Niterider bike light battery pack suddenly won't charge. (pics included)

This battery pack is a niterider pro series 4x li-ion that I bought off ebay for a couple bucks. They retail for about $150 so I want to see if it's possible to fix this guy.
When I first got it, it charged/discharged just fine. The third time I tried to charge it, the LED status indicator never came on which led to to tear it down to find out what's going on.


On to the pics...

Batteries and driver



I assume this is the circuit protection?


I originally thought bad solder joints, so I did a **** poor job of quickly re-soldering the +/- and status wires.


Probed the batteries before the circuit protection


Everything probed after the circuit protection registers the same value (never mind the hard drive in the pic, I used it as a platform to hold the battery )


If I plug in the wall charger and probe again, the .43v goes to .52v and never higher.

Any idea's of what I should do, or if it's possible to fix?

measure the other pair of cells.
are they close in voltage to the others?
if not suspect bad cells.the protection board is doing its job.
those are cheap generic cells anyway.its your excuse to get some higher capacity cells from sanyo,panasonic,lg,ect.

snakebite said:

measure the other pair of cells.
are they close in voltage to the others?
if not suspect bad cells.the protection board is doing its job.
those are cheap generic cells anyway.its your excuse to get some higher capacity cells from sanyo,panasonic,lg,ect.

Click to expand...

Other cells came out to be 3.97v. I also checked the voltage at the charger end and it's 12.5v when not plugged into the pack, but when it's plugged in, I'm only getting .5v. So weird.

short or bad adapter.3.97 4.18 way out of balance too.

So I unsoldered the charger pigtail from the pcb and did a continuity and voltage test on it and it came out to 12.5v, so nothing shorted in the pigtail. Soldered that back to the pcb and unsoldered the batteries from the pcb and re probed the pcb. Reading varies between .11v and .4v so it seems to be a bad pcb. Called up Niterider and they don't sell just the circuitry for the battery packs. Must be a defective chip on the board somewhere. I didn't see any shavings or stray solder anywhere, so I guess the boards junk... :thumbsdow

tsayyote said:

So I unsoldered the charger pigtail from the pcb and did a continuity and voltage test on it and it came out to 12.5v, so nothing shorted in the pigtail. Soldered that back to the pcb and unsoldered the batteries from the pcb and re probed the pcb. Reading varies between .11v and .4v so it seems to be a bad pcb. Called up Niterider and they don't sell just the circuitry for the battery packs. Must be a defective chip on the board somewhere. I didn't see any shavings or stray solder anywhere, so I guess the boards junk... :thumbsdow

Click to expand...

No biggie on the board being toast.

This board will replace what you presently have and allow for other charging options. http://www.ebay.com/itm/4S-14-8V-Li...988801?hash=item1c620b4041:g:~wkAAOSwuAVWzR4e

Sweet, thats good to know! I'm a novice when it comes to the circuitry so forgive my ignorance. Is what you linked to the circuit protection? Just want to make sure as I didn't test the circuit protection, its actually the top pcb in my first pic that has a short in it (the LED driver board).

I forgot to mention in my original post that the driver board has a button that cycles through 3 brightness modes and a strobe mode.


This is what my battery pack looks like, minus the extended wiring pigtail

measure at the board input.if you read low resistance its the board.bad caps in a switchmode wallwart can do this too.
open circuit ok but drops under load

thats a 4s.he needs 2s.
at least that board has a chance of being ok.actually does balancing.

NoNotAgain said:

No biggie on the board being toast.

This board will replace what you presently have and allow for other charging options. http://www.ebay.com/itm/4S-14-8V-Li...988801?hash=item1c620b4041:g:~wkAAOSwuAVWzR4e

Click to expand...

I have the same problem with the same model battery. I was wondering how you opened the case? Did you have to cut it open, or is there a trick to it?

The Case is glued. it is not hard to open, but will need to either be reglued or a new holder fashioned.
The price of a new pack is $150 and they use standard 18650's .
I got enough parts for a nice unit at the REI garage sale because REI would just give up on them and replace at the first sign of trouble, often just needing the batteries balanced,
and dump the things they couldn't easily figure out.