you could use a lighter/thinner wire instead. Each wire is held in place by 2 black plastic P-clip cable clamps (3.3mm to accomodate the wire insulation), and the natural rigidity (springitude?) of the wire keeps the ends pressed against the battery terminals. I attached a zinc-plated "mending plate" to the back board to keep the battery in place, thus:

Basic version

I then modded each "wire-end" into a "Kelvin probe" by just soldering on the 2 relevant wires:

Wire-ends converted to Kelvin probes

Now I can use my rig for accurate 4-wire battery testing and internal resistance measurement using my Zhiyu ZB206+ battery tester, thus:

4-wire battery testing using DIY Kelvin probes

HTH.

jaimet
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