how to charge 3.2v 15.ah cell pack

[hunterstowe]

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

 

[RCinFLA]

What do you plan to do with a 3.2 v LiIon battery to power an LED?

If you have a switching buck-boost current controlled supply then will be okay. If connecting battery to LED, kiss one LED good by.

 

[ronsimpson]

What is the part number for your battery?

 

[hunterstowe]

will the led burn out eventually? if hooked straight to a battery
i built a flashlight that charges by solar panels, i built the flashlight with:
1x cree led 1000 lumen 3v
1x 3.2v 5000mah battery
2x 3.6v 200mah solar panels (total 400mah)

i have everything wired in parallel and works great! takes like 16 hrs of sunlight to charge though.

i need to figure out a way to charege my 3.2v 15.6ah power cell for my next project.
i have 3 cree led lights and a 3.2v 15ah power cell
what else do i need to do it right? chips, chargers, etc.?

 

[hunterstowe]

the 3.2v 15.6ah power cell is made of: 6x k2LFP26650P 3.2v 2.6ah lithium phosphate

What is the part number for your battery?

 

[hunterstowe]

View attachment 68368

this is the very first flashlight i made. In the pic its about 60% finished

this flashlight was:
1000 lumen
3.2v 10.4ah
solar panel 200mah

on a full charge it would run 11+ hours at 1000 lumen

 

[audioguru]

You forgot to plan anything.

A LiFePO4 battery is 3.6V when fully charged which will immediately burn out your 3.0V LEDs. Its voltage slowly drops to 2.8V when it should be have its load disconnected and be charged. If the LEDs have current limiting then they will be dimming slowly then go out while the battery still has plenty of charge remaining.

You need a circuit to boost the voltage (or connect 2 cells in series) and a circuit to limit the current.
You also need a circuit to monitor the battery voltage and disconnect the load when the cell voltage has dropped to 2.8V.

 

[hunterstowe]

the cree led can handle up to 3.7v

the flashlight in the picture i attached works perfect at 3.2v
the cree led never heats up to hot and is extremely bright.
runtime at 1000 lumens is 11+ hours.

the 3 led flashlight i am building should work as well as the first light i made.
my main problem is charging the 3.2v 15.6ah power cell
i dont know how to properly charge the lithium ion power cell

 

[ronsimpson]

I would go to IC vendors that make "lithium charger" ICs. Study the data sheets. Get the data sheet on the battery and look at it. I just picked 3 ICs at random. look at the application notes. Lithium batteries have a complicated battery charge requirement.

You should have looked at white LED drivers. No LED should be connected to a voltage source (battery) with out current limiting. Your comment about working at 3.7V and working at 3.2V shows you do not understand how CREE wants you to use their LEDs.

If you don't follow the requirements on lithium batteries they will die much like your first LED died. I know you can make the battery charge and the LED "work" with out understanding why. It is harder to make them work many times over years.

 

[audioguru]

CAUTION:
The 3 charger ICs shown are for charging ordinary Lithium rechargeable battery cells to 4.2V, not for charging the LiFePO4 battery cells you have that have a maximum allowed charging voltage of 3.6V.

Please attach the datasheet (or the manufacturer's name and part number) of the battery cell and for the Cree LED that you are talking about.