How to Design a 29.4V 4A Charger Circuit for Lithium Ion Battery Packs?

PLEASE HELP ME FOR DESIGNING  CHARGER

Hi Ashish-Please give us more information to go on and we'll try to help.29.4 volts is sort of an odd voltage.  What will this charger be used for?  What is the input voltage?  will there be a load on the battery while it is being charged?-Rick

Rick... 29.4V is 7 Li cells at 4.2V (ie fully charged).    But I agree, without any idea of capacity, load, source power  etc we don't have much to go on.

DC Motors commonly use this voltage, you will come across them in things like Lazyboy chairs, and there ilk. So there are quite a few battery packs and chargers around for this sort of spec (maybe around 2-3 amps) appearing on the market as add ons for these types of chairs. I am looking at them at present, since my wife is disabled, and can't afford to get stuck in a chair if we loose the mains.cheers,Richard

Hi everyone and Ashish!Are you looking for a schematic level or block level design?For a block level design, I can suggest a DC-DC converter IC + external components that can do just the trick (maybe include how to go about putting them together).For a schematic design, this will be a bit more tedious because you have some factors to consider that hinge on theoretical formulas and analysis. If you want an efficient converter, we have to pay attention to the parasitics. Also, if you're opting for monitoring the charge of the battery, we might need to throw in a delta-sigma converter. Hope I could help!Best regards,Justin

sir,
I want to charge my e bicycle li-ion battery which consist total 28 cells , the series combination consist 7 cell and capacity of each cell is 26oomAH .

Hi Asish-That helps a lot.  There are lots of off-the-shelf chargers out there that will do the job, but I take it you would like to design one from the ground up.Here's how I would start. First, choose the chip that will be doing most of the work.  To do this, I would start at DigiKey (just because I like their search engine), and type "Lithium Ion Charger" in the search box. Narrow the search by selecting "PMIC-battery chargers".Narrow it further by selecting "in stock", "Active", and "1-7 cells". Click on "Apply filters".  Now you've narrowed it down the the Texas Instruments BQ24630.Click on the PDF icon just to the left of the thumbnail picture for the part and there's your spec sheet.  There may also be App notes available. Try the same general idea with distributors other than DigiKey so you can have several devices to choose from.Good luck!  Let us know how it goes.  Please feel free to ask more questions.-Rick

thanks rick sir and all ee web members