Recharge.IT – Samsung phone batteries

What happens when you are trying to fix a Samsung phone but the battery is flat, and won’t charge in the phone – for various reasons? Of course, find an identical working phone – put the battery in and charge it on that phone.

A while ago, my brother gave me a Samsung Galaxy S2 to look at. The touch-screen wasn’t working, and also the battery was flat. I also have a S2 but his battery also wouldn’t charge in my phone, so I put that aside. I opened up his S2 and was able to locate the display cable, which I think also included the touch-screen – so when I removed that connector and plugged it back in, the touch-screen started working again, so he got the phone back minus the battery.

Some time later, he gave me a Samsung Galaxy S3 to look at. This one had just stopped and would not boot up. It powers up but then stays at the Samsung Galaxy SIII GT-I9300 screen. I wrote about it here.

I have the battery for the S3 here still, so I thought about charging it. If the phone doesn’t boot up, then it will not charge the battery – very unlike a laptop. While doing a few Google searches, I came across mention of a TP4056 chip that would charge Lithium batteries. On eBay, these are very cheap – so cheap, that I ordered a few, as in five. I have this idea of getting those Lithium cells, like the 16550’s and converting everything to use Lithium instead of NiCad etc.

Of course, not everything works from 3.7 Volts, so I also ordered a few DC-DC boost converters, which will take the 3.7V and get 9V or even 12V etc. Again, not everything wants 5V, so for some things, it might like 3.3V so I also got some DC-DC buck converters. Oh, wouldn’t it be nice to have boost-buck converters?

In converter nomenclature, boost means to get higher voltage, and buck is to get lower voltage – from the input voltage – got? A boost-buck converter would be able to take any input, within reason and produce any output – within certain limits of course. They are available, but not as cheap as the boost or buck converters. Anyway, I am getting off topic.

So, these TP4056 chargers came in eventually. They can take an input voltage and produce up to 4.2V to charge a lithium cell. The charger also has a mini-USB connector on it, so I plugged in my GPS charger that can output 5V at 1A and tried it out.

I made a little jig to fit the battery and some copper wire, sort-of spring loaded to connect to the battery terminals, then used a couple of jury-rig wire clips to connect the battery to the charger. The TP4056 is set to charge at 1A which should be fine, since most phone batteries are more than 1Ah in size.


Jury rigged lithium battery charging system

The S3 battery charged ok, even though it is a 3.8V Lithium-Ion battery. Now I have a fully charged S3 battery – what do I do with it, ok – later. I thought I would try the dead S2 battery, so I connected that one, and to my surprise – it started charging. I had previously tried to charge that battery with a specialized battery charger that could handle lithium batteries, but it had failed to charge.

Now, those of you who are know something about lithium batteries will say that this won’t fully charge a 3.8V battery. Of course, the end-point full charge of a 3.8V lithium battery will be about 4.35V whereas the 4.2V is for a 3.7V lithium battery – I certainly agree, however the difference in charge level is only small – perhaps 90+% of charge, and not 100%.

Let me tell you a little secret, which most of you know anyway. A lithium battery has a certain lifetime – defined as the number of full charge cycles. Let us say, for instance that it is 1000. Most of us, will need to charge the phone almost daily – which means that in about 3 years, if we left it to charge overnight, and in the morning – the phone was fully charged, that is a charge cycle. I didn’t finish, in about 3 years or so, the capacity of the battery will be diminished – it may start to happen in 2 years, and if you are lucky, in 3 years or so. By then of course, most people have already upgraded the phone.

So if everyone knows this, how is it a secret? The secret is – what if we don’t fully charge the battery? I.e. for a 3.7V battery that has a full charge voltage at 4.2V – what if we charged it only to 4.1V – and similarly for a 3.8V battery that has a full charge voltage at 4.35V, what if we only charged it to 4.2V? We actually wouldn’t be using up charge cycles – it’s like driving without the odometer clicking over. Theoretically, that battery would still be in top condition even after 10 years! The reason is business – we want you to replace the battery, so that we can sell batteries. We want you to replace the phone since it is getting old, and the new phone can run a lot more apps than the old one. It is just that simple.

Remove.IT – failed bulging lithium battery from Mio C520 GPS

Last night, we went for a drive into the city as my wife wanted to visit a couple of friends from China. My car had been parked outside in the sun and my GPS mount had come off the windscreen. As I was remounting the GPS, I found that the GPS was bulging where the battery is situated – not a good sign, as it means that the battery is failing and could explode any minute.

Ok – maybe not necessarily, but it is possible – it didn’t explode on the way to the city and it didn’t explode on the way home, so after getting home, I took the GPS back into the house with me. It was a Mio C520 GPS which was bought in December 2007 before our family holiday driving down to Melbourne for the new year. I had replaced the battery in June 2009 after its capacity went very low, like a few minutes.


Mio C520 with original battery

This is the original battery.


Mio C520 with failing, bulging battery

This is what it looks like now. Lithium battery can swell up, due to increase in gas pressure – which can happen due to over charging or due to internal failure. Most reputable lithium batteries come with an overcharge protection circuit – the problem is that over time, and due to heat, that this protection circuit may fail to be effective and the end result is a battery that starts to swell up like a balloon that can eventually pop with disastrous results.

Normally there is no metallic lithium in these batteries, however during overcharging, the metallic lithium may accumulate on the anode faster than it can be dissipated – and can anyone remember high school chemistry where the teacher cuts off a piece of lithium metal and drops it into a pan of water? If not, I will remind you – lithium reacts intensely with water, forming lithium hydroxide and hydrogen gas – the result means a bright flame if the amount of lithium is small – that is why you don’t want to puncture the battery – even though you can feel that it is like a balloon, there is a reason why it is sealed to avoid ingress of humidity, i.e. water in air.


Battery from Mio C520

Ok – after removing the battery, this is what it looks like – before I put it somewhere safe in my garage.

What should I do? Order a replacement battery or get a new GPS? This battery lasted more than 6 years, whereas the original battery only lasted 1.5 years. This Mio C520 GPS does not have upgradeable maps, so there are places in Western Sydney that I cannot navigate to because it doesn’t have the street maps. The cheapest replacement battery I can get is from Netherlands for $15 or from China for $18. There are a number of GPS’s like Garmin, TomTom and Navman available with free lifetime maps for under $200, so question is new battery or new toy?