I have a query about the charging process of batteries... Especially cell phones.. I've seen chargers that have an output of say 5V and 300mA... I wanted to know what would happen if i gave a supply of 5V and 100mA.. Would the battery stop chargin or would it jus charge slowly... Thanks
If the voltage goes down than minimum voltage required by phone to recharge its battery, The phone may not accept the charger or it simply would not charge the battery. For example most of the phones made by SONY ERICSSON won't accept a charger with different voltage or current levels other than specified for a specific phone model. I have seen even chinese made cell phones can not charge their batteries at lower voltage levels other than specified for each model.
As for as the damage to phone by low voltage is concerned, i am not sure but seems not to be a risk in every case.
The worst thing you can do to batteries is to let them sit discharged for long periods. With too low input, the battery will discharge, even though the appliance still is running off the charger. In days to a few weeks, the battery will need replacement.
I don't think so. The problem is when you apply a higher current for charging. I have made homemade battery packs with miscellaneous rechargeables and to be safe, I put a 10 ohm resistor in series to limit my PDA charger output, which is good enough, the batteries don't get hot and the charging is more stable.
I've made the mistake before, charging 300 mA ones using a 5V, 1A output charger, the battery's quality dwindled overnight.
A Li-Ion battery is very dangerous if it is charged or discharged wrong. It will catch on fire with a very hot white flame like magnesium. Water on the fire makes it burn hotter.
Look on the web for instructions on how to charge and discharge a Li-Ion battery. www.batteryuniversity.com has the instructions.
Vizier, to start your charger looks very ghetto... i like it it looks like something that i would make. On the subject of Li-ion batteries, it's no fun unless it catches on fire i saw a video from the AMA one time warning about this exact thing. but the big difference is that Li-ion batteries are lighter than NiCD or NiMH batteries (i think that they said that they can deliver more current or something to that effect). i do have one question though, if a Li-ion battery catches on fire, what's the best way to put it out?
Depriving a lithium reaction of oxygen will stop the fire, it will not stop the exothermic chain reaction if one already exists. Meaning it'll still get hotter than sin, and if you uncover it before it cools it'll explode. The best way to put out a lithium fire is with a dry chemical or C02 extinguisher.
One does not figure the charge and discharge currents for a lithium battery. You get this information from the maker of the battery. Aside from generic voltage warning with Lithium cells it depend entirely on the cell construction and chemistry.
Well, I'd like to gloat... Thanks for the compliment.
The white tubular structure is just actually out of a ballpoint pen, I inserted the wiring into a small hole drilled at a side of the tube. Then I soldered the joints with the pins, and pulled the wire back into the tube into a nice fit, some epoxy glue, and voila! You'd have to indicate the terminals though.