Charging 3.2V 15.6Ah LiFePO4 Pack: Compatible Chargers and Safe Charging Methods

hello,
i just purchased 3 cree 1000 lumen led's. I plan on making a 3000 lumen med. sized flashlight.
I have 6x 3.2v 2600mah li-ion rechargable batteries.
I made a 3.2v 15.6ah power cell with them.
I need help with figuring out how to charge the power cell.
The LED's are 3v .700mah each, I believe
I saw a tenergy 3.2v intellegent 2a lithium charger
on a site but it was sold out.
will this work to safely charge my power cell?
can i buy a dc charger chip board or make one?
will a 3.7v safely charge my power cell?
need help, thank you
I attached a pic of the first flashlight i made
1000 lumen
3.2v 10.4ah
solar panel 200mah
on a full charge it would run 11+ hours at 1000 lumen
i need to charge it also

For charging those batteries, you could use the following to select a Linear IC (for the chemistry, select Li-ion):

* http://www.linear.com/products/battery_management?gclid=COiX15GirrMCFUqoPAod914Anw

I think Texas Instruments (TI) has a similar tool.

Also, Colin is correct about how you are driving those LEDs -- the best way is with current regulated Boost converter with the LEDs in series.

* www.scirp.org/journal/PaperDownload.aspx?paperID=8122
* http://www.linear.com/products/step-up_(boost)_led_drivers
* http://www.digikey.com/us/en/ph/Micrel/MIC3223.html
* http://www.semtech.com/power-management/led-drivers/inductive-boost-led-drivers/

Google "LED boost driver" for more.
I've actually done this with an MCU [PIC].
Also, if using a boost current regulator, then don't, necessarily, arrange the Li-ion cells in series. Look for an optimal input to output voltage ratio (for greatest efficiency) and arrange the cells accordingly -- that could be all parallel or some sort of series/parallel arrangement. This will also be a consideration when choosing the charging method. The beauty of a boost converter is the voltage can be (and should be) lower than the required driving voltage. With the LEDs in series, that driving voltage will be in the approximate range of 9.6V to 11.1V. And, there you can see why driving LEDs with a particular voltage is problematic. LEDs are current devices and thus should be driven with a constant current. If it turns out that it's easier to charge the batteries in series, then consider a buck/boost current regulator.

Also, some fairly good pointers on this page for cheap and simple (but not the best way):

* http://www.instructables.com/id/Circuits-for-using-High-Power-LED-s/

Or, if this is not intended for production (i.e. just a "one off" for your own use) you can just continue doing it the way you're doing it. As long as that works for you -- but you might not get the full life out of those LEDs

See attached some very good links full of info with respect to solar charging of batteries plus solar trackers plus Ti new device for solar power charges and other intersting circuits with which to develop your ideas

www.redrok.com

There is also a full article on this site re this as well in case you missed this

http://www.electronics-lab.com/blog/?tag=tps61200

MD Harrington