Charger for Li battery, very cheap and dirty way

[nironiro]

I am not familiar with battery chargers, and need some quick and dirty DIY solution, so any help would be apreciated.

Problem is: charger for Li battery (for photo camera) is dead.
Unfixable, to many SMD components.
Charger specs are: output = 4.2V 200mA
Li battery is 3.7V 740mAh

Can I use charger for mobile phone (output = 4.9V 700mA) for charging that Li battery?

Just to connect + and - pole from mobile chargers to Li battery?
What about third contact on battery, can I ignore it?

Thanks for any suggestion.

 

[PRR]

> charger for Li battery (for photo camera) is dead..... Li battery is 3.7V 740mAh ..... Can I use charger for mobile phone (output = 4.9V 700mA) for charging that Li battery?

Probably not. The mobile phone probably regulates charge rate internally. The phone power pack alone would over-charge the battery (BOOM!).

If you can order from Amazon or similar, chargers for most popular camera batteries are available for $15-$25. This may not be 'your' battery, but something similar:
Amazon.com : Fujifilm BC-45 Rapid Travel Battery Charger for Fuji NP45 Li-Ion Batteries : Digital Camera Battery Chargers : Camera & Photo

Yes, $23 is "a lot" of money to keep an older camera going. However I bought one for a $5 yard-sale Casio Exilim and am very pleased with the deal.

 

[rayma]

Maybe it's time for a new camera. Unless yours is high performance and expensive,
a new camera may be both better than th eold one, and cheaper than a new charger.

 

[jasonhanjk]

Go buy a battery charger from ebay. It's cheap.

 

[jjasniew]

The problem with charging Li batteries is you have to do it in an intelligent way. The third terminal tells the charger something's wrong, stop charging to avoid a fire. The battery terminal voltage cant exceed 4.2 or so - who knows what'll happen at 4.9 - fire? I recall people saying they charged these in a steel bucket full of sand out in the garage when they first came out. Best off to get a REAL Li intended charger for it - if not for the actual battery you have.

 

[kevinkr]

Incorrectly charging lithium ion batteries is dangerous, go get a proper charger for the cell type you have. Generally available from eBay or Amazon for very little. Do not exceed the rated voltage and current during charge.

 

[nironiro]

Thank you all for good suggestions, because of safety I will buy a new charger than.

Camera is old, Olympus mju 1040, nothing fancy.
New camera is not an option, because camera on my smartphone is good enough, better than this Olympus.
Reason for activating old Olympus is mainly nostalgic, and have CCD sensor, which I prefer.
Smartphone camera is CMOS sensor, very good, but colors and dark black is what I prefer on CCD.

Anyway, thanks for good suggestions from all of you guys!

 

[PRR]

mju 1040 is slightly like my Exlim. Very compact, better pictures than you expect for size and age. And YES I used my Exlim today, big bold pictures of house construction. The raw file is too big to post, here's a resize.

Anyway: If the battery has not been charged in years, you need a new battery also.

I quickly found mju 1040 battery *and* charger for UK £7.65. For 8 clams the mju 1040 is a great camera for purse/jacket or under truck seat, for when you didn't expect to need a picture. (Or don't want your picture automatically uploaded to a cloud...)
Charging Station and Battery Pack for Olympus mju: Amazon.co.uk: Camera & Photo
This particular offer will not ship to me, maybe not to you, but the stuff is out there (and looks new-made, not dusty old stock). Hunt around.

 

[kodabmx]

This might be of interest: 4 Simple Li-Ion Battery Charger Circuits - Using LM317, NE555, LM324 | Homemade Circuit Projects

 

[nironiro]

Thanks kodabmx, I will check those links too!