Guys could you help me about charging batteries ^^

[slashx15]

I am currently doing a project regarding rf harvesting battery pack...

My question is how can i make my charger stop if the battery is full?

transistors? limit switch?

What battery to use? Li-ion? Ni-MH? Li-Po? etc?... < i'm planning to charge stuffs like psp, iphone, ipod and mobile phones>

how much battery capacity should i buy?

Tnx in advance ^^

 

[sreepss]

if ur trying to make charger for portable applications.. Li-Ion is the perfect selection.. But the charging methedology for charging this type of battery is little complex... bcoz the Li-ion battery required very sensitive charging... many monolithic chips are available for this purpose.. just go to National Semi or texas instruments.. u shud get many options from there... and ur design is much more easy

 

[slashx15]

if ur trying to make charger for portable applications.. Li-Ion is the perfect selection.. But the charging methedology for charging this type of battery is little complex... bcoz the Li-ion battery required very sensitive charging... many monolithic chips are available for this purpose.. just go to National Semi or texas instruments.. u shud get many options from there... and ur design is much more easy

Will it be better than Lithium Polymer? hehe i was wondering if you could give me a sample schematic diagram tnx^^

 

[sreepss]

I'm not sue about Li-Pol chemistry.... But in most of the app's Li-ion was proscribed... its why because, it can provide more power for a shortest period(In case of GSM apps, the GSM module need more power during transmission )this link may help u to understand the charging methodology



here s d schematic for charger(Using charger controller IC)

 

[kcyang]

Hi Slashx15, Maxim also makes good lithium ion battery charger chips. Look for MAX8922L, MAX8600A, MAX8903x, or MAX8808.

As far as I know Li+ and Li-poly batteries are very similar and charging them are the same. After you build your charger, it is more convenient to test charger circuit using a battery simulator then a real battery, because you can vary the emulated battery voltage easily as oppose to waiting hours for the real battery to charged.