Battery charging....

steloide

Hi, I have quite a few batterys from old Nokia phones, old laptops bla bla bla. I would like to charge them up and be able to use them in various projects. I have some electronic skills but obviously not enough. I have a power supply I built myself with steady 5v and a variable
0-12v and a switched 300mA or 100mA.
I was hoping it was as easy as setting the voltage and hooking it up to a battery(s) and as these are lithium ion batteries I know it's not as easy as that (or is it?)
I have checked out instructables and a few various sites for building my own charger but can't get one , still hoping I can use my power supply even if I have to modify it.
Any help or direction is much-needed and applicated.

KeithTS

Check this out:
http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries

DublinDilbert

First of all you need to identify the voltage of the battery, most phone batteries will be a single lithium cell @3.7V.

If you google you get lots of circuit for charging up these batteries, many operate of a USB adapter (ie 5V). If its just for a once off charge use a resistor (say 100 ohms) and set your power supply to 3.8V. This will charge the battery in a few hours.

If you are going to power say an arduino from a single lithium cell you will need to boost up the voltage to 5V, so you can by a step up module from ebay/adverts or just build one.

steloide

DublinDilbert wrote: »

First of all you need to identify the voltage of the battery, most phone batteries will be a single lithium cell @3.7V.

If you google you get lots of circuit for charging up these batteries, many operate of a USB adapter (ie 5V). If its just for a once off charge use a resistor (say 100 ohms) and set your power supply to 3.8V. This will charge the battery in a few hours.

If you are going to power say an arduino from a single lithium cell you will need to boost up the voltage to 5V, so you can by a step up module from ebay/adverts or just build one.

Hi. I came across this circuit it looks ideal. What do you think.

http://www.electronics-lab.com/3-7v-li-ion-battery-charger-circuit/

KeithTS

That looks spot on for charging the Li-on alright!

steloide

KeithTS wrote: »

That looks spot on for charging the Li-on alright!

I'm still a little confused though.
If I set an output voltage and set the amps on a power supply unit could i charge the battery from that? The batteries are 3.7v 2200mAh 4.4mA max , I could work out the required charge time and disconnect when needed? Correct me if I'm wrong, but isn't that what the chip is doing?

KeithTS

Typically there's different stages of charging for a Li-ion battery.
The first stage is a contsant current stage. Here the voltage gradulaly increases as the battery is charged up to a certain voltage whilst maintaining a steady current.
The second stage takes over once the voltage has hit the right point, the voltage remains the same while the current steadily decreases to a point of about 10% of the rated current.

The IC's usually top up the charge after this point and stuff and ensure you don't over charge the cell which is a bonus.

The simple answer is sticking 'x' volts across the battery until it's charged isn't really what you want to do.

KeithTS

Forgot to mention that if you want to just breadboard this then wee breakout boards are dead handy for packages such as these. I'd get the SOT-23 rather than the DFN package as DFN canbe a pain to prototype with if you don't have a pcb laid out.

http://www.amazon.co.uk/50Pcs-0-95mm-2-54mm-Adapter-Socket/dp/B00O9YZUWG/ref=sr_1_2?ie=UTF8&qid=1452094552&sr=8-2&keywords=sot23+pcb

They're just SOT-23/SOP-10 pads broken out to standard 2.54mm pins so you can solder your part onto it and it's very easy to interface with. It'll help you avoid any headaches experimenting with the part.

steloide

KeithTS wrote: »

Forgot to mention that if you want to just breadboard this then wee breakout boards are dead handy for packages such as these. I'd get the SOT-23 rather than the DFN package as DFN canbe a pain to prototype with if you don't have a pcb laid out.

http://www.amazon.co.uk/50Pcs-0-95mm-2-54mm-Adapter-Socket/dp/B00O9YZUWG/ref=sr_1_2?ie=UTF8&qid=1452094552&sr=8-2&keywords=sot23+pcb

They're just SOT-23/SOP-10 pads broken out to standard 2.54mm pins so you can solder your part onto it and it's very easy to interface with. It'll help you avoid any headaches experimenting with the part.

Brilliant....thats some good info there. You summed up what I think the recommended website was trying to explain.
Are the SOP-23/10 and DFN related to surface mount?

KeithTS

steloide wrote: »

Brilliant....thats some good info there. You summed up what I think the recommended website was trying to explain.
Are the SOP-23/10 and DFN related to surface mount?

The whole thing is a quite fiddly. I thed to use an IC in my applications and follow the typical application schematic they offer, that's never failed me.

Yes they are surface mount components. SOT23 has pins that are visible and easily soldered if you have a steady hand. The DFN package has it's pins positioned underneath the package which makes it quite tricky to solder.

steloide

KeithTS wrote: »

The whole thing is a quite fiddly. I thed to use an IC in my applications and follow the typical application schematic they offer, that's never failed me.

Yes they are surface mount components. SOT23 has pins that are visible and easily soldered if you have a steady hand. The DFN package has it's pins positioned underneath the package which makes it quite tricky to solder.

Thanks a million for your help. Have you any good sites for buying components? Aliexpress are cheap but tend to take to long.

KeithTS

For all your component needs:

http://uk.farnell.com
http://www.rs-components.com/index.html
http://www.mouser.in/
http://www.digikey.co.uk/

There's also Maplins for the generic stuff but they're not cheap.
There is an RS on Herberton Rd. so if you're on the South side you could actually pop in and grab what you wanted.

steloide

KeithTS wrote: »

For all your component needs:

http://uk.farnell.com
http://www.rs-components.com/index.html
http://www.mouser.in/
http://www.digikey.co.uk/

There's also Maplins for the generic stuff but they're not cheap.
There is an RS on Herberton Rd. so if you're on the South side you could actually pop in and grab what you wanted.

Unfortunately I live in the sticks but I'm sure most of the sites deliver.
I hope I'm not draining you but if you know where I might get PCBs made for a decent price for one off boards or would I be better making them?

KeithTS

They'll all deliver, Farnell and RS may even do next day.

I use these guys for most of my prototyopes:
http://www.printed.cz/eng/rs

They're affordable, much more so than the guys based in Ireland/UK such as pcb-pool. The setup charge is what'll make the first batch more expensive so if you're confident in your design you may be better off getting a few boards done to lower the cost per board. the site I linked lets you pop in your board details to get a rough price so you'll know if it's acceptable or not. As an example, I just put in a 125x80mm dual layer board on 1.55 FR4 and the cost was €53 for two boards including setup. shipping will be a little extra then too most likely.

Play around with quantities too as sometimes, depending on shape and size, an extra board may not affect the price or actually lower it in some cases so you end up with a freebie.

steloide

KeithTS wrote: »

They'll all deliver, Farnell and RS may even do next day.

I use these guys for most of my prototyopes:
http://www.printed.cz/eng/rs

They're affordable, much more so than the guys based in Ireland/UK such as pcb-pool. The setup charge is what'll make the first batch more expensive so if you're confident in your design you may be better off getting a few boards done to lower the cost per board. the site I linked lets you pop in your board details to get a rough price so you'll know if it's acceptable or not. As an example, I just put in a 125x80mm dual layer board on 1.55 FR4 and the cost was €53 for two boards including setup. shipping will be a little extra then too most likely.

Play around with quantities too as sometimes, depending on shape and size, an extra board may not affect the price or actually lower it in some cases so you end up with a freebie.

Thanks a million for all your help.
What is your job, Are you a company? The reason I ask is I'm in my final year Electronics and Wireless bachelors degree as a mature student and I have no ideas what my course qualifies me to do. Most do the 4th year in software or cloud as that seems to be the fashion atm. I can't afford to do the extra year and have been out of work for 5 years after an operation and now beginning to crack with no work. This is a whole new area for me, coming from construction.
I was hoping to assist maybe in the design of PCBs for laptops /PCs/mobiles/tablets or whatever I suppose.

KeithTS

steloide wrote: »

Thanks a million for all your help.
What is your job, Are you a company? The reason I ask is I'm in my final year Electronics and Wireless bachelors degree as a mature student and I have no ideas what my course qualifies me to do. Most do the 4th year in software or cloud as that seems to be the fashion atm. I can't afford to do the extra year and have been out of work for 5 years after an operation and now beginning to crack with no work. This is a whole new area for me, coming from construction.
I was hoping to assist maybe in the design of PCBs for laptops /PCs/mobiles/tablets or whatever I suppose.

I'm working as an electronics design engineer for a company that designs broadcast equipment: FM transmitters, audio processors etc.
I was in a very simialr situation as yourself and went back to college as a mature student a couple of years ago so I feel your pain.

Having an engineering degree you should be quite capable of fitting into a lot of roles. What interests you? Why did you do the specific course in the first place? What kind of stuff have you learned over the last few years?

steloide

KeithTS wrote: »

I'm working as an electronics design engineer for a company that designs broadcast equipment: FM transmitters, audio processors etc.
I was in a very simialr situation as yourself and went back to college as a mature student a couple of years ago so I feel your pain.

Having an engineering degree you should be quite capable of fitting into a lot of roles. What interests you? Why did you do the specific course in the first place? What kind of stuff have you learned over the last few years?

I'm fixing and playing with computers/phones/tablets and game console for a while which directed me the that course and I was quite interested in GSM and wireless Networks which I have learned a good bit of to date. This last semester I believe we are going into detail about 4G.
My first year project was a transformer, second was a wireless temperature sensor which was good fun working with the TX and RX. This last year is an arduino project which I haven't decided on yet! Bluetooth RC Car with WiFi camera maybe?

Your job sounds very interesting, it sounds like something I would like to do. The is also a company in Tullamore called ATSR AUTOMOTIVE CONTROL ELECTRONIC SYSTEMS. Ambulances would be a major contender for them. They design, test and fit in Tullamore which sound enticing as its just 20minutes from me. There's always Intel. It's good paying and fairly secure but something is keeping me away from that kind of job and I don't know why? (don't even know what I would be qualified to do there).

KeithTS

I wouldn't put too much pressure on what you're specifically qualified to do. As a graduate engineer I'm sure you'll have a lot of transferable skills. When i started my job I was rubbish, there's a lot of on the job learning. Speaking from my experience the course gave me a good introduction to a lot of things but I didn't know one area very well at all. When I started on the job I had the skills to pick up what I needed quickly and knew how to teach myself.