Electronics, Lighting, & Gadgets - 4000mah lithium pack with charger for $10

i saw this at biglots last night. seems like a good candidate for hacking... $10 for a lithium, 4000mah, charger, selectable voltage, tidy little pack. am i missing something or is this a pretty jam up deal?

http://ecx.images-amazon.com/images/I/51n2dJ5xHFL._SL500_AA280_.jpg

http://ecx.images-amazon.com/images/I/41nGkoyferL._SS400_.jpg

via amazon (http://www.amazon.com/Digital-Universal-Portable-Polaroid-Closeout/dp/B0012NYC8A)

Sounds like an amazing deal. Not only a dirty cheap Li battery, but a controller as well for LEDs.

I am gonna file this one in the too good to be true category until I hear different.

Even if it does what it claims, current rating could be a problem. 4Ah are no good to you if they only supply it at a trickle.

if the voltage regulator sucks and doesn't supply enough current, couldn't you just bypass the circuit in the pack? or are you saying that the cells might not supply enough current? i should have just picked one up yesterday! the froogle mode of my brain apparently has a few bugs in it! im going back to pick one up today!

any thoughts on how i should go about load testing? i have a fluke meter and a bunch of odds & ends electric devices, but no cool leds yet...

i thought the first pack i bought was doa... turns out you have to have the output cable plugged in for the charge indicator lights to work. (not noted in manual).

after swapping out what was probably a good pack for a new one, i charged it up and connected it via test leads to a luxeon 3 watt flashlight. well, it works... thats all i know for now till i figure out a practical, real world test scenario for the pack. the pack feels a little better built than it looks. the camera connects suck, but the power output cord has a nice rubber jacket and is of the coil type instaed of the straight wire pictured. the 4000mah rating is for a specific output voltage. heres some #'s from the manual:
energy density - 400Wh/l
power max - 9W for 2 hrs
dimension - 96.3 x 79.9 x 23.6mm
weight 195g

working time and capacity depends on output voltage and current:
8.4V - 2000mah
6.5V - 2400mah
6V - 3000mah
5V - 3500mah
4.5V - 4000mah
3V - 6000mah

charging unit:
1st stage rapid charge 90% capacity 1.2 hrs
2nd stage slow charge 10% in 1.5 hrs
output dc 5.0V

over charge protection
over discharge protection
over current protection
short-circuit protection
thermo cut-off
low-voltage protection


so that's the jist of what i know. first impression: VERY PROMISING cheap battery pack, charger, case, & wiring solution for my bike led project!

Good lord that does sound good. I was thinking that there had to be a catch somewhere. 18Wh (9x2) and at $10 per pack you could series/parrallel a few of these for killer runtime.

Stopped after work to try and get one or two. Could not find these at my store.

What department did you find these in?

Stopped after work to try and get one or two. Could not find these at my store.

What department did you find these in?

they were up front, near the checkout area on the battery displays. one display blocked a unused checkout lane. the other was a freestanding ordeal about 10 ft away. good luck!

Good lord that does sound good. I was thinking that there had to be a catch somewhere. 18Wh (9x2) and at $10 per pack you could series/parrallel a few of these for killer runtime.

i was wondering about that too... would the internal voltage regulators be a problem with a series / parallel configuration?

i was wanting to do a setup with at least 2 cree xre q5's or a ssc p7. i haven't figured out how to calculate run times, capacity, loads, voltage, etc yet... any idea where i can find a quick rundown on the basics so i can start macgyvering without cooking anything?

they were up front, near the checkout area on the battery displays. one display blocked a unused checkout lane. the other was a freestanding ordeal about 10 ft away. good luck!


I checked up front battery kiosk area, the electronics section and most of the whole store. No luck. Maybe a regional thing or I am just blind.

Consider yourself lucky!!!!

Let us know how things turn out.

I bought one yesterday at the local BigLots. It was back in the electronics/electrical aisle. They had 2 left--might need to go back and get one more.

So have you guys had a chance to work with this battery? If so, what did you do and how well did it work?

Make sure you don't discharge those Li batteries too fast,you might get a get a little surprise.

Looks pretty cool, I'm thinking about trying something interesting here. I've got a P7 light coming for my bike and would like to try powering it externally. This looks like a good, cheap way to get power to the light, I'm thinking maybe 3 of these in parallel would do nicely. Perhaps I should install protective diodes so they don't try to charge each other though if they have slightly different voltages.

So have you guys had a chance to work with this battery? If so, what did you do and how well did it work?
i used it on a couple of short rides with a luxeon flashlight and some test leads. at 4.5v the luxeon got REAL bright, and REAL hot! i haven't tried it on my cree xre q5 yet. i'll try to borrow my dad's light and see how long i can run a pair @ 3v.

Looks pretty cool, I'm thinking about trying something interesting here. I've got a P7 light coming for my bike and would like to try powering it externally. This looks like a good, cheap way to get power to the light, I'm thinking maybe 3 of these in parallel would do nicely. Perhaps I should install protective diodes so they don't try to charge each other though if they have slightly different voltages.
what does the p7 need for voltage and current?